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Sample records for dien bien phu

  1. Quaternary basin formation along the Dien Bien Phu fault zone and its neotectonic implication of northwestern Vietnam

    NASA Astrophysics Data System (ADS)

    Lai, K.; Chen, Y.; Chung, L.; Li, P.; Lam, D.

    2006-12-01

    The Dien Bien Phu (DBP) fault zone is one of the most conspicuous fault systems in the Indochina, extending over a distance of 150 km from Yunnan, China through the NW Vietnam into Laos. Recent Global Positioning system (GPS) data in China yielded that the present clockwise rotation of the southeastern Tibet block geologically corresponds to a region of left-lateral strike-slip faults, such as the Xianshuihe-Xiaojang fault and Dien Bien Phu fault, which appear to have accommodated clockwise rotation; whereas other GPS data from the network of Southeast Asia proposed that Indochina constitutes a stable tectonic block moving approximately east with respect to Eurasia. Although above GPS data show insignificant differential motion along DBP fault, active sinistral slip can be identified by clear geomorphic features, focal solutions and seismicity distribution in a NNE-striking zone parallel to the fault zone. Mapping of surface fault traces along the DBP fault zone using field outcrops, geophysical data, and geomorphologic features recognized by the aerial photos, SRTM, ASTER imageries and derived digital elevation models shows that virtually all active faults are reactivated structures sub-parallel to chronostratigraphic boundary. Along the DBF fault, three larger basins have been developed by different kinematics from north to south. The northern one at Chan Nua is rhomboidal in shape with a dimension of 2.5 km?.5 km, which can be defined as a pull-apart basin resulted by the strike-slip motion of the DBP fault. The fault configuration associated with the central one changes to two parallel sinistral and sinistral-normal faults forming a narrow subsiding weak zone (10 km?.5 km) filled with Quaternary deposits. The southern one is, however, created by that the main DBP fault bends the strike from NNE to NE where branches out a sinistral- normal fault with N-striking controlling a half-graben basin (17 km? km) filled with Quaternary deposits about 200 m in depth above

  2. Episodes of brittle deformation within the Dien Bien Phu Fault zone, Vietnam: Evidence from K-Ar age dating of authigenic illite

    NASA Astrophysics Data System (ADS)

    Bui, Hoang Bac; Ngo, Xuan Thanh; Khuong, The Hung; Golonka, Jan; Nguyen, Tien Dung; Song, Yungoo; Itaya, Tetsumaru; Yagi, Koshi

    2017-01-01

    Constraining the timing of fault zone origin and movement history is of fundamental geotectonic importance to understand the evolution and processes of the brittle fault structures. The authors present in this paper authigenic illite K-Ar age data from the fault gouge samples, collected from the Dien Bien Phu Fault (DBPF) in the Dien Bien province, Vietnam as well as in a major strike-slip fault zone in South-East Asia; all of which played important roles in the structural formation and geotectonic development of northwestern Vietnam. The gouge fault samples were separated into four grain-size fractions (< 0.1 μm, 0.1-0.4 μm, 0.4-1.0 μm and 1.0-2.0 μm). The K-Ar ages of the fractions were divided into two age groups, from 26 to 29 Ma and 130 Ma. The timing of the fault movements is defined at 26 ± 0.24 Ma, 29 ± 0.61 Ma, 130.1 ± 1.27 Ma and 130.7 ± 1.29 Ma. This indicates that the Dien Bien Phu Fault underwent two movements, first in the Early Cretaceous, with an age of about 130 Ma and second in the Oligocene (Paleogene), with an age of about 26-29 Ma. The ductile deformation of the DBPF terminated during the Early Cretaceous. These studies also indicate slow exhumation of the Dien Bien granitoid complex during the Cretaceous times. The Oligocene ages indicate that the DBPF had been reactivated by the SE extrusion and clock-wise rotation of the Indochina block, caused by the collision of the Indian and Eurasian plates. This tectonic event led to the DBPF brittle-sinistral movement, causing the exhumation phase along the fault. This movement period (ca. 26-29 Ma) is coexistent with 600-700 km sinistral shearing along the Red River-Ailao Shan fault. This is the first report determining the absolute age constraints of multi-activated tectonic events, affecting the Dien Bien Phu Fault using the K-Ar dating method for the gouge samples.

  3. A Description and Analysis of the Sieges of Dien Bien Phu and Khe Sanh

    DTIC Science & Technology

    1986-04-01

    ability to meet resupply requirements. 21 hi ’"_ _’BIBLIOGRAPHY A. REFERENCES CITED Books 1. Bowman, John S. The Vietnam War Almanac. New York: World ... Almanac Publications, 1985. 2. Buttinger, Joseph. Vietnam; A Political History. New York: Frederick A. Praeger, Publishers, 1968. 3. Fall, Bernard B

  4. The Generalship of General Henri E. Navarre during the Battle of Dien Bien Phu

    DTIC Science & Technology

    1994-06-03

    Legionnaires were described as men who were paid "six times what they received in North Africa" while "junior Lieutenants, who could barely make...ends meet in France, were able to keep three servants in Tonkin . . . most legionnaires counted over ten years service." 30 The French Army that Navarre...military leader in the true sense, and not a guerrilla leader . . . . In 1952 they sent another forty thousand rifles, four thousand machine guns, some 120

  5. Why the North Vietnamese Launched a Major Military Offensive During Tet 1968

    DTIC Science & Technology

    1992-06-05

    Since 1945 Seminar: Dien Bien Phu." (Quantico, Virginia: US Marine Corps Command and Staff College, 1985), 12. 16 On 20 November 1946, fighting broke...scheduled peace conference was to begin in Geneva. General Vo Nguyen Giap had conducted a successful siege and battl6 at Dien Bien Phu, a French...Vietnamese conducted the massive Dien Bien Phu offensive operation in order to be able to negotiate from a position of military strength during the

  6. Close Air Support: Why All the Fuss

    DTIC Science & Technology

    1990-01-02

    column, and hamlet defense in Indochina and South Vietnam; and siege-breaking at Dien Bien Phu and Khe Sanh. In all of these cases, CAS substituted...the Dien Bien Phu experience, and, indeed, enabled Khe Sanh to accomplish what the French at Dien Blien Phu had tried and failed to achieve: create a...technological frontiers on which the Air Force has always sought leadership. It fits nicely their service " persona ." But, is it in the Army’s interest to take

  7. Effective Local Security Forces: Some Ideas for the Counterinsurgent

    DTIC Science & Technology

    2011-06-10

    theory.144 The French garrison at Dien Bien Phu was defeated by Giap‘s forces on May 7, 1954.145 The Geneva Accords, which shortly followed the French...Very Small Place: The Siege of Dien Bien Phu (New York: J.B. Lippincott, 1967), 415. 146Herring, 43-45, 51. President Eisenhower and Secretary John...panache that inspired the movement. His persona emanated from both his generous hospitality and from the barrel of his chrome plated .45 revolver

  8. A Conversation with Zoltan P. Dienes

    ERIC Educational Resources Information Center

    Sriraman, Bharath; Lesh, Richard

    2007-01-01

    The name of Zoltan P. Dienes (1916- ) stands with those of Jean Piaget, Jerome Bruner, Edward Begle, and Robert Davis as a legendary figure whose work left a lasting impression on the field of mathematics education. Dienes' name is synonymous with the multibase blocks that he invented for the teaching of place value. Among numerous other things,…

  9. Predictors for dioxin accumulation in residents living in Da Nang and Bien Hoa, Vietnam, many years after Agent Orange use.

    PubMed

    Pham, Diem T; Nguyen, Hang M; Boivin, Thomas G; Zajacova, Anna; Huzurbazar, Snehalata V; Bergman, Harold L

    2015-01-01

    Agent Orange (AO) was the main defoliant used by the US in Vietnam from 1961 to 1971; AO was contaminated with dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD). Three major dioxin “hot spots” remain from previous AO storage and use at former US bases at Bien Hoa, Da Nang, and Phu Cat, posing potential health risks for Vietnamese living on or near these hot spots. We evaluated potential risk factors contributing to serum TCDD levels in Vietnamese residents at and near contaminated sites in Da Nang and Bien Hoa, Vietnam. We used multiple linear regression to analyze possible associations of blood dioxin concentrations with demographic, socioeconomic, lifestyle, and dietary risk factors for residents living on or near these hot spots. For the Da Nang study, fish farming on the site, living on property flooded from monsoon rains, and age were among the factors showing significant positive associations with serum TCDD concentrations. For the Bien Hoa study, fish farmers working at this site and their immediate family members had significantly higher serum TCDD concentrations. Our results suggest that water-related activities, especially fish-farming, at the hot spots increased the risk of exposure to dioxin.

  10. Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea

    SciTech Connect

    Lee, G.H.; Watkins, J.S.

    1996-12-31

    The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive phase characterized by ramp-like depositional geometries followed by a regressive phase characterized by prograding sequences. An early middle Miocene unconformity separates these two phases. During the transgressive phase rising sea level provided favorable conditions for carbonate buildup development. The regressive interval contains a number of third-order depositional sequences composed of seismically resolvable lowstand, highstand, and rarely, transgressive systems tracts. Lacustrine sediments deposited in graben and half-graben lakes during the rifting stage are probably the principal source rocks. Fractured and/or weathered basement, carbonate complexes, basinfloor fans, and shallows water sands may have good reservoir quality. Potential traps include basement hills, carbonate complexes, fault taps, and stratigraphic traps within lowstand systems tracts. Hydrocarbon indicators such as flat spots, bright spots, gas chimneys with gas mounds on the seafloor occur at a number of locations.

  11. Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea

    SciTech Connect

    Lee, G.H. ); Watkins, J.S. )

    1996-01-01

    The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive phase characterized by ramp-like depositional geometries followed by a regressive phase characterized by prograding sequences. An early middle Miocene unconformity separates these two phases. During the transgressive phase rising sea level provided favorable conditions for carbonate buildup development. The regressive interval contains a number of third-order depositional sequences composed of seismically resolvable lowstand, highstand, and rarely, transgressive systems tracts. Lacustrine sediments deposited in graben and half-graben lakes during the rifting stage are probably the principal source rocks. Fractured and/or weathered basement, carbonate complexes, basinfloor fans, and shallows water sands may have good reservoir quality. Potential traps include basement hills, carbonate complexes, fault taps, and stratigraphic traps within lowstand systems tracts. Hydrocarbon indicators such as flat spots, bright spots, gas chimneys with gas mounds on the seafloor occur at a number of locations.

  12. Public Affairs: The Military and the Media, 1962-1968

    DTIC Science & Technology

    1988-01-01

    173d Airborne Brigade Near Bien Hoa .................. 163 Adm iral U . S. G . Sharp ............................................ 171 A B-52 Bom bing...Minh, the battle of Dien Bien Phu, and the rise of Ngo Dinh Diem. Prominent among the newsmen present during those years were Robert Shaplen and Harold...air base at Bien Hoa, near Saigon, where many U.S. airmen lived. The commander of the Pacific Air Forces, General Emmet O’Donnell, told reporters that

  13. Explaining the Bay of Pigs and Vietnam, 1965 Decisions

    DTIC Science & Technology

    1984-06-05

    time of the battle of Dien Bien Phu, Eisenhower referred to the situation in the often to be repeated "falling dminoes" vein. Indeed, Ho Chi Minh’s...though when he states: We do not pull apart thebe models for the sake of independent application. We have no notion that the casual factors

  14. Toward an Air and Space Force: Can We Get There From Here? Naval Aviation and the Implications for Space Power

    DTIC Science & Technology

    1998-06-01

    5 Dramatis Personae : Rear Admiral William A. Moffett ................................................ 6...and influence, and the ones capable of shaping policy are the officers, especially those holding flag ranks. 6 Dramatis Personae : Rear Admiral William...Dien Bien Phu, and the Korean War influenced the perspectives of the cabinet members and essentially determined U.S. intervention policy.20 There is

  15. Close Air Support: Which Way Do We Go?

    DTIC Science & Technology

    1990-12-01

    Reservoir fighting in 1950; outpost, column, and Parameters hamlet defense in Indochina and South Vietnam; and siege-breaking at Dien Bien Phu and Khe...Air Force has always sought leadership. It fits nicely their service persona . But is it in the Army’s interest to take over CAS, much less all of

  16. Southeast Asia Report, No. 1321.

    DTIC Science & Technology

    2007-11-02

    unlikely though not unwilling dramatis persona in the Be-ew refugee scenario, the violent and atrocious episodes of which the young governor of Abra has...ducted ceremonies commemorating the first phase of troop departure in the Dien Bien Phu campaign. These units are: Hanoi, Haiphong, Quang Nam-Da

  17. Center of Gravity in the Asymmetric Environment: Applicable or Not

    DTIC Science & Technology

    2006-06-01

    the first meeting of the Comite Revolutionnaire occurred on the day the French were defeated at Dien Bien Phu. The atmosphere changed and became...the same type of persona that was to create big problems in the Battle of Algiers. 1. Massu’s First Clash with the FLN The FLN planned a general

  18. Moscow’s Post-Brezhnev Reassessment of the Third World.

    DTIC Science & Technology

    1986-02-01

    34Supported by imperial- ist propaganda, the spirit of nationalistic prejudices and a deeply rooted distrust toward persona of the white race have exacerbated...March 1984, p. 343. ’,, 4 Keleman (1984), p. 343. " Ibid.. 424 neFriedmann Bartu, ൦ Years After Dien Bien Phu," S oviss Reiew of World Affairs

  19. Transformation Concepts for National Security in the 21st Century

    DTIC Science & Technology

    2002-09-01

    the types of reductions sought by the administration. The French crisis at Dien Bien Phu in the Spring of 1954 gave the New Look its first real test...his 2 years as Army Chief of Staff, Ridgway was persona non grata in the Eisenhower administration. His replacement, Taylor, brought a sophistication

  20. Claire Lee Chennault: Theorist and Campaign Planner

    DTIC Science & Technology

    1993-05-13

    at Dien Bien Phu. 7 The CIA eventually purchased his fleet and incorporated the clandestine air service into its operations. 8 Back in the dark days of...into a corner, finding himself persona non grata in both the Army and its air arm. He was dejected that the only sympathetic ear for his theories were

  1. Cobalt-Catalysed Asymmetric Hydrovinylation of 1,3-Dienes

    PubMed Central

    Timsina, Yam N.; Sharma, Rakesh K.

    2015-01-01

    In the presence of bidentate 1,n-bis-diphenylphosphinoalkane-CoCl2 complexes {Cl2Co[P~P]} and Me3Al or methylaluminoxane, acyclic (E)-1,3-dienes react with ethylene (1 atmosphere) to give excellent yields of hydrovinylation products. The regioselectivity (1,4- or 1,2-addition) and the alkene configuration (E- or Z-) of the resulting product depend on the nature of the ligand and temperature at which the reaction is carried out. Cobalt(II)-complexes of 1,1-diphenylphosphinomethane and similar ligands with narrow bite angles give mostly 1,2-addition, retaining the E-geometry of the original diene. Complexes of most other ligands at low temperature (−40 °C) give almost exclusively a single branched product, (Z)-3-alkylhexa-1,4-diene, which arises from a 1,4-hydrovinylation reaction. A minor product is the linear adduct, a 5-alkyl-hexa-1,4-diene, also arising from a 1,4-addition of ethylene. As the temperature is increased, a higher proportion of the major 1,4-adduct appears as the (E)-isomer. The unexpectedly high selectivity seen in the Co-catalysed reaction as compared to the corresponding Ni-catalysed reaction can be rationalized by invoking the intermediacy of an η4-[(diene)[P~P]CoH]+-complex and its subsequent reactions. The enhanced reactivity of terminal E-1,3-dienes over the corresponding Z-dienes can also be explained on the basis of the ease of formation of this η4-complex in the former case. The lack of reactivity of the X2Co(dppb) (X = Cl, Br) complexes in the presence of Zn/ZnI2 makes the Me3Al-mediated reaction different from the previously reported hydroalkenylation of dienes. Electron-rich phospholanes, bis-oxazolines and N-heterocyclic carbenes appear to be poor ligands for the Co(II)-catalysed hydrovinylation of 1,3-dienes. An extensive survey of chiral ligands reveals that complexes of DIOP, BDDP and Josiphos ligands are quite effective for these reactions even at −45 °C and enantioselectivities in the range of 90–99 % ee can be realized

  2. Synthetic Methods for Cyclohexa-1,3-dienes

    NASA Astrophysics Data System (ADS)

    Mironov, V. A.; Fedorovich, A. D.; Akhrem, A. A.

    1983-01-01

    The review gives a systematic account of the methods of synthesis of cyclohexa-1,3-diene, its homologues, and derivatives with functional groups. The purity of the preparations obtained by each method is considered on the basis of modern data. The bibliography includes 221 references.

  3. Diffusion of helium (1); buta-1,3-diene (2)

    NASA Astrophysics Data System (ADS)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) helium; (2) buta-1,3-diene

  4. Diffusion of buta-1,3-diene (1); air (2)

    NASA Astrophysics Data System (ADS)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) buta-1,3-diene; (2) air

  5. Process for crosslinking and extending conjugated diene-containing polymers

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L. (Inventor); Havens, Stephen J. (Inventor)

    1977-01-01

    A process using a Diels-Alder reaction which increases the molecular weight and/or crosslinks polymers by reacting the polymers with bisunsaturated dienophiles is developed. The polymer comprises at least 75% by weight based on the reaction product, has a molecular weight of at least 5000 and a plurality of conjugated 1,3-diene systems incorporated into the molecular structure. A dienophile reaction with the conjugated 1,3-diene of the polymer is at least 1% by weight based on the reaction product. Examples of the polymer include polyesters, polyamides, polyethers, polysulfones and copolymers. The bisunsaturated dienophiles may include bis-maleimides, bis maleic and bis tumaric esters and amides. This method for expanding the molecular weight chains of the polymers, preferable thermoplastics, is advantageous for processing or fabricating thermoplastics. A low molecular weight thermoplastic is converted to a high molecular weight plastic having improved strength and toughness for use in the completed end use article.

  6. Civil-Military Relations in the French Fourth Republic during the First Indochina War

    DTIC Science & Technology

    2015-05-21

    turbulence, particularly in the development of a coherent foreign policy regarding Indochina. The French Army emerged from the Second World only to...in hopes of retaining Indochina as a French-controlled territory. France quickly found that this control would not come easy. A rigid foreign policy ...Dien Bien Phu. In the end, an uncompromising foreign and colonial policy required military leaders to view force as the only means to achieve success

  7. The novel, major locus Rpi-phu1 for late blight resistance maps to potato chromosome IX and is not correlated with long vegetation period.

    PubMed

    Sliwka, J; Jakuczun, H; Lebecka, R; Marczewski, W; Gebhardt, C; Zimnoch-Guzowska, E

    2006-08-01

    Despite the long history of breeding potatoes resistant to Phytophthora infestans, this oomycete is still economically the most important pathogen of potato worldwide. The correlation of high levels of resistance to late blight with a long vegetation period is one of the bottlenecks for progress in breeding resistant cultivars of various maturity types. Solanum phureja was identified as a source of effective late blight resistance, which was transferred to the cultivated gene pool by interspecific crosses with dihaploids of Solanum tuberosum. A novel major resistance locus, Rpi-phu1, derived most likely from S. phureja and conferring broad-spectrum resistance to late blight, was mapped to potato chromosome IX, 6.4 cM proximal to the marker GP94. Rpi-phu1 was highly effective in detached leaflet, tuber slice and whole tuber tests during 5 years of quantitative phenotypic assessment. The resistance did not show significant correlation with vegetation period length. Our findings provide a well-characterized new source of resistance for breeding early and resistant-to-P. infestans potatoes.

  8. Rapid assembly of structurally defined and highly functionalized conjugated dienes via tethered enyne metathesis.

    PubMed

    Yao, Q

    2001-06-28

    [reaction: see text] Conjugated dienes are versatile building blocks in organic synthesis, and the development of new methods for their synthesis remains an important topic in modern synthetic organic chemistry. We describe here an expedient synthesis of highly functionalized conjugated dienes through sequential silicon-tethered ring-closing enyne metathesis mediated by Grubbs' Ru carbene catalysts and Tamao oxidation. Notable attributes of this methodology include short synthetic manipulations and the structural complexity it confers on the resulting diene moiety.

  9. Biotransformation of two ent-Pimara-9(11),15-diene derivatives by Gibberella fujikuroi.

    PubMed

    Fraga, Braulio M; Guillermo, Ricardo; Hernández, Melchor G; Chamy, María C; Garbarino, Juan A

    2009-01-01

    The incubation of 19-hydroxy-13-epi-ent-pimara-9(11),15-diene (4) with Gibberella fujikuroi gave 8 alpha,19-dihydroxy-9 alpha,11alpha-epoxy-13-epi-ent-pimara-15-ene (6), 7-oxo-11 alpha,19-dihydroxy-13-epi-ent-pimara-8(9),15-diene (7), 7-oxo-11beta,19-dihydroxy-13-epi-ent-pimara-8(9),15-diene (9), and 8 alpha,19-dihydroxy-9 alpha,11 alpha:15,16-diepoxy-13-epi-ent-pimarane (11), while the feeding of 13-epi-ent-pimara-9(11),15-diene-19-oic acid (5) with this fungus afforded 1-oxo-2 alpha,9 alpha-dihydroxy-13-epi-ent-pimara-11,15-dien-19-oic acid (13), 1-oxo-2 beta,9 alpha-dihydroxy-13-epi-ent-pimara-11,15-dien-19-oic acid (14), 13-epi-ent-pimara-9(11),15-dien-1,19-dioic acid 1,2-lactone (15), and 1-oxo-12 beta-hydroxy-13-epi-ent-pimara-9(11),15-dien-19-oic acid (16). In both biotransformations, the main reaction was the epoxidation of the 9(11)-double bond, followed by rearrangement to afford allylic alcohols. The formation of lactone 15 represents the first time that a Baeyer-Villiger oxidation has been observed in a microbiological transformation with this fungus.

  10. Ab initio vibrational analysis of trans- and gauche-2,3-dimethylbuta-1,3-diene

    NASA Astrophysics Data System (ADS)

    Bock, Charles W.; Panchenko, Yurii N.

    1990-04-01

    The harmonic force fields of the s- trans( anti) and gauche conformers of 2,3-dimethylbuta-1,3-diene have been calculated ab initio at the RHF/6-31G//RHF/6-31G level. These force fields have been further refined using scale factors transferred from analogous calculations at the RHF/6-31G level for s- trans-buta-1,3-diene and ethane. A complete assignment of the experimental vibrational frequencies is given. Regularities in the vibrational spectra of the stable conformers of buta-1,3-diene, isoprene (2-methylbuta-1,3-diene) and 2,3-dimethylbuta-1,3-diene are discussed.

  11. Recent Advances in Boron-Substituted 1,3-Dienes Chemistry: Synthesis and Application.

    PubMed

    Pyziak, Jadwiga; Walkowiak, Jędrzej; Marciniec, Bogdan

    2017-03-13

    In the syntheses developed to access naturally occurring compounds, especially bioactive substances, boron-functionalized dienes (also "linchpin" reagents) are used as key reagents. Structurally unique dienes are found in nature, and play important biological and chemical roles. Recently, linchpin moieties have been proved as useful substrates for a variety of highly functionalized chemical transformations. The products of these processes are potentially of some use for the syntheses of an important class of natural products showing a wide range of biological activities. This review describes progress in the synthesis of borylsubstituted buta-1,3-dienes as well as their application in organic chemistry.

  12. Description of the tadpoles of two endemic frogs: the Phu Luang cascade frog Odorrana aureola (Anura: Ranidae) and the Isan big-headed frog Limnonectes isanensis (Anura: Dicroglossidae) from northeastern Thailand.

    PubMed

    Ampai, Natee; Rujirawan, Attapol; Arkajag, Jirachai; Mcleod, David S; Aowphol, Anchalee

    2015-07-07

    We describe the external morphology of the tadpoles of two frogs endemic to Thailand: the Phu Luang cascade frog    (Odorrana aureola) and the Isan big-headed frog (Limnonectes isanensis) from the type localities in the Phu Luang Wildlife Sanctuary, Loei Province, northeastern Thailand. Morphological and genetic characters (16S rRNA) were used to identify specimen and match tadpoles to the adults. Detailed descriptions of external morphology and coloration in life are provided for both species. We provide a brief discussion of the ecology of these tadpoles and a comparison to previously published data from tadpoles of closely related taxa. Additionally, we provide evidence for the utility of larval morphology in resolving the taxonomic puzzles presented by cryptic species complexes.

  13. Spiro[2.4]hepta-4,6-dienes: synthesis and application in organic synthesis

    NASA Astrophysics Data System (ADS)

    Menchikov, L. G.; Nefedov, O. M.

    2016-03-01

    This review integrates and describes systematically the data in the field of spiro[2.4]hepta-4,6-dienes published in the past 15 years. The changes in the development of studies that took place during this period are noted. The methods for the synthesis, the reactivity details and key chemical transformations of spiro[2.4]hepta-4,6-dienes are considered, with the emphasis on applications of these compounds in organic synthesis. The bibliography includes 207 references.

  14. 1,4-Diiodo-1,3-dienes: versatile reagents in organic synthesis.

    PubMed

    Ananikov, Valentine P; Hazipov, Oleg V; Beletskaya, Irina P

    2011-02-01

    1,4-Diiodo-1,3-dienes are unique reagents in organic synthesis and have been employed in several well-known and recently developed areas of application. Furthermore, these dienes are easily accessible, starting from the alkynes and iodine, and they have demonstrated high reactivity in cross-coupling reactions, organometallic synthesis, in the preparation of heterocyclic compounds, and several other transformations. The high reactivity of the 1,4-diiodo-1,3-dienes allows for the development of synthetic procedures that use mild conditions (room temperature). The key advantages in assembling complex organic molecules, natural products, and compounds for material science using 1,4-diiodo-1,3-dienes as building blocks include high yields, excellent selectivity, and diverse reactivity in carbon-carbon and carbon-heteroatom bond formation. This Focus Review describes the scope and application of the 1,4-diiodo-1,3-dienes in organic synthesis as well as summarizes the methods for preparation of the dienes.

  15. Non-Planar Structures of the High-Energy Rotational Conformers of 2-METHYLBUTA-1,3-DIENE (isoprene) and 2,3-DIMETHYLBUTA-1,3-DIENE

    NASA Astrophysics Data System (ADS)

    Panchenko, Yu. N.; Bock, Ch. W.; Larkin, J. D.; Abramenkov, A. V.; Kühnemann, F.

    2009-06-01

    Optimization of the geometrical parameters and determination of the force fields for rotamers of the title molecules were performed at the MP2(FC)/aug-cc-pVDZ//MP2(FC)/aug-cc-pVDZ computational level. The vibrational analyses of these conformers were carried out using scaled quantum-mechanical force field methodology. Recent experimental wavenumbers for these conformers and their deuteroisomers were incorporated into these analyses. The theoretical non-planar structures of the high-energy conformers of 2-methylbuta-1,3-diene (isoprene) and 2,3-dimethylbuta-1,3-diene were corroborated by good agreement between the experimental and theoretical wavenumbers of the molecules under investigation. The dihedral angles of the non-planar high-energy conformers for rotation around the =C-C= bond are as follows: 41.6^° for 2-methylbuta-1,3-diene (isoprene) and 47.0^° for 2,3-dimethylbuta-1,3-diene. Previous studies performed at the HF/6-31G level gave 41.0^° and 48.5^° for the first and second compounds, respectively. Yu. N. Panchenko, Ch. W. Bock, J. D. Larkin, A. V. Abramenkov, F. Kühnemann, Struct. Chem. 19, 421 (2008). Yu. N. Panchenko, Ch. W. Bock, J. D. Larkin, A. V. Abramenkov, Struct. Chem. 19, 793 (2008)

  16. Solvent-free cyclization of linear dienes using olefin metathesis and the Thorpe-Ingold effect

    SciTech Connect

    Forbees, M.D.E.; Myers, T.L.; Maynard, H.D.; Schulz, G.R. ); Patton, J.T.; Smith, D.W. Jr.; Wagener, K.B. )

    1992-12-30

    The olefin metathesis reaction is of great synthetic utility in polymer chemistry. The recent development of ring-opening (ROMP) and acyclic diene (ADMET) metathesis polymerization reactions has opened new avenues for the synthesis of novel polymeric materials. Recently the authors used ADMET to synthesize several photochemically active poly(keto olefins) using the catalyst Mo(CHCMe[sub 2]Ph)(NAr)(OCMe(CF[sub 3])[sub 2])[sub 2] (Ar = 2,6-diisopropylphenyl) (1) developed by Schrock and co-workers in 1990. In the course of that work, they discovered that neat samples of highly substituted dienes will cyclize quantitatively via metathesis to give difunctional five- and seven-membered rings instead of the expected linear polymer. Examples of substituted diene cyclizations by metathesis even in the presence of a solvent are rare. Their systematic exploitation in organic synthesis has therefore been limited to two recent studies by Fu and Grubbs, who cyclized several substituted diene ethers, amines, and amides to unsaturated oxygen and nitrogen heterocycles. Cyclization of unsubstituted dienes in various solvents has been reported, but complete conversion occurred in only a few cases. Formation of cyclic alkene oligomers from back-biting during the ROMP reaction is also known. The reactions reported here are unusual in that they are intermolecular between catalyst and substrate, yet can give 100% yield of product solely from the monomer in the absence of solvent. 13 refs.

  17. Silicon-containing alka-1,3-dienes and their functional derivatives in organic synthesis

    NASA Astrophysics Data System (ADS)

    Stadnichuk, M. D.; Voropaeva, T. I.

    1995-01-01

    Data on the synthesis and chemical reactions of silicon-containing 1,3-dienes are surveyed for the first time in the present review. It is shown that the addition reactions of 1- and 2-triorganosilylalka-1,3-dienes and their derivatives are the most interesting and promising in fine organic synthesis. The application of the trialkylsilyl group as a protecting group and as a new reaction centre, which makes it possible to obtain carbon-carbon or carbon-heteroatom bonds, is examined. It has been found that the double bonds remote from the silicon atom are the most reactive in addition reactions and that regardless of the nature of the reagent the attacking species always binds to the terminal carbon atom of the buta-1,3-diene fragment. The bibliography includes 329 references.

  18. Oxidative Heck vinylation for the synthesis of complex dienes and polyenes.

    PubMed

    Delcamp, Jared H; Gormisky, Paul E; White, M Christina

    2013-06-12

    We introduce an oxidative Heck reaction for selective complex diene and polyene formation. The reaction proceeds via oxidative Pd(II)/sulfoxide catalysis that retards palladium-hydride isomerizations which previously limited the Heck manifold's capacity for furnishing stereodefined conjugated dienes. Limiting quantities of nonactivated terminal olefins (1 equiv) and slight excesses of vinyl boronic esters (1.5 equiv) that feature diverse functionality can be used to furnish complex dienes and polyenes in good yields and excellent selectivities (generally E:Z = >20:1; internal:terminal = >20:1). Because this reaction only requires prior activation of a single vinylic carbon, improvements in efficiency are observed for synthetic sequences relative to ones featuring reactions that require activation of both coupling partners.

  19. Reversal of the Regiochemistry in the Rhodium-Catalyzed [4+3] Cycloaddition Between Vinyldiazoacetates and Dienes

    PubMed Central

    Guzmán, Pablo E.; Lian, Yajing

    2015-01-01

    A regio-, diastereo- and enantioselective [4+3] cycloaddition between vinylcarbenes and dienes has been achieved using the dirhodium tetracarboxylate catalyst Rh2(S-BTPCP)4. This methodology provides facile access to 1,4-cycloheptadienes that are regioisomers of those formed from the tandem cyclopropanation/Cope rearrangement reaction of vinylcarbenes with dienes. PMID:25266984

  20. Remembering Zoltan Dienes, a Maverick of Mathematics Teaching and Learning: Applying the Variability Principles to Teach Algebra

    ERIC Educational Resources Information Center

    Gningue, Serigne Mbaye

    2016-01-01

    This paper is written in honor of Zoltan Paul Dienes, an internationally renowned mathematician and educator, who passed away in January 2014. It is an attempt to describe, analyze and apply Dienes' theory on how mathematical structures can be taught by applying his four principles of learning upon which he believed a teacher can base concept…

  1. Concerning the reactivity of PTAD with isomeric dienes: the mechanism of the Diels-Alder cycloaddition.

    PubMed

    Alberti, Mariza N; Orfanopoulos, Michael

    2009-04-02

    Cyclopropyl substituted dienes are employed as mechanistic probes in the triazolinedione Diels-Alder (DA) reaction. In aprotic and protic solvents, apart from the DA adducts that bear an intact cyclopropyl group, complicated and rearranged products are also obtained. These results provide solid evidence for the involvement of an open intermediate with a lifetime greater than 2 x 10(-12) s.

  2. Diffusion of 2-methyl-buta-1,3-diene (1); air (2)

    NASA Astrophysics Data System (ADS)

    Winkelmann, J.

    This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) 2-methyl-buta-1,3-diene; (2) air

  3. Oxazole as an electron-deficient diene in the Diels-Alder reaction.

    PubMed

    Suárez-Moreno, Galdina Vanessa; González-Zamora, Eduardo; Méndez, Francisco

    2011-12-16

    The Diels-Alder cycloaddition reaction of oxazole with ethylene is facilitated by addition of an alkyl group or Brønsted or Lewis acids to the oxazole nitrogen atom. The efficacy consists of stabilizing the transition state, lowering the activation barrier and the HOMO(dienophile)-LUMO(diene) gap, and increasing the reaction exothermicity.

  4. Implicit Learning of Nonlocal Musical Rules: A Comment on Kuhn and Dienes (2005)

    ERIC Educational Resources Information Center

    Desmet, Charlotte; Poulin-Charronnat, Benedicte; Lalitte, Philippe; Perruchet, Pierre

    2009-01-01

    In a recent study, G. Kuhn and Z. Dienes (2005) reported that participants previously exposed to a set of musical tunes generated by a biconditional grammar subsequently preferred new tunes that respected the grammar over new ungrammatical tunes. Because the study and test tunes did not share any chunks of adjacent intervals, this result may be…

  5. Regio- and enantioselective hydroamination of dienes by gold(I)/menthol cooperative catalysis.

    PubMed

    Kanno, Osamu; Kuriyama, Wataru; Wang, Z Jane; Toste, F Dean

    2011-10-10

    Alcohol is key: regio- and enantioselective hydroamination of 1,3-dienes has been achieved with the dinuclear catalyst (R)-DTBM-SEGPHOS. The rate and selectivity of the reaction are enhanced by alcohol additives like menthol, which coordinates the cationic gold(I) to generate a Brønsted acid that can participate in catalysis. Mbs=p-methoxybenzenesulfonyl.

  6. Synthesis and chiroptical properties of ferrocene-[4]-helicenequinones: kinetic resolution of a planar-chiral diene.

    PubMed

    Latorre, Alfonso; Urbano, Antonio; Carreño, M Carmen

    2011-07-28

    Both enantiomers of ferrocene [4]-helicenequinone 6, showing planar and helical chiralities, have been synthesized with very high optical purities using, as the key step, a kinetic resolution process between planar-chiral racemic ferrocene diene 2 and enantiopure sulfinyl benzoquinone (S)-3.

  7. STUDY ON BIOLOGICAL CHARACTERISTICS OF HETEROTROPHIC MARINE MICROALGA-SCHIZOCHYTRIUM MANGROVEI PQ6 ISOLATED FROM PHU QUOC ISLAND, KIEN GIANG PROVINCE, VIETNAM(1).

    PubMed

    Hong, Dang Diem; Anh, Hoang Thi Lan; Thu, Ngo Thi Hoai

    2011-08-01

    Schizochytrium sp. PQ6, a heterotrophic microalga isolated from Phu Quoc (PQ) Island in the Kien Giang province of Vietnam, contains a high amount of docosahexaenoic acid (DHA, C22:6n-3). In this study, the culture conditions are developed to maximize biomass and DHA production. Nucleotide sequence analysis of partial 18S rRNA gene from genomic DNA showed that PQ6 has a phylogenetic relationship close to Schizochytrium mangrovei Raghu-Kumar. The highest growth rate and DHA accumulation of this strain were obtained in 6.0% glucose, 1.0% yeast extract, 50% artificial seawater (ASW), and pH 7 at 28°C. In addition, carbon and nitrogen sources could be replaced by glycerol, ammonium acetate, sodium nitrate, or fertilizer N-P-K. Total lipid content reached 38.67% of dry cell weight (DCW), in which DHA and eicosapentaenoic acid (EPA, C20:5n-3) contents accounted for 43.58% and 0.75% of the total fatty acid (TFA), respectively. In 5 and 10 L fermenters, the cell density, DCW, total lipid content, and maximum DHA yield were 46.50 × 10(6)  cells · mL(-1) , 23.7 g · L(-1) , 38.56% of DCW, and 8.71 g · L(-1) (in 5 L fermenter), respectively, and 49.71 × 10(6)  cells · mL(-1) , 25.34 g · L(-1) , 46.23% of DCW, and 11.55 g · L(-1) (in 10 L fermenter), respectively. Biomass of PQ6 strain possessed high contents of Na, I, and Fe (167.185, 278.3, and 43.69 mg · kg(-1) DCW, respectively). These results serve as a foundation for the efficient production of PQ6 biomass that can be used as a food supplement for humans and aquaculture in the future.

  8. A Study of Strategic Lessons Learned in Vietnam. Volume 4. US Domestic Factors Influencing Vietnam War Policy Making

    DTIC Science & Technology

    1980-04-01

    2 / Bi I l Moyers A . INTRODUCTION The war in Vietnam was perceived by many in the United States to be a test of wills that set the US in opposition...CORPORATION / ,/ DIEN BIEN PHU HANOI HAIPHONG A Study of c Lessons Learned in e am VOLU E IV U.S. DOMESTI CTORS INFLUENCING VI T M WAR POLICY AM 1(1...developing definitive analysis of them. The two issues are: (1) The gener- l importance of public sentiment to the foreign policy- making process. (

  9. 1,3-Dien-5-ynes: Versatile Building Blocks for the Synthesis of Carbo- and Heterocycles.

    PubMed

    Aguilar, Enrique; Sanz, Roberto; Fernández-Rodríguez, Manuel A; García-García, Patricia

    2016-07-27

    1,3-Dien-5-ynes have been extensively used as starting materials for the synthesis of a wide number of different carbo- and heterocycles. The aim of this review is to give an overview of their utility in organic synthesis, highlighting the variety of compounds that can be directly accessed from single reactions over these systems. Thus, cycloaromatization processes are initially commented, followed by reactions directed toward the syntheses of five-membered rings, other carbocycles and, finally, heterocycles. The diverse methodologies that have been developed for the synthesis of each of these types of compounds from 1,3-dien-5-ynes are presented, emphasizing the influence of the reaction conditions and the use of additional reagents in the outcome of the transformations.

  10. Concerted Ring Opening and Cycloaddition of Chiral Epoxy Enolsilanes with Dienes.

    PubMed

    Krenske, Elizabeth H; Lam, Sarah; Ng, Jerome P L; Lo, Brian; Lam, Sze Kui; Chiu, Pauline; Houk, Kendall N

    2015-06-15

    Silyl-triflate-catalyzed (4+3) cycloadditions of epoxy enolsilanes with dienes provide a mild and chemoselective synthetic route to seven-membered carbocycles. Epoxy enolsilanes containing a terminal enolsilane and a single stereocenter undergo cycloaddition with almost complete conservation of enantiomeric purity, a finding that argues against the involvement of oxyallyl cation intermediates which have been previously proposed for these types of reactions. Reported are theoretical and experimental investigations of the cycloaddition mechanism. The major enantiomers of the cycloadducts are derived from S(N)2-like reactions of the silylated epoxide with the diene, in which stereospecific ring opening and formation of the two new C-C bonds occur in a single step. Calculations predict, and experiments confirm, that the observed small losses of enantiomeric purity are traced to a triflate-mediated double S(N)2 cycloaddition pathway.

  11. Photochemical reactivity of polyenes: from dienes to rhodopsin, from microseconds to femtoseconds.

    PubMed

    Liu, Robert S H; Hammond, George S

    2003-08-01

    In reviewing the photochemistry of polyenes (from dienes and trienes to the visual retinyl chromophore), we categorize condensed-phase photochemical reactivity of molecules into two groups: those from thermally equilibrated excited species and those from unequilibrated excited species. Classical theories on radiationless transitions are useful for rationalizing the reactivity of molecules belonging to the first set only. The second group includes many of the exciting ultrafast photochemical reactions reported recently for polyenes (including dienes and trienes), in some cases with rates faster than vibrational relaxation. Much of the excited singlet-state reactions of polyenes, including the Hula-twist mechanism of photoisomerization, have been integrated with concepts introduced in other ultrafast spectroscopic/photochemical studies. Taking into consideration the special environment of the retinyl chromophore in rhodopsin, we propose a new mechanism for the phototrigger that accounts for its unusually fast rate of isomerization.

  12. Diastereoselective Synthesis of γ-Substituted 2-Butenolides via (CDC)-Rh-Catalyzed Intermolecular Hydroalkylation of Dienes with Silyloxyfurans.

    PubMed

    Goldfogel, Matthew J; Roberts, Courtney C; Manan, Rajith S; Meek, Simon J

    2017-01-06

    Catalytic intermolecular hydroalkylation of dienes with silyloxyfuran nucleophiles is reported. Reactions are catalyzed by 5 mol % of a (CDC)-Rh complex and proceed in up to 87% yield and 6:1 dr (syn/anti) to provide allylic butenolides bearing vicinal stereocenters. Reactions proceed with terminal aryl and alkyl dienes and with modified silyl enol ether nucleophiles including a thiophenone variant. Utility of the products is demonstrated in the synthesis of a polypropionate anti,syn-stereotriad.

  13. A palladium-catalyzed three-component-coupling strategy for the differential vicinal diarylation of terminal 1,3-dienes.

    PubMed

    Stokes, Benjamin J; Liao, Longyan; de Andrade, Aline Mendes; Wang, Qiaofeng; Sigman, Matthew S

    2014-09-05

    A palladium-catalyzed intermolecular vicinal diarylation of terminal 1,3-dienes using aryldiazonium tetrafluoroborates and arylboronic acids is reported. Using this technology, two different arenes are regioselectively introduced in a vicinal fashion across the terminal alkene of a variety of terminal 1,3-dienes at ambient temperature. Through the action of a chiral bicyclo[2.2.2]octadienyl ligand at -20 °C, good enantioselectivity has also been achieved.

  14. Catalytic cascade hydroalkoxylation/isomerization/ [4 + 2] cycloaddition using enyne alcohols as latent dienes or dienophiles.

    PubMed

    Guo, Rui; Li, Kang-Nan; Gong, Liu-Zhu

    2013-10-21

    Enyne alcohols can react as precursors of either dienes or dienophiles with different substrates after hydroxylation and isomerization by gold catalysis. As such, oxa-bridged tricyclo[5.2.2.02,6]-undec-8-ene-3,5-dione derivatives have been obtained by the Diels–Alder reaction and tetrahydro-1H-furo[3,4-c]pyran derivatives could be accessed by the hetero-Diels–Alder cycloaddition.

  15. Linchpin dienes: key building-blocks in the synthesis of polyenic frameworks.

    PubMed

    Cornil, J; Guérinot, A; Cossy, J

    2015-04-14

    A myriad of biologically active products incorporates polyenic frameworks. Among the syntheses developed to access these moieties, metal-catalyzed cross-couplings emerged as reactions of choice especially due to their high stereoselectivity. Particularly, the use of bifunctionalized compounds (linchpin reagents) allows a fast, modular and efficient access to polyenic chains. In this review, we will focus on the preparation of bifunctionalized dienes and on their utilization in the synthesis of polyenes.

  16. Acid-free aza Diels-Alder reaction of Danishefsky's diene with imines.

    PubMed

    Yuan, Yu; Li, Xin; Ding, Kuiling

    2002-09-19

    [reaction: see text] A highly efficient aza Diels-Alder reaction of Danishefsky's diene with imines was found to occur in methanol in the absence of any acids at room temperature to give corresponding 2-substituted dihydro-4-pyridone derivatives in high yields. This reaction can be also carried out in a three-component one-pot reaction manner. The reaction was found to proceed through a Mannich-type condensation mechanism.

  17. Food as a source of dioxin exposure in the residents of Bien Hoa City, Vietnam.

    PubMed

    Schecter, Arnold; Quynh, Hoang Trong; Pavuk, Marian; Päpke, Olaf; Malisch, Rainer; Constable, John D

    2003-08-01

    Recently, elevated dioxin levels, over 5 parts per trillion (ppt) 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), from Agent Orange was reported in 95% of 43 selected residents of Bien Hoa City, a city in southern Vietnam near a former air base used for Agent Orange-spraying missions. Agent Orange herbicide, contaminated with TCDD, was sprayed in Vietnam between 1962 and 1971 primarily for use as a defoliant. Typical blood TCCD levels are 2 ppt in Vietnamese, but levels are as high as 413 ppt in Bien Hoa City. Elevated TCDD was found in children born many years after Agent Orange spraying ended and in immigrants from non-Agent Orange-sprayed parts of Vietnam, which documented new exposures. Extremely elevated soil TCDD samples, over 1 million ppt, and elevated TCDD in sediment were found in some nearby areas such as Bien Hung Lake. The primary route of intake of almost all dioxins in humans is food. However, in our prior studies in Bien Hoa, food was unavailable for dioxin analysis so the route of intake was not confirmed. In the 1970s, while Agent Orange was still being sprayed, elevated human milk TCDD levels as high as 1850 were detected in milk from Vietnamese people living in Agent Orange-sprayed areas where consumption of fish was high. Furthermore, also in the 1970s, elevated TCDD levels (up to 810 ppt) were found in fish and shrimp from the same area as the milk donors. In the 1980s, we found elevated TCDD and also other organohalogen levels in human tissue, pork, fish, a turtle, and a snake in Southern Vietnam. For these reasons, we recently collected food from Bien Hoa and analyzed it for dioxins, polychlorinated biphenyls (PCBs), DDT and its metabolites, and other organochlorines. We found marked elevation of TCDD, the dioxin characteristic of Agent Orange, in some of the food products, including ducks with 276 ppt and 331 ppt wet weight, chickens from 0.031-15 ppt wet weight, fish from 0.063-65 ppt wet weight, and a toad with 56 ppt wet weight. Usual TCDD

  18. Polymerization of 1,3-Conjugated Dienes with Rare-Earth Metal Precursors

    NASA Astrophysics Data System (ADS)

    Zhang, Zhichao; Cui, Dongmei; Wang, Baoli; Liu, Bo; Yang, Yi

    This chapter surveys the publications except patents related to cis-1,4-, trans-1,4-, 3,4-regio-, and stereoselective polymerizations of 1,3-conjugated dienes with rare-earth metal-based catalytic systems during the past decade from 1999 to 2009. The concerned catalyst systems are classified into the conventional Ziegler-Natta catalysts, the modified Ziegler-Natta catalysts, and the single-site cationic systems composed of lanthanocene and noncyclopentadienyl precursors, respectively. For the conventional Ziegler-Natta catalysts of the most promising industry applicable recipe, the multicomponents based on lanthanide carboxylate or phosphate or alkoxide precursors, research works concern mainly about optimizing the catalyst preparation and polymerization techniques. Special emphases are put on the factors that influence the catalyst homogeneority, catalytic activity and efficiency, as well as cis-1,4-selectivity. Meanwhile, tailor-made lanthanide aryloxide and amide complexes are designed and fully characterized to mimic the conventional Ziegler-Natta catalysts, anticipated to elucidate the key processes, alkylation and cationization, for generating the active species. Regarding to the single-site catalytic systems generally comprising well-defined complexes containing lanthanide-carbon bonds, investigations cover their versatile catalytic activity and efficiency, and the distinguished regio- and stereoselectivity for both polymerization of dienes and copolymerization of dienes with alkenes. The correlation between the sterics and electronics of ligands and the molecular structures of the complexes and their catalytic performances are highlighted. The isolation of the probable active species in these polymerization processes from the stoichiometric reactions of the precursors with activators will be presented.

  19. Regioselectivity in the Cu(I)-catalyzed [4 + 2]-cycloaddition of 2-nitrosopyridine with unsymmetrical dienes.

    PubMed

    Tran, Anh T; Liu, Peng; Houk, K N; Nicholas, Kenneth M

    2014-06-20

    The thermal (uncatalyzed) and Cu(I)-catalyzed reactions of 2-nitrosopyridine (PyrNO) with the dienes 1,3-pentadiene, E,E-2,4-hexadienol, and 1-phenylbutadiene are investigated experimentally and computationally. The uncatalyzed reactions of the first two dienes occur with low regioselectivity, while the latter proceeds with complete proximal selectivity. Using the M06/6-311+G(d,p)-SDD method, various concerted transition states for the reactions of 2-nitrosopyridine with (E)-1,3-pentadiene and 1-phenylbutadiene were computed. In quantitative agreement with the experimental findings, (a) no energy difference (0.0 kcal/mol) is found between the most stable transition states, endo-prox-anti and endo-dist-anti, in the pentadiene/PyrNO reaction, leading to nearly equal amounts of prox and dist cycloadducts, and (b) the proximal transition state is strongly favored (by 3.7 kcal/mol) over the distal for the highly selective phenylbutadiene/PyrNO reaction. The regioselectivity of the pentadiene/PyrNO reaction is improved markedly (90:10 dist/prox) when catalyzed by Cu(CH3CN)4(+); (diimine)2Cu(+) catalysts increase selectivity for the proximal product (55-65%). Modest effects of the catalyst nature on regioselectivity are observed in the sorbyl alcohol and 1-phenylbutadiene reactions. The relative affinity of an equilibrating set of (diimine)2Cu(+) complexes for the prox and dist cycloadducts, assessed by ESI-MS, is marginally correlated with the prox/dist product regioselectivity produced by the corresponding catalysts. Transition states in the Cu(CH3CN)4(+)- and Cu(diimine)2(+)-catalyzed reactions are located that account for the observed regioselectivities. Coordination effects on the regioselectivity are derived from FMO orbital interactions and the extent of electron transfer between the Cu center and the coordinated nitroso and diene units.

  20. Catalyst-Controlled Regioselectivity in the Synthesis of Branched Conjugated Dienes via Aerobic Oxidative Heck Reactions

    PubMed Central

    Zheng, Changwu; Wang, Dian; Stahl, Shannon S.

    2012-01-01

    Pd-catalyzed aerobic oxidative coupling of vinylboronic acids and electronically unbiased alkyl olefins provides regioselective access to 1,3-disubstituted conjugated dienes. Catalyst-controlled regioselectivity is achieved by using 2,9-dimethylphenanthroline as a ligand. The observed regioselectivity is opposite to that observed from a traditional (non-oxidative) Heck reaction between a vinyl bromide and an alkene. DFT computational studies reveal that steric effects of the 2,9-dimethylphenanthroline ligand promote C–C bond-formation at the internal position of the alkene. PMID:22998540

  1. The direct oxidative diene cyclization and related reactions in natural product synthesis

    PubMed Central

    2016-01-01

    Summary The direct oxidative cyclization of 1,5-dienes is a valuable synthetic method for the (dia)stereoselective preparation of substituted tetrahydrofurans. Closely related reactions start from 5,6-dihydroxy or 5-hydroxyalkenes to generate similar products in a mechanistically analogous manner. After a brief overview on the history of this group of transformations and a survey on mechanistic and stereochemical aspects, this review article provides a summary on applications in natural product synthesis. Moreover, current limitations and future directions in this area of chemistry are discussed. PMID:27829917

  2. Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

    PubMed Central

    Miller, Marvin J

    2016-01-01

    Summary The hetero-Diels–Alder reaction between a nitroso dienophile and a conjugated diene to give the 3,6-dihydro-2H-1,2-oxazine scaffold is useful for the synthesis of many biologically interesting molecules due to the diverse opportunities created by subsequent transformations of the resulting 1,2-oxazine ring. This review discusses the rationale for the observed regio- and stereoselectivity and the methods developed in recent years used to control and improve the stereo- and regioselectivity for the synthesis of 1,2-oxazine scaffolds. PMID:27829901

  3. Inverse Vulcanization of Sulfur using Natural Dienes as Sustainable Materials for Lithium-Sulfur Batteries.

    PubMed

    Gomez, Iñaki; Leonet, Olatz; Blazquez, J Alberto; Mecerreyes, David

    2016-12-20

    Lithium-sulfur batteries are among the most promising next-generation battery systems due to the high capacity of sulfur as cathodic material. Beyond its interesting intrinsic properties, sulfur possesses a very low conductivity and complex electrochemistry, which involves the high solubility of the lithium sulfides in the electrolyte. These two characteristics are at the core of a series of limitations of its performance as active cathode material, which leads to batteries with low cyclability. Recently, inverse vulcanized sulfur was shown to retain capacity far better than elemental sulfur, leading to batteries with excellent cyclability. Nevertheless, the diene co-monomers used so far in the inverse vulcanization process are man-made molecules. Herein, a tentative work on exploring inverse vulcanization using two naturally available monomers, diallyl sulfide and myrcene, is presented. The inverse vulcanization of sulfur was successfully completed, and the resulting polymers were characterized by FTIR, NMR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Afterwards these polymers were tested as cathodic materials in lithium-sulfur cells. The sulfur-natural dienes materials exhibited high capacity at different C rates and high lifetime over 200 cycles with very high capacity retention at a moderate C rate of C/5. Altogether, these materials made from inexpensive and abundant chemicals are an excellent option as sustainable materials for electrochemical energy storage.

  4. Unprecedented Intramolecular [4 + 2]-Cycloaddition between a 1,3-Diene and a Diazo Ester.

    PubMed

    Qiu, Huang; Srinivas, Harathi D; Zavalij, Peter Y; Doyle, Michael P

    2016-02-17

    Diazo compounds that are well-known to undergo [3 + 2]-cycloaddition provide the first examples of the previously unknown [4 + 2]-cycloaddition with dienes that occur thermally under mild conditions and in high yields. Reactions are initiated from reactants prepared from propargyl aryldiazoacetates that undergo gold(I)-catalyzed rearrangement to activated 1,3-dienyl aryldiazoacetates. These reactions proceed to mixtures of both [4 + 2]-cycloaddition and the 1,3-dienyl aryldiazoacetate after long reaction times. At short reaction times, however, both E- and Z-1,3-dienyl aryldiazoacetates are formed and, after isolation, thermal reactions with the E-isomers form the products from [4 + 2]-cycloaddition with ΔH(‡)298 = 15.6 kcal/mol and ΔS(‡)298 = -27.3 cal/(mol·°C). The Z-isomer is inert to [4 + 2]-cycloaddition under these conditions. The Hammett relationships from aryl-substituted diazo esters (ρ = +0.89) and aryl-substituted dienes (ρ = -1.65) are consistent with the dipolar nature of this transformation.

  5. Synergistic hypergolic ignition of blends of dienes and dienophiles with red fuming nitric acid as oxidizer

    SciTech Connect

    Panda, S.P.; Kulkarni, S.G.; Prabhakaran, C.

    1989-04-01

    Synergistic hypergolic ignition of several fuel blends and mixtures with red fuming nitric acid (RFNA) as oxidizer has been reported previously. The liquid fuels consisted of blends of 3-carene, cyclopentadiene, or norbornadiene with cardanol in the weight ratio 70:30 for the first two and 85:15 for norbornadiene. In all these cases, synergism in ignition was believed to be due to the fast and exothermic oligomerization of 3-carene, cyclopentadiene, and norbornadiene in the presence of acid. The exothermicity of the systems was enhanced by the addition of cardanol to the unsaturation of oligomers, leading to the formation of highly oxidizable phenolic ethers. Two more important reactions at the preignition stage were nitration and oxidation of the ethers leading to the production of gaseous combustibles and heat. In this case, an attempt has been made to extend the range of possible preignition reactions by introducing diene-dienophile Diels-Alder cycloaddition with low activation energy by replacing cardanol with furfuryl alcohol or furfurylideneacetone having a furan ring to behave as acid polymerizable dienes in the above systems.

  6. Nitroso Diels-Alder (NDA) Reaction as an Efficient Tool for the Functionalization of Diene-Containing Natural Products

    PubMed Central

    Carosso, Serena; Miller, Marvin J.

    2014-01-01

    This review describes the use of nitroso Diels-Alder reactions for the functionalization of complex diene-containing natural products in order to generate libraries of compounds with potential biological activity. The application of this methodology to the structural modification of a series of natural products (thebaine, steroidal dienes, rapamycin, leucomycin, colchicine, isocolchicine and piperine) is discussed using relevant examples from the literature from 1973 onwards. The biological activity of the resulting compounds is also discussed. Additional comments are provided that evaluate the methodology as a useful tool in organic, bioorganic and medicinal chemistry. PMID:25119424

  7. Strategic use of nickel(0)-catalyzed enyne-epoxide reductive coupling towards the synthesis of (−)-cyatha-3,12-diene

    PubMed Central

    Sparling, Brian A.; Simpson, Graham L.; Jamison, Timothy F.

    2009-01-01

    Various situations are explored in which the nickel(0)-catalyzed enyne-epoxide reductive coupling was utilized to access key intermediates towards the total synthesis of (−)-cyatha-3,12-diene (1). Enantioenriched 3,5-dien-1-ols with a variety of functionality were obtained in a straightforward manner from easily accessible 1,3-enynes and terminal epoxides. PMID:20161213

  8. The conformation and molecular structure of a 2,3-diazacyclohepta-1,3-diene derivative. A gas-phase electron diffraction study of perfluoro-(1,4-dimethyl-2,3-diazacyclohepta-1,3-diene)

    NASA Astrophysics Data System (ADS)

    Beagley, B.; Pritchard, R. G.

    1985-08-01

    The molecular structure of the perfluoro-(1,4-dimethyl-2,8-diazacyclohepta-1,3-diene) molecule has been studied using gas-phase electron diffraction data collected on the Balzers KDG2 instrument at UMIST. The data are compatible with a C2 conformer with a torsion angle around the single NN bond of 52.4° ( gauche-diene geometry). The NNC(C 2) fragments are planar; each of these olefin planes also contains a CF bond of a -CF 3 group, with torsion angle NCCF = 0°. The ring conformation closely resembles that of the cyclohepta-1,3-diene ring in 1-hydroxy-2,3-dicarbomethyoxycyclohepta-1,3-diene, rather than that of the parent hydrocarbon. The principal structural parameters are NN = 1.349(19) Å, NC = 1.257(11) Å, CC(mean) = 1.536(3) Å, CF(mean) = 1.340(2) Å, ∠NNC = 121.9(7)°, ∠NCC(F 2) = 124.0(6)°, ∠NCC(F 3) = 117.8(7)°, ∠CCF(CF 3) = 111.1(3)°, ∠FCF(CF 2) = 107.8(6)°.

  9. Le facteur XII de la coagulation: bien plus qu’un stabilisant de la fibrine

    PubMed Central

    Messaoudi, N.; Lamaalmi, F.; Chakour, M.; Belmekki, A.; Naji, M.

    2011-01-01

    Summary Les Auteurs considèrent le rôle du facteur XIII de la coagulation dans la cicatrisation. Identifié depuis 1923, le rôle du facteur XIII ou le facteur stabilisant de la fibrine dans la coagulation a été bien élucidé. Son rôle dans la cicatrisation suggéré dès 1960 est méconnu par les hématologistes et les médecins prenant en charge les brûlés. Les Auteurs se proposent de mettre la lumière sur ce rôle, qui reste encore mystérieux et mérite d’être élucidé. PMID:21991236

  10. Efficient preparation of terminal conjugated dienes by coupling of dienol phosphates with grignard reagents under iron catalysis.

    PubMed

    Cahiez, Gérard; Habiak, Vanessa; Gager, Olivier

    2008-06-19

    An efficient new route to prepare stereoselectively terminal conjugated dienes by coupling Grignard reagents and dienol phosphates in the presence of Fe(acac)3 is described. The synthetic utility of this new iron-catalyzed procedure is illustrated by the synthesis of the pheromone of Diparopsis castanea according to a very expeditious strategy.

  11. Liquid marbles as a micro-reactor for efficient radical alternating copolymerization of diene monomer and oxygen.

    PubMed

    Sato, E; Yuri, M; Fujii, S; Nishiyama, T; Nakamura, Y; Horibe, H

    2015-12-18

    Liquid marbles have been shown to be a novel micro-reactor to synthesize polyperoxides by the radical alternating copolymerization of the 1,3-diene monomer with oxygen in a good yield. Oxygen gas is effectively absorbed as a comonomer by the large and permeable gas-liquid interface of the liquid marbles.

  12. Diastereoselective Construction of Functionalized Homoallylic Alcohols by Ni-Catalyzed Diboron-Promoted Coupling of Dienes and Aldehydes

    PubMed Central

    Cho, Hee Yeon; Morken, James P.

    2009-01-01

    The nickel-catalyzed reaction of carbonyls and dienes was accomplished in a regio- and stereo-selective fashion employing a stoichiometric amount of bis(pinacolato)diboron. This reductive coupling furnishes an allyl boronic esters as the reaction product, a compound which was readily converted to the derived allylic alcohol by oxidative work-up. PMID:18998642

  13. High-Level Production of Amorpha-4,11-Diene, a Precursor of the Antimalarial Agent Artemisinin, in Escherichia coli

    PubMed Central

    Tsuruta, Hiroko; Paddon, Christopher J.; Eng, Diana; Lenihan, Jacob R.; Horning, Tizita; Anthony, Larry C.; Regentin, Rika; Keasling, Jay D.; Renninger, Neil S.; Newman, Jack D.

    2009-01-01

    Background Artemisinin derivatives are the key active ingredients in Artemisinin combination therapies (ACTs), the most effective therapies available for treatment of malaria. Because the raw material is extracted from plants with long growing seasons, artemisinin is often in short supply, and fermentation would be an attractive alternative production method to supplement the plant source. Previous work showed that high levels of amorpha-4,11-diene, an artemisinin precursor, can be made in Escherichia coli using a heterologous mevalonate pathway derived from yeast (Saccharomyces cerevisiae), though the reconstructed mevalonate pathway was limited at a particular enzymatic step. Methodology/ Principal Findings By combining improvements in the heterologous mevalonate pathway with a superior fermentation process, commercially relevant titers were achieved in fed-batch fermentations. Yeast genes for HMG-CoA synthase and HMG-CoA reductase (the second and third enzymes in the pathway) were replaced with equivalent genes from Staphylococcus aureus, more than doubling production. Amorpha-4,11-diene titers were further increased by optimizing nitrogen delivery in the fermentation process. Successful cultivation of the improved strain under carbon and nitrogen restriction consistently yielded 90 g/L dry cell weight and an average titer of 27.4 g/L amorpha-4,11-diene. Conclusions/ Significance Production of >25 g/L amorpha-4,11-diene by fermentation followed by chemical conversion to artemisinin may allow for development of a process to provide an alternative source of artemisinin to be incorporated into ACTs. PMID:19221601

  14. Total (1)H NMR assignment of 3β-acetoxypregna-5,16-dien-20-one.

    PubMed

    Becerra-Martinez, Elvia; Ramírez-Gualito, Karla E; Pérez-Hernández, Nury; Joseph-Nathan, Pedro

    2015-12-01

    This work describes the total and unambiguous assignment of the 750 MHz (1)H NMR spectrum of 3β-acetoxypregna-5,16-dien-20-one or 16-DPA (1), the well-known intermediate utilized in the synthesis of biological important commercial steroids. The task was accomplished by extracting the coupling constant values in the overlapped spectrum region by HSQC, and using these values in the (1)H iterative full spin analysis integrated in the PERCH NMR software. Comparison of the experimental vicinal coupling constants of 1 with the values calculated using Altona provides an excellent correlation. The same procedure, when applied to the published data of progesterone (2) and testosterone (3), afforded an acceptable correlation for 2 and a poor correlation for 3. In the last case, this suggested the reassignment of all four vicinal coupling constants for the methylene signals at the C-15 and C-16 positions, demonstrating the utility of this methodology.

  15. Gas-Phase Synthesis of 1-Silacyclopenta-2,4-diene.

    PubMed

    Yang, Tao; Dangi, Beni B; Thomas, Aaron M; Sun, Bing-Jian; Chou, Tzu-Jung; Chang, Agnes H H; Kaiser, Ralf I

    2016-07-04

    Silole (1-silacyclopenta-2,4-diene) was synthesized for the first time by the bimolecular reaction of the simplest silicon-bearing radical, silylidyne (SiH), with 1,3-butadiene (C4 H6 ) in the gas phase under single-collision conditions. The absence of consecutive collisions of the primary reaction product prevents successive reactions of the silole by Diels-Alder dimerization, thus enabling the clean gas-phase synthesis of this hitherto elusive cyclic species from acyclic precursors in a single-collision event. Our method opens up a versatile and unconventional path to access a previously rather obscure class of organosilicon molecules (substituted siloles), which have been difficult to access through classical synthetic methods.

  16. Catalyst-free synthesis of skipped dienes from phosphorus ylides, allylic carbonates, and aldehydes via a one-pot SN2' allylation-Wittig strategy.

    PubMed

    Xu, Silong; Zhu, Shaoying; Shang, Jian; Zhang, Junjie; Tang, Yuhai; Dou, Jianwei

    2014-04-18

    A catalyst-free allylic alkylation of stabilized phosphorus ylides with allylic carbonates via a regioselective SN2' process is presented. Subsequent one-pot Wittig reaction with both aliphatic and aromatic aldehydes as well as ketenes provides structurally diverse skipped dienes (1,4-dienes) in generally high yields and moderate to excellent stereoselectivity with flexible substituent patterns. This one-pot SN2' allylation-Wittig strategy constitutes a convenient and efficient synthetic method for highly functionalized skipped dienes from readily available starting materials.

  17. Vertical distribution of dioxins in soil of Bien Hoa airbase, Vietnam.

    PubMed

    Huyen, Dang Thuong; Igarashi, Toshifumi; Shiraiwa, Takuya

    2015-01-01

    Bien Hoa airbase is a known dioxin-contaminated hotspot in Vietnam. The contamination occurred during the Vietnam War at the site where dioxins were transported, stored, sprayed, and spilled in the area. Dioxins, which are cancer inducing substances, may transfer from the soil to food crops and finally to human beings living around the area. Many surveys of dioxins in soil, water, organisms, and human have been carried out in this study area since 2002. In this paper vertical distribution of dioxins in undisturbed soil cores were examined. Twelve soil samples from three drilled cores were collected to analyze dioxin levels according to the standard Japanese analytical method. The results showed that the toxicity equivalency quantity (TEQ) in one soil sample at a depth of 2.6 m reached 3,300 pg-TEQ/g-dw. High TEQs were also observed in the clay layer. This anomaly of dioxin concentrations could be attributed to the affinity of dioxins for the clay layer. The isomer patterns in the soils were different from those in the soil of Hokkaido in that 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) was the most dominant in the soil sample. This indicates that the dioxins originate from a defoliant Agent Orange disposed at the site after the Vietnam War.

  18. Total Synthesis of the Galbulimima Alkaloids Himandravine and GB17 Using Biomimetic Diels–Alder Reactions of Double Diene Precursors

    PubMed Central

    Larson, Reed T.; Pemberton, Ryan P.; Franke, Jenna M.; Tantillo, Dean J.; Thomson, Regan J.

    2015-01-01

    The enantioselective total syntheses of himandravine and GB17 were completed through a common biomimetic strategy involving Diels–Alder reactions of unusual double diene containing linear precursors. The double diene precursors, containing or lacking a C12 substituent as required to produce GB17 or himandravine, respectively, were found to undergo Diels–Alder reactions to afford mixtures of regioisomeric cycloadducts that map onto the alternative carbocyclic frameworks of both himandravine and GB17. Computational investigations revealed that these Diels–Alder reactions proceed via transition state structures of similar energy that have a high degree of bispericyclic character and that the low levels of regioselectivity observed in the reactions are a consequence of competing orbital interaction and distortion energies. The combined experimental and computational results provide valuable insights into the biosynthesis of the Galbulimima alkaloids. PMID:26305231

  19. Ruthenium-catalyzed intramolecular metathesis of dienes and its application in the synthesis of bridged and spiro azabicycles

    NASA Astrophysics Data System (ADS)

    Kuznetsov, N. Yu; Bubnov, Yu N.

    2015-07-01

    The review presents a historical excursion into catalytic alkene metathesis, covering the problems of history of the discovery of this process, as well as investigations on the properties, structure and reactivity of the most popular ruthenium catalysts for metathesis, mechanism of their action and decomposition. The main part covers studies devoted to the syntheses of bridged azabicyclic and 1-azaspirocyclic compounds comprising the intramolecular metathesis of dienes as the key step. The formation of a bicyclic skeleton of a series of natural bridged (cocaine, ferruginine, calystegines, and anatoxin-a) and spiro (pinnaic acids, halichlorine, hystrionicotoxin, and cephalotaxine) azabicycles, as well as their analogues and compounds with larger rings is demonstrated. The methods for the synthesis of diene precursors and the conditions for final assembling of the bicyclic compounds are considered in detail. The generalization of the literature data allows one to efficiently carry out the mentioned process taking into account the most important features. The bibliography includes 129 references.

  20. Enantioselective Aminomethylamination of Conjugated Dienes with Aminals Enabled by Chiral Palladium Complex-Catalyzed C-N Bond Activation.

    PubMed

    Liu, Yang; Xie, Yinjun; Wang, Hongli; Huang, Hanmin

    2016-04-06

    A novel highly enantioselective aminomethylamination of conjugated dienes with aminals catalyzed by a chiral palladium complex ligated with BINOL-derived chiral diphosphinite has been successfully developed. This reaction proceeds via a Pd-catalyzed cascade C-N bond activation, aminomethylation, and asymmetric allylic amination reaction under mild reaction conditions, providing a unique and efficient strategy for the synthesis of enantiomerically pure allylic 1,3-diamines.

  1. Intramolecular alkylative arylation of oxabicylic alkene: a potential diene approach for the synthesis of estrone and analogous steroid structures.

    PubMed

    Li, Wei-Dong Z; Wei, Kun

    2004-04-15

    Regioselective and stereospecific intramolecular alkylative arylation of unsaturated oxabicyclic diol 6, mediated by Lewis acid or strong protic acid to give the tetracyclic products 7a and 7b, as shown above, represents the first example of an electrophilic (cationic in character) ring-opening-cyclization of oxabicyclic alkene. This constitutes the key cyclization step for a long-standing and potentially useful diene approach for the synthesis of estrone and analogous steroid structures. [structure: see text

  2. Synthesis, crystal structure and properties of [(dien)2Mn]Ge2S4 with mixed-valent Ge centers

    NASA Astrophysics Data System (ADS)

    Yue, Cheng-Yang; Yuan, Zhuang-Dong; Zhang, Lu-Ge; Wang, Ya-Bai; Liu, Guo-Dong; Gong, Liao-Kuo; Lei, Xiao-Wu

    2013-10-01

    One new manganese thiogermanate, [(dien)2Mn]Ge2S4 (dien=diethylenetriamine), was prepared under mild solvothermal conditions and structurally and spectroscopically characterized. The title compound crystallizes in the orthorhombic system, chiral space group P212121 (no. 19) with a=9.113(4) Å, b=12.475(5) Å, c=17.077(7) Å, V=1941.5(15) Å3 and Z=4. Its structure features a three-dimensional (3D) network composed of a one-dimensional (1D) [Ge2S4]2- anionic chain and a [(dien)2Mn]2+ complex interconnected via various hydrogen bonds. The most interesting structural feature of the compound is the presence of two different oxidation states of germanium centers in the 1D [Ge2S4]2- chain, which is also supported by the result of X-ray photoelectron spectroscopy measurement. The optical property of the title compound has also been studied by UV-vis spectra.

  3. Response of ethylene propylene diene monomer rubber (EPDM) to simulant Hanford tank waste

    SciTech Connect

    NIGREY,PAUL J.

    2000-02-01

    This report presents the findings of the Chemical Compatibility Program developed to evaluate plastic packaging components that may be incorporated in packaging mixed-waste forms for transportation. Consistent with the methodology outlined in this report, the author performed the second phase of this experimental program to determine the effects of simulant Hanford tank mixed wastes on packaging seal materials. That effort involved the comprehensive testing of five plastic liner materials in an aqueous mixed-waste simulant. The testing protocol involved exposing the materials to {approximately}143, 286, 571, and 3,670 krad of gamma radiation and was followed by 7-, 14-, 28-, 180-day exposures to the waste simulant at 18, 50, and 60 C. Ethylene propylene diene monomer (EPDM) rubber samples subjected to the same protocol were then evaluated by measuring seven material properties: specific gravity, dimensional changes, mass changes, hardness, compression set, vapor transport rates, and tensile properties. The author has determined that EPDM rubber has excellent resistance to radiation, this simulant, and a combination of these factors. These results suggest that EPDM is an excellent seal material to withstand aqueous mixed wastes having similar composition to the one used in this study.

  4. Functionalized acetylenic compounds via 1-bromo- 1,2-dienes and organocopper reagents

    SciTech Connect

    Caporusso, A.M.; Iodice, A.; Lardicci, L.; Salvadori, P.

    1995-12-31

    The acetylenic unity provides a convenient handle which may be converted into a variety of functionalities. In this frame, the authors developed a general and efficient method for the synthesis of chiral 1-alkynes, with a tertiary or a quaternary asymmetric carbon atom in the {alpha} position to the triple bond, by stereoselective cross-coupling of bromocuprates [(RCuBr)MaBr LiBr R=Alkyl, aryl] with optically active 1-bromo-1,2-dienes. This method provides terminal acetylenes which can easily converted into biologically active compounds, such as the antiphlogistic (+)-Ibuprofen. The authors report here that this procedure can be extended to the preparation of a large variety of functionalized acetylenic systems. In fact, bromocuprates, obtained from protected functionalized Grignard reagents and LiCuBr{sub 2}, react with bromoallenes affording the 1-alkynes with high yields, regio- and stereoselectivity. Compounds are also conveniently obtained from cyanocuprates, prepared by reaction of functionalized zinc reagents with the cuprous cyanide/lithium chloride complex; the organozinc derivatives are directly obtained from organic halides and highly activated zinc powder, prepared by metal vapour technique.

  5. Combined NMR and quantum chemical studies on the interaction between trehalose and dienes relevant to the antioxidant function of trehalose.

    PubMed

    Oku, Kazuyuki; Kurose, Mayumi; Kubota, Michio; Fukuda, Shigeharu; Kurimoto, Masashi; Tujisaka, Yoshio; Okabe, Atsutoshi; Sakurai, Minoru

    2005-02-24

    In a previous study (Oku, K.; Watanabe, H.; Kubota, M.; Fukuda, S.; Kurimoto, M.; Tujisaka, Y.; Komori, M.; Inoue, Y.; Sakurai, M. J. Am. Chem. Soc. 2003, 125, 12739), we investigated the mechanism of the antioxidant function of trehalose against unsaturated fatty acids (UFAs) and revealed that the key factor relevant to the function is the formation of OH...pi and CH...O hydrogen bonds between trehalose and the cis double bonds of the UFA. Here, we investigate whether such intriguing interactions also occur between this sugar and cis double bonds in other unsaturated compounds. For this purpose, we selected various diene compounds (1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, and 2,5-heptadiene) as interaction partners. All NMR experiments performed, including 1H-1H NOESY measurements, indicated that trehalose selectively interacts with the cis-olefin proton pair in the above diene with a 1:1 stoichiometry, and the C-3 (C-3') and C-6' (C-6) sites of the sugar are responsible for the interaction. Similar interactions were not observed for the mixtures of the diene and other saccharides (neotrehalose, kojibiose, nigerose, maltose, isomaltose, sucrose, maltitol, and sorbitol). Quantum chemical calculations revealed that the OH-3 and OH-6 groups bind to the olefin double bonds of the diene through OH...pi and CH...O types of hydrogen bonds, respectively, and the stabilization energy of the resulting complex is 5-6 kcal mol(-1). These results strongly support the above NMR results. Finally, the activation energies were calculated for the hydrogen abstraction reactions from the activated methylene group of heptadiene. In particular, when the reaction was initiated by a methyl radical, the activation energy was only 10 kcal mol(-1) for the free heptadiene, but on complexation with trehalose it drastically increased to ca. 40 kcal mol(-1). This indicates that trehalose has a significant depression effect on the oxidation of the diene compounds. These results strongly

  6. Reaction of ketones with 1,4-diaza-1,3-diene zirconium and hafnium complexes: First example of a 1,3-dipolar cycloaddition reaction of 1,4-diaza-1,3-diene complexes of early transition metals

    SciTech Connect

    Scholz, J.; Goerls, H.

    1996-07-17

    The chemical preparation of M[O(R)PhCH(CH{double_bond}N(tBu))N(tBu)]{sub 2} (M = Zr, R = Me (4a), R = Ph (4b) and M = Hf, R = Me (5a), R = Ph (5b)) complexes is described. The reaction can be described as a 1,3-dipolar cycloaddition of C{double_bond}O across the M-N-C portion of Zr and Hf 1,4-diaza-1,3-diene complexes. The crystal structures of 4a and 5b are reported.

  7. Low-lying excited states and primary photoproducts of [Os3(CO)10(s-cis-L)] (L=cyclohexa-1,3-diene, buta-1,3-diene)] clusters studied by picosecond time-resolved UV/Vis and IR spectroscopy and by density functional theory.

    PubMed

    Vergeer, Frank W; Matousek, Pavel; Towrie, Michael; Costa, Paulo J; Calhorda, Maria J; Hartl, Frantisek

    2004-07-19

    Combined picosecond transient absorption and time-resolved infrared studies were performed, aimed at characterising low-lying excited states of the cluster [Os(3)(CO)(10)(s-cis-L)] (L=cyclohexa-1,3-diene, 1) and monitoring the formation of its photoproducts. Theoretical (DFT and TD-DFT) calculations on the closely related cluster with L=buta-1,3-diene (2') have revealed that the low-lying electronic transitions of these [Os(3)(CO)(10)(s-cis-1,3-diene)] clusters have a predominant sigma(core)pi*(CO) character. From the lowest sigmapi* excited state, cluster 1 undergoes fast Os-Os(1,3-diene) bond cleavage (tau=3.3 ps) resulting in the formation of a coordinatively unsaturated primary photoproduct (1 a) with a single CO bridge. A new insight into the structure of the transient has been obtained by DFT calculations. The cleaved Os-Os(1,3-diene) bond is bridged by the donor 1,3-diene ligand, compensating for the electron deficiency at the neighbouring Os centre. Because of the unequal distribution of the electron density in transient 1 a, a second CO bridge is formed in 20 ps in the photoproduct [Os(3)(CO)(8)(micro-CO)(2)(cyclohexa-1,3-diene)] (1 b). The latter compound, absorbing strongly around 630 nm, mainly regenerates the parent cluster with a lifetime of about 100 ns in hexane. Its structure, as suggested by the DFT calculations, again contains the 1,3-diene ligand coordinated in a bridging fashion. Photoproduct 1 b can therefore be assigned as a high-energy coordination isomer of the parent cluster with all Os-Os bonds bridged.

  8. Solvothermal syntheses, crystal structures, and properties of lanthanide(III) thioarsenates [Ln(dien)2(μ-1κ,2κ2-AsS4)]n (Ln==Sm, Eu, Gd) and [Ln(dien)2(1κ2-AsS4)] (Ln==Tb, Dy, Ho)

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Tang, Chunying; Chen, Ruihong; Zhang, Yong; Jia, Dingxian

    2013-10-01

    Solvothermal reactions of Ln2O3, As and S in diethylenetriamine (dien) at 170 °C for 6 days afforded two structural types of lanthanide thioarsenates with the general formulae [Ln(dien)2(μ-1κ,2κ2-AsS4)]n [Ln=Sm(1), Eu(2), Gd(3)] and [Ln(dien)2(1κ2-AsS4)] [Ln=Tb(4), Dy(5), Ho(6)]. The Ln2O3 oxides were converted to [Ln(dien)2]3+ complex units in the solvothermal reactions. The As atom binds four S atoms, forming a tetrahedral AsS4 unit. In 1-3, the AsS4 units interconnect the [Ln(dien)2]3+ cations via Ln-S bonds as tridentate μ-1κ,2κ2-AsS4 bridging ligands, resulting in the neutral coordination polymers [Ln(dien)2(μ-1κ,2κ2-AsS4)]n (Ln1). In 4-6, the AsS4 units coordinate with the Ln3+ ion of [Ln(dien)2]3+ as 1κ2-AsS4 chelating ligands to form neutral coordination compounds [Ln(dien)2(1κ2-AsS4)] (Ln2). The Ln3+ ions are in nine- and eight-coordinated environments in Ln1 and Ln2, respectively. The formation of Ln1 and Ln2 is related with ionic size of the Ln3+ ions. Optical absorption spectra showed that 1-6 have potential use as semiconductors with the band gaps in the range 2.18-3.21 eV.

  9. Spectroscopic properties and photochemistry of [Fe(CO) 3(1,4-Diazabuta-1,3-diene)] complexes

    NASA Astrophysics Data System (ADS)

    Stufkens, D. J.; Kokkes, M. W.; Oskam, A.

    1984-03-01

    Different photochemical reactions are found for [Fe(CO) 3(dab)] (dab = 1,4-diazabuta-1,3-diene) in matrices at 10 K and in solutions at room temperature. Matrix photolysis results in loss of CO via an intermediate in which the dab-ligand is π,π-coordinated to the metal, whereas photolysis in solution leads to CO-substitution after breaking of a metal-nitrogen bond. This behaviour is discussed in relationship to the spectroscopic properties of [Fe(CO) 3(dab)].

  10. Palladium-catalyzed stereospecific homocoupling of vinylstannanes as a suitable method for the synthesis of symmetrical 1,3-dienes

    SciTech Connect

    Tolstikov, G.A.; Miftakhov, M.S.; Danilova, N.A.; Vel'der, Ya.L.

    1988-07-20

    The authors have found that functionally substituted vinylstannanes readily enter into a homocoupling reaction in the presence of 5 mole % of PdCl/sub 2/(MeCN)/sub 2/ (in HMPTA at 20/degree/C), giving 85-95% yields of symmetrical 1,3-dienes with retention of the configuration of the substituents at the double bonds. It should be noted that the rate of this reaction is determined by the configuration of the isomers with respect to the double bond and by the structure of the substituent at the double bond.

  11. Influence of the chemical structure on odor qualities and odor thresholds in homologous series of alka-1,5-dien-3-ones, alk-1-en-3-ones, alka-1,5-dien-3-ols, and alk-1-en-3-ols.

    PubMed

    Lorber, Katja; Schieberle, Peter; Buettner, Andrea

    2014-02-05

    Odor qualities and odor thresholds in air in homologous series of synthesized alk-1-en-3-ols and alka-1,5-dien-3-ols and their corresponding ketones were evaluated by gas chromatography-olfactometry. In the series of the alk-1-en-3-ols and alk-1-en-3-ones the odor quality changed successively from pungent for the compounds with five carbon atoms via metallic, vegetable-like for the six- and seven-carbon odorants to mushroom-like for the compounds with eight and nine carbon atoms. With further increase in chain length the mushroom-like impression decreased and changed to citrus-like, soapy, or herb-like. In both series, two odor threshold minima were found for the six-carbon and also for the eight- and nine-carbon odorants, respectively. In contrast to this, the odor qualities in the series of the (Z)- and (E)-alka-1,5-dien-3-ols and their corresponding ketones did not change significantly with geranium-like, metallic odors and an increasing mushroom-like odor note with increasing chain length. The lowest thresholds were found for the eight- and nine-carbon (Z)-compounds, respectively.

  12. Synthesis and characterization of hexadecadienyl compounds with a conjugated diene system, sex pheromone of the persimmon fruit moth and related compounds.

    PubMed

    Nishida, Takanobu; Vang, Van Le; Yamazawa, Hiroyuki; Yoshida, Ryuji; Naka, Hideshi; Tsuchida, Koji; Ando, Tetsu

    2003-04-01

    Hexadecadien-1-ol and the derivatives (acetate and aldehyde) with a conjugated diene system have recently been identified from a pheromone gland extract of the persimmon fruit moth (Stathmopoda masinissa), a pest insect of persimmon fruits distributed in East Asia. The alcohol and acetate showed their base peaks at m/z 79 in a GC-MS analysis by electron impact ionization, but the aldehyde produced a unique base peak at m/z 84, suggesting a 4,6-diene structure. To confirm this inference, four geometrical isomers of each 4,6-hexadecadienyl compound were synthesized by two different routes in which one of two double bonds was furnished in a highly stereoselective manner. Separation of the two isomers synthesized together by each route was facilely accomplished by preparative HPLC. Their mass spectra coincided well with those of natural components, indicating that they were available for use as authentic standards for determining the configuration of the natural pheromone. Furthermore, other hexadecadienyl compounds, including the conjugated diene system between the 3- and 10-positions, were synthesized to accumulate the spectral data of pheromone candidates. 5,7-Hexadecadienal interestingly showed the base peak at m/z 80; meanwhile, the base peaks of its alcohol and acetate were detected at m/z 79 like the corresponding 4,6-dienes. The base peaks of all 6,8-, 7,9-, and 8,10-dienes universally appeared at m/z 67 like 9,11-, 10,12-, and 13,15-dienes, the spectra of which have already been published. Although 3,5-hexadecadienal was not prepared, base peaks at m/z 67 and 79 were recorded for the alcohol and acetate, respectively.

  13. The vibrational spectra, conformational and thermodynamic properties of 2-chlorobuta-1,3-diene (chloroprene) and propenoyl chloride

    NASA Astrophysics Data System (ADS)

    Compton, D. A. C.; George, W. O.; Goodfield, J. E.; Maddams, W. F.

    The vibrational spectrum of 2-chlorobuta-1,3-diene has been recorded in the gaseous, liquid, solid and solution phases, and also in an argon matrix. Several weak bands present in the i.r. spectrum of the fluid phases and unannealed matrix were observed to be absent after careful annealing. Thermodynamic functions for the ideal gas have been estimated from those of other compounds, and their values, taken together with the spectral changes on annealing, are concluded to be evidence of a conformational equilibrium. The most probable molecular structure has been calculated using previous microwave data, and the asymmetric potential function to internal rotation has also been calculated using a value of Δ Hθ of 8.2 kJ mol -1, as derived by statistical methods. The i.r. spectrum of gaseous propenoyl chloride has been recorded to aid in assignment of the spectral features of the isoelectronic compound 2-chlorobuta-1,3-diene, and improved vibrational assignments of both compounds are presented. New values for the thermodynamic functions of propenoyl chloride are presented to take into account the significant changes made to the vibrational assigmnent.

  14. A novel 3α-p-Nitrobenzoylmultiflora-7:9(11)-diene-29-benzoate and two new triterpenoids from the seeds of zucchini (Cucurbita pepo L).

    PubMed

    Tanaka, Reiko; Kikuchi, Takashi; Nakasuji, Saori; Ue, Yasuhiro; Shuto, Daisuke; Igarashi, Keishi; Okada, Rina; Yamada, Takeshi

    2013-06-26

    Three novel multiflorane-type triterpenoids, 3α-p-nitrobenzoylmultiflora-7:9(11)-diene-29-benzoate (1), 3α-acetoxymultiflora-7:9(11)-diene-29-benzoate (2), and 3α-acetoxymultiflora-5(6):7:9(11)-triene-29-benzoate (3), along with two known related compounds 4 and 5 were isolated from the seeds of zucchini (Cucurbita pepo L). Their structures were determined on the basis of 1D and 2D NMR spectroscopy and HREIMS. Triterpenoids possessing a nitro group were not isolated previously.

  15. Thermally induced electrocyclic reaction of methylenecyclopropane methylene diketone derivatives: a facile method for the synthesis of spiro[2.5]octa-3,5-dienes.

    PubMed

    Tang, Xiang-Ying; Wei, Yin; Shi, Min

    2010-11-19

    Thermally induced electrocyclic reactions of methylenecyclopropane (MCP) methylene diketone derivatives afford a novel method for the synthesis of spiro[2.5]octa-3,5-dienes in moderate to good yields. Applying this methodology in a one-pot manner for the reactions of MCP aldehydes with 1,3-diketones, catalyzed by l-proline, also afforded the corresponding spiro derivatives.

  16. Chain Walking as a Strategy for Carbon-Carbon Bond Formation at Unreactive Sites in Organic Synthesis: Catalytic Cycloisomerization of Various 1,n-Dienes.

    PubMed

    Hamasaki, Taro; Aoyama, Yuka; Kawasaki, Junichi; Kakiuchi, Fumitoshi; Kochi, Takuya

    2015-12-30

    Carbon-carbon bond formation at unreactive sp(3)-carbons in small organic molecules via chain walking was achieved for the palladium-catalyzed cycloisomerization of 1,n-dienes. Various 1,n-dienes (n = 7-14) such as those containing cyclic alkenes, acyclic internal alkenes, and a trisubstituted alkene can be used for the chain-walking cycloisomerization/hydrogenation process, and five-membered ring compounds including simple cyclopentane and pyrrolidine derivatives can easily be prepared. Chain walking over a tertiary carbon was also found to be possible in the cycloisomerization. It is not necessary for the linker portion of the diene to contain a quaternary center, and diene substrates with two alkene moieties linked by a tertiary carbon or a nitrogen atom can also be used as substrates. Column chromatography using silica gel containing silver nitrate was found to be effective for isolating some of the cycloisomerization products without hydrogenation. Deuterium-labeling experiments provided direct evidence to show that the reaction proceeds via a chain-walking mechanism.

  17. Double nucleophilic 1,2-addition of silylated dialkyl phosphites to 4-phosphono-1-aza-1,3-dienes: synthesis of gamma-phosphono-alpha-aminobisphosphonates.

    PubMed

    Masschelein, Kurt G R; Stevens, Christian V

    2007-11-23

    gamma-Phosphono-alpha-aminobisphosphonates were synthesized from a new class of 4-phosphono-1-aza-1,3-dienes by the addition of dialkyl trimethylsilyl phosphites to these azadienes in the presence of acid. Depending on the steric demand of the group on nitrogen, double 1,2-addition or tandem 1,4-1,2-addition occurred.

  18. Microbiological transformation of two 15α-hydroxy-ent-kaur-9(11),16-diene derivatives by the fungus Fusarium fujikuroi.

    PubMed

    Fraga, Braulio M; González-Vallejo, Victoria; Guillermo, Ricardo; Amaro-Luis, Juan M

    2013-05-01

    The incubation of 15α-hydroxy-ent-kaur-9(11),16-dien-19-oic acid (15α-hydroxy-grandiflorenic acid) with the fungus Fusarium fujikuroi gave as main metabolite its 3β,6β-dihydroxy derivative, which by an oxidative decarboxylation afforded a 19-nor compound with a 4,18-double bond. Other substances obtained were a 3α-hydroxy-19,6α-lactone, 3β-hydroxy-6β,7β-epoxy-ent-kaur-9(11),16-dien-19-oic acid and 3β-hydroxy-6-oxo-ent-kaur-9(11),16-dien-19-oic acid. Moreover, the biotransformation of 15α,18-dihydroxy-ent-kaur-9(11),16-diene led to the isolation of the corresponding 3β-, 6β-, 7α- and 12β-hydroxy derivatives. Two metabolites formed by 16β,17-epoxidation of the last compound and of the substrate were also obtained. These results indicated that the presence of the 9,11-double bond in the substrate impedes its 7β-hydroxylation, which is necessary for the formation of gibberellins and seco-ring B ent-kaurenoids. However, this 9,11-unsaturation does not hinder a 6,7-dehydrogenation and further 6β,7β-epoxidation, characteristic steps of the kaurenolide biosynthetic pathway.

  19. Transport and bioaccumulation of polychlorinated dibenzo-p-dioxins and dibenzofurans at the Bien Hoa Agent Orange hotspot in Vietnam.

    PubMed

    Van Thuong, Nguyen; Hung, Nguyen Xuan; Mo, Nguyen Thi; Thang, Nguyen Manh; Huy, Pham Quang; Van Binh, Hoang; Nam, Vu Duc; Van Thuy, Nguyen; Son, Le Ke; Minh, Nguyen Hung

    2015-10-01

    The Bien Hoa airbase (south of Vietnam) is known as one of the Agent Orange hotspots which have been seriously contaminated by Agent Orange/dioxin during the Vietnam War. Hundreds of samples including soil, sediment and fish were collected at the Bien Hoa Agent Orange hotspot for assessment of the environmental contamination caused by dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The toxicity equivalency quotient (TEQ) concentration of PCDD/Fs in soil and sediment varied from 7.6 to 962,000 and 17 to 4860 pg/g dry wt, respectively, implying very high contamination of PCDD/Fs in several areas. PCDD/F levels in fish ranged between 1.8 and 288 pg/g TEQ wet wt and was generally higher than advisory guidelines for food consumption. 2,3,7,8-Tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TCDD) contributed 66-99 % of TEQ for most of the samples, suggesting 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) from Agent Orange as the major source of the contamination. The vertical transport of PCDD/Fs was observed in soil column with high TEQ levels above 1000 pg/g dry wt (Vietnamese limit for necessary remediation activities- TCVN 8183:2009 (2009)) even at a depth of 1.8 m. The vertical transport of PCDD/Fs has probably mainly taken place during the "Ranch Hand" defoliant spray activities due to the leaks and spills of phenoxy herbicides and solvents. The congener patterns suggest that transports of PCDD/Fs by weathering processes have led to their redistribution in the low-land areas. Also, an estimate for the total volume of contaminated soil requiring remediation to meet Vietnamese regulatory limits is provided.

  20. A Diels-Alder super diene breaking benzene into C2H2 and C4H4 units

    NASA Astrophysics Data System (ADS)

    Inagaki, Yusuke; Nakamoto, Masaaki; Sekiguchi, Akira

    2014-01-01

    Cyclic polyene with six carbon atoms (benzene) is very stable, whereas cyclic polyene with four carbon atoms (cyclobutadiene) is extremely unstable. The electron-withdrawing pentafluorophenyl group of a substituted cyclobutadiene lowers the energy of the lowest unoccupied molecular orbital, greatly increasing its reactivity as a diene in Diels-Alder reactions with acetylene, ethylene and even benzene. Here we show that the reaction with benzene occurs cleanly at the relatively low temperature of 120 °C and results in the formal fragmentation of benzene into C2H2 and C4H4 units, via a unique Diels-Alder/retro-Diels-Alder reaction. This is a new example of the rare case where breaking the C-C bond of benzene is possible with no activation by a transition metal.

  1. A Diels–Alder super diene breaking benzene into C2H2 and C4H4 units

    PubMed Central

    Inagaki, Yusuke; Nakamoto, Masaaki; Sekiguchi, Akira

    2014-01-01

    Cyclic polyene with six carbon atoms (benzene) is very stable, whereas cyclic polyene with four carbon atoms (cyclobutadiene) is extremely unstable. The electron-withdrawing pentafluorophenyl group of a substituted cyclobutadiene lowers the energy of the lowest unoccupied molecular orbital, greatly increasing its reactivity as a diene in Diels–Alder reactions with acetylene, ethylene and even benzene. Here we show that the reaction with benzene occurs cleanly at the relatively low temperature of 120 °C and results in the formal fragmentation of benzene into C2H2 and C4H4 units, via a unique Diels–Alder/retro-Diels–Alder reaction. This is a new example of the rare case where breaking the C–C bond of benzene is possible with no activation by a transition metal. PMID:24398593

  2. Cholest-3,5-dien-7-one formation in peroxidized human plasma as an indicator of lipoprotein cholesterol peroxidation potential.

    PubMed

    Hahn, M; Tang, M; Subbiah, M T

    1995-04-06

    Lipoprotein peroxidation susceptibility is routinely evaluated using products of unsaturated fatty acids as markers (e.g., malonaldehyde). The significance and factors influencing peroxidation of cholesterol moiety of lipoproteins are relatively unknown due to lack of a reliable marker product which can be measured easily. Under the influence of Cu2+ ions, the major product of lipoprotein cholesterol peroxidation (isolated after saponification) was cholest-3-5-dien-7-one (CSD). Apart from gas-liquid chromatography, this compound lends itself for measurement by alternative methods. Due to lack of the 3 beta-hydroxyl group, CSD was separated from the rest of the oxysterols and cholesterol by passing through digitonin-coated silica-gel G and its concentration was determined by absorption at 283 nm. The recovery of CSD by this method exceeded by 87%. The formation of CSD was also sensitive to vitamin E and therefore could be used as an index of lipoprotein cholesterol susceptibility to peroxidation.

  3. The first chiral diene-based metal-organic frameworks for highly enantioselective carbon-carbon bond formation reactions

    SciTech Connect

    Sawano, Takahiro; Ji, Pengfei; McIsaac, Alexandra R.; Lin, Zekai; Abney, Carter W.; Lin, Wenbin

    2016-02-01

    We have designed the first chiral diene-based metal–organic framework (MOF), E₂-MOF, and postsynthetically metalated E₂-MOF with Rh(I) complexes to afford highly active and enantioselective single-site solid catalysts for C–C bond formation reactions. Treatment of E₂-MOF with [RhCl(C₂H₄)₂]₂ led to a highly enantioselective catalyst for 1,4-additions of arylboronic acids to α,β-unsaturated ketones, whereas treatment of E₂-MOF with Rh(acac)(C₂H₄)₂ afforded a highly efficient catalyst for the asymmetric 1,2-additions of arylboronic acids to aldimines. Interestingly, E₂-MOF·Rh(acac) showed higher activity and enantioselectivity than the homogeneous control catalyst, likely due to the formation of a true single-site catalyst in the MOF. E₂-MOF·Rh(acac) was also successfully recycled and reused at least seven times without loss of yield and enantioselectivity.

  4. Crystal structure of di-n-but-yl-bis-(η (5)-penta-methyl-cyclo-penta-dien-yl)hafnium(IV).

    PubMed

    Arndt, Perdita; Schubert, Kathleen; Burlakov, Vladimir V; Spannenberg, Anke; Rosenthal, Uwe

    2015-02-01

    The crystal structure of the title compound, [Hf(C10H15)2(C4H9)2], reveals two independent mol-ecules in the asymmetric unit. The diffraction experiment was performed with a racemically twinned crystal showing a 0.529 (5):0.471 (5) component ratio. Each Hf(IV) atom is coordinated by two penta-methyl-cyclo-penta-dienyl and two n-butyl ligands in a distorted tetra-hedral geometry, with the cyclo-penta-dienyl rings inclined to one another by 45.11 (15) and 45.37 (16)°. In contrast to the isostructural di(n-butyl)bis(η (5)-penta-methyl-cyclo-penta-dien-yl)zirconium(IV) complex with a noticeable difference in the Zr-butyl bonding, the Hf-Cbut-yl bond lengths differ from each other by no more than 0.039 (3) Å.

  5. Crystal structure of bis-(η(2)-ethyl-ene)(η(5)-penta-methyl-cyclo-penta-dien-yl)cobalt.

    PubMed

    Ramful, Chandika D; Robertson, Katherine N; Ylijoki, Kai E O

    2016-09-01

    The title compound, [Co(C10H15)(C2H4)2], was prepared by Na/Hg reduction of [Co2(C10H15)2(μ-Cl)2] in THF under an ethyl-ene atmosphere and crystallized from pentane at 193 K. The Co-C(olefin) bonds have an average length of 2.022 (2) Å, while the Co-C(penta-dien-yl) bonds average 2.103 (19) Å. The olefin C=C bonds are 1.410 (1) Å. The dihedral angle between the planes defined by the cyclo-penta-dienyl ligand and the two olefin ligands is 0.25 (12)°. In the crystal, mol-ecules are linked into chains by C-H⋯π inter-actions.

  6. Surface modification of argon/oxygen plasma treated vulcanized ethylene propylene diene polymethylene surfaces for improved adhesion with natural rubber

    NASA Astrophysics Data System (ADS)

    Basak, Ganesh C.; Bandyopadhyay, Abhijit; Neogi, Sudarsan; Bhowmick, Anil K.

    2011-01-01

    Vulcanized ethylene propylene diene polymethylene (EPDM) rubber surface was treated in a radio frequency capacitatively coupled low pressure argon/oxygen plasma to improve adhesion with compounded natural rubber (NR) during co-vulcanization. The plasma modified surfaces were analyzed by means of contact angle measurement, surface energy, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive X-ray sulfur mapping and atomic force microscopy. Several experimental variables such as plasma power, length of exposure time and composition of the argon-oxygen gas mixture were considered. It was delineated that plasma treatment changed both surface composition and roughness, and consequently increased peel strength. The change in surface composition was mainly ascribed to the formation of C-O and -Cdbnd O functional groups on the vulcanized surfaces. A maximum of 98% improvement in peel strength was observed after plasma treatment.

  7. Recyclization of 1-amino-3,5-diaryl-2,6,6-tricyanocyclohexa-1,3-dienes to pyridine derivatives

    SciTech Connect

    Abramenko, Yu.T.; Ivashchenko, A.V.; Nogaeva, K.A.; Sharanin, Yu.A.

    1986-11-01

    The base-catalyzed recyclization of 1-amino-3,5-diaryl-2,6,6-tricyanocyclohexa-1,3-dienes to 2,4-diaryl-5-cyano-6-dicyanomethylene-1,2,3,6-tetrahydropyridines, 4,6-diaryl-3-cyano-2-dicyanomethylene-1,2-dihydropyridines, and 4,6-diaryl-3-cyano-2-dicyanomethylpyridines has been investigated. The intermediate products of this reaction - cis,trans-2-amino,4,6-diaryl-1,1,3-tricyanohexa-1,3,5-trienes - have been isolated; on heating these are transformed reversibly into the initial cyclohexadienes or they isomerize irreversibly into trans,trans-hexatrienes, while in the presence of a base (piperidine, diethylamine, triethylamine, KOH), they cyclize to form the above-mentioned pyridine derivatives.

  8. Synthesis, crystal structure and properties of [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} with mixed-valent Ge centers

    SciTech Connect

    Yue, Cheng-Yang; Yuan, Zhuang-Dong; Zhang, Lu-Ge; Wang, Ya-Bai; Liu, Guo-Dong; Gong, Liao-Kuo; Lei, Xiao-Wu

    2013-10-15

    One new manganese thiogermanate, [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} (dien=diethylenetriamine), was prepared under mild solvothermal conditions and structurally and spectroscopically characterized. The title compound crystallizes in the orthorhombic system, chiral space group P2{sub 1}2{sub 1}2{sub 1} (no. 19) with a=9.113(4) Å, b=12.475(5) Å, c=17.077(7) Å, V=1941.5(15) Å{sup 3} and Z=4. Its structure features a three-dimensional (3D) network composed of a one-dimensional (1D) [Ge{sub 2}S{sub 4}]{sup 2−} anionic chain and a [(dien){sub 2}Mn]{sup 2+} complex interconnected via various hydrogen bonds. The most interesting structural feature of the compound is the presence of two different oxidation states of germanium centers in the 1D [Ge{sub 2}S{sub 4}]{sup 2−} chain, which is also supported by the result of X-ray photoelectron spectroscopy measurement. The optical property of the title compound has also been studied by UV–vis spectra. - Graphical abstract: One new thiogermanate, [(dien){sub 2}Mn]Ge{sub 2}S{sub 4}, contains a one-dimensional [Ge{sub 2}S{sub 4}]{sup 2−} anionic chain with two different oxidation states of germanium centers. Display Omitted - Highlights: • One new manganese thiogermanate [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} was prepared. • The compound features 1D [Ge{sub 2}S{sub 4}]{sup 2−} chain composed of [Ge{sup II}S{sub 4}] and [Ge{sup IV}S{sub 4}] tetrahedra. • The first example of inorganic–organic hybrid thiogermanates with mixed valent Ge centers.

  9. Environmental health risk assessment of dioxin exposure through foods in a dioxin hot spot-Bien Hoa City, Vietnam.

    PubMed

    Tuyet-Hanh, Tran Thi; Vu-Anh, Le; Ngoc-Bich, Nguyen; Tenkate, Thomas

    2010-05-01

    This study used the Australian Environmental Health Risk Assessment Framework to assess the human health risk of dioxin exposure through foods for local residents in two wards of Bien Hoa City, Vietnam. These wards are known hot-spots for dioxin and a range of stakeholders from central government to local levels were involved in this process. Publications on dioxin characteristics and toxicity were reviewed and dioxin concentrations in local soil, mud, foods, milk and blood samples were used as data for this risk assessment. A food frequency survey of 400 randomly selected households in these wards was conducted to provide data for exposure assessment. Results showed that local residents who had consumed locally cultivated foods, especially fresh water fish and bottom-feeding fish, free-ranging chicken, duck, and beef were at a very high risk, with their daily dioxin intake far exceeding the tolerable daily intake recommended by the WHO. Based on the results of this assessment, a multifaceted risk management program was developed and has been recognized as the first public health program ever to have been implemented in Vietnam to reduce the risks of dioxin exposure at dioxin hot-spots.

  10. Oxidative Cyclization of 1,5-Dienes with Hydrogen Peroxide Catalyzed by an Osmium(III) Complex: Synthesis of cis-Tetrahydrofurans.

    PubMed

    Sugimoto, Hideki; Kanetake, Takayuki; Maeda, Kazuki; Itoh, Shinobu

    2016-03-18

    Stereoselective oxidative cyclization of 1,5-dienes with hydrogen peroxide catalyzed by [Os(III)(OH)(H2O)(L-N4Me2)](PF6)2 (1: L-N4Me2 = N,N'-dimethyl-2,11-diaza-[3,3](2,6)pyridinophane) is explored. 1,5-Dienes involving geraniol derivatives are converted to the corresponding tetrahydrofurans in modest to high yields. The products exclusively have the cis-conformation with respect to the substituents at the 2- and 5-positions of the tetrahydrofuran ring. The products also have a syn-conformation with respect to the furan oxygen atom and the hydroxyl groups. Mechanistic studies including a direct reaction of the oxo-hydroxo-osmium(V) complex, 2, with a dihydroxylated geraniol derivative are performed.

  11. Crystal structure of trans-1,4-bis-[(tri-methyl-sil-yl)-oxy]cyclo-hexa-2,5-diene-1,4-dicarbo-nitrile.

    PubMed

    Glöcklhofer, Florian; Fröhlich, Johannes; Stöger, Berthold; Weil, Matthias

    2014-08-01

    The asymmetric unit of the title compound, C14H22N2O2Si2, contains one half of the mol-ecule, which is completed by inversion symmetry. The cyclo-hexa-2,5-diene ring is exactly planar and reflects the bond-length distribution of a pair of located double bonds [1.3224 (14) Å] and two pairs of single bonds [1.5121 (13) and 1.5073 (14) Å]. The tetra-hedral angle between the sp (3)-C atom and the two neighbouring sp (2)-C atoms in the cyclo-hexa-2,5-diene ring is enlarged by about 3°.

  12. Acyclic diene metathesis with a monomer from renewable resources: control of molecular weight and one-step preparation of block copolymers.

    PubMed

    Rybak, Anastasiya; Meier, Michael A R

    2008-01-01

    The preparation of a long-chain aliphatic alpha,omega-diene from plant oil derivatives and its subsequent polymerization through acyclic diene metathesis (ADMET) is described. The ADMET bulk polymerization of the thus-obtained monomer, undecyl undecenoate, was investigated and optimized by applying ruthenium-based metathesis catalysts from Grubbs and Hoveyda-Grubbs, leading to high-molecular-weight polyesters. Moreover, by applying different amounts of methyl 10-undecenoate as a chain stopper in this ADMET step growth polymerization, the molecular weight of the resulting polyester could be tuned in a range from approximately 10 to 45 kDa. Finally, the application of a poly(ethylene glycol) methyl ether acrylate as the chain stopper led to the preparation of ABA triblock copolymers in a one-step, one-pot procedure.

  13. Absolute configuration of falcarinol (9Z-heptadeca-1,9-diene-4,6-diyn-3-ol) from Pastinaca sativa.

    PubMed

    Corell, Mireia; Sheehy, Emile; Evans, Paul; Brunton, Nigel; Valverde, Juan

    2013-08-01

    Falcarinol (9Z-heptadeca-1,9-diene-4,6-diyn-3-ol; (1) is a polyacetylene commonly found in several plant families. The absolute configuration of naturally occurring 1 is not clear and contradictory results have been reported in the literature. Determination of the absolute configuration of 1 from Pastinaca sativa L. was carried out. Isolation of 95% pure 1 was performed via successive fractionation and preparative-HPLC. A racemic mixture comprised of 3R-1 and 3S-1 was synthesized in order to confirm the absolute configuration of the isolated natural product using chiral HPLC. Based on a combination of chiral HPLC and specific rotation, 1 present in P. saliva was found to have a 3R absolute configuration (i.e. (3R, 9Z)-heptadeca-1,9-diene-4,6-diyn-3-ol).

  14. B(C6F5)3: A New Class of Strong and Bulky Lewis Acid for Exo-Selective Intermolecular Diels-Alder Reactions of Unreactive Acyclic Dienes with α,β-Enals.

    PubMed

    Zhou, Jia-Hui; Jiang, Bing; Meng, Fei-Fan; Xu, Yun-He; Loh, Teck-Peng

    2015-09-18

    Lewis acid B(C6F5)3 catalyzed the Diels-Alder reactions of multisubstituted open-chain dienes and α,β-enals to afford the desired products with high exo-selectivities are reported. The substituent effect of the dienes and dienophiles on the product's stereoselectivity was thoroughly investigated, and it was found that most of the desired exo-Diels-Alder products could be obtained in good yields and with high exo-stereoselectivities.

  15. Synthesis and biochemical studies of 7 alpha-substituted androsta-1,4-diene-3,17-diones as enzyme-activated irreversible inhibitors of aromatase.

    PubMed

    Ebrahimian, S; Chen, H H; Brueggemeier, R W

    1993-09-01

    Several 7 alpha-thiosubstituted derivatives of androstenedione have demonstrated effective inhibition of aromatase, the cytochrome P450 enzyme complex responsible for the biosynthesis of estrogens. Introduction of an additional double bond in the A ring resulted in 7 alpha-(4'-amino)phenylthioandrosta-1,4-diene-3,17-dione (7 alpha-APTADD), a potent inhibitor that inactivated aromatase by an enzyme-catalyzed process. Additional 7 alpha-thiosubstituted androsta-1,4-diene-3,17-dione derivatives were designed to further examine enzyme-catalyzed inactivation. Two halogenated and one unsubstituted 7 alpha-phenylthioandrosta-1,4-diene-3,17-diones were synthesized via an acid-catalyzed conjugate Michael addition of substituted thiophenols with androsta-1,4,6-triene-3,17-dione. Two 7 alpha-naphthylthioandrosta-1,4-diene-3,17-diones were synthesized via either acid-catalyzed or based-catalyzed conjugate Michael addition of substituted thionaphthols with androsta-1,4,6-triene-3,17-dione. These agents were evaluated for aromatase inhibitory activity in the human placental microsomal preparation. Under initial velocity assay conditions of low product formation, the inhibitors demonstrated potent inhibition of aromatase, with apparent Ki's ranging from 12 to 27 nM. Furthermore, these compounds produced time-dependent, first-order inactivation of aromatase in the presence of NADPH, whereas no aromatase inactivation was observed in the absence of NADPH. This enzyme-activated irreversible inhibition, also referred to as mechanism-based inhibition, can be prevented by the substrate androstenedione. Thus, the apparent Ki values for these inhibitors are consistent with earlier studies on 7 alpha-substituted competitive inhibitors that indicate bulky substituents can be accommodated at the 7 alpha-position.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Synthesis of Tetraphenylstrannacy-clopentadienes (Stannoles). III. Attempted Route to the Parent Stannoles through Closure of 1,4-Dichlorobuta-1,3-diene.

    DTIC Science & Technology

    1980-10-01

    Journal of Organometallic Chemistry I$. SUPPLEMENTARY NOTES 19. KEY WORDS (Continue on reverse side /I necessary and Identfly by block naemb.,) Organotin ...Metalloles, Stannoles, Siloles, l,4-Dicblorobuta-1,3-diene, Lithiation, Organochlorosilanes, Organotin chlorides, Dehydrochlorination, Multiple bond...material. The infusible white solid polymer leaves no silicon or tin(IV) oxide residue on burning, and exhibits in its infrared spectrum absorption bands

  17. Phosphine-catalyzed [4+1] annulation of 1,3-(aza)dienes with maleimides: highly efficient construction of azaspiro[4.4]nonenes.

    PubMed

    Yang, Mei; Wang, Tianyi; Cao, Shixuan; He, Zhengjie

    2014-11-14

    Phosphine-catalyzed [4+1] annulation of electron-deficient 1,3-dienes or 1,3-azadienes with maleimides has been successfully developed under very mild conditions, providing a convenient and highly efficient method for constructing 2-azaspiro[4.4]nonenes and 1,7-diazaspiro[4.4]nonenes. This reaction represents the first example of [4+1] cyclization between electron-deficient 4π-conjugated systems and non-allylic phosphorus ylides.

  18. Regio-, Diastereo-, and Enantioselective Nitroso-Diels-Alder Reaction of 1,3-Diene-1-carbamates Catalyzed by Chiral Phosphoric Acids.

    PubMed

    Pous, Jonathan; Courant, Thibaut; Bernadat, Guillaume; Iorga, Bogdan I; Blanchard, Florent; Masson, Géraldine

    2015-09-23

    Chiral phosphoric acid-catalyzed asymmetric nitroso-Diels-Alder reaction of nitrosoarenes with carbamate-dienes afforded cis-3,6-disubstituted dihydro-1,2-oxazines in high yields with excellent regio-, diastereo-, and enantioselectivities. Interestingly, we observed that the catalyst is able not only to control the enantioselectivity but also to reverse the regioselectivity of the noncatalyzed nitroso-Diels-Alder reaction. The regiochemistry reversal and asynchronous concerted mechanism were confirmed by DFT calculations.

  19. Theoretical investigation of the stereochemistry of the polymerization of. cap alpha. -olefins and dienes with the participation of Ziegler-Natta catalysts

    SciTech Connect

    Minsker, K.S.; Karpasas, M.M.

    1986-09-01

    The processes involved in the formation of the active polymerization sites in heterogeneous Ziegler-Natta catalysts have been investigated with consideration of the real structure of the components by the atom-atom potential method, the Monte-Carlo method, a modified diatomics-in-molecules method, and the CNDO/2 method with the aid of the available experimental facts. It has been shown that three types of bimetallic active sites (AS), which differ with respect to the spatial configuration of the coordination sphere, viz., AS-1, AS-2, and AS-3, form, depending on the electronic structure of the homogeneous component R /SUB n/ M, the ionic radius of M (M is a metal from groups I-III), and the unit-cell parameters of the heterogeneous component MeX /SUB m/ (Me is a transition metal from groups IV-VIII). Only the AS-1 sites are stereospecific in the polymerization of ..cap alpha..-olefins and 1,3-dienes (isotactic polyolefins and 1,4-trans-polydienes form); the AS-2 sites are nonstereospecific in the polymerization of ..cap alpha..-olefins, but they form stereoregular 1,4-cis-polydienes; the AS-3 sites are nonstereospecific in the polymerization of both ..cap alpha..-olefins and 1,3-dienes. The phenomenon of stereoregularization in the polymerization of ..cap alpha..-olefins and 1,3-dienes is determined by the steric and electrostatic factors.

  20. Solvothermal syntheses, crystal structures, and properties of lanthanide(III) thioarsenates [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} (Ln==Sm, Eu, Gd) and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] (Ln==Tb, Dy, Ho)

    SciTech Connect

    Wang, Fang; Tang, Chunying; Chen, Ruihong; Zhang, Yong; Jia, Dingxian

    2013-10-15

    Solvothermal reactions of Ln{sub 2}O{sub 3}, As and S in diethylenetriamine (dien) at 170 °C for 6 days afforded two structural types of lanthanide thioarsenates with the general formulae [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} [Ln=Sm(1), Eu(2), Gd(3)] and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] [Ln=Tb(4), Dy(5), Ho(6)]. The Ln{sub 2}O{sub 3} oxides were converted to [Ln(dien){sub 2}]{sup 3+} complex units in the solvothermal reactions. The As atom binds four S atoms, forming a tetrahedral AsS{sub 4} unit. In 1−3, the AsS{sub 4} units interconnect the [Ln(dien){sub 2}]{sup 3+} cations via Ln−S bonds as tridentate μ-1κ,2κ{sup 2}-AsS{sub 4} bridging ligands, resulting in the neutral coordination polymers [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} (Ln1). In 4−6, the AsS{sub 4} units coordinate with the Ln{sup 3+} ion of [Ln(dien){sub 2}]{sup 3+} as 1κ{sup 2}-AsS{sub 4} chelating ligands to form neutral coordination compounds [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] (Ln2). The Ln{sup 3+} ions are in nine- and eight-coordinated environments in Ln1 and Ln2, respectively. The formation of Ln1 and Ln2 is related with ionic size of the Ln{sup 3+} ions. Optical absorption spectra showed that 1−6 have potential use as semiconductors with the band gaps in the range 2.18−3.21 eV. - Graphical abstract: Two types of Ln-thioarsenates [Ln(dien){sub 2}(μ-1κ,2κ{sup 2}-AsS{sub 4})]{sub n} and [Ln(dien){sub 2}(1κ{sup 2}-AsS{sub 4})] were prepared by solvothermal methods and the soft Lewis basic AsS{sub 4}{sup 3–} ligand to Ln(III) centers with polyamine co-ligand was obtained. Display Omitted - Highlights: • Lanthanide thioarsenates were prepared by solvothermal methods. • The soft Lewis basic AsS{sub 4} ligand coordinate Ln{sup 3+} ions with coexistence polyamine ligands. • Two structural types of Ln-thioarsenates with structural turnover at Tb were obtained along Ln series. • The Ln-thioarsenates are potential semiconductors

  1. Estimating regio and stereoselectivity in [4+2] cycloadditions of vinyl-substituted cyclic dienes with maleic anhydride.

    PubMed

    Gayatri, Gaddamanugu; Sastry, G Narahari

    2009-10-29

    Density functional theory calculations are performed to examine the regio and stereoselective preferences in [4+2] cycloaddition reactions of vinyl cyclopentadiene (1 and 2) and vinyl heterocyclic (1-N, 1-O, 1-S, 2-N, 2-O and 2-S) systems with maleic anhydride. Stepwise and concerted pathways of model systems 1 and 2 as dienes with ethylene as dienophile reveal that the reactions proceed through asynchronous and concerted pathway. 3-Vinyl systems (2) are predicted to be more reactive compared to 2-vinyl systems (1). The regio and stereoselective preferences are evaluated based on activation energies, reaction energies, density functional based descriptors and atoms in molecules analysis. In all cases, extra-annular cycloadducts are more feasible compared to intra-annular cycloadducts. Stereoselectivity depends on the favorable secondary orbital interactions. Solvents such as water, tetrahydrofuran, acetone, and dimethyl sulphoxide are employed to understand the effects of solvents on the cycloadduct formation. The computational results thus obtained are compared with the earlier experimental observations that are available.

  2. Metal Catalysis in Thiolation and Selenation Reactions of Alkynes Leading to Chalcogen‐Substituted Alkenes and Dienes

    PubMed Central

    2015-01-01

    Abstract This review covers recent achievements in metal‐catalyzed Z−H and Z−Z (Z=S, Se) bond addition to the triple bonds of alkynes—a convenient and atom‐efficient way to carbon‐element bond formation. Various catalytic systems (both homogeneous and heterogeneous) developed to date to obtain mono‐ and bis‐chalcogen‐substituted alkenes or dienes, as well as carbonyl compounds or heterocycles, starting from simple and available alkynes and chalcogenols or dichalcogenides are described. The right choice of metal and ligands allows us to perform these transformations with high selectivities under mild reaction conditions, thus tolerating unprotected functional groups in substrates and broadening ways of further modification of the products. The main aim of the review is to show the potential of the catalytic methods developed in synthetic organic chemistry. Thus, emphasis is made on the scope of reactions, types of products that can be selectively formed, convenience, and scalability of the catalytic procedures. A brief mechanistic description is also given to introduce new readers to the topic. PMID:27308193

  3. Diene Valepotriates from Valeriana glechomifolia Prevent Lipopolysaccharide-Induced Sickness and Depressive-Like Behavior in Mice

    PubMed Central

    Müller, Liz G.; Borsoi, Milene; Stolz, Eveline D.; Herzfeldt, Vivian; Viana, Alice F.; Ravazzolo, Ana Paula; Rates, Stela Maris K.

    2015-01-01

    Valeriana glechomifolia, a native species from southern Brazil, presents antidepressant-like activity and diene valepotriates (VAL) contribute to the pharmacological properties of the genus. It is known that depression can develop on an inflammation background in vulnerable patients and antidepressants present anti-inflammatory properties. We investigated the effects of VAL (10 mg/kg, p.o.) on sickness and depressive-like behaviors as well as proinflammatory cytokines (IL-1β and TNF-α) and BDNF expression in the cortex of mice exposed to a 5 min swimming session (as a stressful stimulus) 30 min before the E. coli LPS injection (600 µg/kg, i.p.). The forced swim + LPS induced sickness and depressive-like behaviors, increased the cortical expression of IL-1β and TNF-α, and decreased BDNF expression. VAL was orally administered to mice 1 h before (pretreatment) or 5 h after (posttreatment) E. coli LPS injection. The pretreatment with VAL restored the behavioral alterations and the expression of cortical proinflammatory cytokines in LPS-injected animals but had no effects on BDNF expression, while the posttreatment rescued only behavioral alterations. Our results demonstrate for the first time the positive effects of VAL in an experimental model of depression associated with inflammation, providing new data on the range of action of these molecules. PMID:26170871

  4. Radiation processed polychloroprene-co-ethylene-propene diene terpolymer blends: Effect of radiation vulcanization on solvent transport kinetics

    NASA Astrophysics Data System (ADS)

    Dubey, K. A.; Bhardwaj, Y. K.; Chaudhari, C. V.; Kumar, Virendra; Goel, N. K.; Sabharwal, S.

    2009-03-01

    Blends of polychloroprene rubber (PCR) and ethylene propylene diene terpolymer rubber (EPDM) of different compositions were made and exposed to different gamma radiation doses. The radiation sensitivity and radiation vulcanization efficiency of blends was estimated by gel-content analysis, Charlesby-Pinner parameter determination and crosslinking density measurements. Gamma radiation induced crosslinking was most efficient for EPDM ( p0/ q0 ˜ 0.08), whereas it was the lowest for blends containing 40% PCR ( p0/ q0 ˜ 0.34). The vulcanized blends were characterized for solvent diffusion characteristics by following the swelling dynamics. Blends with higher PCR content showed anomalous swelling. The sorption and permeability of the solvent were not strictly in accordance with each other and the extent of variation in two parameters was found to be a function of blend composition. The Δ G values for solvent diffusion were in the range -2.97 to -9.58 kJ/mol and indicated thermodynamically favorable sorption for all blends. These results were corroborated by dynamic swelling, experimental as well as simulated profiles and have been explained on the basis of correlation between crosslinking density, diffusion kinetics, thermodynamic parameters and polymer-polymer interaction parameter.

  5. Assessment of the role of in situ generated (E)-2,4-diene-valproic acid in the toxicity of valproic acid and (E)-2-ene-valproic acid in sandwich-cultured rat hepatocytes

    SciTech Connect

    Surendradoss, Jayakumar; Chang, Thomas K.H.; Abbott, Frank S.

    2012-11-01

    Valproic acid (VPA) undergoes cytochrome P450-mediated desaturation to form 4-ene-VPA, which subsequently yields (E)-2,4-diene-VPA by β-oxidation. Another biotransformation pathway involves β-oxidation of VPA to form (E)-2-ene-VPA, which also generates (E)-2,4-diene-VPA by cytochrome P450-mediated desaturation. Although the synthetic form of (E)-2,4-diene-VPA is more hepatotoxic than VPA as shown in various experimental models, there is no conclusive evidence to implicate the in situ generated (E)-2,4-diene-VPA in VPA hepatotoxicity. The present study investigated the effects of modulating the in situ formation of (E)-2,4-diene-VPA on markers of oxidative stress (formation of 2′,7′-dichlorofluorescein; DCF), steatosis (accumulation of BODIPY 558/568 C{sub 12}), necrosis (release of lactate dehydrogenase; LDH), and on cellular total glutathione (GSH) levels in sandwich-cultured rat hepatocytes treated with VPA or (E)-2-ene-VPA. Treatment with either of these chemicals alone increased each of the toxicity endpoints. In VPA-treated hepatocytes, (E)-2,4-diene-VPA was detected only at trace levels, even after phenobarbital (PB) pretreatment and there was no effect on the toxicity of VPA. Furthermore, pretreatment with a cytochrome P450 enzyme inhibitor, 1-aminobenzotriazole (1-ABT), did not influence the extent of VPA toxicity in both PB-pretreated and vehicle-pretreated hepatocytes. However, in (E)-2-ene-VPA-treated hepatocytes, PB pretreatment greatly enhanced the levels of (E)-2,4-diene-VPA and this was accompanied by a further enhancement of the effects of (E)-2-ene-VPA on DCF formation, BODIPY accumulation, LDH release, and GSH depletion. Pretreatment with 1-ABT reduced the concentrations of (E)-2,4-diene-VPA and the extent of (E)-2-ene-VPA toxicity; however, this occurred in PB-pretreated hepatocytes, but not in control hepatocytes. In conclusion, in situ generated (E)-2,4-diene-VPA is not responsible for the hepatocyte toxicity of VPA, whereas it

  6. The presence of amorpha-4, 11-diene synthase, a key enzyme in artemisinin production in ten Artemisia species

    PubMed Central

    Hosseini, R.; Yazdani, N.; Garoosi, GA.

    2011-01-01

    Background and the purpose of the study Artemisinin is one of the most effective medicine against malaria, which is produced naturally by Artemisia annua in low yield. It is produced in a metabolic pathway, in which several genes and gene products are involved. One of the key genes in this pathway is am1, which encodes amorpha-4, 11-diene synthase (ADS), a key enzyme in artemisinin biosynthesis pathway. The aim of this study was to determine the presence of this gene in ten Artemisia species in order to increase the yield of production of Artemisinin. Methods The experiments were carried out using PCR. Specific primers were designed based on the published am1 gene sequence obtained from A. annua (NCBI, accession number AF327527). Results The amplification of this gene by the specific primers was considered as a positive sign for the potentiality of artemisinin production. Since the entire am1 gene was not amplified in any of the 10 species used, four parts of the gene, essential in ADS enzyme function, corresponding to a) pair site of Arg10-Pro12 in the first 100 amino acids, b) aspartate rich motif (DDXXD), c) active site final lid and d) active site including farnesyl diphosphate (FDP) ionization sites and catalytic site in the ADS enzyme, were investigated. Major conclusion The sequence corresponding to ADS active site was amplified only in A. annua, A. aucheri and A. chamaemelifolia. The negative results obtained with other species could be due to some sequence alteration, such as point mutations or INDELs. We propose A. aucheri and A. chamaemelifolia as two potential candidate species for further characterization, breeding and transferring am1 gene for artemisinin overproduction. PMID:22615678

  7. The Labdane Ent-3-Acetoxy-Labda-8(17), 13-Dien-15-Oic Decreases Blood Pressure In Hypertensive Rats

    PubMed Central

    Simplicio, Janaina A.; Simão, Marilia R.; Ambrosio, Sergio R.; Tirapelli, Carlos R.

    2016-01-01

    Background Labdane-type diterpenes induce lower blood pressure via relaxation of vascular smooth muscle; however, there are no studies describing the effects of labdanes in hypertensive rats. Objective The present study was designed to investigate the cardiovascular actions of the labdane-type diterpene ent-3-acetoxy-labda-8(17), 13-dien-15-oic acid (labda-15-oic acid) in two-kidney 1 clip (2K-1C) renal hypertension. Methods Vascular reactivity experiments were performed in aortic rings isolated from 2K-1C and normotensive (2K) male Wistar rats. Nitrate/nitrite (NOx) measurement was performed in aortas by colorimetric assay. Blood pressure measurements were performed in conscious rats. Results Labda-15-oic acid (0.1-300 µmol/l) and forskolin (0.1 nmol/l - 1 µmol/l) relaxed endothelium-intact and endothelium-denuded aortas from both 2K-1C and 2K rats. Labda-15-oic acid was more effective at inducing relaxation in endothelium-intact aortas from 2K pre-contracted with phenylephrine when compared to the endothelium-denuded ones. Forskolin was more potent than labda-15-oic acid at inducing vascular relaxation in arteries from both 2K and 2K-1C rats. Labda-15-oic acid-induced increase in NOx levels was lower in arteries from 2K-1C rats when compared to 2K rats. Intravenous administration of labda-15-oic acid (0.3-3 mg/kg) or forskolin (0.1-1 mg/kg) induced hypotension in conscious 2K-1C and 2K rats. Conclusion The present findings show that labda-15-oic acid induces vascular relaxation and hypotension in hypertensive rats. PMID:27096521

  8. On the mechanism of the Di-. pi. -methane rearrangement of bicyclo(3. 2. 1)octa-2,6-diene: Deuterium labeling and generation of diradical intermediates via photolysis and thermolysis of appropriate azoalkanes

    SciTech Connect

    Adam, W.; Doerr, M. ); De Lucchi, O. )

    1989-07-05

    The direct (254 nm) and acetone-sensitized (300 nm) photolyses of 2,4,4-trideuteriobicyclo(3.2.1)octa-2,6-diene (D-1) gave exclusively 3,5,5-trideuteriotricyclo(4.2.0.0)oct-3-ene (D-7) and 2,6,6-trideuteriotricyclo(3.2.1.0)oct-3-ene (D-8) but no rearranged diene, namely, 2,8,8-trideuteriobicyclo(3.2.1)octa-2,6-diene (D-1{prime}). Pyrolysis (400{degree}C) and direct (334 nm) and benzophenone-sensitized (364 nm) photolyses of the azoalkane 3,5,5-trideuterio-9,10-diazatricyclo(4.4.0.0)deca-3,9-diene (D-9) afforded a mixture of tricyclooctenes D-7 (major product) and D-8 and bicyclooctadiene D-1, but no rearranged diene D-1{prime}. These three modes of denitrogenation of the azoalkane 2,2,7-trideuterio-4,5-diazatricyclo(4.3.1.0)deca-4,8-diene (D-10) led only to the tricyclooctene D-8 (major product) and equal amounts of the bicyclooctadienes D-1 and D-1{prime}. Distinct temperature profiles were observed in the product fingerprints of the direct photolysis (334 nm) of the azoalkanes 9 and 10. For both azoalkanes 9 and 10 the quantum yields of denitrogenation increased with rising temperature. In none of these transformations could bicyclo(3.3.0)octa-2,7-diene (2) be detected. These results imply that the di-{pi}-methane rearrangement of the bicyclooctadienes 1 (D-1) and the denitrogenations of the azoalkanes 9 (D-9) and 10 (D-10) are disjoint chemical events. The intervention of diazenyl diradicals (one-bond cleavage of the azoalkanes) is postulated to be responsible for this disparity. The intervention of cyclopropyldicarbinyl diradical 3 as bona fide reaction intermediate in the di-{pi}-methane rearrangement of bicyclooctadiene 1 is questioned.

  9. Asymmetric [4 + 3] cycloadditions between vinylcarbenoids and dienes: application to the total synthesis of the natural product (-)-5-epi-vibsanin E.

    PubMed

    Schwartz, Brett D; Denton, Justin R; Lian, Yajing; Davies, Huw M L; Williams, Craig M

    2009-06-17

    The total synthesis of (-)-5-epi-vibsanin E (2) has been achieved in 18 steps. The synthesis combines the rhodium-catalyzed [4 + 3] cycloaddition between a vinylcarbenoid and a diene to rapidly generate the tricyclic core with an effective end game strategy to introduce the remaining side-chains. The [4 + 3] cycloaddition occurs by a cyclopropanation to form a divinylcyclopropane followed by a Cope rearrangement to form a cycloheptadiene. The quaternary stereogenic center generated in the process can be obtained with high asymmetric induction when the reaction is catalyzed by the chiral dirhodium complex, Rh(2)(S-PTAD)(4).

  10. 1,4-Bis(4-bromo-2,6-diisopropyl­phen­yl)-1,4-diaza­buta-1,3-diene

    PubMed Central

    Guzei, Ilia A.; Hill, Nicholas J.; Van Hout, Matthew R.

    2010-01-01

    The molecule of the title compound, C26H34Br2N2, lies on a crystallographic inversion center and hence the two imine groups are s-trans. The dihedral angle between the central 1,4-diaza­buta-1,3-diene unit and the attached substituted phenyl ring is 88.4 (7)°. The structure features a C—H⋯N close contact. The crystal selected for this study proved to be a non-merohedral twin with a minor component of 21.8 (3)%. PMID:21580146

  11. Crystal structure of dimethyl 3,4,5,6-tetra-phenyl-cyclo-hexa-3,5-diene-1,2-di-carboxyl-ate.

    PubMed

    Greenberg, Fred H; Nazarenko, Alexander Y

    2016-07-01

    In the title compound, C34H28O4, the cyclo-hexa-diene ring has a screw-boat conformation with a torsion angle between the double bonds being on average ca 15° [15.2 (3) and -15.3 (3) in the two independent mol-ecules]. All four phenyl rings in both mol-ecules are arranged in a propeller-like conformation. The two mol-ecules exhibit S,R- and R,S- chirality, respectively, and are connected via C-H⋯O inter-molecular inter-actions. In turn, these weakly bound dimers form the mol-ecular crystal.

  12. Heat of Mixing and Solution of Cyclohexa-1,3-diene C6H8 + C12H22 Bicyclohexyl (HMSD1111, LB4033_H)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of Cyclohexa-1,3-diene C6H8 + C12H22 Bicyclohexyl (HMSD1111, LB4033_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  13. Heat of Mixing and Solution of Cyclohexa-1,3-diene C6H8 + C12H16 Cyclohexylbenzene (HMSD1111, LB4039_H)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of Cyclohexa-1,3-diene C6H8 + C12H16 Cyclohexylbenzene (HMSD1111, LB4039_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  14. Spectroscopic studies of [M(CO) 5M'(CO) 3(1,4-diazabuta-1,3-diene)] (M,M' = Mn, Re) and their photolysis products

    NASA Astrophysics Data System (ADS)

    Kokkes, M. W.; Brouwers, A. M. F.; Stufkens, D. J.; Oskam, A.

    1984-03-01

    Photolysis of [M(CO) 5M'(CO) 3(dab)] (M, M' = Mn, Re; dab = 1,4-diazabuta-1,3-diene, RNCHCHNR) in 2-Me-THF leads to both homolytic and heterolytic splitting of the metalmetal bond depending on the solution temperature. In a rigid medium such as a CH 4-matrix no breaking of the metalmetal bond is observed but instead formation of [M(CO) 3M'(CO) 3(dab)] in which compound the dab-ligand is σ,σ,π,π bridging between M and M'.

  15. Volumetric Properties of the Mixture Cyclohexa-1,3-diene C6H8 + C12H16 Cyclohexylbenzene (VMSD1211, LB3967_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexa-1,3-diene C6H8 + C12H16 Cyclohexylbenzene (VMSD1211, LB3967_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  16. Volumetric Properties of the Mixture Cyclohexa-1,3-diene C6H8 + C12H22 Bicyclohexyl (VMSD1211, LB3961_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexa-1,3-diene C6H8 + C12H22 Bicyclohexyl (VMSD1211, LB3961_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  17. Rhodium/chiral diene-catalyzed asymmetric 1,4-addition of arylboronic acids to chromones: a highly enantioselective pathway for accessing chiral flavanones.

    PubMed

    He, Qijie; So, Chau Ming; Bian, Zhaoxiang; Hayashi, Tamio; Wang, Jun

    2015-03-01

    Chromone has been noted to be one of the most challenging substrates in the asymmetric 1,4-addition of α,β-unsaturated carbonyl compounds. By employing the rhodium complex associated with a chiral diene ligand, (R,R)-Ph-bod*, the 1,4-addition of a variety of arylboronic acids was realized to give high yields of the corresponding flavanones with excellent enantioselectivities (≥97% ee, 99% ee for most substrates). Ring-opening side products, which would lead to erosion of product enantioselectivity, were not observed under the stated reaction conditions.

  18. Synthesis of 2-Aryl- and 2-Vinylpyrrolidines via Copper-Catalyzed Coupling of Styrenes and Dienes with Potassium β-Aminoethyl Trifluoroborates.

    PubMed

    Um, Chanchamnan; Chemler, Sherry R

    2016-05-20

    2-Arylpyrrolidines occur frequently in bioactive compounds, and thus, methods to access them from readily available reagents are valuable. We report a copper-catalyzed intermolecular carboamination of vinylarenes with potassium N-carbamoyl-β-aminoethyltrifluoroborates. The reaction occurs with terminal, 1,2-disubstituted, and 1,1-disubstituted vinylarenes bearing a number of functional groups. 1,3-Dienes are also good substrates, and their reactions give 2-vinylpyrrolidines. Radical clock mechanistic experiments are consistent with the presence of carbon radical intermediates and do not support participation of carbocations.

  19. [Overexpressing 3-ketosteroid-Δ1-dehydrogenase for degrading phytosterols into androst-1,4-diene-3,17-dione].

    PubMed

    Zhang, Lele; Zhang, Xian; Shao, Minglong; Chen, Rongrong; Rao, Zhiming; Li, Hu; Xu, Zhenghong

    2015-11-01

    We constructed plasmid pMTac to overexpress 3-ketosteroid-Δ1-dehydrogenase (KSDD) in Mycobacterium neoaurum JC-12 for improving androst-1,4-diene-3,17-dione (ADD) production. To construct pMTac, pACE promoter on pMF41 was replaced by tac promoter, and then four recombinants were constructed, which were M. neoaurum JC-12/pMF41-gfp, M. neoaurum JC-12/pMTac-gfp, M. neoaurum JC-12/pMF41-ksdd and M. neoaurum JC-12/pMTac-ksdd. Fluorescence detection results show that much more green fluorescent protein (GFP) was expressed in M. neoaurum JC-12/pMTac-ksdd than M. neoaurum JC-12/pMF41-ksdd. The activity of KSDD was 2.41 U/mg in M. neoaurum JC-12/pMTac-ksdd, 6.53-fold as that of M. neoaurum JC-12 and 4.36-fold as that of M. neoaurum JC-12/pMF41-ksdd. In shake flask fermentation, ADD production of M. neoaurum JC-12/pMTac-ksdd was 5.94 g/L, increased about 22.2% compared to the original strain M. neoaurum JC-12 and 12.7% to M. neoaurum JC-12/pMF41-ksdd. AD (4-androstene-3,17-dione) production of JC-12/pMTac-ksdd was 0.17 g/L, decreased 81.5% compared to M. neoaurum JC-12 and 71.2% to M neoaurum JC-12/pMF41-ksdd. In the 5 L fermenter, 20 g/L phytosterols was used as substrate, ADD production of M. neoaurum JC-12/pMTac-ksdd was improved to 10.28 g/L. pMTac is favorable for expressing KSDD in M. neoaurum JC-12, and overexpression of KSDD has beneficial effect on ADD producing, and it is the highest level ever reported using fermentation method in M. neoaurum.

  20. Subphthalocyanines Axially Substituted with a Tetracyanobuta-1,3-diene-Aniline Moiety: Synthesis, Structure, and Physicochemical Properties.

    PubMed

    Winterfeld, Kim A; Lavarda, Giulia; Guilleme, Julia; Sekita, Michael; Guldi, Dirk M; Torres, Tomás; Bottari, Giovanni

    2017-04-06

    A 1,1,4,4-tetracyanobuta-1,3-diene (TCBD)-aniline moiety has been introduced, for the first time, at the axial position of two subphthalocyanines (SubPcs) peripherally substituted with hydrogen (H12SubPc) or fluorine atoms (F12SubPc). Single-crystal X-ray analysis of both SubPc-TCBD-aniline systems showed that each conjugate is a racemic mixture of two atropisomers resulting from the almost orthogonal geometry adopted by the axial TCBD unit, which were separated by chiral high-performance liquid chromatography. Remarkably, the single-crystal X-ray structure of one atropisomer of each SubPc-TCBD-aniline conjugate has been solved, allowing to unambiguously assign the atropisomers' absolute configuration, something, to the best of our knowledge, unprecedented in TCBD-based conjugates. Moreover, the physicochemical properties of both SubPc-TCBD-aniline racemates have been investigated using a wide range of electrochemical as well as steady-state and time-resolved spectroscopic techniques. Each of the two SubPc-TCBD-aniline conjugates presents a unique photophysical feature never observed before in SubPc chemistry. As a matter of fact, H12SubPc-TCBD-aniline showed significant ground-state charge transfer interactions between the H12SubPc macrocycle and the electron-withdrawing TCBD unit directly attached at its axial position. In contrast, F12SubPc-TCBD-aniline gave rise to an intense, broad emission, which red shifts upon increasing the solvent polarity and stems from an excited complex (i.e., an exciplex). Such an exciplex emission, which has also no precedent in TCBD chemistry, results from intramolecular interactions in the excited state between the electron-rich aniline and the F12SubPc π-surface, two molecular fragments kept in spatial proximity by the "unique" three-dimensional geometry adopted by the F12SubPc-TCBD-aniline. Complementary transient absorption studies were carried out on both SubPc-TCBD-aniline derivatives, showing the occurrence, in both cases

  1. Role of Heteroatoms in Diastereofacial Control in Cycloaddition to a Dissymmetric Cyclohexa-1,3-diene Moiety in a Polycyclic Framework. Remarkable Stereodirecting Influence of Distal Protective Groups.

    PubMed

    Mehta; Uma

    2000-03-24

    Diels-Alder cycloaddition to several derivatives of a facially dissymmetric diene, the hexacyclo[7.5.1.0.(1,6)0.(6,13)0.(8,12)0(10,14)]pentadeca-2,4-diene-7,15-dione 4a, with a variety of dienophiles such as singlet oxygen, N-phenyltriazolinedione, dimethyl acetylenedicarboxylate, maleic anhydride, and N-methylmaleimide has been studied. The stereochemistry of the resulting adducts has been unambiguously secured by (1)H and (13)C NMR spectral data, chemical correlations, and X-ray crystal structure determination. While a variety of dienophiles undergo [4 + 2]-cycloadditions with 4a predominantly from the carbonyl face, protection of the carbonyl groups in 4a as simple mono- or bis-acetals 4b-e or thioacetals 9a,b leads to complete reversal in selectivity, favoring addition from the cyclobutane face, with heterodienophiles and acetylenic dienophiles. The reversal in selectivity observed in mono- and bis-acetals 4b-e has been attributed to unfavorable electrostatic interaction between the oxygen atom and the incoming dienophile. Whereas, in the case of thioacetals 9a,b, apart from unfavorable electrostatic interactions, Cieplak-type hyperconjugative interactions have to be given due consideration in order to account for the observed selectivities. Our studies highlight the role of simple protective groups (acetals in the present case) in modulating diastereoselection during [4 + 2]-cycloadditions.

  2. Effect of lanthanide contraction on the mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien): Syntheses and characterizations of lanthanide complexes with a tetraelenidoantimonate ligand

    SciTech Connect

    Zhao Jing; Liang Jingjing; Pan Yingli; Zhang Yong; Jia Dingxian

    2011-06-15

    Mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) (Ln=lanthanide, en=ethylenediamine, dien=diethylenetriamine, trien=triethylenetetramine) were investigated under solvothermal conditions, and novel mixed-coordinated lanthanide(III) complexes [Ln(en){sub 2}(dien)({eta}{sup 2}-SbSe{sub 4})] (Ln=Ce(1a), Nd(1b)), [Ln(en){sub 2}(dien)(SbSe{sub 4})] (Ln=Sm(2a), Gd(2b), Dy(2c)), [Ln(en)(trien)({mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4})]{sub {infinity}} (Ln=Ce(3a), Nd(3b)) and [Sm(en)(trien)({eta}{sup 2}-SbSe{sub 4})] (4a) were prepared. Two structural types of lanthanide selenidoantimonates were obtained across the lanthanide series in both en+dien and en+trien systems. The tetrahedral anion [SbSe{sub 4}]{sup 3-} acts as a monodentate ligand mono-SbSe{sub 4}, a bidentate chelating ligand {eta}{sup 2}-SbSe{sub 4} or a tridentate bridging ligand {mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4} to the lanthanide(III) center depending on the Ln{sup 3+} ions and the mixed ethylene polyamines, indicating the effect of lanthanide contraction on the structures of the lanthanide(III) selenidoantimonates. The lanthanide selenidoantimonates exhibit semiconducting properties with E{sub g} between 2.08 and 2.51 eV. - Graphical Abstract: Two structural types of lanthanide(III) selenidoantimonates are formed in both en-dien and en-trien mixed polyamines across lanthanide series, indicating the lanthanide contraction effect on the structures of the lanthanide(III) selenidoantimonates. Highlights: > Two structural types of lanthanide selenidoantimonates are prepared across the lanthanide series in both Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) systems. > The [SbSe{sub 4}]{sup 3-} anion acts as a mono-SbSe{sub 4}, a {eta}{sup 2}-SbSe{sub 4} or a {mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4} ligand to the Ln{sup 3+} ions. > The soft base ligand [SbSe{sub 4}]{sup 3-} can be controlled to coordinate to the Ln{sup 3+} ions with en+dien and en+trien as co-ligands.

  3. Novel oxazolinyl derivatives of pregna-5,17(20)-diene as 17α-hydroxylase/17,20-lyase (CYP17A1) inhibitors.

    PubMed

    Kuzikov, Alexey V; Dugin, Nikita O; Stulov, Sergey V; Shcherbinin, Dmitry S; Zharkova, Maria S; Tkachev, Yaroslav V; Timofeev, Vladimir P; Veselovsky, Alexander V; Shumyantseva, Victoria V; Misharin, Alexander Y

    2014-10-01

    New oxazolinyl derivatives of [17(20)E]-pregna-5,17(20)-diene: 2'-{[(E)-3β-hydroxyandrost-5-en-17-ylidene]methyl}-4',5'-dihydro-1',3'-oxazole 1 and 2'-{[(E)-3β-hydroxyandrost-5-en-17-ylidene]methyl}-4',4'-dimethyl-4',5'-dihydro-1',3'-oxazole 2 were evaluated as potential CYP17A1 inhibitors in comparison with 17-(pyridin-3-yl)androsta-5,16-dien-3β-ol 3 (abiraterone). Differential absorption spectra of human recombinant CYP17A1 in the presence of compound 1 (λmax=422 nm, λmin=386 nm) and compound 2 (λmax=416 nm) indicated significant differences in enzyme/inhibitors complexes. CYP17A1 activity was measured using electrochemical methods. Inhibitory activity of compound 1 was comparable with abiraterone 3 (IC50=0.9±0.1 μM, and IC50=1.3±0.1 μM, for compounds 1 and 3, respectively), while compound 2 was found to be weaker inhibitor (IC50=13±1 μM). Docking of aforementioned compounds to CYP17A1 revealed that steroid fragments of compound 1 and abiraterone 3 occupied close positions; oxazoline cycle of compound 1 was coordinated with heme iron similarly to pyridine cycle of abiraterone 3. Configuration of substituents at 17(20) double bond in preferred docked position corresponded to Z-isomers of compounds 1 and 2. Presence of 4'-substituents in oxazoline ring of compound 2 prevents coordination of oxazoline nitrogen with heme iron and worsens its docking score in comparison with compound 1. These data indicate that oxazolinyl derivative of [17(20)E]-pregna-5,17(20)-diene 1 (rather than 4',4'-dimethyl derivative 2) may be considered as potential CYP17A1 inhibitor and template for development of new compounds affecting growth and proliferation of prostate cancer cells.

  4. Bifunctional Organo/Metal Cooperatively Catalyzed [3 + 2] Annulation of para-Quinone Methides with Vinylcyclopropanes: Approach to Spiro[4.5]deca-6,9-diene-8-ones.

    PubMed

    Yuan, Zhenbo; Wei, Weiwei; Lin, Aijun; Yao, Hequan

    2016-07-15

    A novel [3 + 2] annulation between para-quinone methides and vinylcyclopropanes for the synthesis of spiro[4.5]deca-6,9-diene-8-ones has been described. The palladium and phosphine-thiourea cooperative catalysis system played an important role in high yields and diastereoselectivities. The reaction exhibited good functional group tolerance and scalability.

  5. Photoredox-Catalyzed Intramolecular Difluoromethylation of N-Benzylacrylamides Coupled with a Dearomatizing Spirocyclization: Access to CF2H-Containing 2-Azaspiro[4.5]deca-6,9-diene-3,8-diones.

    PubMed

    Zhang, Zuxiao; Tang, Xiao-Jun; Dolbier, William R

    2016-03-04

    A visible light-mediated difluoromethylation of N-benzylacrylamides with HCF2SO2Cl as the HCF2 radical precursor is described. The reaction incorporates a tandem cyclization/dearomatization process to afford various difluoromethylated 2-azaspiro[4.5]deca-6,9-diene-3,8-diones bearing adjacent quaternary stereocenters under mild conditions in moderate to excellent yields.

  6. Synthesis, structure of [H{sub 3} dien].(MF{sub 6}).H{sub 2}O (M=Cr, Fe) and {sup 57}Fe Moessbauer study of [H{sub 3} dien].(FeF{sub 6}).H{sub 2}O

    SciTech Connect

    Ben Ali, Amor Trang Dang, Minh; Greneche, Jean-Marc; Hemon-Ribaud, Annie; Leblanc, Marc; Maisonneuve, Vincent

    2007-06-15

    Single crystals of [H{sub 3} dien].(FeF{sub 6}).H{sub 2}O (I) and [H{sub 3} dien].(CrF{sub 6}).H{sub 2}O (II) are obtained by solvothermal synthesis under microwave heating. I is orthorhombic (Pna2{sub 1}) with a=11.530(2) A, b=6.6446(8) A, c=13.787(3) A, V=1056.3(2) A{sup 3} and Z=4. II is monoclinic (P2{sub 1} /c) with a=13.706(1) A, b=6.7606(6) A, c=11.3181(9) A, {beta}=99.38(1){sup o}, V=1034.7(1) A{sup 3} and Z=4. The structure determinations, performed from single crystal X-ray diffraction data, lead to the R {sub 1}/wR {sub 2} reliability factors 0.028/0.066 for I and 0.035/0.102 for II. The structures of I and II are built up from isolated FeF{sub 6} or CrF{sub 6} octahedra, water molecules and triprotonated amines. In both structures, each octahedron is connected by hydrogen bonds to six organic cations and two water molecules. The iron-based compound is also characterized by {sup 57}Fe Moessbauer spectrometry: the hyperfine structure confirms the presence of Fe{sup 3+} in octahedral coordination and reveals the existence of paramagnetic spin fluctuations. - Graphical abstract: Moessbauer spectra of [H{sub 3} dien].(FeF{sub 6}).H{sub 2}O.

  7. Neolignans with a Rare 2-Oxaspiro[4.5]deca-6,9-dien-8-one Motif from the Stem Bark of Cinnamomum subavenium.

    PubMed

    Lai, Yongji; Liu, Tingting; Sa, Rongjian; Wei, Xialan; Xue, Yongbo; Wu, Zhaodi; Luo, Zengwei; Xiang, Ming; Zhang, Yonghui; Yao, Guangmin

    2015-07-24

    Two pairs of racemic spirodienone neolignans with a rare 2-oxaspiro[4.5]deca-6,9-dien-8-one motif, named (±)-subaveniumins A (1) and B (2), were isolated from the bark of Cinnamomum subavenium. The chiral separation of the (+)-1, (-)-1, (+)-2, and (-)-2 enantiomers was accomplished via high-performance liquid chromatography on a chiral column. Their structures were elucidated using single-crystal X-ray diffraction and spectroscopic analyses (UV, IR, HRESIMS, and 1D and 2D NMR). The absolute configurations of the enantiomers were determined by comparing the experimental and calculated electronic circular dichroic spectra. The (+)-1, (-)-1, (+)-2, and (-)-2 enantiomers exhibited moderate inhibitory effects against NO production in RAW264.7 mouse macrophages induced by lipopolysaccharide, with IC50 values of 17.9, 5.6, 15.1, and 4.3 μM, respectively.

  8. Enantio- and Stereoselective Cyclopolymerization of Hexa-1,5-diene Catalyzed by Zirconium Complexes Possessing Optically Active Bis(phenolato) Ligands.

    PubMed

    Nakata, Norio; Watanabe, Takanori; Toda, Tomoyuki; Ishii, Akihiko

    2016-09-26

    Enantio- and stereoselective cyclopolymerization of hexa-1,5-diene was achieved by enantiomerically pure dichloro zirconium(IV) pre-catalysts 2 possessing chiral [OSSO]-type bis(phenolate) ligands (-)-1 and (+)-1 in combination with dried methylaluminoxane (dMAO) as an activator. The corresponding activities were recorded with quite high values up to 1,960 g mmol(2)(-1) h(-1) , which are extremely larger than those of the related complexes. The microstructure analysis for the PMCPs furnished by pre-catalysts (Λ,S,S)-2 and (Δ,R,R)-2 showed good isotacticity factors (α = 75-78%) and relatively high proportions of trans-cyclopentane rings (σ = 14-21%). These enantiomeric PMCPs exhibited large specific optical rotations ([α]D = +28 to +32° from (Λ,S,S)-2, -26 to -34° from (Δ,R,R)-2).

  9. Crystal structure of dimethyl 2,5-bis-[(di-phen-oxy-phosphor-yl)-oxy]cyclo-hexa-1,4-diene-1,4-di-carboxyl-ate.

    PubMed

    Gao, Lei; Ma, Zongshan; Yan, Hong

    2015-06-01

    In the title compound, C34H30O12P2, which was synthesized via the esterification of dimethyl 2,5-dioxo-1,4-cyclo-hexa-nedi-carboxyl-ate with diphenyl chloro-phosphate, the mol-ecule has crystallographic inversion symmetry. The dihedral angles between the plane of the cyclo-hexa-1,4-diene ring and those of the two benzene rings of the substituent phosphate groups are 41.0 (1) and 89.5 (1)°, while that with the ester group is 3.1 (3)°. In the crystal, only weak inter-molecular C-H⋯O hydrogen bonds are present.

  10. Crystal structure of chlorido­bis­[(1,2,5,6-η)-cyclo­octa-1,5-diene]iridium(I)

    PubMed Central

    Rahman, A. K. Fazlur; Wilklow-Marnell, Miles; Brennessel, William W.; Jones, William D.

    2017-01-01

    The title complex, [IrCl(C8H12)2], was synthesized directly from the reaction of IrCl3·3H2O with a large excess of cod (cod = cyclo­octa-1,5-diene) in alcoholic solvent. Large yellow needles were obtained by the slow cooling of a hot solution. Based on the positions of the chloride ligand and the mid-points of the four C=C bonds, the mol­ecule adopts a five-coordinate geometry that is midway between square pyramidal and trigonal bipyramidal. The material crystallizes in the ortho­rhom­bic space group Pbca with one mol­ecule per asymmetric unit in a general position and shows no significant inter­molecular inter­actions. Individual mol­ecules are aligned along [010], and these rows form a pseudo-hexa­gonal packing arrangement. PMID:28217358

  11. Influence of diene substitution on Diels-Alder reactions between vinyl dihydronaphthalenes and (SS)-2-(p-tolylsulfinyl)-1,4-benzoquinone.

    PubMed

    Carreño, M Carmen; García-Cerrada, Susana; Sanz-Cuesta, M Jesús; Urbano, Antonio

    2003-05-30

    The asymmetric Diels-Alder reaction between 2-(E-2-acetoxyvinyl)-8-tert-butyl-3,4-dihydronaphthalene (8) and enantiopure (SS)-2-(p-tolylsulfinyl)-1,4-benzoquinone (1) takes place exclusively on the unsubstituted C(5)-C(6) double bond of (SS)-1 with a very high control of the chemo-, regio-, and diastereoselectivity of the process affording tetracyclic sulfinyl derivative 13a possessing five stereogenic centers. The analogue diene 9, lacking the tert-butyl group, gave a less chemoselective reaction (C(2)-C(3)/C(5)-C(6): 60/40) in favor of reaction through the sulfoxide-substituted double bond C(2)-C(3) of 1. Steric effects of the remote tert-butyl group and electronic factors due to the OAc substituent are controlling the process.

  12. Enantioselective aza-Diels-Alder reaction of aldimines with "Danishefsky-type diene" catalyzed by chiral scandium(III)-N,N'-dioxide complexes.

    PubMed

    Shang, Deju; Xin, Junguo; Liu, Yanling; Zhou, Xin; Liu, Xiaohua; Feng, Xiaoming

    2008-01-18

    A new kind of complex prepared from scandium(III) triflate and l-proline-derived N,N'-dioxides has been developed to catalyze the enantioselective aza-Diels-Alder reaction between 1,3-butadiene (diene 1) and aldimines 2, affording the corresponding 2,5-disubstituted dihydropyridinones in moderate to high yields (up to 92%) with good enantioselectivities (up to 90% ee) at room temperature. A variety of aldimines including aromatic, heteroaromatic, conjugated, and aliphatic imines were found to be suitable substrates. Enantiopure samples (up to 99% ee) were obtained for some products by a single recrystallization. The absolute configuration of the products was determined by X-ray diffraction and CD analysis. On the basis of the investigation of 1H NMR spectra and the positive nonlinear effect, the catalyst structure was carefully discussed.

  13. Bioactive (3Z,5E)-11,20-Epoxybriara-3,5-dien-7,18-olide Diterpenoids from the South China Sea Gorgonian Dichotella gemmacea

    PubMed Central

    Li, Cui; La, Ming-Ping; Sun, Peng; Kurtan, Tibor; Mandi, Attila; Tang, Hua; Liu, Bao-Shu; Yi, Yang-Hua; Li, Ling; Zhang, Wen

    2011-01-01

    Six new (3Z,5E)-11,20-epoxybriara-3,5-dien-7,18-olide diterpenoids, gemmacolides N–S (1–6), were isolated together with four known analogues, juncenolide D, and juncins R, S and U (7–10), from the South China Sea gorgonian Dichotella gemmacea. The structures of the new compounds were elucidated by the detailed analysis of spectroscopic data in combination with the comparison with reported data. The absolute configuration of 1 was determined by a TDDFT calculation of its solution ECD spectrum, affording the determination of absolute configuration of other analogues by simply comparing their ECD spectra with that of 1. The cytotoxic and antimicrobial activities of these compounds were evaluated. In preliminary in vitro bioassays, compounds 4, 5, 6, 8 and 9 showed cytotoxicity against A549 and MG63, while compounds 1, 2, 4, 7–10 showed antimicrobial activity against the fungus Septoria tritici and the bacterium Escherichia coli. PMID:21892354

  14. (η6-Benzophenone)(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II) tetra­phenyl­borate

    PubMed Central

    Loughrey, Bradley T.; Nadin, Kevin; Williams, Michael L.; Healy, Peter C.

    2009-01-01

    The structure of the title compound, [Ru(C10H15)(C13H10O)](C24H20B), consists of discrete [Cp*Ru(II)benzophenone] cations and tetra­phenyl­borate anions (Cp* = penta­methyl­cyclo­penta­dien­yl). Tethering the Cp*Ru group to one aryl ring of benzophenone results in average values of 1.42 (1) and 1.38 (1) Å for the C—C bond lengths in the Ru-tethered and untethered phenyl rings, respectively. The dihedral angle between the benzene and phenyl rings of the benzophenone group is 50.5 (1)°. PMID:21578208

  15. Crystal structure of bis­(η2-ethyl­ene)(η5-penta­methyl­cyclo­penta­dien­yl)cobalt

    PubMed Central

    Ramful, Chandika D.; Robertson, Katherine N.; Ylijoki, Kai E. O.

    2016-01-01

    The title compound, [Co(C10H15)(C2H4)2], was prepared by Na/Hg reduction of [Co2(C10H15)2(μ-Cl)2] in THF under an ethyl­ene atmosphere and crystallized from pentane at 193 K. The Co—C(olefin) bonds have an average length of 2.022 (2) Å, while the Co—C(penta­dien­yl) bonds average 2.103 (19) Å. The olefin C=C bonds are 1.410 (1) Å. The dihedral angle between the planes defined by the cyclo­penta­dienyl ligand and the two olefin ligands is 0.25 (12)°. In the crystal, mol­ecules are linked into chains by C—H⋯π inter­actions. PMID:27920922

  16. Separation of n-hexane/acetone mixtures by pervaporation using high density polyethylene/ethylene propylene diene terpolymer rubber blend membranes.

    PubMed

    Kumar, P V Anil; Anilkumar, S; Varughese, K T; Thomas, Sabu

    2012-01-15

    Polymer membranes were prepared by blending high density polyethylene (HDPE) with ethylene propylene diene terpolymer rubber (EPDM). These blend membranes were evaluated for the selective separation of n-hexane from acetone. The flux and selectivity of the membranes were determined both as a function of the blend composition and feed mixture composition. Results showed that polymer blending method could be very useful to develop new membranes with improved selectivity. Pervaporation properties could be optimized by adjusting the blend composition. The effects of blend ratio, feed composition, and penetrant size on the pervaporation process were analyzed. The permeation properties have been explained on the basis of interaction between the membrane and solvents and blend morphology. Flux increases with increasing alkane content in the feed composition.

  17. Highly diastereoselective 1,3-dipolar cycloadditions of chiral non-racemic nitrones to 1,2-diaza-1,3-dienes: an experimental and computational investigation.

    PubMed

    Majer, Roberta; Konechnaya, Olga; Delso, Ignacio; Tejero, Tomas; Attanasi, Orazio A; Santeusanio, Stefania; Merino, Pedro

    2014-11-28

    Asymmetric 1,3-dipolar cycloadditions between 1,2-diaza-1,3-dienes and chiral non-racemic nitrones to give 3-substituted-5-diazenyl isoxazolidines were studied both experimentally and theoretically. Whereas cyclic nitrones provide complete selectivity for the cycloaddition reaction (only one isomer is obtained), acyclic nitrones derived from D-glyceraldehyde and D-galactose lead to 1 : 1 mixtures of two isomers. A DFT analysis based on reactivity indices correctly predicts the regiochemistry of the reaction in agreement with the high electron-withdrawing character of the diazenyl group. The same theoretical studies considering solvent effects (PCM model) based on transition state theory are in qualitative agreement with the observed experimental results.

  18. Thermoplastic vulcanizate nanocomposites based on polypropylene/ethylene propylene diene terpolymer (PP/EPDM) prepared by reactive extrusion

    NASA Astrophysics Data System (ADS)

    Mirzadeh, Amin

    using the solvent extraction and gravimetry technique. Additionally, the effect of continuity on rheological behaviour of TPE nanocomposites was investigated. The ultimate goal in this field is to maximize the rubber like behaviour by controlling the blend morphology and the level of crosslinking. Therefore, this study also covers the effects of nanoclay presence and its dispersion level on the crosslinking reaction of thermoplastic vulcanizate nanocomposites prepared by reactive extrusion. Here, the rubber phase was dynamically vulcanized using dimethylol phenolic resin or octylphenol-formaldehyde resin along with stannous chloride dihydrate as the catalyst. In the present study, the dynamic vulcanization of the prepared TPVs and corresponding nanocomposites are characterized using different criteria, such as gel content, viscosity and normalized storage modulus in the time sweep tests, nuclear magnetic resonance (NMR) signal line width, bound curative content and residual diene concentration. The combination of the above parameters appears to be sufficient to provide a clear description of the systems. The last part of the present study is devoted to find how the dispersion level of nanoclay and consequently the extent of crosslinking change the rubber like behaviour and the morphology of the prepared TPVs. Therefore, recently developed method named temperature scanning stress relaxation (TSSR) was used to estimate the rubber indices of TPVs and TPV nanocomposites. The mentioned method also successfully provided information about the extent of crosslinking reaction. It is shown that the rubber like behaviour of the blends containing 50wt% and 60wt% of EPDM in which morphological studies suggest the presence of the rubber droplets in vicinity of irregular shape rubber particles with a low level of interconnectivity, correlates with the rubber droplet size. Therefore, the nanoclay presence affects the rubber index values mainly through its effect on the size of the

  19. (meso-5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetra­azacyclo­tetra­deca-4,11-diene)copper(II) bis­[O,O′-bis­(4-methyl­phen­yl) dithio­phosphate

    PubMed Central

    He, Lin-Xin; Zou, Li-Ke; Xie, Bin; Xiang, Yang-Guang; Feng, Jian-Shen

    2010-01-01

    The title compound, [Cu(C16H32N4)](C14H14O2PS2)2 or [Cu(trans[14]dien)][S2P(OC6H4Me-4)2]2, where trans[14]dien is meso-5,7,7,12,14,14-hexa­methyl-1,4,8,11-tetra­azacyclo­tetra­deca-4,11-diene, was obtained by the reaction of [Cu(trans[14]dien)](ClO4)2 and [(C2H5)2NH]2 [S2P(OC6H4Me-4)2]2. The CuII atom lies on a centre of inversion and possesses a relatively undistorted square-planar coordination arrangement with four N atoms of the macrocyclic tetra­mine trans[14]dien [Cu—N = 1.9716 (19) and 2.0075 (19) Å]. The two uncoordinated [(4-MeC6H4O)2PS2]− groups act as counter-ions to balance the charge and inter­act with the [Cu(trans[14]dien)]2+ complex cation through N—H⋯S hydrogen bonds. PMID:21580524

  20. Enzymatic conjugation of hexachloro-1,3-butadiene with glutathione. Formation of 1-(glutathion-S-yl)-1,2,3,4,4-pentachlorobuta-1,3-diene and 1,4-bis(glutathion-S-yl)-1,2,3,4-tetrachlorobuta-1,3-diene.

    PubMed

    Dekant, W; Vamvakas, S; Henschler, D; Anders, M W

    1988-01-01

    The glutathione-dependent metabolism of the nephrotoxin and nephrocarcinogen hexachloro-1,3-butadiene (HCBD) was investigated in subcellular fractions from rat liver and kidney. HCBD was metabolized by hepatic glutathione S-transferases to (E)- and (Z)-1-(glutathion-S-yl)-pentachlorobuta-1,3-diene (GPCB) in a ratio of 20:1, which were identified by secondary ion MS and by GC-MS after acid hydrolysis. The formation of GPCB was dependent on time and on protein and glutathione concentrations. Microsomal glutathione S-transferases from rat liver catalyzed GPCB formation more efficiently than did cytosolic glutathione S-transferases; very low rates of GPCB formation were observed in kidney subcellular fractions. GPCB is also a substrate for glutathione S-transferases and is metabolized to a diglutathione conjugate, which was identified by secondary ion MS and 13C NMR spectrometry as 1,4-bis(glutathion-S-yl)-1,2,3,4-tetrachlorobuta-1,3-diene (BTCB). BTCB formation from GPCB was dependent on time and on protein, glutathione, and GPCB concentrations. Hepatic cytosol catalyzed BTCB formation more efficiently than did hepatic microsomes; significant amounts of BTCB were also formed in kidney cytosol. Hepatic formation of glutathione S-conjugates, translocation of the S-conjugates to the kidney, and renal processing to form reactive intermediates may be the cause of HCBD-induced nephrotoxicity and, perhaps, nephrocarcinogenicity.

  1. Sequential metabolism of 7-dehydrocholesterol to steroidal 5,7-dienes in adrenal glands and its biological implication in the skin.

    PubMed

    Slominski, Andrzej T; Zmijewski, Michal A; Semak, Igor; Sweatman, Trevor; Janjetovic, Zorica; Li, Wei; Zjawiony, Jordan K; Tuckey, Robert C

    2009-01-01

    Since P450scc transforms 7-dehydrocholesterol (7DHC) to 7-dehydropregnenolone (7DHP) in vitro, we investigated sequential 7DHC metabolism by adrenal glands ex vivo. There was a rapid, time- and dose-dependent metabolism of 7DHC by adrenals from rats, pigs, rabbits and dogs with production of more polar 5,7-dienes as detected by RP-HPLC. Based on retention time (RT), UV spectra and mass spectrometry, we identified the major products common to all tested species as 7DHP, 22-hydroxy-7DHC and 20,22-dihydroxy-7DHC. The involvement of P450scc in adrenal metabolic transformation was confirmed by the inhibition of this process by DL-aminoglutethimide. The metabolism of 7DHC with subsequent production of 7DHP was stimulated by forscolin indicating involvement of cAMP dependent pathways. Additional minor products of 7DHC metabolism that were more polar than 7DHP were identified as 17-hydroxy-7DHP (in pig adrenals but not those of rats) and as pregna-4,7-diene-3,20-dione (7-dehydroprogesterone). Both products represented the major identifiable products of 7DHP metabolism in adrenal glands. Studies with purified enzymes show that StAR protein likely transports 7DHC to the inner mitochondrial membrane, that 7DHC can compete effectively with cholesterol for the substrate binding site on P450scc and that the catalytic efficiency of 3betaHSD for 7DHP (V(m)/K(m)) is 40% of that for pregnenolone. Skin mitochondria are capable of transforming 7DHC to 7DHP and the 7DHP is metabolized further by skin extracts. Finally, 7DHP, its photoderivative 20-oxopregnacalciferol, and pregnenolone exhibited biological activity in skin cells including inhibition of proliferation of epidermal keratinocytes and melanocytes, and melanoma cells. These findings define a novel steroidogenic pathway: 7DHC-->22(OH)7DHC-->20,22(OH)(2)7DHC-->7DHP, with potential further metabolism of 7DHP mediated by 3betaHSD or CYP17, depending on mammalian species. The 5-7 dienal intermediates of the pathway can be a source

  2. Sequential Metabolism of 7-Dehydrocholesterol to Steroidal 5,7-Dienes in Adrenal Glands and Its Biological Implication in the Skin

    PubMed Central

    Slominski, Andrzej T.; Zmijewski, Michal A.; Semak, Igor; Sweatman, Trevor; Janjetovic, Zorica; Li, Wei; Zjawiony, Jordan K.; Tuckey, Robert C.

    2009-01-01

    Since P450scc transforms 7-dehydrocholesterol (7DHC) to 7-dehydropregnenolone (7DHP) in vitro, we investigated sequential 7DHC metabolism by adrenal glands ex vivo. There was a rapid, time- and dose-dependent metabolism of 7DHC by adrenals from rats, pigs, rabbits and dogs with production of more polar 5,7-dienes as detected by RP-HPLC. Based on retention time (RT), UV spectra and mass spectrometry, we identified the major products common to all tested species as 7DHP, 22-hydroxy-7DHC and 20,22-dihydroxy-7DHC. The involvement of P450scc in adrenal metabolic transformation was confirmed by the inhibition of this process by DL-aminoglutethimide. The metabolism of 7DHC with subsequent production of 7DHP was stimulated by forscolin indicating involvement of cAMP dependent pathways. Additional minor products of 7DHC metabolism that were more polar than 7DHP were identified as 17-hydroxy-7DHP (in pig adrenals but not those of rats) and as pregna-4,7-diene-3,20-dione (7-dehydroprogesterone). Both products represented the major identifiable products of 7DHP metabolism in adrenal glands. Studies with purified enzymes show that StAR protein likely transports 7DHC to the inner mitochondrial membrane, that 7DHC can compete effectively with cholesterol for the substrate binding site on P450scc and that the catalytic efficiency of 3βHSD for 7DHP (Vm/Km) is 40% of that for pregnenolone. Skin mitochondria are capable of transforming 7DHC to 7DHP and the 7DHP is metabolized further by skin extracts. Finally, 7DHP, its photoderivative 20-oxopregnacalciferol, and pregnenolone exhibited biological activity in skin cells including inhibition of proliferation of epidermal keratinocytes and melanocytes, and melanoma cells. These findings define a novel steroidogenic pathway: 7DHC→22(OH)7DHC→20,22(OH)27DHC→7DHP, with potential further metabolism of 7DHP mediated by 3βHSD or CYP17, depending on mammalian species. The 5–7 dienal intermediates of the pathway can be a source of

  3. Crystal structure of 4,4-di-bromo-1-(3,4-di-meth-oxy-phen-yl)-2-aza-buta-1,3-diene-1-carbo-nitrile.

    PubMed

    Chaabene, Marwa; Khatyr, Abderrahim; Knorr, Michael; Askri, Moheddine; Rousselin, Yoann; Kubicki, Marek M

    2016-08-01

    The title compound, C12H10Br2N2O2, represents an example of a planar π-con-jugated 2-aza-butadiene mol-ecule, which is both an inter-esting starting material for further organic transformations and a potential ligand in organometallic coordination chemistry. Its metric mol-ecular parameters are typical for the family of 2-aza-buta-1,3-dienes not substituted at the (CH) 3-position. In the crystal, the almost planar (r.m.s. deviation = 0.0658 Å) aza-diene mol-ecules form one-dimensional double-wide ribbons through inter-molecular halogen bonds (C-Br⋯O and C-Br⋯Br-C), which then stack in a slipped manner through weak C-H⋯Br and π-π inter-actions to generate a three-dimensional network.

  4. Nickel(II)-Catalyzed Cascade Vinylogous Mukaiyama 1,6-Michael/Michael Addition of 2-Silyloxyfuran with N-Sulfonyl-1-aza-1,3-dienes: Access to Fused Piperidine/Butyrolactone Skeletons.

    PubMed

    Liu, Kang; Chang, Xin; Wang, Chun-Jiang

    2016-12-16

    An unprecedented and highly efficient nickel-catalyzed cascade vinylogous Mukaiyama 1,6-Michael/Michael addition of 2-silyloxyfuran with N-sulfonyl-1-aza-1,3-dienes is reported, in which 2-silyloxyfuran was successfully employed as nucleophile and electrophile sequentially. This methodology combined with subsequent reduction provides a facile access to biologically important fused piperidine/butyrolactone skeletons in good yield with exclusive diastereoselectivity under mild reaction conditions.

  5. Expedient synthesis of 17α,21-dihydroxy-9β,11β-epoxy-16α-methylpregna-1,4-diene-3,20-dione 21-acetate from prednisolone utilising a novel Mattox rearrangement.

    PubMed

    Hulcoop, David G; Shapland, Peter D P

    2013-12-11

    A six step transformation of prednisolone to 17α,21-dihydroxy-9β,11β-epoxy-16α-amethylpregna-1,4-diene-3,20-dione 21-acetate has been achieved in 13% unoptimised yield. Novel conditions for effecting a Mattox rearrangement and double dehydration of prednisolone were identified. Enhanced knowledge on the oxidation of silyl Δ(19,20)-enol ethers and structural factors that impact the success of the oxidation are also presented.

  6. An ortho-rhom-bic polymorph of N (1),N (4)-diphenyl-3,6-bis-(phenyl-imino)-cyclo-hexa-1,4-diene-1,4-di-amine.

    PubMed

    Ohno, Keiji; Fujihara, Takashi; Nagasawa, Akira

    2014-04-01

    A new ortho-rhom-bic polymorph of the title compound, C30H24N4, with a density of 1.315 Mg m(-3), has been obtained. The mol-ecule is centrosymmetric with the centroid of the cyclo-hexa-1,4-diene ring located on an inversion center. The two unique benzene rings are almost perpendicular to each other [dihedral angle = 86.70 (6)°] and are oriented at dihedral angles of 30.79 (5) and 68.07 (5)° with respect to the central cyclo-hexa-diene ring. In the crystal, π-π stacking is observed between the central cyclo-hexa-1,4-diene-1,4-di-amine unit and a phenyl ring of a neighboring mol-ecule [centroid-centroid distance = 3.7043 (7) Å]. The crystal structure of the triclinic polymorph [Ohno et al. (2014 ▶). Acta Cryst. E70, o303-o304] showed chains running along the b-axis direction through weak C-H⋯π inter-actions.

  7. Preparative isolation and purification of cuminaldehyde and p-menta-1,4-dien-7-al from the essential oil of Cuminum cyminum L. by high-speed counter-current chromatography.

    PubMed

    Chen, Qinqin; Hu, Xuefang; Li, Jingming; Liu, Ping; Yang, Yang; Ni, Yuanying

    2011-03-09

    High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale was successfully used in isolation and purification of cuminaldehyde and p-menta-1,4-dien-7-al from the essential oil of Cuminum cyminum L. by using a two-phase solvent system composed of n-hexane-methanol-water (5:4:1, v/v/v). The targeted compounds were isolated, collected, purified by HSCCC in the head-tail mode, and then analyzed by gas chromatography (GC). A total of 12.72 ± 0.22 mg of cuminaldehyde and 10.61 ± 0.27 mg of p-menta-1,4-dien-7-al were obtained from 50 mg of the essential oil of C. cyminum L. in less than 6 h, with purities of 95.42% and 97.21%, respectively. In addition to GC-EI/MS, the identity of the cuminaldehyde was further confirmed with the retention time using the method of standard addition, while, the structural identification of p-menta-1,4-dien-7-al was performed with GC-EI/MS, (1)H NMR and (1)H-(1)H COSY.

  8. Dual Regulation of Cell Death and Cell Survival upon Induction of Cellular Stress by Isopimara-7,15-Dien-19-Oic Acid in Cervical Cancer, HeLa Cells In vitro

    PubMed Central

    Abu, Nadiah; Yeap, Swee K.; Pauzi, Ahmad Z. Mat; Akhtar, M. Nadeem; Zamberi, Nur R.; Ismail, Jamil; Zareen, Seema; Alitheen, Noorjahan B.

    2016-01-01

    The Fritillaria imperialis is an ornamental flower that can be found in various parts of the world including Iraq, Afghanistan, Pakistan, and the Himalayas. The use of this plant as traditional remedy is widely known. This study aims to unveil the anti-cancer potentials of Isopimara-7,15-Dien-19-Oic Acid, extracted from the bulbs of F. imperialis in cervical cancer cell line, HeLa cells. Flow cytometry analysis of cell death, gene expression analysis via cDNA microarray and protein array were performed. Based on the results, Isopimara-7,15-Dien-19-Oic acid simultaneously induced cell death and promoted cell survival. The execution of apoptosis was apparent based on the flow cytometry results and regulation of both pro and anti-apoptotic genes. Additionally, the regulation of anti-oxidant genes were up-regulated especially thioredoxin, glutathione and superoxide dismutase- related genes. Moreover, the treatment also induced the activation of pro-survival heat shock proteins. Collectively, Isopimara-7,15-Dien-19-Oic Acid managed to induce cellular stress in HeLa cells and activate several anti- and pro survival pathways. PMID:27065873

  9. DFT investigation of the mecahanism and stereochemistry of electrophilic transannular addition reaction of bromine to tricyclo[4.2.2.02,5]deca-3,7-diene.

    PubMed

    Abbasoglu, Rza; Misir, Miraç Nedim

    2012-03-01

    Full geometric optimization of tricyclo[4.2.2.02,5]deca-3,7-diene (TDD) has been done by DFT/B3LYP methods and the structure of the molecule was investigated. Cyclobuten double bond (I) of molecule is syn pyramidalized, and bicyclookten double bond (II) is also exo pyramidalized. The double bond (I) is more pyramidalized than the double bond (II) and it has higher reactivity. The TDD-Br2 system has been investigated by B3LYP/6-311++G(d,p) method and their stable configurations have been determined. The cationic intermediates and products obtained as a result of the addition reaction has been studied using B3LYP/6-311G(d,p) and B3LYP/6-311++G(d,p) methods. Bridged bromonium cation is more stable than U-type cation. Considering that the bridged cation does not isomerize to the less stable U-type cation, it is not possible for the U-type product to be obtained in the reaction. The bridged bromonium cation transformed into the more stable N-type cation and the N-type product was obtained via this cation. The thermodynamic stability of the anti, exo and anti, endo isomers of N-type dibromide molecule were almost identical. N-type product is 11.759 kcal mol more stable than U-type product.

  10. Morphology study of peroxide-induced dynamically vulcanized polypropylene/ethylene-propylene-diene monomer/zinc dimethacrylate blends during tensile deformation.

    PubMed

    Chen, Yukun; Xu, Chuanhui; Cao, Liming; Wang, Yanpeng; Fang, Liming

    2013-06-27

    Polypropylene (PP)/ethylene-propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blend (EPDM/PP ratio of 30/70) with remarkable extensibility was successfully prepared via peroxide dynamic vulcanization. The uniaxial tensile properties, crystallization behavior, structure, and morphology during stretching were investigated. The tensile process study showed that the PP/EPDM/ZDMA blend exhibited the rubbery-like behavior with an elongation beyond 600%. The ZDMA graft-product domain increased the compatibility and interfacial adhesion between rubber and PP phases, while it reduced the crystallinity of the PP phase. On the basis of TEM and SEM analyses, we found that the cross-linked rubber particles could be elongated and oriented along the tensile direction, whereas the ZDMA graft-product domain "encapsulated" rubber phase together, acting as a "bridge" between elongated rubber phases and the PP phase during uniaxial stretching. The stress could be effectively transferred from the PP phase to the numerous elongated rubber phases due to the excellent compatibility and interfacial adhesion between rubber and PP phases, resulting in the rubbery-like behavior.

  11. The Diels-Alder reaction of 4,6-dinitrobenzofuroxan with 1-trimethylsilyloxybuta-1,3-diene: a case example of a stepwise cycloaddition.

    PubMed

    Lakhdar, Sami; Terrier, François; Vichard, Dominique; Berionni, Guillaume; El Guesmi, Nizar; Goumont, Régis; Boubaker, Taoufik

    2010-05-17

    The reaction of 4,6-dinitrobenzofuroxan (DNBF) with 1-trimethylsilyloxybuta-1,3-diene (8) is shown to afford a mixture of [2+4] diastereomeric cycloadducts (10, 11) through stepwise addition-cyclization pathways. Zwitterionic intermediate sigma-adduct 9, which is involved in the processes, has been successfully characterized by (1)H and (13)C NMR spectroscopy and UV/visible spectrophotometry in acetonitrile. A kinetic study has been carried out in this solvent that revealed that the rate of formation of 9 nicely fits the three-parameter equation log k=s(E+N) developed by Mayr to describe the feasibility of nucleophile-electrophile combinations. This significantly adds to the NMR spectroscopic evidence that the overall cycloadditions take place through a stepwise mechanism. The reaction has also been studied in dichloromethane and toluene. In these less polar solvents, the stability of 9 is not sufficient to allow direct characterization by spectroscopic methods, but a kinetic investigation supports the view that stepwise processes are still operating. An informative comparison of our reaction with previous interactions firmly identified as prototype stepwise cycloadditions is made on the basis of the global electrophilicity index, omega, defined by Parr within the density functional theory, and highlighted by Domingo et al. as a powerful tool for understanding Diels-Alder reactions.

  12. Enhanced Production of Androst-1,4-Diene-3,17-Dione by Mycobacterium neoaurum JC-12 Using Three-Stage Fermentation Strategy.

    PubMed

    Shao, Minglong; Zhang, Xian; Rao, Zhiming; Xu, Meijuan; Yang, Taowei; Li, Hui; Xu, Zhenghong

    2015-01-01

    To improve the androst-1,4-diene-3,17-dione (ADD) production from phytosterol by Mycobacterium neoaurum JC-12, fructose was firstly found favorable as the initial carbon source to increase the biomass and eliminate the lag phase of M. neoaurum JC-12 in the phytosterol transformation process. Based on this phenomenon, two-stage fermentation by using fructose as the initial carbon source and feeding glucose to maintain strain metabolism was designed. By applying this strategy, the fermentation duration was decreased from 168 h to 120 h with the ADD productivity increased from 0.071 g/(L·h) to 0.108 g/(L·h). Further, three-stage fermentation by adding phytosterol to improve ADD production at the end of the two-stage fermentation was carried out and the final ADD production reached 18.6 g/L, which is the highest reported ADD production using phytosterol as substrate. Thus, this strategy provides a possible way in enhancing the ADD production in pharmaceutical industry.

  13. The electronic states of buta-1,3-diene studied by ab initio configuration interaction and DFT methods, and electron energy loss spectroscopy

    NASA Astrophysics Data System (ADS)

    H., Michael; | Isobel C., Palmer; Walker

    2010-08-01

    The electronic vertical excitation energies for singlet and triplet valence, and Rydberg states of trans-buta-1,3-diene have been computed using ab initio multi-reference multi-root CI procedures with a [4s3p3d3f] set of Rydberg functions. Close numerical agreement between theory and experiment was found for a number of low-lying electronic states. The present CI and CASSCF [8MO,8e] calculations suggest that both the vertical and adiabatic order of the valence (ππ∗) states is: A˜1A

  14. First acyclic diene metathesis polymerization under biphasic conditions using a dicationic ruthenium alkylidene: access to high-molecular-weight polymers with very low ruthenium contamination.

    PubMed

    Zhao, Jing; Wang, Dongren; Autenrieth, Benjamin; Buchmeiser, Michael R

    2015-01-01

    The acyclic diene metathesis (ADMET) polymerization of 6-hydroxy-1,10-undecadiene (M1) and 6-acetoxy-1,10-undecadiene (M2) by the action of two different catalysts, i.e., the second-generation Grubbs-Hoveyda system ([RuCl2(IMesH2)(CH-2-(2-PrO-C6H4)]) (1) and the dicationic ruthenium alkylidene [Ru(DMF)3(IMesH2)(CH-2-(2-PrO-C6H4)] (2, IMesH2 = 1,3-dimesitylimidazolin-2-ylidene) is reported. Biphasic conditions using 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([BDMIM(+)BF4(-)]) and 1,2,4-trichlorobenzene (TCB) are applied. Under the chosen conditions (T = 75 °C, 20 mbar), the use of catalyst 1 results only in the formation of low-molecular-weight polymers (Mn ≤ 10,000 g mol(-1)), while catalyst 2 allows for the high yield synthesis of high-molecular-weight polymers (Mn ≤ 40,000 g mol(-1), yields ≤ 99%). Irrespective of the catalyst used, all polymers display a high trans-content (>95%). Notably, Ru-contamination of the target polymers without any additional purification is as low as 1.2 ppm with catalyst 2. Together with the high yields and high molecular weights, the low Ru-contaminations clearly illustrate the advantages of the biphasic setup.

  15. Prise maternelle d’anti-inflammatoires non stéroïdiens et fermeture du canal artériel

    PubMed Central

    Ndour, Daouda Diamane

    2016-01-01

    Nous rapportons un cas de fermeture prématurée in utero du canal artériel diagnostiqué chez un fœtus en état d’anasarque avec insuffisance cardiaque majeure après prise d’anti-inflammatoire non stéroïdiens (AINS) par la mère. Une échographie obstétricale au deuxième trimestre a permis la découverte d’une asymétrie des cavités cardiaques. L’indication de césarienne a été posée à 30 semaines d’aménorrhées devant un fœtus en état d’anasarque avec insuffisance cardiaque majeure sur une fermeture anténatale du canal artériel. A partir de ce cas nous nous proposons de réaliser une revue de la littérature pour illustrer les complications fœtales et néonatales potentielles résultant de la fermeture précoce du canal artériel secondaire à la prise d’AINS pendant la grossesse. PMID:28293367

  16. New gastroprotective labdeneamides from (4S,9R,10R) methyl 18-carboxy-labda-8,13(E)-diene-15-oate.

    PubMed

    Olate, Verónica Rachel; Pertino, Mariano Walter; Theoduloz, Cristina; Yesilada, Erdem; Monsalve, Francisco; González, Paulo; Droguett, Daniel; Richomme, Pascal; Hadi, A Hamid; Schmeda-Hirschmann, Guillermo

    2012-03-01

    Starting from the diterpene (4S,9R,10R) methyl 18-carboxy-labda-8,13(E)-dien-15-oate (PMD) and its 8(9)-en isomer [PMD 8(9)-en], 11 amides were prepared and assessed for a gastroprotective effect in the ethanol/HCl-induced gastric lesions model in mice. Basal cytotoxicity of the compounds was determined on the following human cell lines: normal lung fibroblasts (MRC-5), gastric epithelial adenocarcinoma (AGS), and hepatocellular carcinoma (Hep G2). All compounds are described for the first time. At the single oral dose of 0.1 mg/kg, compounds 1, 10, and 11 presented a strong gastroprotective effect, at least comparable with that of the reference compound lansoprazole at 1 mg/kg, reducing gastric lesions by 76.7, 67.7, and 77.2 %, respectively. The leucyl amide methyl ester 3, tryptophanyl amide methyl ester 5, and benzyl amide 6 of PMD presented a selective basal cytotoxicity on Hep G2 cells with IC₅₀ values of 136.8, 105.3, and 94.2 µM, respectively, while the IC₅₀ values towards AGS cells were 439.5, 928.0, and 937.3 µM, respectively. The three compounds did not affect fibroblast viability with IC₅₀ values > 1000 µM. Compounds 7, 8, 10, and 11 showed no toxic effect against the three selected cell lines.

  17. Prostaglandin-induced radioprotection of murine intestinal crypts and villi by a PGE diene analog (SC-44932) and a PGI analog (Iloprost)

    NASA Astrophysics Data System (ADS)

    Hanson, Wayne R.; Collins, Paul W.

    The aminothiols exemplified by WR-2721 are effective radioprotectors; however, their toxicity associated with hypotension, nausea, and emesis has limited their development for applications in medicine or in hazardous radiation environments. There is a need for new radioprotectors that have fewer toxic side effects when given alone or combined with reduced amounts of thiols. A variety of prostaglandins (PGs) have been shown to be radioprotective agents and some appear to have fewer toxic side effects than the aminothiols. Iloprost, a stable PGI, analog protects the clonogenic epithelial cells of intestinal crypts but does not protect epithelial cells of the villi. In contrast, an E-series omega chain diene analog designated SC-44932 protects epithelial cells of both crypts and villi. When the two are combined, protection of the crypts is additive and the villi are protected to the same degree as when SC-44932 is given alone. Since radioprotection for some PGs has been shown to be dependent upon receptors, we suggest that the pattern of radioprotection seen with these two analogs depend on the location of the respective receptors or on the ability of differentiated villus cells to respond to PGs. By studying different analogs, we hope to identify mechanisms associated with PG-induced radioprotection and to identify the most protective PG analogs for applications of radioprotection.

  18. Crystal structure of di-n-but­yl­bis­(η 5-penta­methyl­cyclo­penta­dien­yl)hafnium(IV)

    PubMed Central

    Arndt, Perdita; Schubert, Kathleen; Burlakov, Vladimir V.; Spannenberg, Anke; Rosenthal, Uwe

    2015-01-01

    The crystal structure of the title compound, [Hf(C10H15)2(C4H9)2], reveals two independent mol­ecules in the asymmetric unit. The diffraction experiment was performed with a racemically twinned crystal showing a 0.529 (5):0.471 (5) component ratio. Each HfIV atom is coordinated by two penta­methyl­cyclo­penta­dienyl and two n-butyl ligands in a distorted tetra­hedral geometry, with the cyclo­penta­dienyl rings inclined to one another by 45.11 (15) and 45.37 (16)°. In contrast to the isostructural di(n-butyl)bis(η 5-penta­methyl­cyclo­penta­dien­yl)zirconium(IV) complex with a noticeable difference in the Zr–butyl bonding, the Hf—Cbut­yl bond lengths differ from each other by no more than 0.039 (3) Å. PMID:25878834

  19. Bis[bis-(penta-methyl-cyclo-penta-dien-yl)cobalt(III)] tetra-chlorido-cobaltate(II) di-chloro-methane disolvate.

    PubMed

    Merola, Joseph S; Ngo, Mai; Karpin, George W

    2013-01-01

    The title compound, [Co(C10H15)2]2[CoCl4]·2CH2Cl2, was isolated as a dichloromethane solvate and was formed in the reaction between lithium penta-methyl-cyclo-penta-dienide and anyhydrous cobalt(II) chloride in tetra-hydro-furan. There are two deca-methyl-cobaltocenium cations, one tetrachloridocobaltate(II) anion and two di-chloro-methane solvent mol-ecules in the formula unit. There is a slight disorder of the di-chloro-methane solvent which was treated with a two-site model [occupancy rates = 0.765 (4) and 0.235 (4)]. The di-chloro-methane mol-ecules display significant C-H⋯Cl inter-actions with the tetrachloridocobaltate(II) dianion. The cobalt atom of the deca-methyl-cobaltocenium cation sits on a twofold rotation axis, with only one penta-methyl-cyclo-penta-diene ligand being unique and the second generated by symmetry. The cobalt atom of the [CoCl4](-2) ion sits on a special site with -4 symmetry, with one unique chloride ligand and the others generated by the fourfold inversion axis.

  20. Growth and characterization of a new organic nonlinear optical crystal: 1-(3-Nitrophenyl)-5-phenylpenta-2,4-dien-1-one

    NASA Astrophysics Data System (ADS)

    Patil, P. S.; Kumar, P. Ajay; Venugopal Rao, S.; Bhagavannarayana, G.

    2015-08-01

    Organic nonlinear optical single crystal of 1-(3-Nitrophenyl)-5-phenylpenta-2,4-dien-1-one (Ci3NC) with dimensions 25×15×10 mm3 was successfully grown for the first time by the slow evaporation solution growth technique (SEST). The structural perfection of the grown crystals has been analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements, and it was found that the crystalline perfection is reasonably good having very low angle (tilt angle ≤1‧) internal structural grain boundary. Thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. Powder test with Nd:YAG laser radiation shows second harmonic generation which is about 7 times that of urea. The optical transmittance window and the lower cutoff wavelength of the Ci3NC have been identified by UV-vis-NIR studies. Third-order nonlinear optical (NLO) response of Ci3NC has been examined using Z-scan technique with femtosecond (fs), MHz pulses at wavelengths of 870 nm and 900 nm. Various NLO coefficients such as two-photon absorption (2PA) coefficient (β), three photon absorption (3PA) coefficient (γ), and nonlinear refractive index (η2) were evaluated.

  1. In situ reactive compatibilization of polypropylene/ethylene-propylene-diene monomer thermoplastic vulcanizate by zinc dimethacrylate via peroxide-induced dynamic vulcanization.

    PubMed

    Chen, Yukun; Xu, Chuanhui; Liang, Xingquan; Cao, Liming

    2013-09-12

    This work demonstrates an approach of in situ reactive compatibilization between polypropylene (PP) and ethylene-propylene-diene monomer (EPDM) by using zinc dimethacrylate (ZDMA) as a compatibilizer and, simultaneously, as a very strong reinforcing agent. With the incorporation of 7phr ZDMA in the PP/EPDM (30/70, w/w) thermoplastic vulcanizate (TPV), the tensile strength, tear strength, elongation at break, and hardness of PP/EPDM/ZDMA TPV were increased from 5.3 MPa, 31.3 kN/m, 222%, and 78 up to 11.2 MPa, 64.2 kN/m, 396%, and 83, respectively. This tremendous reinforcing as well as the compatibilization effect of the ZDMA was understood by polymerization of ZDMA and ZDMA reacted with EPDM and PP during peroxide-induced dynamic vulcanization. A peculiar phase structure that rubber particles were surrounded and "bonded" by a thick transition zone that contained numerous of nanoparticles with dimensions of about 20-30 nm was observed from transmission electron microscopy. Scanning electron microscopy results confirmed that incorporation of ZDMA reduced the size of the cross-linked EPDM particles. Moreover, we found that the compatibilized TPV showed a higher tan δ peak temperature for EPDM phase and a lower tan δ peak temperature for PP phase. The suggested method for in situ reactive compatibilization of PP and EPDM offers routes to the design of new TPV-based technical products for diversified applications.

  2. Abcès thyroïdien révélant un basedow: à propos d’un cas et revue de la littérature

    PubMed Central

    Chenguir, Meriem; Souldi, Hajar; Loufad, Fatima Zahra; Rouadi, Sami; Abada, Reda; Roubal, Mohamed; Mahtar, Mohamed

    2016-01-01

    L’abcès thyroïdien est une entité clinique très rare. Elle représente 0,1% des pathologies chirurgicales de la thyroïde. Les caractéristiques anatomique et physiologique de la glande lui procurent une résistance vis-à-vis des agents pathogènes. Les infections à Streptococcies et Staphylococcus sont les plus fréquentes. La tuberculose reste rarement rapportée dans la littérature. La survenue de l’infection sur goitre toxique est exceptionnelle. Les auteurs rapportent un cas rare d’abcès thyroïdien révélant un goitre toxique chez un jeune de 22 ans. Il s’est présenté aux urgences ORL pour une tuméfaction cervicale antérieure, légèrement latéralisée à gauche, mobile à la déglutition, associée à des hémoptysies, signes de dysthyroïdie, fièvre et sueurs nocturnes. La TDM cervicale a montré une masse occupant le lobe thyroïdien gauche de contenu liquidien mesurant 2 cm, avec un liquide purulent à la cytoponction. L’examen cyto-bactériologique a mis en évidence un Staphylococcus avec recherche de BK positive. Une radiographie thoracique a été demandée montrant un foyer alvéolaire pulmonaire apical droit. L’étude cytobactériologique des crachats ont isolé le bacille de koch. Le bilan biologique thyroïdien était en faveur d’un Basedow. La prise en charge était médicale comprenait une tri-antibiothérapie par voie parentérale, anti-bacillaire et anti-thyroïdien de synthèse avec bonne évolution. Le diagnostic de la tuberculose doit être évoqué devant toute abcédation thyroïdienne avec un tableau clinique peu bruyant. Il s’agit le plus souvent d’une dissémination hématogène à partir d’un autre foyer de primo-infection surtout pulmonaire. Le traitement est basé sur les anti-bacillaires associé parfois à la chirurgie. PMID:27795799

  3. Abcès thyroïdien à Escherichia coli: à propos d’un cas et revue de la littérature

    PubMed Central

    Fassih, Malika; Moujahid, Essadik; Abada, Reda; Rouadi, Sami; Mahtar, Mohamed; Roubal, Mohamed; Essadi, Moustapha; El Kadiri, Mohamed Fatmi

    2012-01-01

    L’abcès de la thyroïde est une entité pathologique extrêmement rare, représentant seulement 0.1% des pathologies chirurgicales de la thyroïde. C’est une situation inhabituelle en raison des caractéristiques anatomiques et physiologiques de la glande qui lui donne une capacité de résistance vis-à-vis des infections. Nous rapportons un cas rare d’abcès thyroïdien à Escherichia. coli survenu chez une patiente de 55 ans, immunodéprimée: diabétique insulinodépendante non équilibrée, hypertendue mal suivie avec insuffisance cardiaque gauche, et en insuffisance rénale chronique terminale. La patiente s’est présentée aux urgences avec une tuméfaction basi-cervicale antérieure évoluant sur 10 jours, prédominante à droite, mesurant 6 cm, sensible, inflammatoire, mobile à la déglutition, avec une dyspnée mixte, sueurs et fièvre. Un scanner cervico-thoracique mettait en évidence un énorme processus du lobe thyroïdien droit à contenu liquidien de 9cm, refoulement des voies aériennes supérieures. Une cytoponction à l’aiguille ramenait 10 ml de liquide purulent. Le drainage chirurgical a été réalisé sous anesthésie locale vue le risque d’intubation difficile devant le blindage cervical en présence d’une trachée difficilement accessible. Une E. coli était isolée après la culture du liquide de drainage. La patiente était porteuse d’un bricker depuis l’enfance pour malformation de la vessie. Ceci suggère une bactériémie à point de départ urinaire, avec embole septique au niveau de la glande thyroïde. L’évolution était bonne sous tri-antibiothérapie, et des pansements biquotidiens, avec équilibration de son diabète et insuffisance rénale chronique. Nous rappellerons à travers cette observation les moyens de défense de la thyroïde contre les infections, les différents facteurs prédisposant à l’abcès de la thyroïde, et les germes incriminés dans chaque étiologie. Nous discuterons les

  4. Administration d’anti-inflammatoires non stéroïdiens aux enfants ayant des antécédents de sibilance

    PubMed Central

    Sih, Kendra; Goldman, Ran D.

    2016-01-01

    Résumé Question Un enfant qui fréquente ma clinique s’est récemment fait une entorse à la cheville et il éprouve de la douleur et de la difficulté à supporter son poids sur la jambe affectée. Sa mère lui donne de l’acétaminophène parce qu’on lui a dit de ne jamais utiliser d’anti-inflammatoires non stéroïdiens (AINS) en raison de son asthme contrôlé par pharmacologie. L’asthme chez un enfant est-il une contre-indication à l’administration d’AINS? La maladie respiratoire exacerbée par les AINS existe-t-elle comme entité réelle? Réponse Les AINS sont des médicaments analgésiques et antipyrétiques efficaces. La maladie respiratoire exacerbée par des AINS a été décrite chez des adultes ayant certains facteurs de prédisposition, mais n’a pas été clairement identifiée chez un grand nombre d’enfants. Les AINS peuvent donc être recommandés aux enfants ayant une sibilance connue qui n’ont pas d’antécédents de maladie respiratoire déclenchée par des AINS. PMID:27521406

  5. Phase I Study of the Synthetic Triterpenoid, 2-Cyano-3, 12-Dioxoolean-1, 9-Dien-28-Oic Acid (CDDO), in Advanced Solid Tumors

    PubMed Central

    Speranza, Giovanna; Gutierrez, Martin E.; Kummar, Shivaani; Parker, Robert J.; Collins, Jerry; Yu, Yunkai; Cao, Liang; Murgo, Anthony J.; Doroshow, James H.; Chen, Alice

    2015-01-01

    Background The triterpenoid 2-Cyano-3, 12-Dioxoolean-1, 9-Dien-28-Oic Acid (CDDO, previously RTA-401) is a multifunctional molecule that controls cellular growth and differentiation. It is capable of activating the transcription factor peroxisome proliferator activator receptor-γ (PPARγ) and inducing apoptosis in malignant cells in vitro and in vivo. We conducted a phase I dose-escalation study to determine the toxicity, the maximum tolerated dose, and the pharmacokinetics and pharmacodynamics of CDDO, administered as a 5-day continuous infusion every 28 days in patients with advanced cancers. Methods An accelerated titration design was followed, with one patient per cohort entered, and doses ranging from 0.6 mg/m2/hr to 38.4 mg/m2/hr. Pharmacokinetics of CDDO was assessed and cleaved poly (ADP-ribose) polymerase (c-PARP), as a marker of apoptosis, was measured in peripheral blood mononuclear cells to assess drug effect. Results Seven patients, one patient per dose level up to dose level 7 (38.4 mg/m2/hr), were enrolled and received a total of 11 courses of treatment. Cmax increased proportionally with dose. Preclinically determined efficacious blood level (1 μM) of drug was attained at the highest dose level. One patient, at dose level 6, experienced grade 2 mucositis, nausea, vomiting, and anorexia. Four patients, on different dose levels, developed thromboembolic events subsequently considered as dose-limiting toxicity. No anti-tumor activity was noted. Conclusion A causal relationship of observed thromboembolic events to CDDO was considered possible but could not be established. Because of the adverse events and the development of an orally bioavailable derivative compound, CDDO methyl ester, this trial was terminated. PMID:21805353

  6. Synthesis and characterization of PTP/[Fe(CN)3(dien)]·H2O nanocomposite; study of electrical, thermal and photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Moosvi, Syed Kazim; Majid, Kowsar; Ara, Tabassum

    2016-10-01

    Polythiophene/[Fe(CN)3(dien)]·H2O nanocomposite was synthesised by oxidative chemical polymerisation method. Photoadduct was synthesised by irradiating an equimolar mixture of potassium ferricyanide and diethylenetriamine which was then reduced to nanosize by high energy ball mill. The reduction of photoadduct to nanosize was confirmed from XRD. Nanocomposite of PTP with photoadduct was then prepared by oxidative chemical polymerisation using FeCl3 as oxidant. The successful synthesis of nanocomposite was confirmed from FTIR, XRD and SEM. TGA revealed higher thermal stability of nanocomposite as compared to pure PTP. I-V characteristics plotted on a log-log scale showed two distinct power law regions in case of nanocomposite. At lower voltages, the transport mechanism follows Ohm's law. At higher voltages, the mechanism is consistent with space charge-limited emission. Furthermore, nanocomposite shows enhanced conductivity as compared to pure PTP. From dielectric studies, an appreciable high value of dielectric constant (4.4 × 106 at 100 Hz) and ac conductivity (2.1 × 109 S/m at 300 kHz) of nanocomposite was obtained. This indicates the possible application of this nanocomposite in charge storage devices. The photocatalytic activity of the materials was studied against the methyl orange (MO) dye under UV-Vis light and 76% degradation of MO dye was achieved in presence of nanocomposite in just 2 h, hence indicating its better photocatalytic efficiency. Results thus obtained indicate the synthesised nanocomposite can be used as a multifunctional material for different nanoelectronic devices.

  7. Heat of Mixing and Solution of Cyclohexa-1,3-diene C6H8 + C10H18 Bicyclo[4.4.0]decane (HMSD1111, LB4030_H)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of Cyclohexa-1,3-diene C6H8 + C10H18 Bicyclo[4.4.0]decane (HMSD1111, LB4030_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  8. Volumetric Properties of the Mixture Cyclohexa-1,3-diene C6H8 + C10H12 1,2,3,4-Tetrahydronaphthalene (VMSD1211, LB3964_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexa-1,3-diene C6H8 + C10H12 1,2,3,4-Tetrahydronaphthalene (VMSD1211, LB3964_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  9. Volumetric Properties of the Mixture Cyclohexa-1,3-diene C6H8 + C10H18 Bicyclo[4.4.0]decane (VMSD1211, LB3958_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Cyclohexa-1,3-diene C6H8 + C10H18 Bicyclo[4.4.0]decane (VMSD1211, LB3958_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  10. Magnetic field effect on the exciplex between all-s-trans-1,4-diphenylbuta-1,3-diene and 1,4-dicyanobenzene: a comparative study with other α,ω-diphenyl polyenes

    NASA Astrophysics Data System (ADS)

    Sengupta, Tamal; Basu, Samita

    2001-04-01

    The exciplex between all-s-trans-1,4-diphenylbuta-1,3-diene and 1,4-dicyanobenzene has been studied by steady state fluorescence along with the magnetic field effect (MFE) and compared with the other α,ω-diphenyl polyenes. The exciplex formation and magnetic field effect are dictated by the chain length of the polyene rather than the electronic requirement of these phenomena. The wavelength dependence of the MFE confirms the presence of two different charge-transfer complexes.

  11. Heat of Mixing and Solution of Cyclohexa-1,3-diene C6H8 + C10H12 1,2,3,4-Tetrahydronaphthalene (HMSD1111, LB4036_H)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of Cyclohexa-1,3-diene C6H8 + C10H12 1,2,3,4-Tetrahydronaphthalene (HMSD1111, LB4036_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  12. Magnetic field effect on the exciplex between all-s-trans- 1,4-diphenylbuta- 1,3-diene and 1,4-dicyanobenzene: a comparative study with other alpha,omega-diphenyl polyenes.

    PubMed

    Sengupta, T; Basu, S

    2001-04-01

    The exciplex between all-s-trans-1,4-diphenylbuta-1,3-diene and 1,4-dicyanobenzene has been studied by steady state fluorescence along with the magnetic field effect (MFE) and compared with the other alpha,omega-diphenyl polyenes. The exciplex formation and magnetic field effect are dictated by the chain length of the polyene rather than the electronic requirement of these phenomena. The wavelength dependence of the MFE confirms the presence of two different charge-transfer complexes.

  13. 5-Amino-3-eth­oxy-1,8,8-trimethyl-2-aza­bicyclo­[2.2.2]octa-2,5-diene-4,6-dicarbo­nitrile

    PubMed Central

    Chantrapromma, Suchada; Suwunwong, Thitipone; Ruanwas, Pumsak; Boonnak, Nawong; Fun, Hoong-Kun

    2012-01-01

    The title 2-aza­bicyclo­[2.2.2]octa-2,5-diene derivative, C14H18N4O, crystallized out with two independent mol­ecules with similar conformations in the asymmetric unit. In each mol­ecule, the three six-membered rings adopt boat conformations. The mol­ecules exist in the enamine form. In the crystal, mol­ecules are linked by N—H⋯O and N—H⋯N hydrogen bonds into a two-dimensional network parallel to the ab plane. PMID:22969511

  14. C-24 Stereochemistry of Marine Sterols: (22E)-25,28-Dimethyl- stigmasta-5,22,28-trien-3β-ol and 25,28-Dimethylstigmasta-5,28-dien-3β-ol.

    PubMed

    Nojo, Rie; Echigo, Shizue; Hara, Noriyuki; Fujimoto, Yoshinori

    2014-12-01

    The C-24 configurations of (22E)-25,28-dimethylstigmasta-5,22,28-trien-3β-ol (1) and 25,28-dimethylstigmasta-5,28-dien-3β-ol (2), isolated from the sponge Topsentia ophiraphidites in our previous work, were determined to be both S, through the synthesis of stereodefined (24S)- and (24R)-epimers of 1 and 2 and comparison of the 1H and 13C NMR spectroscopic data. In addition, the C-24 configurations of the marine sterols having the same structures as 1 and 2 and their derivatives were also assigned for the first time by NMR comparison.

  15. Solution structure and dynamics of lanthanide complexes of the macrocyclic polyamino carboxylate DTPA-dien. NMR study and crystal structures of the lanthanum(III) and europium(III) complexes

    SciTech Connect

    Franklin, S.J.; Raymond, K.N.

    1994-12-07

    An 18-membered macrocyclic DTPA-bis(amide) ligand (DTPA = diethylenetriaminepentaacetic acid) containing a heteroatom in the amide link has been prepared via the condensation of DTPA-dianhydride and diethylenetriamine. The solution structures of the two isomeric pairs present in the Ln(III) complexes of DTPA-dien have been investigated by {sup 1}H NMR. The structures of the lanthanum(III) and europium(III) DTPA-dien complexes have been determined by X-ray analysis. [La(DTPA-dienH{sup +})H{sub 2}O]{sub 2}(CF{sub 3}SO{sub 3}{sup -}){sub 2}{center_dot}18H{sub 2}O (I) crystallizes as a carboxylate-bridged dimer about a center of inversion in the orthorhombic space group Pbca with a = 12.626(2) {angstrom}, b = 21.405(3) {angstrom}, c = 26.422(9) {angstrom}, and Z = 8. Each lanthanum ion is 11-coordinate with octadentate ligand coordination, an {eta}{sup 2} bridging carboxylate, and one water. [Eu(DTPA-dienH{sup +})]{sub 4}(CF{sub 3}SO{sub 3}{sup -}){sub 4}{center_dot}6NaCF{sub 3}SO{sub 3}{center_dot}20H{sub 2}O (II) crystallizes as a carboxylate-bridged tetramer with two crystallographically independent Eu(III) positions (Z = 8 for each) in the monoclinic space group C2/c: a = 30.94(1) {angstrom}, b = 23.456(3) {angstrom}, c = 22.611(4) {angstrom}, {beta} = 105.78(2){degrees}. The coordination geometries about Eu1 and Eu2 are nearly identical and are described as a nine-coordinate tricapped trigonal prism with octadentate ligand coordination plus an {eta}{sup 1} bridging carboxylate. The tendency to oligomerize is attributed to the constraints imposed by the macrocycle and the hydrogen bonding available with the link heteroatom. The structural differences between the two complexes are attributed to a difference in La(III) and Eu(III) ionic size.

  16. Redirection of carotenoid metabolism for the efficient production of taxadiene [taxa-4(5),11(12)-diene] in transgenic tomato fruit.

    PubMed

    Kovacs, Katalin; Zhang, Lina; Linforth, Robert S T; Whittaker, Benjamin; Hayes, Christopher J; Fray, Rupert G

    2007-02-01

    The taxanes are a group of polycyclic diterpenes produced by various species of yew. The potent anticancer drug paclitaxel (marketed as Taxol) is the commercially most important taxane with annual sales in 2000 exceeding 1.6 billion dollars. Paclitaxel is currently obtained either by direct extraction from yew trees or by the extraction of the precursor 10-deactilbaccatin III, which is then converted to paclitaxel by semi-synthesis. Apart from cost, one of the main draw backs to taxol in cancer treatment is the development of resistance by tumours, commonly due to the expression of ABC transporter efflux pumps which remove the drug from the target cell. A number of natural taxanes and semisynthetic derivates, have recently been shown to act as potent inhibitors of ABC transport proteins. These compounds have no effect upon microtubule polymerization (the normal target of paclitaxel), but have the ability to restore drug sensitivity when given in combination with paclitaxel to resistant cell lines. In work to be described elsewhere, we sort to carry out a structure function analysis of the ability of novel oxidised taxanes to act as ABC transporter inhibitors. For this study 100 mg or more of taxadiene [taxa-4(5),11(12)-diene], the first taxane in the paclitaxel pathway, was required as starting material from which to synthesize these compounds. Taxadiene is synthesised directly from geranylgeranyl diphosphate (GGPP), which is found in most plant tissues where it serves as a common precursor for many metabolites. The synthesis and use of GGDP are tightly regulated in most vegetative organs, however, in tomato fruit it is used almost exclusively for the production of coloured carotenoids which accumulate to high levels in the plastid as lycopene crystals. Expressing taxadiene synthase in a yellow-fruited tomato line that lacks the ability to utilise GGPP for carotenoid synthesis allowed GGPP normally utilised for making carotenoids to be re-routed for the production

  17. Eléments traces dans le sérum des enfants malnutris et bien nourris vivants à Lubumbashi et Kawama dans un contexte d'un environnement de pollution minière

    PubMed Central

    Musimwa, Aimée Mudekereza; Kanteng, Gray Wakamb; Kitoko, Hermann Tamubango; Luboya, Oscar Numbi

    2016-01-01

    Introduction La place des éléments traces métalliques essentiels en nutrition humaine ne peut plus être ignorée. Les déficits d'apports, les carences secondaires souvent sous – estimées, et les carences iatrogènes font le lit de pathologies telles que les infections et autres. D'où leurs dosages ont une importance particulière pour en évaluer la gravité et faciliter une prise en charge précoce ou améliorer le régime alimentaire. Cette étude a eu pour objectif de déterminer le profil sanguin en éléments traces (cuivre, sélénium, zinc, fer, chrome, cobalt, etc) chez les enfants malnutris et biens nourris dans un milieu minier à Lubumbashi. Méthodes Trois cents onze cas ont été colligés, 182 malnutris et 129 biens nourris, dans une étude descriptive transversale, effectuée de juillet 2013 à décembre 2014. Pour lequel un échantillonnage exhaustif a été réalisé. Le dosage des métaux dans le sérum s'est fait à l’ ICP-OES (spectrométrie de masse à plasma gon induit) au laboratoire de l'Office Congolais de Contrôle de Lubumbashi. Résultats Les oligoéléments essentiels (cuivre, zinc, sélénium et fer) se retrouvent à des concentrations très basses chez les enfants malnutris comme chez les biens nourris. L'arsenic, le cadmium, le magnésium et le manganèse se présentent à des concentrations normales par rapport aux valeurs de références chez les enfants biens nourris. L'antimoine, le chrome, le plomb et le cobalt se retrouvent élevés chez les malnutris et biens nourris. Le nickel est normal chez les malnutris et les biens nourris. Le magnésium, manganèse se sont présentés à des taux très bas chez les enfants malnutris. Conclusion Les enfants malnutris et biens nourris présentent une malnutrition aux oligo-éléments essentiels associés aux éléments traces métalliques. Ce qui permet de supposer qu'une carence en micronutriments essentiel favorise l'absorption des métaux lourds. PMID:27583075

  18. Roadside BTEX and other gaseous air pollutants in relation to emission sources

    NASA Astrophysics Data System (ADS)

    Truc, Vo Thi Quynh; Kim Oanh, Nguyen Thi

    Hourly concentrations of benzene, toluene, ethylbenzene, m, p-xylenes, and o-xylene (BTEX) plus CO, NO x, SO 2 were monitored at roadsides simultaneously with the traffic volume during the dry season of 2004, in Hanoi, Vietnam. The selected three streets included Truong Chinh (TC) with high traffic volume, Dien Bien Phu (DBP) with low traffic volume, and Nguyen Trai (NT) with high traffic volume running through an industrial estate. BTEX were sampled by SKC charcoal tubes and analyzed by GC-FID. Geometric means of hourly benzene, toluene, ethylbenzene, m, p-xylenes and o-xylene are, respectively, 65, 62, 15, 43, and 22 μg m -3 in TC street; 30, 38, 9, 26, and 13 μg m -3 in DBP street; and 123, 87, 24, 56, and 30 μg m -3 in NT street. Levels of other gaseous pollutants including CO, NO x, and SO 2, measured by automatic instruments, were low and not exceeding the Vietnam national ambient air quality standards. BTEX levels were comparatively analyzed for different downwind distances (3-50 m) from the street, between peak hours and off-peak hours, as well as between weekdays and weekend. Results of principal component analysis suggest that the gaseous pollutants are associated with different vehicle types.

  19. Crystal structure of 4,4-di­bromo-1-(3,4-di­meth­oxy­phen­yl)-2-aza­buta-1,3-diene-1-carbo­nitrile

    PubMed Central

    Chaabene, Marwa; Khatyr, Abderrahim; Knorr, Michael; Askri, Moheddine; Rousselin, Yoann; Kubicki, Marek M.

    2016-01-01

    The title compound, C12H10Br2N2O2, represents an example of a planar π-con­jugated 2-aza­butadiene mol­ecule, which is both an inter­esting starting material for further organic transformations and a potential ligand in organometallic coordination chemistry. Its metric mol­ecular parameters are typical for the family of 2-aza­buta-1,3-dienes not substituted at the (CH) 3-position. In the crystal, the almost planar (r.m.s. deviation = 0.0658 Å) aza­diene mol­ecules form one-dimensional double-wide ribbons through inter­molecular halogen bonds (C—Br⋯O and C—Br⋯Br—C), which then stack in a slipped manner through weak C—H⋯Br and π–π inter­actions to generate a three-dimensional network. PMID:27536405

  20. 3,4-Dihydroxy-1,6-bis(4-methoxyphenyl)hexa-2,4-diene-1,6-dione, its 4-methylphenyl analogue, and a potassium salt of 2-hydroxy-4-(4-methoxyphenyl)-4-oxobut-2-enoic acid.

    PubMed

    Nye, Luke; Turnbull, Mark M; Wikaira, Jan L

    2013-11-01

    Reaction of 4-methoxyacetophenone with diethyl oxalate under basic conditions produced 3,4-dihydroxy-1,6-bis(4-methoxyphenyl)hexa-2,4-diene-1,6-dione, C20H18O6, (1). The molecules lie across a crystallographic inversion centre and intramolecular hydrogen bonding, similar to acetylacetone, is observed, confirming that the molecule is in the di-enol-dione tautomeric form. Additional O-H...O hydrogen bonds link the molecules into chains parallel to the b axis. The structure is compared with that of redetermined 4-methylphenyl compound 3,4-dihydroxy-1,6-bis(4-methylphenyl)hexa-2,4-diene-1,6-dione, C20H18O4, (2), which crystallizes in a similar fashion. The salt, catena-poly[[μ2-2-hydroxy-4-(4-methoxyphenyl)-4-oxobut-2-enoato-κ(3)O(1),O(2):O(4)][μ2-2-hydroxy-4-(4-methoxyphenyl)-4-oxobut-2-enoic acid-κ(2)O(1):O(4)]potassium], [K(C11H9O5)(C11H10O5)]n, (3), was isolated as a by-product of the synthesis of (1). The two organic species are linked by a strong hydrogen bond between the carboxylic acid and carboxylate groups. They are further stabilized and linked into a double-chain structure via the seven-coordinate potassium ion.

  1. Design and synthesis of 2-phenyl-1,4-dioxa-spiro[4.5]deca-6,9-dien-8-ones as potential anticancer agents starting from cytotoxic spiromamakone A.

    PubMed

    Fuse, Shinichiro; Inaba, Kennichi; Takagi, Motoki; Tanaka, Masahiro; Hirokawa, Takatsugu; Johmoto, Kohei; Uekusa, Hidehiro; Shin-Ya, Kazuo; Takahashi, Takashi; Doi, Takayuki

    2013-08-01

    The spirocycle is a key structure found in many bioactive compounds. From the cytotoxic and spirocyclic natural product, spiromamakone A (1) and its analogues, a more synthetically accessible spiroacetal template 4 was designed based on structural similarity analysis. A total of 50 compounds were rapidly synthesized in only one or two synthetic steps from the starting compound, and their cytotoxicity was evaluated. As a result, (±)-(2R*,5R*)-2-(4-iodophenyl)-7-chloro-1,4-dioxa-spiro[4.5]deca-6,9-dien-8-one (7d-II) was discovered and found to be fifteen-fold more cytotoxic than 1. The easily accessible spiroacetal 7d-II appeared to act in a manner similar to the highly oxidized natural product, spiromamakone A (1).

  2. Fe(III) halides as effective catalysts in carbon-carbon bond formation: synthesis of 1,5-dihalo-1,4-dienes, alpha,beta-unsaturated ketones, and cyclic ethers.

    PubMed

    Miranda, Pedro O; Díaz, David D; Padrón, Juan I; Ramírez, Miguel A; Martín, Víctor S

    2005-01-07

    Iron(III) halides have proven to be excellent catalysts in the coupling of acetylenes and aldehydes. When terminal acetylenes were used the main products obtained were 1,5-dihalo-1,4-dienes with (E,Z)-stereochemistry contaminated in some cases with (E)-alpha,beta-unsaturated ketones. The former carbonyl derivatives were the sole products isolated when nonterminal aromatic alkynes were used. When homopropargylic alcohols were used, a Prins-type cyclization occurred yielding 2-alkyl-4-halo-5,6-dihydro-2H-pyrans. In addition, anhydrous ferric halides are also shown to be excellent catalysts for the standard Prins cyclization with homoallylic alcohols. Isolation of an intermediate acetal, calculations, and alkyne hydration studies provide substantiation of a proposed mechanism.

  3. [4+2] cycloaddition reactions between 1,8-disubstituted cyclooctatetraenes and diazo dienophiles: stereoelectronic effects, anticancer properties and application to the synthesis of 7,8-substituted bicyclo[4.2.0]octa-2,4-dienes.

    PubMed

    Grange, Rebecca L; Gallen, Michael J; Schill, Heiko; Johns, Jenny P; Dong, Lin; Parsons, Peter G; Reddell, Paul W; Gordon, Victoria A; Bernhardt, Paul V; Williams, Craig M

    2010-08-02

    A detailed examination of [4+2] cycloaddition reactions between 1,8-disubstituted cyclooctatetraenes and diazo compounds revealed that 4-phenyl-1,2,4-triazole-3,5-dione (PTAD) reacts to form either 2,3- or 3,4-disubstituted adducts. The product distribution can be controlled by modulating the electron density of the cyclooctatetraene. Unprecedented [4+2] cycloadditions between diisopropyl azodicarboxylate (DIAD) and 1,8-disubstituted cyclooctatetraenes are also described and further manipulation of a resulting cycloadduct uncovered a new pathway to the synthetically challenging bicyclo[4.2.0]octa-2,4-diene family. Variation of the substituents resulted in a range of compounds displaying selective action against different human tumour cell types.

  4. Chemistry and Tumor Cell Growth Inhibitory Activity of 11,20-Epoxy-3Z,5(6)E-diene Briaranes from the South China Sea Gorgonian Dichotella gemmacea

    PubMed Central

    Li, Cui; Jiang, Mei; La, Ming-Ping; Li, Tie-Jun; Tang, Hua; Sun, Peng; Liu, Bao-Shu; Yi, Yang-Hua; Liu, Zhiyong; Zhang, Wen

    2013-01-01

    Eighteen new 11,20-epoxy-3Z,5E-dien briaranes, gemmacolides AA–AR (1–18), were isolated together with three known analogs, dichotellides F (19) and I (20), and juncenolide C (21), from the South China Sea gorgonian Dichotella gemmacea. The structures of the compounds were elucidated by detailed spectroscopic analysis and comparison with reported data. The absolute configuration was determined based on the ECD experiment. In the in vitro bioassay, compounds 1–3, 5, 6, 8–12, and 14–19 exhibited different levels of growth inhibition activity against A549 and MG63 cell lines. Preliminary structure-activity analysis suggests that 12-O-isovalerate may increase the activity whereas 13- or 14-O-isovalerate may decrease the activity. Contribution of substitutions at C-2 and C-16 remains uncertain. PMID:23697947

  5. (η5-Penta­methyl­cyclo­penta­dien­yl)(η6-p-toluene­sulfonamide)ruthenium(II) tetra­phenyl­borate

    PubMed Central

    Loughrey, Bradley T.; Williams, Michael L.; Poulsen, Sally-Ann; Healy, Peter C.

    2008-01-01

    The crystal structure of the title compound, [Ru(C10H15)(C7H9NO2S)]C24H20B, has been determined as part of our investigation into the structural and biological properties of organometallic RuII–arene–Cp* complex salts of the type [R-PhRuCp*]+·X − (where Cp* is penta­methyl­cyclo­penta­diene). Tethering the RuCp* group to the benzene ring of p-toluene­sulfonamide results in only minor changes to the mol­ecular geometry of the sulfonamide, but, together with crystallization as the [BPh4]− salt, effectively blocks involvement of the sulfonamide group in N—H⋯O hydrogen-bonding networks. PMID:21581173

  6. (η5-Penta­methyl­cyclo­penta­dien­yl)(η6-4-phenyl­butan-2-one)ruthenium(II) tetra­phenyl­borate

    PubMed Central

    Loughrey, Bradley T.; Williams, Michael L.; Healy, Peter C.

    2010-01-01

    The title compound, [Ru(C10H15)(C10H12O)][B(C6H5)4], crystallizes as discrete (η5-penta­methyl­cyclo­penta­dien­yl)Ru(η6-4-phenyl­butan-2-one)]+ cations and [BPh4]− anions. In the cation, the non-H atoms of the butan-2-one group are approximately planar (r.m.s. deviation = 0.056 Å) and lie nearly perpendicular to the plane of the phenyl ring with a dihedral angle between the two planes of 69.3 (1)°. No significant C—H⋯O inter­actions are observed between the methyl and phenyl H atoms and the carbonyl O atom. PMID:21589253

  7. Crystal structure of dimethyl 3,4,5,6-tetra­phenyl­cyclo­hexa-3,5-diene-1,2-di­carboxyl­ate

    PubMed Central

    Greenberg, Fred H.; Nazarenko, Alexander Y.

    2016-01-01

    In the title compound, C34H28O4, the cyclo­hexa­diene ring has a screw-boat conformation with a torsion angle between the double bonds being on average ca 15° [15.2 (3) and −15.3 (3) in the two independent mol­ecules]. All four phenyl rings in both mol­ecules are arranged in a propeller-like conformation. The two mol­ecules exhibit S,R- and R,S- chirality, respectively, and are connected via C—H⋯O inter­molecular inter­actions. In turn, these weakly bound dimers form the mol­ecular crystal. PMID:27555937

  8. Lewis Acid and Substituent Effects on the Molecular Mechanism for the Nazarov Reaction of Penta-1,4-dien-3-one and Derivatives. A Topological Analysis Based on the Combined Use of Electron Localization Function and Catastrophe Theory.

    PubMed

    Polo, Victor; Andrés, Juan

    2007-05-01

    The joint use of the topological analysis provided by the electron localization function (ELF) and catastrophe theory (CT), at the B3LYP/6-31G(d) calculation level, allows us to examine the Lewis acid (protonation H(+) and presence of BH3) and the role of an electron donor substituent (-OCH3) at α and β positions along the course of the molecular mechanism for the Nazarov rearrangement of penta-1,4-dien-3-one and eight derivatives. The progress of the reaction is monitored by the changes of the ELF structural stability domains (SSDs), each change being controlled by a turning point derived from CT. These SSDs and the corresponding turning points are associated with a sequence of elementary chemical steps. Along the cyclization path of penta-1,4-diene-3-one, four SSDs as well as three turning points (cusp1-fold1-cusp2) have been characterized. The first and second SSDs correspond to a polarization of the C-O bond and electronic redistribution among the C-C bonds, respectively, and they can be associated with the formation of an oxyallyl structure. The third and fourth SSDs can be assigned to the ring closure process. Protonation of the oxygen atom shifts the reactive directly into the second SSD, greatly reducing the activation and reaction energies. The electronic effects due to Lewis acids and electron donor substituents have been rationalized in terms of calculations of mesomeric structures from ELF basin populations. The combination of Lewis acids together with α and β -OCH3 substitutions renders a cooperative and competitive effect on activation and reaction free energies, respectively.

  9. Vietnam: A Failure of Strategy and Leadership

    DTIC Science & Technology

    2013-04-30

    check. When, in 1954, communist forces led by Ho Chi Minh defeated the French at Diem Bien Phu, America was faced with a problem of whether to...military strategy and a much more aggressive diplomatic effort. 15 Nixon was a well known and virulent anti-communist and his persona lent

  10. A comparison between the effects of gamma radiation and sulfur cure system on the microstructure and crosslink network of (styrene butadiene rubber/ethylene propylene diene monomer) blends in presence of nanoclay

    NASA Astrophysics Data System (ADS)

    Shoushtari Zadeh Naseri, Aida; Jalali-Arani, Azam

    2015-10-01

    Rubber blends based on (styrene-butadiene rubber (SBR)/ethylene-propylene-diene monomer (EPDM)) with and without organoclay (OC) were prepared through a melt mixing process. The concentration ratio of the rubber phases (EPDM/SBR; 50/50 wt%) and the amount of the OC were kept constant. The samples were then vulcanized by means of gamma radiation using a Co-60 gamma source as well as sulfur cure system. The effect of absorbed dose on the formation of the crosslinks was confirmed by the Fourier transform infrared spectroscopy (FTIR). The effects of absorbed dose, sulfur cure system and OC on the gel content, and crosslink density were evaluated by the chemical tests. Applying the Charlesby-Pinner equation to estimate the radiation chemical yield, revealed that the use of OC in the blend caused 20% reduction in the degradation/crosslinking ratio. Employing the swelling test data, some thermodynamic parameters were determined. Using field emission scanning electron microscopy (FE-SEM) to investigate microstructure of the samples revealed a more homogeneous structure and also an increase in compatibility of the blend components in the sample cured by the irradiation in comparison to that cured by the sulfur curing system.

  11. The antidiabetic compound 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione, isolated from Averrhoa carambola L., demonstrates significant antitumor potential against human breast cancer cells.

    PubMed

    Gao, Ying; Huang, Renbin; Gong, Yixuan; Park, Hyo Sim; Wen, Qingwei; Almosnid, Nadin Marwan; Chippada-Venkata, Uma D; Hosain, Najlaa Abdulrhman; Vick, Eric; Farone, Anthony; Altman, Elliot

    2015-09-15

    2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) is a cyclohexanedione found in the roots of Averrhoa carambola L., commonly known as starfruit. Researchers have shown that DMDD has significant therapeutic potential for the treatment of diabetes; however, the effects of DMDD on human cancers have never been reported. We investigated the cytotoxic effects of DMDD against human breast, lung and bone cancer cells in vitro and further examined the molecular mechanisms of DMDD-induced apoptosis in human breast cancer cells. DMDD suppressed the growth of breast carcinoma cells, but not normal mammary epithelial cells, via induction of G1 phase cell cycle arrest, oxidative stress and apoptosis. DMDD increased the level of intracellular reactive oxygen species (ROS) and DMDD-induced ROS generation was found to be associated with the mitochondrial activity. The cytotoxicity that was induced by DMDD was attenuated by co-treatment with the antioxidant N-acetyl-L-cysteine (NAC). DMDD-induced cell apoptosis involved the activation of both the intrinsic mitochondrial pathway and the extrinsic receptor pathway. In addition, DMDD inhibited the canonical NF-κB signaling pathway at all steps, including TNF-α production, phosphorylation of NF-κB p65 and IκBα, as well as TNF-α activated NF-κB p65 nuclear translocation.Collectively, our studies indicate that DMDD has significant potential as a safe and efficient therapeutic agent for the treatment of breast cancer.

  12. The antidiabetic compound 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione, isolated from averrhoa carambola L., demonstrates significant antitumor potential against human breast cancer cells

    PubMed Central

    Gao, Ying; Huang, Renbin; Gong, Yixuan; Park, Hyo Sim; Wen, Qingwei; Almosnid, Nadin Marwan; Chippada-Venkata, Uma D.; Hosain, Najlaa Abdulrhman; Vick, Eric; Farone, Anthony; Altman, Elliot

    2015-01-01

    2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) is a cyclohexanedione found in the roots of Averrhoa carambola L., commonly known as starfruit. Researchers have shown that DMDD has significant therapeutic potential for the treatment of diabetes; however, the effects of DMDD on human cancers have never been reported. We investigated the cytotoxic effects of DMDD against human breast, lung and bone cancer cells in vitro and further examined the molecular mechanisms of DMDD-induced apoptosis in human breast cancer cells. DMDD suppressed the growth of breast carcinoma cells, but not normal mammary epithelial cells, via induction of G1 phase cell cycle arrest, oxidative stress and apoptosis. DMDD increased the level of intracellular reactive oxygen species (ROS) and DMDD-induced ROS generation was found to be associated with the mitochondrial activity. The cytotoxicity that was induced by DMDD was attenuated by co-treatment with the antioxidant N-acetyl-L-cysteine (NAC). DMDD-induced cell apoptosis involved the activation of both the intrinsic mitochondrial pathway and the extrinsic receptor pathway. In addition, DMDD inhibited the canonical NF-κB signaling pathway at all steps, including TNF-α production, phosphorylation of NF-κB p65 and IκBα, as well as TNF-α activated NF-κB p65 nuclear translocation. Collectively, our studies indicate that DMDD has significant potential as a safe and efficient therapeutic agent for the treatment of breast cancer. PMID:26203774

  13. Effect of 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione, isolated from Averrhoa carambola L. (Oxalidaceae) roots, on advanced glycation end-product-mediated renal injury in type 2 diabetic KKAy mice.

    PubMed

    Zheng, Ni; Lin, Xing; Wen, Qingwei; Kintoko; Zhang, Shijun; Huang, Jianchun; Xu, Xiaohui; Huang, Renbin

    2013-05-10

    The roots of Averrhoa carambola L. (Oxalidaceae) have a long history of medical use in traditional Chinese medicine for treating diabetes and diabetic nephropathy. 2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) was isolated from the tuberous roots of A. carambola L. The purpose of this study was to investigate the beneficial effect of DMDD on the advanced glycation end-product-mediated renal injury in type 2 diabetic KKAy mice with regard to prove its efficacy by local traditional practitioners in the treatment of kidney frailties in diabetics. KKAy mice were orally administrated DMDD (12.5, 25, 50mg/kg body weight/d) or aminoguanidine (200mg/kg body weight/d) for 8 weeks. Hyperglycemia, renal AGE formation, and the expression of related proteins, such as the AGE receptor, nuclear factor-κB, transforming growth factor-β1, and N(ε)-(carboxymethyl)lysine, were markedly decreased by DMDD. Diabetes-dependent alterations in proteinuria, serum creatinine, creatinine clearance, and serum urea-N and glomerular mesangial matrix expansion were attenuated after treatment with DMDD for 8 weeks. The activities of superoxide dismutase and glutathione peroxidase, which are reduced in the kidneys of KKAy mice, were enhanced by DMDD. These findings suggest that DMDD may inhibit the progression of diabetic nephropathy and may be a therapeutic agent for regulating several pharmacological targets to treat or prevent of diabetic nephropathy.

  14. DNA incision evaluation, binding investigation and biocidal screening of novel metallonucleases of 1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione based Knoevenagel condensate having methionine: Synthesis and structural validation

    NASA Astrophysics Data System (ADS)

    Chandrasekar, Thiravidamani; Pravin, Narayanaperumal; Raman, Natarajan

    2015-02-01

    Four new metallonucleases of the composition [MLCl] (where M = Cu(II), Ni(II), Zn(II) and Co(II); L = Knoevenagel condensate Schiff base, obtained by the condensation reaction of 1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione with p-nitrobenzaldehyde and methionine amino acid) have been synthesised and characterized thoroughly by microanalytical data, magnetic susceptibility, molar conductivity, UV-Vis., IR, 1H NMR, 13C NMR and EPR spectral techniques. Their geometry is investigated and established to have square planar geometry. Electronic absorption spectroscopy, cyclic voltammetry and viscosity measurements reveal that the complexes strongly bind to calf thymus DNA via an intercalation mechanism. DNA cleavage efficiency of these complexes is explored by gel electrophoresis, and they are found to endorse the cleavage of pBR322 DNA in presence of oxidant H2O2. These results reveal that all the complexes show better nuclease activity. Moreover, the biological screening against few pathogens reveals that that the complexes have potent biocidal activity than the free ligand.

  15. Therapeutic effects of C-28 methyl ester of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO-Me; bardoxolone methyl) on radiation-induced lung inflammation and fibrosis in mice.

    PubMed

    Wang, Yan-Yang; Zhang, Cui-Ying; Ma, Ya-Qiong; He, Zhi-Xu; Zhe, Hong; Zhou, Shu-Feng

    2015-01-01

    The C-28 methyl ester of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO-Me), one of the synthetic triterpenoids, has been found to have potent anti-inflammatory and anticancer properties in vitro and in vivo. However, its usefulness in mitigating radiation-induced lung injury (RILI), including radiation-induced lung inflammation and fibrosis, has not been tested. The aim of this study was to explore the therapeutic effect of CDDO-Me on RILI in mice and the underlying mechanisms. Herein, we found that administration of CDDO-Me improved the histopathological score, reduced the number of inflammatory cells and concentrations of total protein in bronchoalveolar lavage fluid, suppressed secretion and expression of proinflammatory cytokines, including transforming growth factor-β and interleukin-6, elevated expression of the anti-inflammatory cytokine interleukin-10, and downregulated the mRNA level of profibrotic genes, including for fibronectin, α-smooth muscle actin, and collagen I. CDDO-Me attenuated radiation-induced lung inflammation. CDDO-Me also decreased the Masson's trichrome stain score, hydroxyproline content, and mRNA level of profibrotic genes, and blocked radiation-induced collagen accumulation and fibrosis. Collectively, these findings suggest that CDDO-Me ameliorates radiation-induced lung inflammation and fibrosis, and this synthetic triterpenoid is a promising novel therapeutic agent for RILI. Further mechanistic, efficacy, and safety studies are warranted to elucidate the role of CDDO-Me in the management of RILI.

  16. Anabolic action of dianabol (17 alpha-methyl-17beta-hydroxyandrosta-1, 4-dien-3-one) on the nitrogen balance and skeletal muscle composition of rats fed on field bean (Vicia faba L.).

    PubMed

    Santidrián, S

    1981-07-01

    The addition of Dianabol (17alpha-methyl-17beta-hydroxyandrosta-1,4-dien-3-one) (1 mg/100 g of diet) to a diet containing raw field bean (Vicia faba L.) as the sole source of protein has been studied in young male rats, fed for two weeks on the legume diet, as compared to casein-fed animals. A significant improvement (p less than 0.02) in the biological value and net protein utilization was found in the rats fed the legume diet with Dianabol added. Furthermore, a significant reduction (p less than 0.02) in the non-protein nitrogenous fraction of the skeletal musculature, together with a significant rise (p less than 0.02) in the sarcoplasmic and myofibrillar nitrogenous fractions of this musculature, was found in the rats fed the raw legume diet with Dianabol added. Serum insulin levels, significantly reduced (p less than 0.02) in the legume-fed rats, reached the values of the control group by the addition of Dianabol to the legume diet. The possible nature of these effects is discussed.

  17. (17α,20E)-17,20-[(1-methoxyethylidene)bis(oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester (YK11) is a partial agonist of the androgen receptor.

    PubMed

    Kanno, Yuichiro; Hikosaka, Ritsuko; Zhang, Shu-Yun; Inoue, Yoshimi; Nakahama, Takayuki; Kato, Keisuke; Yamaguchi, Akemi; Tominaga, Nobuaki; Kohra, Shinya; Arizono, Koji; Inouye, Yoshio

    2011-01-01

    A novel steroid compound, (17α,20E)-17,20-[(1-methoxyethylidene)bis(oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester (YK11), was found to be a partial agonist of the androgen receptor (AR) in an androgen responsive element (ARE)-luciferase reporter assay. YK11 accelerates nuclear translocation of AR. Furthermore, YK11 does not induce amino/carboxyl-terminal (N/C) interaction and prevents 5-α-dihydrotestosterone (DHT)-mediated N/C interaction. Thus, YK11 activates AR without causing N/C interaction, which may in turn be responsible for the partially agonistic nature of YK11 observed in the ARE-luciferase reporter system. YK11 acts as a gene-selective agonist of AR in MDA-MB 453 cells. The effect of YK11 on gene expression relative to that of androgen agonist varies depending on the gene context. YK11 activated the reporter gene by inducing the translocation of the AR into the nuclear compartment, where its amino-terminal domain (NTD) functions as a constitutive activator of AR target genes. Our results suggest that YK11 might act as selective androgen receptor modulator (SARM).

  18. Bis[bis­(penta­methyl­cyclo­penta­dien­yl)cobalt(III)] tetra­chlorido­cobaltate(II) di­chloro­methane disolvate

    PubMed Central

    Merola, Joseph S.; Ngo, Mai; Karpin, George W.

    2013-01-01

    The title compound, [Co(C10H15)2]2[CoCl4]·2CH2Cl2, was isolated as a dichloromethane solvate and was formed in the reaction between lithium penta­methyl­cyclo­penta­dienide and anyhydrous cobalt(II) chloride in tetra­hydro­furan. There are two deca­methyl­cobaltocenium cations, one tetrachloridocobaltate(II) anion and two di­chloro­methane solvent mol­ecules in the formula unit. There is a slight disorder of the di­chloro­methane solvent which was treated with a two-site model [occupancy rates = 0.765 (4) and 0.235 (4)]. The di­chloro­methane mol­ecules display significant C—H⋯Cl inter­actions with the tetrachloridocobaltate(II) dianion. The cobalt atom of the deca­methyl­cobaltocenium cation sits on a twofold rotation axis, with only one penta­methyl­cyclo­penta­diene ligand being unique and the second generated by symmetry. The cobalt atom of the [CoCl4]−2 ion sits on a special site with -4 symmetry, with one unique chloride ligand and the others generated by the fourfold inversion axis. PMID:24426998

  19. Supervision of Ethylene Propylene Diene M-Class (EPDM) Rubber Vulcanization and Recovery Processes Using Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy and Multivariate Analysis.

    PubMed

    Riba Ruiz, Jordi-Roger; Canals, Trini; Cantero, Rosa

    2017-01-01

    Ethylene propylene diene monomer (EPDM) rubber is widely used in a diverse type of applications, such as the automotive, industrial and construction sectors among others. Due to its appealing features, the consumption of vulcanized EPDM rubber is growing significantly. However, environmental issues are forcing the application of devulcanization processes to facilitate recovery, which has led rubber manufacturers to implement strict quality controls. Consequently, it is important to develop methods for supervising the vulcanizing and recovery processes of such products. This paper deals with the supervision process of EPDM compounds by means of Fourier transform mid-infrared (FT-IR) spectroscopy and suitable multivariate statistical methods. An expedited and nondestructive classification approach was applied to a sufficient number of EPDM samples with different applied processes, that is, with and without application of vulcanizing agents, vulcanized samples, and microwave treated samples. First the FT-IR spectra of the samples is acquired and next it is processed by applying suitable feature extraction methods, i.e., principal component analysis and canonical variate analysis to obtain the latent variables to be used for classifying test EPDM samples. Finally, the k nearest neighbor algorithm was used in the classification stage. Experimental results prove the accuracy of the proposed method and the potential of FT-IR spectroscopy in this area, since the classification accuracy can be as high as 100%.

  20. Photoinduced anisotropy of push-pull chromophores incorporating 5-(1,3-benzodithiol-2-ylidene)-1-(4-nitrophenyl) penta-1,3-diene embedded into photopolymer oligoetheracrylate matrices

    NASA Astrophysics Data System (ADS)

    Sahraoui, B.; Kityk, I. V.; Kasperczyk, J.; Salle, M.; Nguyen, T. T.

    2000-04-01

    Photoinduced (PI) birefringence (Δ n) and phototransparency ( T) have been studied for a wavelength of 633 nm (He-Ne laser) under photoillumination by doubled-frequency YAG:Nd pulse laser polarized beam ( λ=0.53 μm; pulse duration τ=10-50 ps). The push-pull chromophore 5-(1,3-benzodithiol-2-ylidene)-1-(4-nitrophenyl) penta-1,3-diene was incorporated into an oligoetheracrylate photopolymer matrix in a concentration of about 2.5 wt.%. Special properties of the molecule are connected with substantial role played by electron-vibration interactions in the observed PI effects. The Δ n decreases with decreasing temperature. Optical density D depends non-linearly on the PI beam power. With increasing photoinducing power (up to 0.41 GW/cm 2), the PI birefringence Δ n and the optical density D approaches (1.4-1.7)×10 -3 and 1.5%, respectively. The intensity dependence of intramolecular (669 cm -1) and intermolecular (89.5 cm -1) vibration mode has a maximum and a broad minimum (at a PI power of about 0.45 GW/cm 2), respectively. Such behavior correlates well with the PI dependencies of the Δ n and the optical density D. Description of the obtained results is based on quantum chemical calculations with taking into account an electron-vibration anharmonicity of the chromophore. Essential role of the PI electrostatic potential redistribution under influence of the PI polarized light beam has been demonstrated. Possible mechanisms of the observed phenomena are discussed within a phenomenological as well as microscopic approach.

  1. In Vitro Activity of 2-methoxy-1,4-naphthoquinone and Stigmasta-7,22-diene-3β-ol from Impatiens balsamina L. against Multiple Antibiotic-Resistant Helicobacter pylori

    PubMed Central

    Wang, Yuan-Chuen; Li, Wan-Yu; Wu, Deng-Chyang; Wang, Jeh-Jeng; Wu, Cheng-Hsun; Liao, Jyun-Ji; Lin, Cheng-Kun

    2011-01-01

    Infection with Helicobacter pylori is strongly associated with gastric cancer and gastric adenocarcinoma. WHO classified H. pylori as a group 1 carcinogen in 1994. Impatiens balsamina L. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures and fingernail inflammation. In this study, we isolated anti-H. pylori compounds from this plant and investigated their anti- and bactericidal activity. Compounds of 2-methoxy-1,4-naphthoquinone (MeONQ) and stigmasta-7,22-diene-3β-ol (spinasterol) were isolated from the pods and roots/stems/leaves of I. balsamina L., respectively. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) for MeONQ were in the ranges of 0.156–0.625 and 0.313–0.625 μg mL−1, respectively, and in the ranges of 20–80 μg mL−1 both of MICs and MBCs for spinasterol against antibiotic (clarithromycin, metronidazole and levofloxacin) resistant H. pylori. Notably, the activity of MeONQ was equivalent to that of amoxicillin (AMX). The bactericidal H. pylori action of MeONQ was dose-dependent. Furthermore, the activity of MeONQ was not influenced by the environmental pH values (4–8) and demonstrated good thermal (121°C for 15 min) stability. MeONQ abounds in the I. balsamina L. pod at the level of 4.39% (w/w db). In conclusion, MeONQ exhibits strong potential to be developed as a candidate agent for the eradication of H. pylori infection. PMID:19773391

  2. Cytoprotection of human endothelial cells against oxidative stress by 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im): application of systems biology to understand the mechanism of action.

    PubMed

    Wang, Xinyu; Bynum, James A; Stavchansky, Solomon; Bowman, Phillip D

    2014-07-05

    Cellular damage from oxidative stress, in particular following ischemic injury, occurs during heart attack, stroke, or traumatic injury, and is potentially reducible with appropriate drug treatment. We previously reported that caffeic acid phenethyl ester (CAPE), a plant-derived polyphenolic compound, protected human umbilical vein endothelial cells (HUVEC) from menadione-induced oxidative stress and that this cytoprotective effect was correlated with the capacity to induce heme oxygenase-1 (HMOX1) and its protein product, a phase II cytoprotective enzyme. To further improve this cytoprotective effect, we studied a synthetic triterpenoid, 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im), which is known as a potent phase II enzyme inducer with antitumor and anti-inflammatory activities, and compared it to CAPE. CDDO-Im at 200nM provided more protection to HUVEC against oxidative stress than 20μM CAPE. We explored the mechanism of CDDO-Im cytoprotection with gene expression profiling and pathway analysis and compared to that of CAPE. In addition to potent up-regulation of HMOX1, heat shock proteins (HSP) were also found to be highly induced by CDDO-Im in HUVEC. Pathway analysis results showed that transcription factor Nrf2-mediated oxidative stress response was among the top canonical pathways commonly activated by both CDDO-Im and CAPE. Compared to CAPE, CDDO-Im up-regulated more HSP and some of them to a much higher extent. In addition, CDDO-Im treatment affected Nrf2 pathway more significantly. These findings may provide an explanation why CDDO-Im is a more potent cytoprotectant than CAPE against oxidative stress in HUVEC.

  3. Une association exceptionnelle d’un liposarcome dédifférencié retro péritonéal et d’un liposarcome bien différencié péri colique: à propos d’un cas

    PubMed Central

    Sinaa, Mohamed

    2016-01-01

    Le liposarcome est une tumeur mésenchymateuse maligne de nature adipeuse très rare. L'organisation mondiale de la santé classe les liposarcomes en cinq sous-types: bien différencié, myxoïde, pléomorphe, dédifférencié et mixte. L'association de localisation multiples et synchrones de plusieurs sous types des liposarcomes est exceptionnelle. Seulement 34 cas sont décrits dans la littérature. Nous rapportons une observation d'une association synchrone d'un liposarcome dédifférencié retro péritonéal et deux petits liposarcomes bien différenciés type lipoma-like péri coliques. Les aspects anatomopathologiques, les options thérapeutiques et les facteurs pronostics des liposarcomes seront revus dans cet article. PMID:28293370

  4. (2R*,4R*,7S*,10R*,12R*)-3,11,13,15-Tetra-oxa-penta-cyclo-[5.5.3.0(1,7).0(2,4).0(10,12)]penta-deca-5,8-dien-14-one.

    PubMed

    Mehta, Goverdhan; Sen, Saikat; Kumar, C S Ananda

    2013-01-01

    The title compound, C11H8O5, features a 'skipped' diene, an anti-bis-(epoxide) and a cyclic carbonate, all embedded in a densely functionalized [4.4.3]propellane scaffold. The crystal packing of this diepoxide is effected primarily by C-H⋯O hydrogen bonds, which link the mol-ecules into tapes along the b axis. Inter-tape connectivity is brought about by centrosymmetrically disposed pairs of C⋯O contacts [3.183 (4) Å] between the C(δ+)=O(δ-) dipoles of neighbouring carbonate moieties.

  5. Anticarcinogenic effect of bis-1,7-(2-hydroxyphenyl)-hepta-1,6-diene-3,5-dione a curcumin analog on DMH-induced colon cancer model.

    PubMed

    Devasena, T; Rajasekaran, K N; Gunasekaran, G; Viswanathan, P; Menon, Venugopal P

    2003-02-01

    1,2-Dimethylhydrazine (DMH) is a toxic environmental pollutant which was reported also to be a colon-specific carcinogen. This study was performed to study the effect of bis-1,7-(2-hydroxyphenyl)-hepta-1,6-diene-3,5-dione, a bisdemethoxycurcumin analog (BDMC-A) on DMH-induced colon carcinogenesis in male Wistar rats and effects were compared with that of the reference drug, curcumin. Rats were given a weekly subcutaneous injection of DMH (20mg/kg body weight) in the groin, for 15 weeks. After a total experimental period of 32 weeks (including 2 weeks of acclimatization) tumor incidence was 100% in DMH-treated rats. Tumor was identified histologically as adenocarcinoma. Dysplasia, papillary pattern, cellular pleomorphism and carcinomatous glands were also noticed in DMH-treated rats. However, there was no colonic tumor in DMH+BDMC-A- and DMH+curcumin-treated rats but, lymphocyte infiltrations were observed. The levels of total bile acids and cholesterol in 24h fecal samples were significantly lower in DMH administered rats when compared to control rats, while, the excretion of bile acids and cholesterol were significantly increased and was near normal levels in DMH+BDMC-A- and DMH+curcumin-treated rats. In DMH-induced tumor bearing rats the levels of colonic and intestinal cholesterol was significantly increased whereas, the levels of phospholipid was decreased with a concomitant increase in the activities of phospholipase A (PLA) and phospholipase C (PLC), compared to untreated control rats. Intragastric administration of BDMC-A and curcumin to DMH administered rats significantly lowered the cholesterol content and raised the phospholipid content and lowered the activities of PLA and PLC towards near normal values. Our study shows that the protective effect of BDMC-A during DMH-induced colon carcinogenesis may be due to its modulatory effects on (i). histological changes, (ii). bile acids, (iii). cholesterol, and (iv). phospholipid metabolism in the target organ

  6. Clinical association of baseline levels of conjugated dienes in low-density lipoprotein and nitric oxide with aggressive B-cell non-Hodgkin lymphoma and their relationship with immunoglobulins and Th1-to-Th2 ratio

    PubMed Central

    Haddouche, Mustapha; Meziane, Warda; Hadjidj, Zeyneb; Mesli, Naima; Aribi, Mourad

    2016-01-01

    Objective The aim of this study was to highlight the clinical association of baseline levels of conjugated dienes in low-density lipoprotein (LDL-BCD) and nitric oxide (NO) with immunoglobulins (Igs) and T helper (Th)1/Th2 ratio in patients with newly diagnosed B-cell non-Hodgkin lymphoma (NHL). Patients and methods Thirty-two newly diagnosed patients with aggressive B-cell NHL and 25 age-, sex-, and body-mass-index-matched healthy controls were randomly selected for a cross-sectional case–control study conducted at the Hematology Department of Tlemcen Medical Centre University (northwest of Algeria). Results Circulating levels of LDL-BCD and NO and those of IgA and IgM were significantly higher in patients than in controls. The levels of Th1/Th2 ratio and plasma total antioxidant capacity were significantly lower in patients compared with controls, while malondialdehyde and protein carbonyl levels were significantly higher in patients. B-cell NHL was significantly associated with high levels of LDL-BCD from 25th to 75th percentile (25th percentile: relative risk [RR] =2.26, 95% confidence interval [CI] 1.42–3.59, P=0.014; 50th percentile: RR =2.84, 95% CI 1.72–4.68, P<0.001; 75th percentile: RR =5.43, 95% CI 2.58–11.42, P<0.001). Similarly, the disease was significantly associated with high levels of NO production from 25th to 75th percentile (25th percentile: RR =2.07, 95% CI 1.25–3.44, P=0.024; 50th percentile: RR =2.78, 95% CI 1.63–4.72, P<0.001; 75th percentile: RR =4.68, 95% CI 2.21–9.91, P<0.001). Moreover, LDL-BCD levels were positively and significantly correlated with interferon (IFN)-γ, whereas NO levels were inversely and significantly correlated with IFN-γ and Th1/Th2 ratio. Conclusion LDL-BCD and NO production seem to be associated with aggressive B-cell NHL and alteration of Th1/Th2 ratio. Our results have to be examined using ex vivo mechanistic studies leading to further investigations of these parameters, with an interest in the

  7. Organic Chemistry Self Instructional Package 13: Dienes.

    ERIC Educational Resources Information Center

    Zdravkovich, V.

    This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The…

  8. A new sulfonic acid derivative, (Z)-4-methylundeca-1,9-diene-6-sulfonic acid, isolated from the cold water sea urchin inhibits inflammatory responses through JNK/p38 MAPK and NF-κB inactivation in RAW 264.7.

    PubMed

    Lee, Dong-Sung; Cui, Xiang; Ko, Wonmin; Kim, Kyoung-Su; Kim, Il Chan; Yim, Joung Han; An, Ren-Bo; Kim, Youn-Chul; Oh, Hyuncheol

    2014-08-01

    In this study, we isolated a new sulfonic acid derivative, (Z)-4-methylundeca-1,9-diene-6-sulfonic acid (1), from the sea urchin collected from the Sea of Okhotsk. We established the structure of this new compound by analysis of NMR and HRMS data, along with comparison of the data with those of the related compounds reported in the literature. In addition, we investigated its anti-inflammatory effects in LPS-stimulated RAW264.7 macrophages. Compound 1 inhibited the production of NO, iNOS, PGE2, and COX-2, and it also suppressed the production of pro-inflammatory cytokines, such as TNF-α and IL-1β. It inhibited the translocation of the NF-κB subunit p65 into the nucleus by interrupting the phosphorylation and degradation of IκB-α. In addition, compound 1 significantly decreased the phosphorylation of JNK and p38 in LPS-stimulated RAW264.7 macrophages, suggesting that suppression of the inflammation process by compound 1 was mediated through the MAPK pathway. Taken together, this study showed that the anti-inflammatory effects of a new sulfonic acid derivative, (Z)-4-methylundeca-1,9-diene-6-sulfonic acid were mediated through the inhibition of NF-κB and JNK/p38 MAPK signaling pathways.

  9. Crystal structure of (±)-(1SR,5SR,6SR,7SR,10SR,11SR,13SR)-13-benz-yloxy-7-meth-oxy-meth-oxy-11,15,18,18-tetra-methyl-3-oxo-2,4-dioxa-tetra-cyclo-[12.3.1.0(1,5).0(6,11)]octa-deca-14,16-dien-10-yl benzoate.

    PubMed

    Oishi, Takeshi; Fukaya, Keisuke; Yamaguchi, Yu; Sugai, Tomoya; Watanabe, Ami; Sato, Takaaki; Chida, Noritaka

    2015-05-01

    In the title compound, C36H42O8, the dioxolane ring adopts a twist conformation; the two adjacent C atoms deviate alternately from the mean plane of other atoms by -0.287 (5) and 0.174 (5) Å. The cyclo-hexane, cyclo-hexa-diene and central cyclo-octane rings show chair, half-chair and boat-chair forms, respectively. As a result of the strained ring system, the tetra-subsituted olefin in the cyclo-hexa-diene is skewed from an ideal planar structure. In the crystal, C-H⋯O hydrogen bonds connect the mol-ecules into a sheet parallel to (100). The sheets are further linked by other weak C-H⋯O and C-H⋯π inter-actions, forming a three-dimensional network.

  10. MMHD [(S,E)-2-methyl-1-(2-methylthiazol-4-yl) hexa-1,5-dien-ol], a novel synthetic compound derived from epothilone, suppresses nuclear factor-kappaB-mediated cytokine expression in lipopolysaccharide-stimulated BV-2 microglia.

    PubMed

    Jeon, Na-Ra; Koppula, Sushruta; Kim, Byung-Wook; Park, Su-Ho; Lee, Hyo-Won; Choi, Dong-Kug

    2010-01-01

    The effects of MMHD [(S,E)-2-methyl-1-(2-methylthiazol-4-yl) hexa-1,5-dien-ol], a novel synthetic compound derived from epothilone, was investigated for its effects on the expression of proinflammatory mediators in lipopolysaccharide-stimulated BV-2 microglia. MMHD attenuated the expressions of inducible nitric oxide synthase and cyclooxygenase-2 mRNA and protein without affecting cell viability. Moreover, MMHD suppressed nuclear factor-kappaB (NF-kappaB) activation via the translocation of p65 into the nucleus. These results indicate that MMHD exerts anti-inflammatory properties by suppressing the transcription of proinflammatory cytokine genes through the NF-kappaB signaling pathway.

  11. Synthesis of Pyrazolo[5,1-a]isoindoles and Pyrazolo[5,1-a]isoindole-3-carboxamides through One-Pot Cascade Reactions of 1-(2-Bromophenyl)buta-2,3-dien-1-ones with Isocyanide and Hydrazine or Acetohydrazide.

    PubMed

    Tian, Miaomiao; He, Yan; Zhang, Xinying; Fan, Xuesen

    2015-08-07

    A novel and efficient method for the construction of the pyrazolo[5,1-a]isoindole scaffold via a one-pot three-component cascade reaction of 1-(2-bromophenyl)buta-2,3-dien-1-one with hydrazine and isocyanide promoted by a Pd catalyst is described. This cascade process proceeds through initial condensation of the allenic ketone with hydrazine followed by Pd-catalyzed isocyanide insertion into the C-Br bond and intramolecular C-N bond formation. Interestingly, when acetohydrazide was used in place of hydrazine, a more sophisticated procedure involving condensation, isocyanide insertion into C-H and C-Br bonds, deacetylation, and formation of C-C, C-O, and C-N bonds occurred to afford pyrazolo[5,1-a]isoindole-3-carboxamides with good efficiency.

  12. Crystal structure of μ-fluorido-bis­{(η4-cyclo­octa­diene)[hexa­fluorido­anti­monato(V)]platinum(II)} hexa­fluorido­anti­monate(V) hydrogen fluoride 0.75-solvate1

    PubMed Central

    Seppelt, Konrad; Friedemann, Roland

    2016-01-01

    In the complex cation of the binuclear solvated title salt, [Pt2F(SbF6)2(C8H12)2]SbF6·0.75HF, an F atom bridges the two platinum(II) atoms with a bond angle of 123.3 (2)°. The corresponding Pt—F bond lengths are in the range of other fluorine-bridged binuclear platinum(II) complexes. Two of the three SbF6 − anions each coordinate with one F atom to one platinum(II) atom. Including the η4-bound cyclo­octa­diene (COD) ligands, the overall coordination sphere of each platinum(II) atom is square-planar. The third SbF6 − anion is not bound to the complex. Hydrogen fluoride is present in the crystal structure as a solvent disordered over three positions, each with an occupancy of 0.25. F⋯F distances of 2.5512 (7), 2.6076 (8) and 3.2215 (10) Å to surrounding SbF6 − anions are indicative of F—H⋯F hydrogen-bonding inter­actions although no H atoms could be localized for the disordered solvent mol­ecules. The resulting hydrogen-bonded network is three-dimensional. PMID:26870575

  13. (μ-3,4-Diacetyl­hexa-2,4-diene-2,5-diol­ato-κ4 O 2,O 3:O 4,O 5)bis­[aqua(1,10-phen­an­thro­line-κ2 N,N′)copper(II)] bis­(tetra­fluorid­oborate) monohydrate

    PubMed Central

    Tovilla, Jorge A.; Hernández-Ortega, Simón; Valdés-Martínez, Jesús

    2009-01-01

    In the title compound, [Cu2(C10H12O4)(C12H8N2)2(H2O)2](BF4)2·H2O, the two Cu atoms are each chelated by the acetyl­acetonate unit of the 3,4-diacetyl­hexa-2,4-diene-2,5-diolate (tae) ligand. The Cu atoms are square-pyramidally penta­coordinated, with one bidentate 1,10-phenanthroline (phen) and the tae ligand basal and one water mol­ecule apical. The pyridyl rings of the phen ligands participate in π–π [centroid–centroid distance = 3.894 (3) Å] and C—H ⋯ π inter­actions, generating layers which are inter­connected through O—H⋯O and O—H⋯F hydrogen bonds between the water mol­ecules and the tetra­fluorido­borate anions. The F atoms of both tetra­fluorido­borate anions are each disordered over two positions of equal occupancy. PMID:21582322

  14. "Bien Educado": Measuring the Social Behaviors of Mexican American Children

    ERIC Educational Resources Information Center

    Bridges, Margaret; Cohen, Shana R.; McGuire, Leah Walker; Yamada, Hiro; Fuller, Bruce; Mireles, Laurie; Scott, Lyn

    2012-01-01

    Young children's expected social behaviors develop within particular cultural contexts and contribute to their academic experience in large part through their relationships with their teachers. Commonly used measures focus on children's problem behaviors, developed from psychopathology traditions, and rarely situate normative and positive…

  15. Paleomagnetic data from Upper Cretaceous Red Beds, Northwest Vietnam (Song Da Terrane), and Their Bearing on the Extrusion History of Indochina and Deformation Along its Margins

    NASA Astrophysics Data System (ADS)

    Geissman, J. W.; Pho, N.; Burchfiel, B.; Muggleton, S. R.

    2008-12-01

    Northwest Vietnam mainly consists of the Song Da terrane, which is bounded to the east by the NW-oriented Ailao Shan/Red River (ASRR) fault system, interpreted to be the southwest margin of the South China Block, and the NW-oriented Song Ma fault. The northern termination of the Song Da terrane is considered to be where the NE-oriented, right lateral Dien Bien Phu fault intersects the ASRR. Whether the Song Da terrane is part of the extruded Indochina Block, paleomagnetic data from which suggest some 10°+ southward latitudinal displacement, can be evaluated with paleomagnetic data from rocks of the appropriate age. Our paleomagnetic sampling concentrated on the Upper Cretaceous Yen Chau Formation, which unconformably overlies Paleozoic and Triassic sedimentary rocks. The Yen Chau Formation is locally up to about 1300 m thick, and is characterized by medium to thick bedded, coarse to fine-grained sandstones and siltstones, all of which are partially cemented by hematite. Samples were collected from 10 localities using a portable drill, with 6 to 19 sites collected per locality, and 7 to 15 samples collected from each site. This approach allows evaluation of the integrity of the remanence at the locality level, where, presumably, considerable time is recorded in each section. Each locality is a homoclinal road cut exposure, with bedding dips varying from sub-horizontal to moderately overturned. NRM intensities range from about 0.7 mA/m to about 25 mA/m; values which are relatively low in comparison to many red beds. A varied response to alternating field (AF) demagnetization indicates that magnetite carries a considerable (over 50 percent) of the remanence; the finest grained samples of relatively high NRM intensity reveal little response to AF treatment, indicating a dominance by hematite, as also supported by three-component IRM thermal demagnetization. Samples with the highest NRM intensities and the least contribution by magnetite respond favorably to thermal

  16. Polymerization of 1,3-Dienes with Functional Groups. 4.

    NASA Astrophysics Data System (ADS)

    Takenaka, Katsuhiko; Shibata, Natsuyo; Tsuchida, Shinsuke; Takeshita, Hiroki; Miya, Masamitsu; Shiomi, Tomoo

    Anionic polymerization of N,N-diethyl-2-methylene-3-butenamide (DEA), which is a 1,3-butadiene derivative containing a diethylamide function, was carried out in tetrahydrofurane (THF) under various conditions. When DEA was polymerized in THF at -78°C using potassium naphthalenide (K-Naph) or diphenylmethylpotassium (DPMK) as an initiator, a polymer of predictable molecular weight with a narrow molecular weight distribution was obtained. However, the rate of polymerization was extremely slow to reach 80% conversion after 720 h. When the polymerization temperature was raised to 20°C, a low molecular weight oligomer with a broad molecular weight distribution was obtained because of a chain transfer reaction. On the other hand, no such side reaction occurred even at 20°C, when polymerization was carried out in the presence of LiCl. Also, the chain transfer reaction did not occur in lithium naphthalenide (Li-Naph) initiated polymerization. The microstructure of the polymer prepared using a potassium counter cation was a 1 : 1 mixture of 1,4-E and 1,2- structures. In the case of Li-Naph or DPMK/LiCl systems, the microstructure was a complicated mixture of 1,4-E, 1,4-Z, and 1,2-structures.

  17. Tandem isomerization/telomerization of long chain dienes

    NASA Astrophysics Data System (ADS)

    Torrente Murciano, Laura; Nielsen, David; Cavell, Kingsley; Lapkin, Alexei

    2014-06-01

    The first example of a tandem reaction involving double-bond migration in combination with telomerization is reported. Homogeneous and heterogeneous Ru catalysts were employed as isomerisation catalysts, and telomerization was realized using a homogeneous Pd(0) precursor complex with a N-heterocyclic carbene (IMes) ligand. Overall conversions approaching 60 % were achieved with the best selectivity to telomerization products of 91% attained at 11 % conversion. Conversion was markedly higher in the presence of longer-chain alcohol (1-butanol) as the nucleophile (telogen).

  18. Numerical Simulation of Petroleum Generation and Migration in the Song Hong Basin, Vietnam

    NASA Astrophysics Data System (ADS)

    Son, Byeong-Kook; Thi Nguyen, Hong; Park, Mee-Sook

    2014-05-01

    The numerical modeling of petroleum systems is an effective tool to understand generation, migration and accumulation of hydrocarbons in a sedimentary basin and hence to determine future targets for the hydrocarbon exploration. The numerical modeling identifies two petroleum systems in the Song Hong Basin, which is a petroliferous Cenozoic basin, offshore eastern Vietnam. These petroleum systems were named DinhCao-PhuCu(.) Petroleum System and SongHuong-BienDong(.) Petroleum System. DinhCao-PhuCu(.) Petroleum System covers northern and central parts of the Song Hong basin with Oligocene shale and coaly shale source rocks of Dinh Cao formation, which are dominated by type II-III kerogens. The hydrocarbon generation starts at 13 Ma within deeply buried Oligocene strata located in the centre of the basin. The hydrocarbon expels from the Oligocene source rock and migrates laterally and then up dip toward marginal areas where Middle Miocene sandstones of Phu Cu formation are present as major reservoirs. The numerical model shows that the critical moment occurs at about 3.5 Ma. The DinhCao-PhuCu(.) petroleum system is confirmed by sparse occurrence of oil and gas along the coast of eastern Vietnam. SongHuong-BienDong(.) Petroleum System is identified in limited areas of the central and southern Song Hong basin. The major source rock of this petroleum system is Lower Miocene dark claystones of Song Huong formation which contain gas prone, type III kerogen. The migration model shows that hydrocarbons are generated from the Miocene source rocks in the center of the basin at about 12 Ma, and migrates updip through sand bodies of Quang Ngai formation to the major boundaries faults, and further moves into highly permeable up-dipping units, the Bien Dong formation. The best depiction of the generation-migration-accumulation of hydrocarbons occurs at about 2 Ma. The presence of the SongHuong-BienDong(.) Petroleum System is indicated by the large gas fields in the central and

  19. Silurian and Devonian in Vietnam—Stratigraphy and facies

    NASA Astrophysics Data System (ADS)

    Thanh, Tống Duy; Phương, Tạ Hoàng; Janvier, Philippe; Hùng, Nguyễn Hữu; Cúc, Nguyễn Thị Thu; Dương, Nguyễn Thùy

    2013-09-01

    Silurian and Devonian deposits in Viet Nam are present in several zones and regions, including Quang Ninh, East Bac Bo, and West Bac Bo Zones of the Bac Bo Region, the Dien Bien-Nghe An and Binh Tri Thien Zones of the Viet-Lao Region, and the South Trung Bo, and Western Nam Bo Zones of the South Viet Nam Region (Fig. 1). The main lithological features and faunal composition of the Silurian and Devonian Units in all these zones are briefly described. The Silurian consists of deep-water deposits of the upper parts of the Co To and Tan Mai Formations in the Quang Ninh Zone, the upper parts of the Phu Ngu Formation in the East Bac Bo Zone and the upper parts of the Long Dai and Song Ca Formations in the Viet-Lao Region. Shallow water facies Silurian units containing benthic faunas are more widely distributed, including the upper part of the Sinh Vinh and Bo Hieng Formations in the West Bac Bo Zone, the Kien An Formation in the Quang Ninh Zone, and, in the Viet-Lao Region, the Dai Giang Formation and the upper part of the Tay Trang Formation. No Lower and Middle Devonian deposits indicate deep water facies, but they are characterized by different shallow water facies. Continental to near shore, deltaic facies characterize the Lower Devonian Song Cau Group in the East Bac Bo Zone, the Van Canh Formation in the Quang Ninh Zone, and the A Choc Formation in the Binh Tri Thien Zone. Similar facies also occur in the Givetian Do Son Formation of the Quang Ninh Zone, and the Tan Lap Formation in the East Bac Bo Zone, and consist of coarse terrigenous deposits—cross-bedded conglomerates, sandstone, etc. Most Devonian units are characterized by shallow marine shelf facies. Carbonate and terrigenous-carbonate facies dominate, and terrigenous facies occur in the Lower and Middle Devonian sections in some areas only. The deep-water-like facies is characteriztic for some Upper Devonian formations in the Bac Bo (Bang Ca and Toc Tat Formations) and Viet-Lao Regions (Thien Nhan and

  20. Pa/enser bien le corps: Cognitive and Curative Language in Montaigne's Essais.

    PubMed

    Robert, Julie

    2015-09-01

    Montaigne's writings on medicine and the body have always been seen as part of a larger project about knowing ourselves. Responding to medical developments that seemed to privilege the anatomical body over the mind or the emotions, Montaigne defended the humoral link between mind and body. His essays make use of word play, puns, and anecdotes based on his own experience and reports from antiquity to counter what he perceived to be an increasingly one-sided approach to medicine. The result is a witty but nuanced argument for a more balanced outlook to what is now known as psychosomatic medicine.

  1. Morphology and vulcanizate properties of ethylene-propylene-diene rubber/ styrene-butadiene rubber blends.

    PubMed

    Park, Gayoung; Kim, Yun Hee; Kim, Dong Soo; Ko, Young Chun

    2010-05-01

    Morphology and vulcanizate properties of EPDM/SBR blends were investigated. AAHR (a mixture of aliphatic and aromatic hydrocarbon resins) was used as a compatibilizer and bis(3-triethoxysilylpropyl)tetrasulfide (TESPT) was used as a coupling agent. The vulcanizate properties and the morphological studies revealed that EPDM and SBR were incompatible, and the addition of AAHR was very effective to enhance the compatibility between EPDM and SBR. The weight percent of bound rubbers was increased with increasing SBR contents. The addition of an AAHR increased the amounts of bound rubbers, and hence the vulcanizate properties such as tear strength and fatigue resistance of the EPDM/SBR blends were improved. The dynamic mechanical analysis and the morphological studies revealed that the addition of TESPT increased the weight of bound rubbers and provided better dispersion of carbon black, resulting in good mechanical properties such as tear strength and fatigue resistance of the vulcanized EPDM/SBR blends. The smaller particle of zinc oxide (i.e., 50 nm > 100 nm > 1000 nm) yielded to the better blending properties of the polymer blend.

  2. 1-CHLORO-(2S, 3S)-DIHYDROXYCYCLO-HEXA-4, 6-DIENE. (R826113)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  3. Envisioning an enzymatic Diels-Alder reaction by in situ acid-base catalyzed diene generation.

    PubMed

    Linder, Mats; Johansson, Adam Johannes; Manta, Bianca; Olsson, Philip; Brinck, Tore

    2012-06-07

    We present and evaluate a new and potentially efficient route for enzyme-mediated Diels-Alder reactions, utilizing general acid-base catalysis. The viability of employing the active site of ketosteroid isomerase is demonstrated.

  4. Excited-state reaction pathways for s-cis buta-1,3-diene

    NASA Astrophysics Data System (ADS)

    Celani, Paolo; Bernardi, Fernando; Olivucci, Massimo; Robb, Michael A.

    1995-04-01

    The topology and energetics of the potential energy surfaces associated with the 2A1 and 1B2 valence excited states of s-cis butadiene have been investigated via ab initio quantum chemical computations at a level of theory which includes dynamic correlation effects and extended basis sets. The results support a photochemical ring-closure mechanism involving 1B2 and 2A1 reaction/relaxation pathways that are disrotatory. The reaction path on the 2A1 surface begins at a 1B2/2A1 conical intersection and the ground state photoproducts are produced via radiationless decay at a second 2A1/1A1 conical intersection which has been documented in a previous publication. A local Cs equilibrium structure on 1B2 potential energy surface has been optimized using the complete active space-self-consistent field and configuration interaction singles methods. The 1B2/2A1 conical intersection is located near this Cs equilibrium structure and offers a rationalization of the experimentally observed femtosecond lifetime of this state. The observed preferential disrotatory stereochemistry appears to be simply determined by a difference in the energy barriers located along the 2A1 disrotatory and conrotatory paths. This finding is in contrast with the generally accepted notion that the stereochemistry is determined by a different rate of internal conversion at a ``disrotatory'' and ``conrotatory'' avoided crossing minima. Indeed, no avoided crossing can be located along the 2A1 paths.

  5. Synthesis and Polymerization of Azaethylenes and Aza-1,3-dienes

    DTIC Science & Technology

    1993-04-08

    TERMS polymerization imine azadiene IT. SECURITY CLASSIFICATION EM RIRCRT CL SECURITY CLASS»ICATION at um Raw J£ SECURITY CLASSIFICATION m Miisat...program on the synthesis and polymerization of suitably substituted imines and azadienes under USARO sponsorship. We have shown that proper choice of... azadienes could be purified. NHoCN TiCt4 EtaN R = H, Me Neither azadiene would homopolymerize under either free radical or anionic conditions. With

  6. Bis(η(5)-penta-methyl-cyclo-penta-dien-yl)aluminium tetra-bromido-aluminate.

    PubMed

    Purdy, Andrew P; Dugger, Cherrelle; Butcher, Ray J

    2014-03-01

    The title compound, [Al(C10H15)2][AlBr4], was formed during the reduction of a mixture of Cp*AlBr2 and AlBr3. The Al(III) atoms of the two crystallographically independent cations each lie on an inversion center, and the [AlBr4](-) anions are on general positions. At 123 K, the structure exhibits disorder in two of the Br atoms of the [AlBr4](-) ion, with a ratio occupancy of 0.733 (6): 0.267 (3). In the crystal, there is possible weak hydrogen bonding between some methyl groups and Br atoms. The interactions link the moieties in a three-dimensional array.

  7. Field Test Results of Experimental EPDM (Ethylene Propylene Diene Monomer) and PUF (Polyurethane Foam) Roofing.

    DTIC Science & Technology

    1984-09-01

    43 Benning; PUF roofing at Fort Benning; PUF roofing . . . asphalt -saturated and coated glass fiber base sheet in at Fort Knox; and EPDM, PUF, and BUR... roofing at - hot asphalt , 2 in. (64 mm) of rigid inorganic board Fort Lewis. USA-CERL Technical Report M-298 0 stock with asphalt -saturated organic...a two-ply vapor performance of the materials in a roof assembly. retarder of No. 15 asphalt -saturated organic felt, a American Society for Testing and

  8. Polar, Functional Diene-Based Materials: Free Radical Polymerization of 2-Cyanomethyl-1,3-Butadiene

    SciTech Connect

    Jing, Y

    2000-09-12

    This thesis presented here focuses on the synthesis of 2-cyanomethyl-l ,3-butadiene and the free-radical polymerization of this monomer. In addition to the bulk, solution and emulsion polymerizations,, copolymerization with styrene and acrylonitrile will also be discussed. The comonomers were chosen due to the potential applications mentioned above. Furthermore, the thermal properties and rnicrostructures of the homopolymers and the copolymers are examined.

  9. World heritage site - Bien du Patrimoine Mondial - Kluane/Wrangell-St. Elias/Glacier Bay/Tatshenshini-Alsek

    USGS Publications Warehouse

    Labay, Keith A.; Wilson, Frederic H.

    2004-01-01

    The four parks depicted on this map make up a single World Heritage Site that covers 24.3 million acres. Together, they comprise the largest internationally protected land-based ecosystem on the planet. The United Nations Educational, Scientific and Cultural Organization (UNESCO) established the World Heritage Program in 1972 for the identification and protection of the world?s irreplaceable natural and cultural resources. World Heritage Sites are important as storehouses of memory and evolution, as anchors for sustainable tourism and community, and as laboratories for the study and understanding of the earth and culture. This World Heritage Site protects the prominent mountain ranges of Kluane, Wrangell, Saint Elias, and Chugach. It includes many of the tallest peaks on the continent, the world's largest non-polar icefield, extensive glaciers, vital watersheds, and expanses of dramatic wilderness. [Les quatre parcs figurant sur cette carte ne constituent qu?un seul site du patrimoine mondial recouvrant plus de 99 millions de km2, ce qui en fait le plus grand ecosysteme terrestre protege par loi internationale. En 1972, L?UNESCO (l?organisation des Nations Unies pour les sciences, l'education et la culture) a etabli le programme du patrimoine mondial afin d?identifier et de proteger les ressources naturelles et culturelles irremplacables de notre plan?te. Si les sites du patrimoine mondial sont si importants c'est parce qu'ils representent a la fois des livres ouverts sur l?histoire de la Terre, le point de depart du tourisme durable et du developpement des collectivites, des laboratoires pour etudier et comprendre la nature et la culture. Ce site du patrimoine mondial assure la protection des chaines de montagnes de Kluane, Wrangell, Saint Elias, et Chugach. On y trouve plusieurs des plus hauts sommets du continent, le plus grand champ de glace non-polaire du monde, d?immenses glaciers, des bassins hydrologiques essentiels, et de la nature sauvage a perte de vue.

  10. Le mécanisme d'Anticythère, une machine bien mystérieuse (1)

    NASA Astrophysics Data System (ADS)

    Dupas, Jean-Jacques

    2016-09-01

    A roman shipwreck was discovered in 1900, near the coast of a small island, Antikythera. Among findings was an object full of gears and axles, with inscriptions. It is called Antikythera Mechanism. The interdisciplinary researches, with modern technics (tomography), proved that it is a mechanical calculating device which displays calendars and related astronomical phenomena : egyptian calendar, metonic calendar, callipic calendar, Saros and Exelgimos dials, Games dials, Sun's motion, Moon's motion realized through a remarkable epicycle gears train. The origin of the Mechanism and his designer are unknown. However, it was probably built during the second half of the 2nd century BCE, as part of the tradition of “sphere making” originated by Archimedes. May be, Poseidonios, from Rhodes, would be the designer. Antikythera Mechanism has not delivered all its mysteries yet. A second paper in a following issue of "l'Astronomie" is devoted to the subject.

  11. Mental Health and Well-Being across the Military Spectrum (Bien-etre et sante mentale dans le milieu militaire)

    DTIC Science & Technology

    2011-04-01

    seek help. Implementing the desirable attitude change within a traditionally tough ( macho ) military culture is a real challenge and specific...changement souhaitable de comportement dans un environnement militaire de culture traditionnellement rude ( macho ) est un vrai défi, et il est recommandé

  12. E. C. Meyer, General, United States Army, Chief of Staff, June 1979-June 1983

    DTIC Science & Technology

    1983-01-01

    there may be just enough bet- bag. Called to service in South East Asia, we read ween us if, and I emphasize if, we can find the the history of Dien Bien ...commend it to your persona . process of professional search and reflection, we library if it is not already present, for these pur- risk losing the...the maturity and spirit be-to the Nation. to try in a persona quest for excellence can forge the hammer by which we break the link which You’ve

  13. [η5-1,3-Bis(trimethyl­sil­yl)cyclo­penta­dien­yl]dichlorido[η5-(trimethyl­sil­yl)cyclo­penta­dien­yl]titanium(IV)

    PubMed Central

    Perdih, Franc

    2011-01-01

    In the title compound, [Ti(C8H13Si)(C11H21Si2)Cl2], the TiIV atom is bonded to two Cl atoms, one 1,3-bis­(trimethyl­sil­yl)cyclo­penta­dienyl (Si2Cp) and one (trimethyl­sil­yl)cyclo­penta­dienyl ring (SiCp). The Si2Cp centroid–titanium distance is 2.0763 (10) Å and the SiCp centroid–titanium distance is 2.0793 (10) Å. The angle subtended at the Ti atom by the centroids of both cyclo­penta­dienyl rings is 131.22 (4)° and the Cl—Ti—Cl angle is 94.14 (2)°. PMID:22199510

  14. Thermal Reactions of RuCO)3(C2H4)2 with Acrylic, Non-Conjugated Dienes and Photochemistry of Ru(CO)4(eta squared-diene) Complexes

    DTIC Science & Technology

    1988-08-15

    1981, 103, 2129. 7. Turner, J. J.; Poliakoff, M. ACS Symposium, No 211, 1983, pp 35. 8. Fleckner, H.; Grevels , F.-W.; Hess, D. J. Am. Chem. Scc., 1984...106, 2027. 9. Kiel, G. K.; Takats, J.; Grevels , F.-W. J. Am. Chem. Soc., 1987, 109, 2227. 10. Mitchener, J. C.; Wrighton, M. S. J. Am. Chem. Soc., 1981

  15. Bilingual Dictionary of Mathematical Terms. English-Vietnamese = Tu-Dien Song Ngu Danh-Tu Toan. Anh-Viet.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Bilingual Education.

    This bilingual dictionary was developed for use by Vietnamese junior high and high school students to assist them in their understanding of mathematical vocabulary and concepts in English. Terminology and definitions are provided in English, with Vietnamese translations directly below each entry. When possible, an illustration is included.…

  16. Crystal structure of 1,6-di-thia-cyclo-deca-cis-3,cis-8-diene (DTCDD).

    PubMed

    Baughman, Russell G; Delanty, Molly C; Ortwerth, Michael F

    2014-11-01

    The title compound, C8H12S2 (trivial name DTCDD), was obtained as a side product of the reaction between cis-1,4-di-chloro-but-2-ene and sodium sulfide. The asymmetric unit consists of one-quarter of the mol-ecule (S site symmetry 2) and the complete mol-ecule has 2/m (C 2h ) point symmetry with the C=C bond in an E conformation. The geometry of the title compound is compared to those of a chloro derivative and a mercury complex.

  17. Diels-Alder Trapping of Photochemically Generated Dienes with Acrylic Esters: A Novel Approach to Photocured Polymer Film Development

    NASA Technical Reports Server (NTRS)

    Ilhan, Faysal; Tyson, Daniel S.; Smith, Deedee; Meador, Mary Ann; Meador, Michael A.

    2004-01-01

    Diels-Alder cycloadditions have often been utilized in polymer synthesis as an alternative to condensation reactions. In our earlier efforts, we developed a new method for the preparation of linear aromatic polyimides, which employs o-quionodimethanes (o-QDMs), generated by a well-known photochemical reaction: the photoenolization of o-methylphenyl ketones. Photolysis of o-methylbenzophenone 1 produces hydroxy-o-quino- diemthane 2, which can be trapped with dienophiles, such as dimethyl acetylenedicarboxylate, to efficiently yield the corresponding cycloadduct (Scheme 1). Here we extend this approach to a novel photocuring process for development of polymer films. We synthesized a series of molecules with multi o-mehtylphenyl ketone functionalities. We further investigated these molecules as photoreactive monomers to obtain polyester films through Diels-Alder cycloadditions.

  18. 1,3,5-Tris(pyridin-3-yl)-2,4-diaza­penta-1,4-diene

    PubMed Central

    Quiroa-Montalván, Claudia M.; Aguirre, Gerardo; Parra-Hake, Miguel

    2012-01-01

    In the solid state, the structure of the title compound, C18H15N5, is stabilized by weak C—H⋯N interactions. Mol­ecules are arranged in layers parallel to the bc plane forming an inter­esting supra­molecular structure. PMID:22412625

  19. Picosecond laser spectroscopy of photocycloaddition reaction of 9-cyanoanthracene-1,3-diene systems and photodecomposition reaction of the cycloadducts

    NASA Astrophysics Data System (ADS)

    Okada, Tadashi; Kida, Kenji; Mataga, Noboru

    1982-04-01

    Transient absorption spectra of singlet biradical in addition to exciplex have been observed in the course of the photocycloaddition reaction of 9-cyanoanthracene (CNA) with 2,5-dimethyl-2,4-hexadiene (DMHD) while no intermediate was detected in CNA-1,3-cyclohexadiene (CHD). The cycloadduct with CHD shows an efficient adiabatic photodissociation into 1CNA ≠ and CHD immediately after excitation.

  20. Mechanistic interpretation of selective catalytic hydrogenation and isomerization of alkenes and dienes by ligand deactivated Pd nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhu, Jie S.; Shon, Young-Seok

    2015-10-01

    Unsupported thiolate-capped palladium nanoparticle catalysts are found to be highly substrate-selective for alkene hydrogenation and isomerization. Steric and poisoning effects from thiolate ligands on the nanoparticle surface control reactivity and selectivity by influencing alkene adsorption and directing either di-σ or mono-σ bond formation. The presence of overlapping p orbitals and α protons in alkenes greatly influences the catalytic properties of deactivated palladium nanoparticles leading to easily predictable hydrogenation or isomerization products.Unsupported thiolate-capped palladium nanoparticle catalysts are found to be highly substrate-selective for alkene hydrogenation and isomerization. Steric and poisoning effects from thiolate ligands on the nanoparticle surface control reactivity and selectivity by influencing alkene adsorption and directing either di-σ or mono-σ bond formation. The presence of overlapping p orbitals and α protons in alkenes greatly influences the catalytic properties of deactivated palladium nanoparticles leading to easily predictable hydrogenation or isomerization products. Electronic supplementary information (ESI) available: Supplementary figures, methods, materials, and characterization data. See DOI: 10.1039/c5nr05090a

  1. 17β-Hy­droxy-17α-methyl­androsta-1,4-dien-3-one

    PubMed Central

    Karpinska, Jolanta; Erxleben, Andrea; McArdle, Patrick

    2013-01-01

    The title compound, C20H28O2, is a steroid with strong anabolic properties. The present solvent-free form crystallizes with two mol­ecules per asymmetric unit. In the crystal, both mol­ecules are involved in the formation of O—H⋯O hydrogen-bonded chains which extend along the b-axis direction. PMID:23476441

  2. Stereoselective Synthesis of 8,12-Furanoeudesmanes from Santonin. Absolute Stereochemistry of Natural Furanoeudesma-1,3-diene and Tubipofurane.

    PubMed

    Blay, Gonzalo; Cardona, Luz; García, Begoña; Pedro, José R.; Sánchez, Juan J.

    1996-05-31

    Ketobutenolide 3, easily obtained from santonin (1), has been transformed into two natural furanoeudesmanes 4 and 5, isolated from Commiphora molmol and Tubipora musica, respectively. trans- And cis-decalin systems were obtained by stereoselective reduction of the C(4)-C(5) double bond in 3 in the following way: hydrogenation of 3 over Pd/C followed by acidic treatment gave the cis isomer 10 as the major product; selective hydrogenation of the C(1)-C(2) double bond with the Wilkinson's catalyst followed by reduction with NaTeH yielded mainly the trans isomer 9. Compounds 9 and 10 were transformed into 4 and 5 in parallel sequences. Optical rotation and CD measurements of the synthetic products revealed that the stereochemistry of both natural products should be revised to their enantiomeric form.

  3. Iodidobis(η5-penta­methyl­cyclo­penta­dien­yl)titanium(III)

    PubMed Central

    Kessler, Monty; Spannenberg, Anke; Rosenthal, Uwe

    2010-01-01

    In the title complex mol­ecule, [Ti(C10H15)2I], the paramagnetic Ti(III) atom is coordinated by two penta­methyl­cyclo­penta­dienyl (Cp*) ligands and one iodide ligand. The two Cp* ligands are in a staggered orientation. The coordination geometry at the titanium atom can be described as distorted trigonal-planar. PMID:21588833

  4. Bis(η5-penta­methyl­cyclo­penta­dien­yl)cobalt(II)

    PubMed Central

    Clark, Meghan M.; Brennessel, William W.; Holland, Patrick L.

    2009-01-01

    The crystal structure of the title compound, deca­methyl­cobaltocene, [Co(C10H15)2], has been determined. High-quality single crystals were grown from a cold saturated hexa­methyl­disiloxane solution. The structure is related to the manganese and iron analogs. The molecule has D 5d symmetry, with the Co atom in a crystallographic 2/m position. The cobalt–centroid(C5) distance is 1.71Å and the centroid(C5)–Co–centroid(C5) angle is 180°, by symmetry. PMID:21582340

  5. Azido-(η(5)-penta-methyl-cyclo-penta-dien-yl)[2-(pyridin-2-yl)phen-yl]iridium(III).

    PubMed

    Ariyoshi, Keita; Suzuki, Takayoshi

    2013-01-01

    In the title compound, [Ir(C10H15)(C11H8N)(N3)], the Ir(III) ion is coordinated by three anionic ligands, namely, penta-methyl-cyclo-penta-dienyl (Cp*(-)), 2-(pyridin-2-yl)phenyl (ppy(-)) and azide (N3 (-)), and adopts a three-legged piano-stool geometry The coordination mode of N3 (-) is typical for Cp*Ir(III)-N3 complexes, with an Ir-N(N3) bond length of 2.125 (2) Å and an Ir-N=N bond angle of 116.5 (2)°. The N3 (-) ligand is almost linear [N=N=N = 176.0 (3)°], and the N=N bond length between the central and coordinating N atom and that between the central and non-coordinating terminal N atom are 1.194 (3) and 1.157 (3) Å, respectively. For the ppy(-) ligand, the Ir-C and Ir-N bond lengths are 2.066 (3) and 2.079 (3) Å, respectively, which are rather close to each other, compared to the related Ir(III)- or Rh(III)-ppy complexes. The Ir-C(Cp*) bond lengths vary in the range 2.163 (2)-2.232 (2) Å, indicating a strong trans influence of the cyclo-metallated C-donor atom of the ppy(-) ligand.

  6. Hybrid metal/organo relay catalysis enables enynes to be latent dienes for asymmetric Diels-Alder reaction.

    PubMed

    Han, Zhi-Yong; Chen, Dian-Feng; Wang, Ya-Yi; Guo, Rui; Wang, Pu-Sheng; Wang, Chao; Gong, Liu-Zhu

    2012-04-18

    The hybrid Au(I)/Brønsted acid binary catalyst system enables enynes to serve as latent 1,3-silyloxydienes capable of participating in the first cascade hydrosiloxylation of an enynyl silanol/asymmetric Diels-Alder reaction. A variety of polycyclic compounds bearing multistereogenic centers were obtained in high yields and excellent enantioselectivities from the relay catalytic cascade reaction between (2-(but-3-en-1-ynyl)phenyl) silanols and quinones catalyzed by the combined achiral gold complex and chiral N-triflyl phosphoramide.

  7. Katimavik Participant's Manual, Book VIII, Nutrition and Well-Being = Katimavik manuel du participant, cahier VIII, l'alimentation et le bien-etre.

    ERIC Educational Resources Information Center

    Crelinsten, Michael, Ed.

    The bilingual student manual focuses on the nutrition and well-being learning activity portion of Katimavik, a nine-month volunteer community service and experiential learning program for 17 to 21 year old Canadians. Providing participants with basic information and tools to assess and improve nutritional states and tie nutrition concerns into a…

  8. Family Incomes: Will Your Children Be as Well Off as Your? = Les revenue familiaux: vos enfants s'en tireront-ils aussi bien que vous?

    ERIC Educational Resources Information Center

    Theilheimer, Ish, Ed.

    1993-01-01

    Against the background of recent radical changes in the Canadian economy, this issue of the Canadian journal "Transition" examines the question of parents' concerns for their children's economic futures. "Changes in Family Incomes and Labour Market Participation in Post-War Canada" (David Ross and Clarence Lochhead) charts…

  9. L'eveil a la lecture et a l'ecriture debute bien avant l'ecole (Awakening To Reading and Writing Begins Well before School).

    ERIC Educational Resources Information Center

    Blain, Francois

    2001-01-01

    The Marie-Victorin school board, in cooperation with 11 community organizations in Longueuil, Quebec, launched "De A a Z, On s'aide!," a project designed to encourage an interest in reading and writing in families with children 0-4 years old and break the recurrent cycle of illiteracy that plagues poor neighborhoods. (TD)

  10. Les expériences de victimisation, la santé mentale et le bien-être de jeunes trans au Québec

    PubMed Central

    Raymond, Guillaume; Blais, Martin; Bergeron, Félix-Antoine; Hébert, Martine

    2016-01-01

    Résumé Les normes traditionnelles de genre prescrivent l’adéquation de l’expression de la masculinité et de la féminité au sexe anatomique de naissance. Les personnes qui présentent des variations dans l’expression de genre sont sujettes à diverses formes de réactions sociales suggérant la réprobation (des regards désapprobateurs aux violences physiques) susceptibles d’influencer négativement leur santé mentale. Trente-sept (37) jeunes se décrivant comme trans ou en questionnement sur leur identité de genre ont été recrutés dans le cadre de l’enquête sur les Parcours Amoureux des Jeunes de minorités sexuelles du Québec. Leurs expériences de victimisation parentale et de victimisation basée sur la non-conformité de genre ainsi que des indicateurs de santé mentale (détresse psychologique, estime de soi) ont été mesurés. Afin de comparer les expériences de victimisation et l’état de santé mentale des jeunes trans, ils ont été appariés à 37 garçons et 37 filles cisgenres sur la base de leurs caractéristiques sociodémographiques. Des analyses de prévalence et un modèle acheminatoire ont été réalisés. Les résultats mettent en évidence que les jeunes trans sont plus susceptibles de présenter des scores cliniques de détresse psychologique et de faible estime d’eux-mêmes que leurs pairs cisgenres. La violence verbale parentale et la victimisation basée sur la non-conformité de genre influencent négativement l’estime de soi, ce qui en retour augmente la probabilité de vivre de la détresse psychologique. Les résultats appuient l’importance des interventions de soutien à la diversité sexuelle et de genre. PMID:26966849

  11. 77 FR 34935 - Certain Frozen Warmwater Shrimp From the Socialist Republic of Vietnam: Notice of Court Decision...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-12

    ... Company; Phu Cuong Seafood Processing and Import-Export Co., Ltd.; Sao Ta Foods Joint Stock Company; Soc... Company (`Nha Trang 0.26 Seafoods''). Phu Cuong Seafood Processing and Import-Export 0.26 Co., Ltd. Sao Ta Foods Joint Stock Company (``Fimex 0.26 VN''), aka Sao Ta Seafood Factory. Soc Trang Seafood Joint...

  12. The in vitro digestibility of beef varies with its inherent ultimate pH.

    PubMed

    Farouk, Mustafa M; Wu, Guojie; Frost, Deborah A; Clerens, Stefan; Knowles, Scott O

    2014-11-01

    Animal carcasses and cuts of meat are usually differentiated and valued according to size and compositional attributes. An underappreciated variable of red meat is its inherent ultimate pH (pHu) value, which affects organoleptic and processing characteristics. This study tests the hypothesis that high pHu aged meat would be more digestible than low pHu unaged (fresh) meat. Longissimus dorsi muscles collected from 59 bull carcasses had pHu values of 5.6-6.9. These were aged for 21 days at -1.5 °C, then raw and cooked (72 °C) samples were enzymatically digested at 37 °C with pepsin (pH 1.9 for 90 min) followed by pancreatin (pH 8.0 for an additional 120 min) to simulate conditions in the stomach and small intestine, respectively. Meat proteins and peptides in the digests were separated by 1D SDS PAGE. Regardless of pHu, ageing or cooking, most sarcoplasmic and myofibrillar proteins were rapidly digested by pepsin, with concomitant release of products identified by LC-MS/MS as mainly myosin-1, -2 and -7, α-actinin-2 or -3 and tropomyosin beta and alpha chains. These products were resistant to further digestion for the entire 210 min duration of the incubation. In terms of rate and extent of digestibility of these resistant products, high pHu > low pHu (P < 0.001), whereas aged > unaged (P < 0.003), with the effect of cooking dependent on pHu and varying somewhat by protein. Overall, the digestibility of meat samples increased with increasing pHu (P < 0.001). Beef meat was highly digestible but could be further differentiated on the basis of its pHu and the ease of digestibility of proteins. Specific carcasses or cuts could be targeted to consumer groups in order to provide benefits and add value.

  13. Huong Dan Cho Phu Huynh Ve Thanh Qua La Viec Quan Trong Nhat: Ke hoach giao duc cua Maryland cho cac lop chuan bi hoc mau giao den lop 12, 2002-2003. (A Parent's Guide to Achievement Matters Most: Maryland's Plan for PreK-12 Education, 2002-2003).

    ERIC Educational Resources Information Center

    Maryland State Dept. of Education, Baltimore.

    To raise the achievement of every student in the state, Maryland implemented "Achievement Matters Most," a new plan for public elementary and secondary schools that sets goals in the areas of achievement, teaching, testing, safety, and family involvement in schools. This Vietnamese-language guide for parents outlines the goals and…

  14. Diels-Alder Cycloadditions: A MORE Experiment in the Organic Laboratory Including a Diene Identification Exercise Involving NMR Spectroscopy and Molecular Modeling

    ERIC Educational Resources Information Center

    Shaw, Roosevelt; Severin, Ashika; Balfour, Miguel; Nettles, Columbus

    2005-01-01

    Two Diels-Alder reactions are described that are suitable for a MORE (microwave-induced organic reaction enhanced) experiment in the organic chemistry laboratory course. A second experiment in which the splitting patterns of the vinyl protons in the nuclear magnetic resonance (NMR) spectra of two MORE adducts are used in conjunction with molecular…

  15. Synthesis, antityrosinase activity of curcumin analogues, and crystal structure of (1 E,4 E)-1,5-bis(4-ethoxyphenyl)penta-1,4-dien-3-one

    NASA Astrophysics Data System (ADS)

    Chantrapromma, S.; Ruanwas, P.; Boonnak, N.; Chantrapromma, K.; Fun, H.-K.

    2016-12-01

    Five derivatives of curcumin analogue ( R = OCH2CH3 ( 1), R = N(CH3)2 ( 2), R = 2,4,5-OCH3 ( 3), R = 2,4,6-OCH3 ( 4), and R = 3,4,5-OCH3 ( 5)) were synthesized and characterized by 1H NMR, FT-IR and UV-Vis spectroscopy. The synthesized derivatives were screened for antityrosinase activity, and found that 4 and 5 possess such activity. The crystal structure of 1 was determined by single crystal X-ray diffraction: monoclinic, sp. gr. P21/ c, a = 17.5728(15) Å, b = 5.9121(5) Å, c = 19.8269(13) Å, β = 121.155(5)°, Z = 4. The molecule 1 is twisted with the dihedral angle between two phenyl rings being 15.68(10)°. In the crystal packing, the molecules 1 are linked into chains by C-H···π interactions and further stacked by π···π interactions with the centroid-centroid distance of 3.9311(13) Å.

  16. Penta-cyclo-[9.3.1.1(2,6).1(4,8).1(9,13)]octa-deca-1(2),8(9)-diene.

    PubMed

    Ioannou, Savvas; Moushi, Eleni

    2012-07-01

    The title compound, C(18)H(24), was the main product of thermolysis of noradamantene dimer (hepta-cyclo-[9.3.1.1(2,6).1(4,8).1(9,13).0(1,9).0(2,8)]octa-deca-ne). The crystal structure was determined to prove that the thermolysis product of noradamantene dimer is favored by stretch release due to ring opening of the four-membered ring. The bond length of the quaternary C atoms of the starting material was calculated as 1.6 Å, enlarged in comparison to other single bonds. After the rearrangement, the stretch release of the above carbons leads to an increase of the distance between them (2.824 Å) with respect to the crystallographic data.

  17. Complexation of 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-diene dithiocyanate with nickel (II) acetate

    SciTech Connect

    Ishak, Nur Iliyani Mohd; Yamin, Bohari M.

    2013-11-27

    The complexation of nickel acetate with tetraaza involves deprotonation of protonated amine nitrogen to form neutral ligand coordinated to the nickel via the four nitrogen atom. The dication complex is paired with thiocyanate anions. The complex was characterized by elemental analysis, UV-VIS and FTIR spectroscopic method. The crystal structure of nickel complex characterized by X-Ray crystallography and adopts square planar geometry.

  18. Effect of chronic aluminum exposure on the levels of conjugated dienes and enzymatic antioxidants in hippocampus and whole brain of rat

    SciTech Connect

    Gupta, A.; Shukla, G.S.

    1995-11-01

    The reported association between elevated tissue levels of aluminum (Al) and certain human neurological disorders have evoked increasing attention on the neurotoxic effects of aluminum. High levels of Al have been reported in hippocampal neurons comprising neurofibrillary tangles in senile dementia of Alzheimer`s type, amyotropic lateral sclerosis and Parkinsonian dementia of Guam. Aluminum is considered to be the causal factor for a high incidence of dialysis encephalopathy. It has been shown that the incidence of Alzheimer`s disease was higher in places with a high Al content in drinking water compared to low level areas. Varied uses of Al in pharmaceutical preparations, foods, water purification and many house-hold items have increased the risk of its exposure to general population. The exposure may be as high as 500 mg/kg/day in children with uremia who are treated with Al containing phosphate binding gels. Aluminum ingestion in humans and experimental animals have been reported to produce behavioural dysfunctions. The mechanism of al neurotoxicity is not understood at present. Attempts made in this direction have reported its interaction with blood-brain barrier function, decreased membrane fluidity, glutathione depletion and increased brain lipid peroxidation. These studies indicate the possibility that oxidative stress may be one of the possible mechanisms of Al-induced neurotoxicity. Since Al has been reported to be in high concentrations in hippocampal neurons in certain neurological diseases and there is wealth of evidence implicating hippocampal impairment and memory dysfunction, we attempted to investigate the effect of chronic Al intoxication on the status of enzymatic antioxidants and the extent of peroxidative damage in hippocampus and whole brain of rat. 16 refs., 4 figs., 1 tab.

  19. Synthesis of Tetraphenyl Stannacyclopentadienes (Stannoles) III. Attempted Route to the Parent Stannoles through Closure of 1,4-Dichlorobuta-1,3-Diene.

    DTIC Science & Technology

    1981-06-01

    from a v(C-Cl) mode. Carbonylation of the expected 1,4-dilithio intermediate with carbon dioxide did not give an unambiguous 1,4-dicarboxylic acid...Ber., 97, 602 (1964). 9. R. Criegee , W. Horauf and W. D. Schellenberg, Chem. Ber., 86, 126 (1953). 10. W. Bauer, Chimia, 5, 147 (1951). 11. W

  20. Effect of molecular-mass characteristics of ethylene-propylene-diene monomer rubber on impact resistance and mobility of the melt of its modified blends with polypropylene

    NASA Astrophysics Data System (ADS)

    Ryzhikova, I. G.; Bauman, N. A.; Volkov, A. M.; Kazakov, Yu. M.; Volfson, S. I.

    2014-05-01

    The study concerned the effect of molecular-mass characteristics and Mooney viscosity of the initial EPDM rubber on the changes in the structure, impact strength and rheological properties of PP/EPDM blends as a result of their modification in a melt under the action of organic peroxide and peroxide-trimethylolpropane triacrylate (TMPTA) system.

  1. Bis(η5-cyclo­penta­dien­yl)bis­(2,4,6-tri­methyl­phenyl­tellurolato)zirconium(IV)

    PubMed Central

    Hector, Andrew L.; Levason, William; Reid, Gillian; Reid, Stuart D.; Webster, Michael

    2008-01-01

    The structure of the title compound, [Zr(C5H5)2(C9H11Te)2], consists of a zirconium(IV) centre bonded to two η5-coord­inated cyclo­penta­dienyl groups and two mesityltellurolate ligands; the discrete mol­ecule has crystallographic twofold rotation symmetry. The structural parameters compared with those in [(η5-Me5Cp)2Zr(TePh)2] [Howard, Trnka & Parkin (1995 ▶). Inorg. Chem. 34, 5900–5909] show that the greater steric demands of the bulky mesityl substituents are accommodated by widening Te—Zr—Te (∼8°) and by more acute Zr—Te—C (∼5°) angles, although the Zr—Te distances are essentially the same. The crystal studied exhibited some inversion twinning. PMID:21202209

  2. Processable, high temperature polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and bis-dienes

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.

    1988-01-01

    1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene reacts with various anthracene end-capped polyimide oligomers to form Diels-Alder cycloaddition copolymers. The polymers are soluble in common organic solvents, and have molecular weights of approximately 21,000 to 32,000. These resins exhibit lower weight loss in air than in nitrogen. This is suggested to be due to dehydration (loss of water ranges from 2 to 5 percent) at temperatures of 390 to 400 C to give thermooxidatively stable pentiptycene units along the polymer backbone. Because of their high softening points and good thermooxidative stability, the polymers have potential as processable, matrix resins for high temperature composite applications.

  3. Addition polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and Bis-dienes: Processable resins for high temperature application

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.

    1987-01-01

    1,4,5,8-Tetrahydro-1,4;5,8-diepoxyanthracene reacts with various anthracene endcapped polyimide oligomers to form Diels-Alder cycloaddition copolymers. The polymers are soluble in common organic solvents, and have molecular weights of approximately 21,000 to 32,000. Interestingly, these resins appear to be more stable in air then in nitrogen. This is shown to be due to a unique dehydration (loss of water ranges from 2 to 5 percent) at temperatures of 390 to 400 C to give thermo-oxidatively stable pentiptycene units along the polymer backbone. Because of their high softening points and good thermo-oxidative stability, the polymers have potential as processible, matrix resins for high temperature composite applications.

  4. Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylates

    PubMed Central

    Edmunds, Michael; Raheem, Mohammed Abdul; Boutin, Rebecca; Tait, Katrina

    2016-01-01

    Summary Palladium-catalyzed ring-opening reactions of C1 substituted 7-oxanorbornadiene derivatives with aryl iodides were investigated. The optimal conditions for this reaction were found to be PdCl2(PPh3)2, ZnCl2, Et3N and Zn in THF. Both steric and electronic factors played a role in the outcome of the reaction as increasing the steric bulk on the bridgehead carbon decreased the yield. These reactions were found to be highly regioselective, giving only one of the two possible regioisomers in all cases. A diverse collection of novel, highly substituted biphenyl derivatives were obtained. PMID:26977182

  5. Volumetric Properties of the Mixture Hexafluorobenzene C6F6 + C6H8 Cyclohexa-1,3-diene (LB0327, VMSD1211)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Hnědkovský, L.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A `Binary Liquid Systems of Nonelectrolytes' of Volume 23 `Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV `Physical Chemistry'. It corresponds to the data set LB0327 of the ELBT database.

  6. Diversification of ortho-Fused Cycloocta-2,5-dien-1-one Cores and Eight- to Six-Ring Conversion by σ Bond C-C Cleavage.

    PubMed

    Eccleshare, Lee; Lozada-Rodríguez, Leticia; Cooper, Phillippa; Burroughs, Laurence; Ritchie, John; Lewis, William; Woodward, Simon

    2016-08-22

    Sequential treatment of 2-C6 H4 Br(CHO) with LiC≡CR(1) (R(1) =SiMe3 , tBu), nBuLi, CuBr⋅SMe2 and HC≡CCHClR(2) [R(2) =Ph, 4-CF3 Ph, 3-CNPh, 4-(MeO2 C)Ph] at -50 °C leads to formation of an intermediate carbanion (Z)-1,2-C6 H4 {CA (=O)C≡CB R(1) }{CH=CH(CH(-) )R(2) } (4). Low temperatures (-50 °C) favour attack at CB leading to kinetic formation of 6,8-bicycles containing non-classical C-carbanion enolates (5). Higher temperatures (-10 °C to ambient) and electron-deficient R(2) favour retro σ-bond C-C cleavage regenerating 4, which subsequently closes on CA providing 6,6-bicyclic alkoxides (6). Computational modelling (CBS-QB3) indicated that both pathways are viable and of similar energies. Reaction of 6 with H(+) gave 1,2-dihydronaphthalen-1-ols, or under dehydrating conditions, 2-aryl-1-alkynylnaphthlenes. Enolates 5 react in situ with: H2 O, D2 O, I2 , allylbromide, S2 Me2 , CO2 and lead to the expected C-E derivatives (E=H, D, I, allyl, SMe, CO2 H) in 49-64 % yield directly from intermediate 5. The parents (E=H; R(1) =SiMe3 , tBu; R(2) =Ph) are versatile starting materials for NaBH4 and Grignard C=O additions, desilylation (when R(1) =SiMe) and oxime formation. The latter allows formation of 6,9-bicyclics via Beckmann rearrangement. The 6,8-ring iodides are suitable Suzuki precursors for Pd-catalysed C-C coupling (81-87 %), whereas the carboxylic acids readily form amides under T3P® conditions (71-95 %).

  7. Biomimetic cationic polyannulation reaction catalyzed by Bi(OTf)3: cyclization of 1,6-dienes, 1,6,10-trienes, and aryl polyenes.

    PubMed

    Godeau, Julien; Olivero, Sandra; Antoniotti, Sylvain; Duñach, Elisabet

    2011-07-01

    Nonactivated trienes and aryltrienes were cyclized into polycyclic compounds in good to excellent yields under bismuth triflate catalysis in a biomimetic fashion. The reaction showed broad applicability and allowed for the formation of functionalized bicyclic to tetracyclic structures from simple precursors in one pot. For some specific substrates, the cyclization was followed by a methyl shift as encountered in terpenoid biosynthesis.

  8. Synthesis of Isochromene-Type Scaffolds via Single-Flask Diels–Alder-[4 + 2]-Annulation Sequence of a Silyl-Substituted Diene with Menadione

    PubMed Central

    2015-01-01

    A sequential Diels–Alder reaction/silicon-directed [4 + 2]-annulation was developed to assemble hydroisochromene-type ring systems from menadione 2. In the first step, a Diels–Alder of the 1-silyl-substituted butadiene 1 with 2 furnished an intermediate cyclic allylsilane. Subsequently, TMSOTf promoted a [4 + 2]-annulation through trapping of an oxonium, generated by condensation between an aldehyde and the TBS protected alcohol resulted in the formation of a cis-fused hydroisochromene 13. PMID:24918110

  9. (η5-Penta­methyl­cyclo­penta­dien­yl)(η6-toluene)­ruthenium(II) hexa­fluorido­phosphate

    PubMed Central

    O, Wylie W. N.; Lough, Alan J.; Morris, Robert H.

    2010-01-01

    In the title complex, [Ru(C7H8)(C10H15)]PF6, the cation lies on a mirror plane and the anion lies on an inversion center. The distance between the Ru atom and the centroid of the benzene ring is 1.706 (5) Å and the distance between the Ru atom and the cyclo­penta­dienyl ring is 1.811 (5) Å. The crystal structure is stabilized by weak C—H⋯F hydrogen bonds. The H atoms of the methyl groups which lie on the mirror plane are disordered over two sites with equal occupancies. PMID:21587411

  10. μ-Oxido-bis­[bis­(penta­fluoro­phenolato)(η5-penta­methyl­cyclo­penta­dien­yl)titanium(IV)

    PubMed Central

    Lee, Junseong; Kim, Youngjo

    2011-01-01

    The dinuclear title complex, [Ti2(C10H15)2(C6F5O)4O], features two TiIV atoms bridged by an O atom, which lies on an inversion centre. The TiIV atom is bonded to a η5-penta­methyl­cyclo­penta­dienyl ring, two penta­fluoro­phenolate anions and to the bridging O atom. The environment around the TiIV atom can be considered as a distorted tetra­hedron. The cyclo­penta­dienyl ring is disordered over two sets of sites [site occupancy = 0.824 (8) for the major component]. PMID:22090906

  11. (2,2-Bipyrid­yl)bis­(η5-penta­methyl­cyclo­penta­dien­yl)strontium(II)

    PubMed Central

    Kazhdan, Daniel; Hu, Yung-Jin; Kokai, Akos; Levi, Zerubba; Rozenel, Sergio

    2008-01-01

    In the title compound, [Sr(C10H15)2(C10H8N2)], the Sr—N distances are 2.624 (3) and 2.676 (3) Å, the Sr⋯Cp ring centroid distances are 2.571 and 2.561 Å and the N—C—C—N torsion angle in the bipyridine ligand is −2.2 (4)°. Inter­estingly, the bipyridine ligand is tilted. The angle between the plane defined by the Sr atom and the two bipyridyl N atoms and the plane defined by the 12 atoms of the bipyridine ligand is 10.7 (1)°. PMID:21201592

  12. Aqua-bis-(4-methyl-benzene-sulfonato-κO)(η(5)-penta-methyl-cyclo-penta-dien-yl)rhodium(III) monohydrate.

    PubMed

    Roy, Christopher P; Boyer, Pauline M; Merola, Joseph S

    2013-05-01

    The title half-sandwich rhodium(III) complex, [Rh(C10H15)(C7H7O3S)2(H2O)]·H2O, consists of a π-bonded penta-methyl-cyclo-penta-dienyl group, two σ-bonded tosyl-ate groups and an aqua ligand. The structure displays both inter- and intra-molecular O-H⋯O hydrogen bonding. The inter-molecular hydrogen bonding results in an extended helical chain along a 21 screw axis parallel to c, due to hydrogen bonding from the coordinating water ligand to the lattice water mol-ecule and then to a sulfonate O atom of a different asymmetric unit.

  13. Dichlorido(9-methyl­adenine-κN 7)(η5-penta­methyl­cyclo­penta­dien­yl)iridium(III) dichloromethane solvate

    PubMed Central

    Bruhn, Clemens; Küger, Thomas; Steinborn, Dirk

    2008-01-01

    In the title complex, [Ir(C10H15)Cl2(C6H7N5)]·CH2Cl2 or [Ir(η5-C5Me5)Cl2(9-MeAde-κN 7)]·CH2Cl2 (9-MeAde = 9-methyl­adenine), the coordination geometry of the IrIII atom approximates to a three-legged piano stool. The 9-methyl­adenine ligand is coordinated in a monodentate fashion to the Ir centre through its N-7 atom. The crystal structure contains centrosymmetric pairs of mol­ecules, inter­acting through two N—H⋯N hydrogen bonds. An intra­molecular N—H⋯Cl hydrogen bond is formed between the H atom of an NH2 group and a chlorido ligand. Further short intra- and inter­molecular C—H⋯Cl contacts are observed. PMID:21201851

  14. (Cyanido-κC)(2,2-di-phenyl-acetamido-κ(2) N,O)bis-(η(5)-penta-methyl-cyclo-penta-dien-yl)zirconium(IV).

    PubMed

    Becker, Lisanne; Spannenberg, Anke; Arndt, Perdita; Rosenthal, Uwe

    2014-02-01

    In the title compound, [Zr(C10H15)2(C14H12NO)(CN)], the Zr(IV) atom is coordinated by two penta-methyl-cyclo-penta-dienyl ligands, the amidate ligand via the N and O atoms, and an additional C N ligand. The four-membered metallacycle is nearly planar (r.m.s. deviation = 0.008 Å). In the crystal, the mol-ecules are connected into centrosymmetric dimers via pairs of N-H⋯N hydrogen bonds.

  15. (2,2'-Bipyrid-yl-κ(2) N,N')bis-(η(5)-penta-methyl-cyclo-penta-dien-yl)barium.

    PubMed

    Kazhdan, Daniel; Rozenel, Sergio S

    2013-01-01

    In the title compound, [Ba(C10H15)2(C10H8N2)], the Ba-N distances are 2.798 (3) and 2.886 (3) Å, and the Cp ring centroid distances to Ba(2+) are 2.7291 (7) and 2.7192 (9) Å. The angle between the N atoms in the bypyridine ligand and the metal ion is 56.80 (8)° and the N-C-C-N torsion angle in the bi-pyridine ligand is 1.7 (4)°. The bi-pyridine ligand is almost planar, the dihedral angle formed by the intersection of the planes defined by the pyridyl rings being 3.04 (19)°, and the angle between the plane defined by the Ba(2+) ion and the two bipyridyl N atoms and the plane defined by the 12 atoms of the bi-pyridine ligand is 10.2 (3)°. The average Ba-N and Ba-centroid distances are 0.16 and 0.14 Å longer, respectively, than the equivalent distances in the isotypic strontium compound [Kazhdan et al. (2008 ▶). Acta Cryst. E64, m1134]. This difference is in accord with the difference between the ionic radii of 0.16 Å suggested by Shannon [Acta Cryst. (1976 ▶), A32, 751-767].

  16. Azido­(η5-penta­methyl­cyclo­penta­dien­yl)[2-(pyridin-2-yl)phen­yl]iridium(III)

    PubMed Central

    Ariyoshi, Keita; Suzuki, Takayoshi

    2013-01-01

    In the title compound, [Ir(C10H15)(C11H8N)(N3)], the IrIII ion is coordinated by three anionic ligands, namely, penta­methyl­cyclo­penta­dienyl (Cp*−), 2-(pyridin-2-yl)phenyl (ppy−) and azide (N3 −), and adopts a three-legged piano-stool geometry The coordination mode of N3 − is typical for Cp*IrIII–N3 complexes, with an Ir—N(N3) bond length of 2.125 (2) Å and an Ir—N=N bond angle of 116.5 (2)°. The N3 − ligand is almost linear [N=N=N = 176.0 (3)°], and the N=N bond length between the central and coordinating N atom and that between the central and non-coordinating terminal N atom are 1.194 (3) and 1.157 (3) Å, respectively. For the ppy− ligand, the Ir—C and Ir—N bond lengths are 2.066 (3) and 2.079 (3) Å, respectively, which are rather close to each other, compared to the related IrIII– or RhIII–ppy complexes. The Ir—C(Cp*) bond lengths vary in the range 2.163 (2)–2.232 (2) Å, indicating a strong trans influence of the cyclo­metallated C-donor atom of the ppy− ligand. PMID:24098189

  17. Bis(η5-penta­methyl­cyclo­penta­dien­yl)aluminium tetra­bromido­aluminate

    PubMed Central

    Purdy, Andrew P.; Dugger, Cherrelle; Butcher, Ray J.

    2014-01-01

    The title compound, [Al(C10H15)2][AlBr4], was formed during the reduction of a mixture of Cp*AlBr2 and AlBr3. The AlIII atoms of the two crystallographically independent cations each lie on an inversion center, and the [AlBr4]− anions are on general positions. At 123 K, the structure exhibits disorder in two of the Br atoms of the [AlBr4]− ion, with a ratio occupancy of 0.733 (6): 0.267 (3). In the crystal, there is possible weak hydrogen bonding between some methyl groups and Br atoms. The interactions link the moieties in a three-dimensional array. PMID:24764951

  18. Acetonitrile­dicarbon­yl(η5-penta­methyl­cyclo­penta­dien­yl)iron(II) tetra­fluorido­borate

    PubMed Central

    M’thiruaine, Cyprian M.; Friedrich, Holger B.; Changamu, Evans O.; Bala, Muhammad D.

    2011-01-01

    In the structure of the title compound, [Fe{η5-C5(CH3)5}(NCCH3)(CO)2]BF4, the arrangement of ligands around the Fe atom is in a pseudo-octa­hedral three-legged piano-stool fashion in which the penta­methyl­cyclo­penta­dienyl (Cp*) ligand occupies three apical coordination sites, while the two carbonyl and one acetonitrile ligands form the basal axes of the coordination. The Fe—N bond length is 1.924 (3) Å and the Fe—Cp* centroid distance is 1.722 Å. PMID:21836908

  19. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  20. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  1. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  2. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  3. 40 CFR 721.6900 - Polymer of bisphenol A di-glyc-i-dal ether, substituted al-kenes, and but-a-diene.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polymer of bisphenol A di-glyc-i-dal... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6900 Polymer of bisphenol A di-glyc-i... subject to reporting. (1) The chemical substances identified generically as polymer of bisphenol...

  4. Synthesis of isochromene-type scaffolds via single-flask Diels-Alder-[4 + 2]-annulation sequence of a silyl-substituted diene with menadione.

    PubMed

    Lee, Jihoon; Panek, James S

    2014-06-20

    A sequential Diels-Alder reaction/silicon-directed [4 + 2]-annulation was developed to assemble hydroisochromene-type ring systems from menadione 2. In the first step, a Diels-Alder of the 1-silyl-substituted butadiene 1 with 2 furnished an intermediate cyclic allylsilane. Subsequently, TMSOTf promoted a [4 + 2]-annulation through trapping of an oxonium, generated by condensation between an aldehyde and the TBS protected alcohol resulted in the formation of a cis-fused hydroisochromene 13.

  5. CATALYZED CYCLIZATION OF [ALPHA],[OMEGA]-DIENES: A VERSATILE PROTOCOL FOR THE SYNTHESIS OF FUNCTIONALIZED CARBOCYCLIC AND HETEROCYCLIC COMPOUNDS. (R826120)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  6. Crystal structure of (1,3-di-tert-butyl-η5-cyclo­penta­dien­yl)tri­methyl­hafnium(IV)

    PubMed Central

    Pérez-Redondo, Adrián; Varela-Izquierdo, Víctor; Yélamos, Carlos

    2015-01-01

    The mol­ecule of the title organometallic hafnium(IV) com­pound, [Hf(CH3)3(C13H21)] or [HfMe3(η5-C5H3-1,3-tBu2)], adopts the classical three-legged piano-stool geometry for mono­cyclo­penta­dienylhafnium(IV) derivatives with the three methyl groups bonded to the Hf(IV) atom at the legs. The C atoms of the two tert-butyl group bonded to the cyclo­penta­dienyl (Cp) ring are 0.132 (5) and 0.154 (6) Å above the Cp least-squares plane. There are no significant inter­molecular inter­actions present between the mol­ecules in the crystal structure. PMID:25995884

  7. Bloc atrio-ventriculaire transitoire au cours d'un goitre multinodulaire: à propos d'un cas

    PubMed Central

    Millogo, Georges Rosario Christian; Konaté, Lassina; Samandoulougou, André; Kambiré, Yibar; Yaméogo, Nobila Valentin; Kologo, Koudougou Jonas; Tindano, Caleb; Toguyeni, Jean Yves; Zabsonré, Patrice

    2014-01-01

    Les troubles de conduction auriculo-ventriculaire sont relativement fréquents en Afrique grâce à l’élévation de l'expérience de vie dans nos sociétés en pleine transition épidémiologique. Ces troubles sont le plus souvent dus à une dégénérescence du tissu de conduction. La prise en charge des troubles conductifs (BAV3) consiste en l'implantation d'un stimulateur cardiaque définitif. Mais cette thérapeutique doit être précédée par une enquête étiologique pour détecter les autres causes de BAV transitoire. Nous rapportons l'observation d'une patiente de 75 ans, admise pour bloc auriculo-ventriculaire 2/1 et un goitre multi-nodulaire hyperthyroïdique; le traitement avec des antithyroïdiens de synthèse a vu la disparition du trouble conductif. Les BAV au cours de l'hyperthyroïdie sont rares, mais bien décrits. L’évolution est favorable sous traitement par antithyroïdiens de synthèse. Il ne faudrait donc pas implanter des pacemakers définitifs en première intention. PMID:25667715

  8. Symbiotic Expression of Cosmid-Borne Bradyrhizobium japonicum Hydrogenase Genes †

    PubMed Central

    Lambert, Grant R.; Harker, Alan R.; Cantrell, Michael A.; Hanus, F. Joe; Russell, Sterling A.; Haugland, Richard A.; Evans, Harold J.

    1987-01-01

    The expression of cosmid-borne Bradyrhizobium japonicum hydrogenase genes in alfalfa, clover, and soybean nodules harboring Rhizobium transconjugants was studied. Cosmid pHU52 conferred hydrogen uptake (Hup) activity in both free-living bacteria and in nodules on the different plant hosts, although in nodules the instability of the cosmid resulted in low levels of Hup activity. In contrast, cosmid pHU1, which does not confer Hup activity on free-living bacteria, gave a Hup+ phenotype in nodules on alfalfa and soybean. Nodules formed by B. japonicum USDA 123Spc(pHU1) recycled about 90% of nitrogenase-mediated hydrogen evolution. Both subunits of hydrogenase (30- and 60-kilodalton polypeptides) were detected in enzyme-linked immunosorbent assays of bacteroid preparations from nodules harboring B. japonicum strains with pHU1 or pHU52. Neither pHU53 nor pLAFR1 conferred detectable Hup activity in either nodules or free-living bacteria. Based on the physical maps of pHU1 and pHU52, it is suggested that a 5.5-kilobase EcoRI fragment unique to pHU52 contains a gene or part of a gene required for Hup activity in free-living bacteria but not in nodules. This conclusion is supported by the observation that two Tn5 insertions in the chromosome of B. japonicum USDA 122DES obtained by marker exchange with Tn5-mutagenized pHU1 abolished Hup activity in free-living bacteria but not in nodules. Images PMID:16347291

  9. [1-Dimethyl­silyl-2-phenyl-3-(η5-tetra­methyl­cyclo­penta­dien­yl)­prop-1-en-1-yl-κC 1](η5-penta­methyl­cyclo­penta­dien­yl)titanium(III)

    PubMed Central

    Lamač, Martin; Spannenberg, Anke; Arndt, Perdita; Rosenthal, Uwe

    2009-01-01

    The title compound, [Ti(C10H15)(C20H26Si)], was obtained from the reaction of [Ti{η5:η1-C5Me4(CH2)}(η5-C5Me5)] with the alkynylsilane PhC2SiMe2H. The complex crystallizes with two independent mol­ecules in the asymmetric unit, which differ in the conformation of the propenyl unit, resulting in their having opposite helicity. No inter­molecular inter­actions or inter­actions involving the Si—H bond are present. The observed geometrical parameters are unexceptional compared to known structures of the same type. PMID:21578203

  10. Spring 2006. Industry Study. Manufacturing Industry

    DTIC Science & Technology

    2006-01-01

    Vuong Co., Ltd, HCMC, Vietnam Mitsubishi Heavy Industries, Nagoya, Japan Nike Factory, Dong Nai, Vietnam NTK/NGK, Komaki City, Japan OPV...Corporation, Nagoya, Japan US Consul General, HCMC, Vietnam US Consulate, Nagoya, Japan US Embassy, Beijing, China UTC, P&W Chengdu Aerotech...Manufacturing, Chengdu, China Vina Kyoei Steel, Ltd, Phu My, Vietnam Yamazaki Mazak, Minokamo City, Japan Yara, Phu My, Vietnam 1 INTRODUCTION “A

  11. Metabolic engineering of E.coli for the production of a precursor to artemisinin, an anti-malarial drug [Chapter 25 in Manual of Industrial Microbiology and Biotechnology, 3rd edition

    SciTech Connect

    Petzold, Christopher; Keasling, Jay

    2011-07-18

    This document is Chapter 25 in the Manual of Industrial Microbiology and Biotechnology, 3rd edition. Topics covered include: Incorporation of Amorpha-4,11-Diene Biosynthetic Pathway into E. coli; Amorpha-4,11-Diene Pathway Optimization; "-Omics" Analyses for Increased Amorpha-4,11-Diene Production; Biosynthetic Oxidation of Amorpha-4,11-Diene.

  12. English-as-a-Second-Language Programs in Basic Skills Education Program 1. Appendix

    DTIC Science & Technology

    1984-01-01

    personas en los cursos de ingl~s...alistarse en el Ej~rcito? nada um poco mucho 5. Cuando le hablan on ing1~s, Lentiende usted? =Wy bien - bien un ,- 0 - A-7 Questionnaire A.page 2 6. ZQug tan... bien habla usted ingl~s? muy bien ___ bien ___ ufl poco, nada____ T. IQug tan bien lee usted ingle’s? muy bien bien ___ un poco, nada____ 8. &Qug

  13. Intra- and interspecies transfer and expression of Rhizobium japonicum hydrogen uptake genes and autotrophic growth capability

    PubMed Central

    Lambert, Grant R.; Cantrell, Michael A.; Hanus, F. Joe; Russell, Sterling A.; Haddad, Karen R.; Evans, Harold J.

    1985-01-01

    Cosmids containing hydrogen uptake genes have previously been isolated in this laboratory. Four new cosmids that contain additional hup gene(s) have now been identified by conjugal transfer of a Rhizobium japonicum 122DES gene bank into a Tn5-generated Hup- mutant and screening for the acquisition of Hup activity. The newly isolated cosmids, pHU50-pHU53, contain part of the previously isolated pHU1 but extend as far as 20 kilobases beyond its border. pHU52 complements five of six Hup- mutants and confers activity on several Hup- wild-type R. japonicum strains in the free-living state and where tested in nodules. Transconjugants obtained from interspecies transfer of pHU52 to Rhizobium meliloti 102F28, 102F32, and 102F51 and Rhizobium leguminosarum 128C53 showed hydrogen-dependent methyleneblue reduction, performed the oxyhydrogen reaction, and showed hydrogen-dependent autotrophic growth by virtue of the introduced genes. The identity of the presumptive transconjugants was confirmed by antibiotic-resistance profiles and by plant nodulation tests. Images PMID:16578786

  14. Impacts of a measles outbreak in Western Sydney on public health resources.

    PubMed

    Flego, Kristina L; Belshaw, Daniel A; Sheppeard, Vicky; Weston, Kathryn M

    2013-09-30

    During February and March 2011, an outbreak of 26 confirmed cases of measles was reported to the Parramatta Public Health Unit (PHU) in western Sydney. This paper describes the impact of the outbreak on PHU resources. A retrospective review of information obtained from case notification forms and associated contact tracing records was carried out for each of the confirmed cases. Seven cases (27%) required hospital admission for more than 1 day and 10 (38%) cases required management within a hospital emergency department. There were no cases of encephalitis or death. The number of contacts was determined for each case as well as the number who required post-exposure prophylaxis. In total, 1,395 contacts were identified in this outbreak. Of these, 79 (5.7%) required normal human immunoglobulin and 90 (6.5%) were recommended to receive the measles-mumps-rubella vaccine. A case study detailing the PHU costs associated with the contact management of a hospitalised measles case with 75 identified contacts is also included and the estimated total cost to the PHU of containing this particular case of measles was A$2,433, with staff time comprising the major cost component. Considerable effort and resources are required to manage measles outbreaks. The total cost of this outbreak to the PHU alone is likely to have exceeded A$48,000.

  15. Addition polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and Bis-dienes. 2: Evidence for thermal dehydration occurring in the cure process

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Olshavsky, Michael A.; Meador, Michael A.; Ahn, Myong-Ku

    1988-01-01

    Diels-Alder cycloaddition copolymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and anthracene end-capped polyimide oligomers appear, by thermogravimetric analysis (TGA), to undergo dehydration at elevated temperatures. This would produce thermally stable pentiptycene units along the polymer backbone, and render the polymers incapable of unzipping through a retro-Diels-Alder pathway. High resolution solid 13C nuclear magnetic resonance (NMR) of one formulation of the polymer system before and after heating at elevated temperatures, shows this to indeed be the case. NMR spectra of solid samples of the polymer before and after heating correlated well with those of the parent pentiptycene model compound before and after acid-catalyzed dehydration. Isothermal gravimetric analyses and viscosities of the polymer before and after heat treatment support dehydration as a mechanism for the cure reaction.

  16. (Cyanido-κC)(2,2-di­phenyl­acetamido-κ2 N,O)bis­(η5-penta­methyl­cyclo­penta­dien­yl)zirconium(IV)

    PubMed Central

    Becker, Lisanne; Spannenberg, Anke; Arndt, Perdita; Rosenthal, Uwe

    2014-01-01

    In the title compound, [Zr(C10H15)2(C14H12NO)(CN)], the ZrIV atom is coordinated by two penta­methyl­cyclo­penta­dienyl ligands, the amidate ligand via the N and O atoms, and an additional C N ligand. The four-membered metallacycle is nearly planar (r.m.s. deviation = 0.008 Å). In the crystal, the mol­ecules are connected into centrosymmetric dimers via pairs of N—H⋯N hydrogen bonds. PMID:24764823

  17. 5,5,7,12,14,14-Hexamethyl-1,8-diaza-4,11-diazo­niacyclo­tetra­deca-4,11-diene dichloride trihydrate

    PubMed Central

    Ismail, Wafiuddin; Yamin, Bohari M.; Daran, Jean-Claude

    2012-01-01

    In the title compound, C16H34N4 2+·2Cl−·3H2O, the two protonated N atoms in the macrocyclic ring of the dication are located at diagonally opposite positions. There are two intramolecular N—H⋯N hydrogen bonds in the cation. The crystal structure features O—H⋯Cl, O—H⋯O, C—H⋯Cl and N—H⋯Cl hydrogen bonds. PMID:22590349

  18. Cytoprotection of Human Endothelial Cells Against Oxidative Stress by 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im): Application of Systems Biology to Understand the Mechanism of Action

    DTIC Science & Technology

    2014-04-03

    and exogenous oxidants, electrophiles , and toxicants. Activation of this pathway was reported to facilitate the induction of HMOX1 (Heiss et al., 2009...cytoprotective effect of caffeic acid phenethyl ester (CAPE) and fluorinated derivatives: effects on heme oxygenase-1 induction and antioxidant

  19. Ameliorative Effects of Operculina turpethum and its Isolated Stigma-5,22dien-3-o-β-D-glucopyranoside on the Hematological Parameters of Male Mice Exposed to N-Nitrosodimethylamine, a Potent Carcinogen

    PubMed Central

    Sharma, Veena; Singh, Manu

    2014-01-01

    Objectives: Enormous propensity of plants to synthesize a variety of structurally diverse bioactive compounds, has made the plant kingdom a potential source of chemical constituents with various therapeutic values, including antitumor and cytotoxic activities. Blood is a good indicator to determine the physiological and pathological status of man and animal. The objective of the present study is to determine the effect of Operculina turpethum root extract and its isolated glycoside treatment on the hematological parameters in the mice with N-Nitrosodimethylamine (NDMA) induced cancer. Materials and Methods: The body weights of the animals were recorded before and after the experiment. Non-coagulated blood was tested for total erythrocyte count, total leukocyte count, hemoglobin, differential leukocyte count (DLC) and for other blood indices. Results: A significant (P < 0.01), (P < 0.001) recovery of the red blood cell and white blood cell counts, packed cell volume and hemoglobin content in the host after 21 day treatment was shown. Conclusion: These results show that the extract of Operculina turpethum is relatively safe following oral administration and have possible stimulatory effect on red blood cell production and there was dose dependent therapeutic effect. PMID:24748732

  20. (Glycol-κ2 O,O′)nitros­yl(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II) bis­(tri­fluoro­methane­sulfonate)

    PubMed Central

    Munie, Semeret; Larsen, Anna; Gembicky, Milan

    2008-01-01

    The title compound, [Ru(C10H15)(NO)(HOCH2CH2OH)](CF3SO3)2, possesses a three-legged piano-stool geometry around the Ru atom, with an average Ru—O distance of 2.120 (6) Å and an Ru—N—O angle of 159.45 (14)°. The ethyl­eneglycol ligand forms a non-planar metallacyclic ring by chelating the Ru atom via the O atoms. The O⋯O distances of 2.554 (2) and 2.568 (2) Å are indicative of hydrogen bonding between coordinated ethyl­eneglycol and outer-sphere trifluoro­methane­sulfonate fragments. The crystal packing is stabilized by ionic forces and several CH3⋯·F (2.585 and 2.640 Å) and CH3⋯O inter­actions (2.391, 2.678, 2.694 and 2.699 Å) between the penta­methyl­cyclo­penta­dienyl ligand and trifluoro­methane­sulfonate anion. There is noticeable short inter­molecular contact [2.9039 (16) Å], between an O atom of the SO3 group and a C atom of the penta­methyl­cyclo­penta­dienyl ligand. PMID:21201270

  1. Bis[μ-2-(aminosulfanyl)pyridine(1−)]bis­[(η5-penta­methyl­cyclo­penta­dien­yl)iridium(III)] diiodide

    PubMed Central

    Sekioka, Yusuke; Suzuki, Takayoshi

    2009-01-01

    In the title dinuclear iridium(III) complex, [Ir2(C10H15)2(C5H5N2S)2]I2, the iridium(III) atoms are bridged by 2-(aminosulfanyl)pyridine(1−) [(2-py)SNH] ligands in a μ-(2-py)SNH-κ2 N(py),N(NH):κN(NH) mode. The dinuclear complex cation lies on a crystallographic inversion center, resulting in a planar Ir2N2 ring with an Ir—N(py) bond length of 2.085 (9) Å and bridging Ir—N(NH) bonds of 2.110 (9) and 2.113 (9) Å. The two (2-py)S units have mutually anti configurations with respect to the Ir2N2 ring PMID:21577749

  2. (2,2′-Bipyrid­yl-κ2 N,N′)bis­(η5-penta­methyl­cyclo­penta­dien­yl)barium

    PubMed Central

    Kazhdan, Daniel; Rozenel, Sergio S.

    2013-01-01

    In the title compound, [Ba(C10H15)2(C10H8N2)], the Ba—N distances are 2.798 (3) and 2.886 (3) Å, and the Cp ring centroid distances to Ba2+ are 2.7291 (7) and 2.7192 (9) Å. The angle between the N atoms in the bypyridine ligand and the metal ion is 56.80 (8)° and the N—C—C—N torsion angle in the bi­pyridine ligand is 1.7 (4)°. The bi­pyridine ligand is almost planar, the dihedral angle formed by the intersection of the planes defined by the pyridyl rings being 3.04 (19)°, and the angle between the plane defined by the Ba2+ ion and the two bipyridyl N atoms and the plane defined by the 12 atoms of the bi­pyridine ligand is 10.2 (3)°. The average Ba—N and Ba—centroid distances are 0.16 and 0.14 Å longer, respectively, than the equivalent distances in the isotypic strontium compound [Kazhdan et al. (2008 ▶). Acta Cryst. E64, m1134]. This difference is in accord with the difference between the ionic radii of 0.16 Å suggested by Shannon [Acta Cryst. (1976 ▶), A32, 751–767]. PMID:24109262

  3. Chlorido[1-diphenyl­phosphanyl-3-(phenyl­sulfan­yl)propane-κ2 P,S](η5-penta­methyl­cyclo­penta­dien­yl)iridium(III) chloride monohydrate

    PubMed Central

    Ludwig, Gerd; Korb, Marcus; Rüffer, Tobias; Lang, Heinrich; Steinborn, Dirk

    2012-01-01

    The crystal structure of the title compound, [Ir(C10H15)Cl(C21H21PS)]Cl·H2O, consists of discrete [Ir(η5-C5Me5)Cl{Ph2P(CH2)3SPh-κP,κS}]+ cations, chloride anions and water mol­ecules. The IrIII atom is coordinated by an η5-C5Me5 ligand, a chloride and a Ph2P(CH2)3SPh-κP,κS ligand, leading to a three-legged piano-stool geometry. In the crystal, two water molecules and two chloride anions are linked by weak O—H⋯Cl hydrogen bonding into tetra­mers that are located on centers of inversion. The H atoms of one of the methyl groups are disordered and were refined using a split model. PMID:22719391

  4. (η6-Isopropyl N-phenyl­carbamate)(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II) tetra­phenyl­borate acetone monosolvate

    PubMed Central

    Loughrey, Bradley T.; Williams, Michael L.; Healy, Peter C.

    2011-01-01

    The title complex, [Ru(C10H15)(C10H13NO2)](C24H20B)·C3H6O, is related to the analogous O-methyl complex. The average Ru—C distance to the penta­methyl­cyclo­penta­dienyl (Cp*) group is 2.19 (3) Å, and 2.21 (1) Å to the ortho, meta and para C atoms of the arene ring. The Ru—Cipso bond length of 2.272 (3) Å is significantly longer, reflecting movement of the Ru atom away from the C atoms with electronegative substituents attached. The amide H atom in the cation forms an inter­molecular N—H⋯O hydrogen bond with the carbonyl O atom of the acetone solvent mol­ecule. A C—H⋯O inter­action also occurs. PMID:22058857

  5. μ-Oxido-bis­{bis­[(penta­fluoro­phen­yl)methano­lato](η5-penta­methyl­cyclo­penta­dien­yl)titanium(IV)}

    PubMed Central

    Lee, Junseong; Kim, Youngjo

    2011-01-01

    The dinuclear title complex, [Ti2(C10H15)2(C7H2F5O)4O], features two TiIV atoms bridged by an O atom. Each Ti atom is bonded to a η5-penta­methyl­cyclo­penta­dienyl ring, two (penta­fluoro­phen­yl)methano­late anions and to the bridging O atom. The environment around each Ti atom can be considered as a distorted tetra­hedron. PMID:22090876

  6. [1,2-Bis(diphenyl­phosphino)ethane]­chlorido(η5-penta­methyl­cyclo­penta­dien­yl)iron(II) dichloro­methane solvate

    PubMed Central

    Ou, Ya-ping; Feng, Dan; Yuan, Jing-jing

    2010-01-01

    In the title compound, [Fe(C10H15)Cl(C26H24P2)]·CH2Cl2, the FeII atom is coordinated by two P atoms from a 1,2-bis­(diphenyl­phosphino)ethane ligand [Fe—P = 2.2130 (7) and 2.2231 (7) Å], a chloride anion [Fe—Cl = 2.3329 (7) Å] and a penta­methyl­cyclo­penta­dienyl (Cp*) ligand [Fe—centroid(Cp*) = 1.732 (3) Å] in a typical piano-stool geometry. In the crystal structure, the complex and solvent mol­ecules are paired via weak C—H⋯Cl inter­actions. PMID:21588156

  7. Tri-μ-chlorido-bis­[(η5-penta­methyl­cyclo­penta­dien­yl)rhodium(III)] hexa­fluorido­phosphate from synchrotron radiation

    PubMed Central

    Ezzedinloo, Lida; Shrestha, Sumi; Bhadbhade, Mohan; Colbran, Stephen

    2014-01-01

    In the title complex salt, [{(η5-C5Me5)Rh}2(μ-Cl)3]PF6, the dinuclear, single-charged cation is formed by the cojoining of two classic (η5-C5Me5)RhCl3 ‘piano-stool’ units by bridging of the three choride ligand ‘legs’. The crystal structure shows several close H⋯F contacts between the hexa­fluorido­phosphate counter-ions and the C5Me5 ligands. PMID:24855466

  8. Chlorido(chloro­diphenyl­phosphine-κP)(diphenyl­piperidinophosphine-κP)(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II)

    PubMed Central

    Jantscher, Florian; Kirchner, Karl; Mereiter, Kurt

    2009-01-01

    The title compound, [Ru(C10H15)Cl(C12H10ClP)(C17H20NP)], is a half-sandwich complex of RuII with the chloro­diphenyl­phosphine ligand formed from the diphenyl­piperidinophosphine and chlorine of the precursor complex [Ru(η5-C5Me5)(κ1P—Ph2PNC5H10)Cl2] by an unexpected reaction with NaBH4. The complex has a three-legged piano-stool geometry, with Ru—P bond lengths of 2.2598 (5) Å for the chloro­phosphine and 2.3303 (5) Å for the amino­phosphine. PMID:21583392

  9. Crystal structure of bis-{μ2-[(2-imino-cyclo-pentyl-idene)methyl-idene]aza-nido-κ(2) N:N'}bis-[(η(5)-penta-methyl-cyclo-penta-dien-yl)zirconium(IV)] hexane monosolvate.

    PubMed

    Becker, Lisanne; Spannenberg, Anke; Arndt, Perdita; Rosenthal, Uwe

    2015-12-01

    The title compound, [Zr2(C10H15)4(C6H6N2)2]·C6H14, was obtained by the stoichiometric reaction of adipo-nitrile with [Zr(C10H15)2(η(2)-Me3SiC2SiMe3)]. Intra-molecular nitrile-nitrile couplings and deprotonation of the substrate produced the (1-imino-2-enimino)-cyclo-pentane ligand, which functions as a five-membered bridge between the two metal atoms. The Zr(IV) atom exhibits a distorted tetra-hedral coordination sphere defined by two penta-methyl-cyclo-penta-dienyl ligands, by the imino unit of one (1-imino-2-enimino)-cyclo-pentane and by the enimino unit of the second (1-imino-2-enimino)-cyclo-pentane. The cyclo-pentane ring of the ligand shows an envelope conformation. The asymmetric unit contains one half of the complex and one half of the hexane solvent mol-ecule, both being completed by the application of inversion symmetry. One of the penta-methyl-cyclo-penta-dienyl ligands is disordered over two sets of sites with a refined occupancy ratio of 0.8111 (3):0.189 (3). In the crystal, the complex mol-ecules are packed into rods extending along [100], with the solvent mol-ecules located in between. The rods are arranged in a distorted hexa-gonal packing.

  10. Aqua­bis­(4-methyl­benzene­sulfonato-κO)(η5-penta­methyl­cyclo­penta­dien­yl)rhodium(III) monohydrate

    PubMed Central

    Roy, Christopher P.; Boyer, Pauline M.; Merola, Joseph S.

    2013-01-01

    The title half-sandwich rhodium(III) complex, [Rh(C10H15)(C7H7O3S)2(H2O)]·H2O, consists of a π-bonded penta­methyl­cyclo­penta­dienyl group, two σ-bonded tosyl­ate groups and an aqua ligand. The structure displays both inter- and intra­molecular O—H⋯O hydrogen bonding. The inter­molecular hydrogen bonding results in an extended helical chain along a 21 screw axis parallel to c, due to hydrogen bonding from the coordinating water ligand to the lattice water mol­ecule and then to a sulfonate O atom of a different asymmetric unit. PMID:23723770

  11. Un mode de découverte inhabituel d'hyperparathyroïdie primaire: fractures multiples sur tumeurs brunes secondaires à un adénome parathyroïdien ectopique médiastinal

    PubMed Central

    Yassine, Asmaa; Guerboub, Ahmed Anas; Arsalane, Adil; Biyi, Abdelhamid; Moussaoui, Souad El; Belmejdoub, Ghizlaine

    2015-01-01

    La tumeur brune est une entité clinique bénigne apparaissant comme une manifestation squelettique rare de l'hyperparathyroïdie primaire. Il s'agit d'une cause inhabituelle de fractures pathologiques. Nous rapportons ici le cas clinique d'un patient âgé de 20 ans chez qui l'hyperparathyroïdie primitive a été découverte devant des tumeurs brunes multiples. PMID:26966486

  12. Otite externe maligne à Candida Albicans

    PubMed Central

    Elayoubi, Fahd; Lachkar, Azeddine; Aabach, Ahmed; Chouai, Mohamed; Ghailan, Mohamed Rachid

    2016-01-01

    L’otite externe maligne est une ostéomyélite de la base du crane. Le Pseudomonas aeruginosa est le germe le plus incriminé. Cependant l’origine fongique n’est pas rare. Patiente âgée de 80 ans avait présenté une otalgie gauche persistante depuis deux mois malgré un traitement bien conduit. L’examen otologique mettait en évidence des signes inflammatoires au niveau du pavillon, une sténose du conduit avec des granulomes, et otorrhée d’allure purulente. Le scanner montrait un comblement otomastoïdien, un processus inflammatoire extensif des tissus pré et rétro-auriculaire et une lyse du tympanal. Vu l’absence d’amélioration un examen mycologique a été réalisé et qui a révélé la présence de Candida Albicans. Les cas d’otite externe maligne à Candida Albicans sont rarement rapportés. L’origine fongique doit être suspecté devant la négativité des prélèvements bactériologiques et la non amélioration malgré un traitement antibiotique bien conduit, et confirmée par des prélèvements mycologiques parfois multiples. L’otite externe maligne à Candida Albicans est une infection rare potentiellement mortelle. PMID:28154677

  13. Breed differences in the biochemical determinism of ultimate pH in breast muscles of broiler chickens--a key role of AMP deaminase?

    PubMed

    El Rammouz, R; Berri, C; Le Bihan-Duval, E; Babilé, R; Fernandez, X

    2004-08-01

    The biochemical determinism of ultimate pH (pHu) was studied in the pectoralis muscle of broiler chickens. Thirty birds of 3 genetic types (a fast-growing standard (FG), a slow-growing French "Label Rouge" (SG), and a heavy line type (HL)) were kept under conventional breeding methods until the usual marketing age (6, 12, and 6 wk for FG, SG, and HL birds, respectively). The birds were divided into 3 different antemortem treatment groups: minimum stress, shackling for a longer time (2 min), and heat stress (exposure to 35 degrees C for 3.5 h and shackling for 2 min before stunning). The birds were slaughtered on the same day. The pHu differed (P < 0.001) among the 3 genetic types, ranking as follows: FG (5.95+/-0.01) > HL (5.85+/-0.02) > SG (5.73+/-0.02). In SG and HL birds, pHu was strongly correlated with muscle glycogen content at slaughter (r = -0.74 and -0.82; P < 0.01 respectively), whereas this correlation was weak in FG birds. Regardless of genetic type, neither buffering capacity nor lactate accumulation significantly contributed to pHu variations (P > 0.05). The activity of adenosine monophosphate deaminase (AMPd) was significantly higher in FG chickens (0.98+/-0.31; P < 0.05) than in HL and SG birds (0.46+/-0.24 and 0.34+/-0.18, respectively). Significant correlations were found between AMPd activity, pHu, and glycolytic potential (GP) at slaughter (r = 0.34 and -.29; P < 0.01, respectively). Further research is needed to study in more detail the role of AMPd in the determinism of pHu, particularly in fast-growing broilers.

  14. A cobalt complex of a microbial arene oxidation product

    PubMed Central

    2011-01-01

    We report the first synthesis of a cobalt Cp diene complex wherein the diene is derived by microbial dearomatising dihydroxylation of an aromatic ring. The complex has been characterised crystallographically and its structure is compared to that of an uncomplexed diene precursor. PMID:22152033

  15. Short Access to Belt Compounds with Spatially Close C=C Bonds and Their Transannular Reactions.

    PubMed

    Camps, Pelayo; Gómez, Tània; Otermin, Ane; Font-Bardia, Mercè; Estarellas, Carolina; Luque, Francisco Javier

    2015-09-28

    Two domino Diels-Alder adducts were obtained from 3,7-bis(cyclopenta-2,4-dien-1-ylidene)-cis-bicyclo[3.3.0]octane and dimethyl acetylenedicarboxylate or N-methylmaleimide under microwave irradiation. From the first adduct, a C20H24 diene with C2v symmetry was obtained by Zn/AcOH reduction, hydrolysis, oxidative decarboxylation, and selective hydrogenation. Photochemical [2+2] cycloaddition of this diene gave a thermally unstable cyclobutane derivative, which reverts to the diene. However, both the diene and the cyclobutane derivatives could be identified by X-ray diffraction analysis upon irradiation of the diene crystal. New six-membered rings are formed upon the transannular addition of bromine or iodine to the diene. The N-type selectivity of the addition was examined by theoretical calculations, which revealed the distinct susceptibility of the doubly bonded carbon atoms to the bromine attack.

  16. Δ2-Triterpenes: Early intermediates in the diagenesis of terrigenous triterpenoids

    NASA Astrophysics Data System (ADS)

    ten Haven, H. L.; Peakman, T. M.; Rullkötter, J.

    1992-05-01

    A series of Δ2-triterpenoids (oleana-2,12-diene, oleana-2,13(18)-diene, oleana-2,18-diene, ursa-2, 12-diene, and taraxera-2,14-diene) has been identified in Holocene buried mangrove sediments (Florida, USA) by comparison of the mass spectra of and by co-injections with authentic standards. In the Oligocene Brandon lignite (Vermont, USA) oleana-2,12-diene and oleana-2,13(18)-diene were also identified, along with two A-ring contracted amyrin derivatives. By comparison with the sedimentary occurrence of related analogues of oxyallobetulin and betulin and the demonstrated diagenetic formation of lup-2-ene from lupan-3-one, these novel terrigenous biological markers are considered diagenetic products formed by dehydration of precursor molecules, such as α- and β-amyrin, and taraxerol. The identification of these early intermediates brings us one step closer to the full understanding of the diagenetic fate of terrigenous triterpenoids.

  17. Delta. sup 2 -triterpenes: Early intermediates in the diagenesis of terrigenous triterpenoids

    SciTech Connect

    Ten Haven, H.L. ); Peakman, T.M. ); Rullkoetter, J. )

    1992-05-01

    A series of {Delta}{sup 2}-triterpenoids (oleana-2,12-diene, oleana-2,13(18)-diene, oleana-2,18-diene, ursa-2,12-diene, and tarazera-2,14-diene) has been identified in Holocene buried mangrove sediments (Florida, USA) by comparison of the mass spectra of and by co-injections with authentic standards. In the Oligocene Brandon lignite (Vermont, USA) oleana-2,12-diene and oleana-2,13(18)-diene were also identified, along with two A-ring contracted amyrin derivatives. By comparison with the sedimentary occurrence of related analogues of oxyallobetulin and betulin and the demonstrated diagenetic formation of lup-2-ene from lupan-3-one, these novel terrigenous biological markers are considered diagenetic products formed by dehydration of precursor molecules, such as {alpha}- and {beta}-amyrin, and tarazerol. The identification of these early intermediates brings us one step closer to the full understanding of the diagenetic fate of terrigenous triterpenoids.

  18. The French Officers: Craftsmen of the Conquest and Pacification of Tonkin (1871-1897)

    DTIC Science & Technology

    2012-06-08

    and a mixed company took possession of Hung Yen (23 November 1873), Phu Ly (26 November) then Hai Duong (5 December).95 In the north, junior... fever .87 The combat effectiveness of the Tonkin Expeditionary Force severely suffered from the climate with almost 5 percent of the soldiers

  19. Vietnam and the Home Front: How DoD Installations Adapted, 1962-1975

    DTIC Science & Technology

    2014-06-01

    History Project, American Folklife Center, Library of Congress Tom Herold Navy USS Bradley , USS Goldsboro Well, I went to boot camp in the Great...1/12 Activated at Camp Pendleton -- > Camp Mcnair, Japan ---> South Camp Fuji -->Vietnam Phu Bai, Da Nang, Cam Lo, Khe Sanh, and Camp Carroll

  20. Two cycles of recurrent maternal half-sib selection reduce foliar late blight in a diploid hybrid Solanum phureja-S. stenotomum population by two-thirds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foliar late blight, caused by Phytophthora infestans, is an important disease problem worldwide. Foliar resistance to late blight was found in a hybrid population of the cultivated diploid species Solanum phureja-S. stenotomum (phu-stn). The objective of this study was to determine if resistance t...

  1. Metastase axillaire d'un carcinome papillaire de la thyroïde: à propos d'un cas

    PubMed Central

    El Khiati, Rhizlane; Ouaissi, Laila; Rouadi, Sami; Abada, Redallah; Mahtar, Mohamed; Roubal, Mohamed; Janah, Abdellah; Essaadi, Mustapha; Kadiri, Fatmi

    2013-01-01

    Les métastases axillaires dans le cadre d'un cancer de la thyroïde sont extrêmement rares. Plusieurs hypothèses expliquent ce drainage. Nous rapportons le cas d'un patient de 78 ans ayant pour antécédents chirurgicaux une lobo-isthmectomie en 1987, puis une totalisation chirurgicale en 1997 non documentés, admis en septembre 2008 pour exploration d'une masse latéro-cervicale gauche. Le reste de l'examen clinique révèle la présence de multiples adénopathies axillaires bilatérales. La biopsie exérèse d'une adénopathie axillaire droite (côté controlatéral) retrouve une métastase ganglionnaire d'un carcinome papillaire de la thyroïde avec effraction capsulaire. La tomodensitométrie cervico-thoracique note la présence d'un processus tumoral latéro-cervical gauche, un lobe thyroïdien droit siège de multiples nodules hypodenses, des adénopathies cervicales et axillaires et des lésions suspectes au niveau du parenchyme pulmonaire. Une thyroïdectomie totale avec curage ganglionnaire cervical est décidée, complétée par une ablation des ganglions axillaires macroscopiquement atteints. Des cures d'iode radioactif (IRA-thérapie) sont indiquées. Bien qu'exceptionnelle, la présence de métastases axillaires d'un carcinome thyroïdien est de pronostic péjoratif. On se demande alors si ces patients ne nécessitent pas une prise en charge particulière. Une réflexion à une stratégie thérapeutique est donc nécessaire. PMID:24498461

  2. Selecting broiler chickens for ultimate pH of breast muscle: analysis of divergent selection experiment and phenotypic consequences on meat quality, growth, and body composition traits.

    PubMed

    Alnahhas, N; Berri, C; Boulay, M; Baéza, E; Jégo, Y; Baumard, Y; Chabault, M; Le Bihan-Duval, E

    2014-09-01

    Genetic parameters for ultimate pH of pectoralis major muscle (PM-pHu) and sartorius muscle (SART-pHu); color parameters L*, a*, b*; logarithm of drip loss (LogDL) of pectoralis major (PM) muscle; breast meat yield (BMY); thigh and drumstick yield (TY); abdominal fat percentage (AFP); and BW at 6 wk (BW6) were estimated in 2 lines of broiler chickens divergently selected for PM-pHu. Effects of selection on all the previous traits and on glycolytic potential, pectoralis major muscle pH at 15 min postmortem, curing-cooking yield (CCY), cooking loss (CL), and Warner-Bratzler shear force (WBSF) of the PM muscle were also analyzed after 5 generations. Strong genetic determinism of PM-pHu was observed, with estimated h(2) of 0.57 ± 0.02. There was a significant positive genetic correlation (rg) between PM-pHu and SART-pHu (0.54 ± 0.04), indicating that selection had a general rather than a specific effect on energy storage in skeletal muscles. The h(2) estimates of L*, a*, and b* parameters were 0.58 ± 0.02, 0.39 ± 0.02, and 0.48 ± 0.02, respectively. Heritability estimates for TY, BMY, and AFP were 0.39 ± 0.04, 0.52 ± 0.01, and 0.71 ± 0.02, respectively. Our results indicated different genetic control of LogDL and L* of the meat between the 2 lines; these traits had a strong rg with PM-pHu in the line selected for low ultimate pH (pHu) value (pHu-; -0.80 and -0.71, respectively), which was not observed in the line selected for high pHu value (pHu+; -0.04 and -0.29, respectively). A significant positive rg (0.21 ± 0.04) was observed between PM-pHu and BMY but not between PM-pHu and BW6, AFP, or TY. Significant phenotypic differences were observed after 5 generations of selection between the 2 lines. The mean differences (P < 0.001) in pHu between the 2 lines were 0.42 and 0.21 pH units in the breast and thigh muscle, respectively. Breast meat in the pHu+ line exhibited lower L* (-5 units; P < 0.001), a* (-0.22 units; P < 0.001), b* (-1.53 units; P < 0.001), and

  3. Holo- and apo-bound structures of bacterial periplasmic heme-binding proteins.

    PubMed

    Ho, Winny W; Li, Huiying; Eakanunkul, Suntara; Tong, Yong; Wilks, Angela; Guo, Maolin; Poulos, Thomas L

    2007-12-07

    An essential component of heme transport in Gram-negative bacterial pathogens is the periplasmic protein that shuttles heme between outer and inner membranes. We have solved the first crystal structures of two such proteins, ShuT from Shigella dysenteriae and PhuT from Pseudomonas aeruginosa. Both share a common architecture typical of Class III periplasmic binding proteins. The heme binds in a narrow cleft between the N- and C-terminal binding domains and is coordinated by a Tyr residue. A comparison of the heme-free (apo) and -bound (holo) structures indicates little change in structure other than minor alterations in the heme pocket and movement of the Tyr heme ligand from an "in" position where it can coordinate the heme iron to an "out" orientation where it points away from the heme pocket. The detailed architecture of the heme pocket is quite different in ShuT and PhuT. Although Arg(228) in PhuT H-bonds with a heme propionate, in ShuT a peptide loop partially takes up the space occupied by Arg(228), and there is no Lys or Arg H-bonding with the heme propionates. A comparison of PhuT/ShuT with the vitamin B(12)-binding protein BtuF and the hydroxamic-type siderophore-binding protein FhuD, the only two other structurally characterized Class III periplasmic binding proteins, demonstrates that PhuT/ShuT more closely resembles BtuF, which reflects the closer similarity in ligands, heme and B(12), compared with ligands for FhuD, a peptide siderophore.

  4. Holo- And Apo- Structures of Bacterial Periplasmic Heme Binding Proteins

    SciTech Connect

    Ho, W.W.; Li, H.; Eakanunkul, S.; Tong, Y.; Wilks, A.; Guo, M.; Poulos, T.L.

    2009-06-01

    An essential component of heme transport in Gram-negative bacterial pathogens is the periplasmic protein that shuttles heme between outer and inner membranes. We have solved the first crystal structures of two such proteins, ShuT from Shigella dysenteriae and PhuT from Pseudomonas aeruginosa. Both share a common architecture typical of Class III periplasmic binding proteins. The heme binds in a narrow cleft between the N- and C-terminal binding domains and is coordinated by a Tyr residue. A comparison of the heme-free (apo) and -bound (holo) structures indicates little change in structure other than minor alterations in the heme pocket and movement of the Tyr heme ligand from an 'in' position where it can coordinate the heme iron to an 'out' orientation where it points away from the heme pocket. The detailed architecture of the heme pocket is quite different in ShuT and PhuT. Although Arg{sup 228} in PhuT H-bonds with a heme propionate, in ShuT a peptide loop partially takes up the space occupied by Arg{sup 228}, and there is no Lys or Arg H-bonding with the heme propionates. A comparison of PhuT/ShuT with the vitamin B{sub 12}-binding protein BtuF and the hydroxamic-type siderophore-binding protein FhuD, the only two other structurally characterized Class III periplasmic binding proteins, demonstrates that PhuT/ShuT more closely resembles BtuF, which reflects the closer similarity in ligands, heme and B{sub 12}, compared with ligands for FhuD, a peptide siderophore.

  5. Source identification and distribution reveals the potential of the geochemical Antarctic sea ice proxy IPSO25

    NASA Astrophysics Data System (ADS)

    Belt, S. T.; Smik, L.; Brown, T. A.; Kim, J.-H.; Rowland, S. J.; Allen, C. S.; Gal, J.-K.; Shin, K.-H.; Lee, J. I.; Taylor, K. W. R.

    2016-08-01

    The presence of a di-unsaturated highly branched isoprenoid (HBI) lipid biomarker (diene II) in Southern Ocean sediments has previously been proposed as a proxy measure of palaeo Antarctic sea ice. Here we show that a source of diene II is the sympagic diatom Berkeleya adeliensis Medlin. Furthermore, the propensity for B. adeliensis to flourish in platelet ice is reflected by an offshore downward gradient in diene II concentration in >100 surface sediments from Antarctic coastal and near-coastal environments. Since platelet ice formation is strongly associated with super-cooled freshwater inflow, we further hypothesize that sedimentary diene II provides a potentially sensitive proxy indicator of landfast sea ice influenced by meltwater discharge from nearby glaciers and ice shelves, and re-examination of some previous diene II downcore records supports this hypothesis. The term IPSO25--Ice Proxy for the Southern Ocean with 25 carbon atoms--is proposed as a proxy name for diene II.

  6. Intramolecular Diels–Alder Reactions of Cycloalkenones: Stereoselectivity, Lewis Acid Acceleration, and Halogen Substituent Effects

    PubMed Central

    2015-01-01

    The intramolecular Diels–Alder reactions of cycloalkenones and terminal dienes occur with high endo stereoselectivity, both thermally and under Lewis-acidic conditions. Through computations, we show that steric repulsion and tether conformation govern the selectivity of the reaction, and incorporation of either BF3 or α-halogenation increases the rate of cycloaddition. With a longer tether, isomerization from a terminal diene to the more stable internal diene results in a more facile cycloaddition. PMID:24410341

  7. Diversity-Oriented Approaches to Polycyclics and Bioinspired Molecules via the Diels-Alder Strategy: Green Chemistry, Synthetic Economy, and Beyond.

    PubMed

    Kotha, Sambasivarao; Chavan, Arjun S; Goyal, Deepti

    2015-05-11

    We describe diverse approaches to various dienes and their utilization in the Diels-Alder reaction to produce a variety of polycycles. The dienes covered here are prepared by simple alkylation reaction or via the Claisen rearrangement or by enyne metathesis of alkyne or enyne building blocks. Here, we have also included the Diels-Alder chemistry of dendralenes, a higher analog of cross-conjugated dienes. The present article is inclusive of o-xylylene derivatives that are generated in situ starting with benzosultine or benzosulfone derivatives. The Diels-Alder reaction of these dienes with various dienophiles gave diverse polycyclic systems and biologically important targets.

  8. Crystal structure of (1S,2R,6R,7R,8S,12S)-4,10,17-triphenyl-15-thia-4,10-diaza-penta-cyclo[5.5.5.0(1,16).0(2,6).0(8,12)]hepta-deca-13,16-diene-3,5,9,11-tetrone p-xylene hemisolvate.

    PubMed

    Noland, Wayland E; Kroll, Neil J; Huisenga, Matthew P; Yue, Ruixian A; Lang, Simon B; Klein, Nathan D; Tritch, Kenneth J

    2014-12-01

    The title tetrone compound, C32H22N2O4S· 0.5C8H10, is the major product (50% yield) of an attempted Diels-Alder reaction of 2-(α-styr-yl)thio-phene with N-phenyl-male-imide (2 equivalents) in toluene. Recrystallization of the resulting powder from p-xylene gave the title hemisolvate; the p-xylene mol-ecule is located about an inversion center. In the crystal, the primary tetrone contacts are between a carbonyl O atom and the four flagpole H atoms of the bi-cyclo-[2.2.2]octene core, forming chains along [001].

  9. Crystal structure of bis­(η5-cyclo­penta­dien­yl)(1,4-di-tert-butyl­buta-1-en-3-yn-1-yl)zirconium(IV) μ2-hydroxido-bis­[tris(penta­fluoro­phen­yl)borate

    PubMed Central

    Burlakov, Vladimir V.; Spannenberg, Anke; Arndt, Perdita; Rosenthal, Uwe

    2015-01-01

    Alkyl zirconocene cations have been of considerable inter­est as reactive species in many polymerization processes. In the crystal structure of the title compound, [Zr(C12H19)(C5H5)2](C36HB2F30O), the [Zr(C5H5)2((t-Bu)C=C(H)—C2(t-Bu))]+ cation displays a buta-1-en-3-yne ligand side-on coordinated to a typical bent zirconocene [centroid(cp)—Zr—centroid(cp) = 131.4 (3)°, Zr—C(buta-1-en-3-yne) = 2.255 (3), 2.597 (3) and 2.452 (2) Å]. In the [HO(B(C6F5)3)2]− anion, intra­molecular O—H⋯F hydrogen bonds are observed. One tert-butyl group in the complex cation is disordered over two sets of sites with occupancies 0.701(4):0.299(4). PMID:25844214

  10. Trichlorido-1κ2 Cl,2κCl-(2,6-dimethyl­phenolato-2κO)-μ-oxido-bis{1,2(η5)-2,3,4,5-tetra­methyl-1-[4-(trimethyl­silyl)phen­yl]cyclo­penta­dien­yl}dititanium(IV)

    PubMed Central

    Luo, Xuyang; Wu, Qiaolin; Mu, Ying

    2011-01-01

    The title dinuclear titanocene, [Ti2(C8H9O)(C18H25Si)2Cl3O], contains one Ti atom tetra­hedrally coordinated by two Cl atoms, a bridging O atom and the substituted cyclo­penta­dienyl ligand, and another Ti atom tetra­hedrally coordinated by a Cl atom, a bridging O atom, the 2,6-dimethyl­phenolate ligand and the substituted cyclo­penta­dienyl ligand. The bridging O atom lies on a twofold rotation axis. PMID:22064795

  11. [1,1′-Bis(di­phenyl­phosphan­yl)cobalto­cenium-κ2 P,P′](η5-cyclo­penta­dien­yl){2-[4-(4-ethynylphen­yl)phen­yl]ethynyl-κC}ruthenium(II) hexa­fluorido­phosphate

    PubMed Central

    Zeng, Ling-Zhen; Wu, Yun-Ying; Tian, Guang-Xuan; Li, Zhen

    2013-01-01

    In the title compound, [CoRu(C5H5)(C16H9)(C17H14P)2]PF6, the RuII atom is coordinated by a cyclo­penta­dienyl ring in an η5-mode, one C atom from a 4,4′-diethynyl-1,1′-biphenyl ligand and two P atoms from a chelating 1,1′-bis­(di­phenyl­phosphan­yl)cobaltocenium ligand, giving a three-legged piano-stool geometry. In the crystal, weak C—H⋯F hydrogen bonds link the complex cations and hexa­fluorido­phosphate anions into a three-dimensional supra­molecular structure. PMID:24454037

  12. Trichlorido-1κCl,2κCl-(2,6-dimethyl-phenolato-2κO)-μ-oxido-bis{1,2(η)-2,3,4,5-tetra-methyl-1-[4-(trimethyl-silyl)phen-yl]cyclo-penta-dien-yl}dititanium(IV).

    PubMed

    Luo, Xuyang; Wu, Qiaolin; Mu, Ying

    2011-10-01

    The title dinuclear titanocene, [Ti(2)(C(8)H(9)O)(C(18)H(25)Si)(2)Cl(3)O], contains one Ti atom tetra-hedrally coordinated by two Cl atoms, a bridging O atom and the substituted cyclo-penta-dienyl ligand, and another Ti atom tetra-hedrally coordinated by a Cl atom, a bridging O atom, the 2,6-dimethyl-phenolate ligand and the substituted cyclo-penta-dienyl ligand. The bridging O atom lies on a twofold rotation axis.

  13. Cobalt(I), -(II), and -(III) complexes of a tetraaza 14-membered macrocycle, 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene (L). Crystal and molecular structures of (CoL(CO))ClO sub 4 , trans-CoLCl sub 2 , and cis-(CoL(CO sub 3 ))ClO sub 4

    SciTech Connect

    Szalda, D.J.; Fujita, E.; Creutz, C. )

    1989-04-19

    The carbon monoxide adduct of the cobalt(I) title macrocycle has been prepared via reaction of CoL{sup +} with CO{sub 2} and with CO and isolated as a perchlorate salt: IR (Nujol){nu}{sub CO} 1916 cm{sup {minus}1}; UV-vis (CH{sub 3}CH, {lambda}{sub max} ({epsilon})) 310 nm (3900 M{sup {minus}1} cm{sup {minus}1}), 430 sh (770), 510 sh (360), 1040 (240). In CH{sub 3}CN solvent its stability constant is {approx} 3 {times} 10{sup 8} M{sup {minus}1} at 25{degree}C. Structures of the square-pyramidal carbonyl complex and two other complexes of the title macrocycle have been determined from single-crystal x-ray diffraction data collected with use of Mo K{alpha} radiation. Crystallographic data: (CoL(CO))(ClO{sub 4}) (1), C2, a = 15.362 (3) {angstrom}, b = 7.580 (5) {angstrom}, c = 9.611 (3) {angstrom}, {beta} = 108.91 (2){degree}, V = 1059 (1) {angstrom}{sup 3}, Z = 2 (R = 0.057, R{sub w} = 0.069); N-meso,trans-CoLCl{sub 2} (2), Pbca, a = 11.570 (3) {angstrom}, b = 12.695 (3) {angstrom}, c = 13.309 (2) {angstrom}, V = 1954 (1) {angstrom}{sup 3}, Z = 4 (R = 0.075, R{sub w} = 0.070); cis-(CoL(CO{sub 3}))ClO{sub 4} (3), C2, a = 15.072 (5) {angstrom}, b = 7.603 (4) {angstrom}, c = 9.703 (3) {angstrom}, {beta} = 109.74 (3){degree}, V = 1047 (1) {angstrom}{sup 3}, Z = 2 (R = 0.033, R{sub w} = 0.048). The three structures contain square-pyramidal, five-coordinate cobalt(I) (1), strongly axially distorted six-coordinate cobalt(II) (2), and six-coordinate cobalt(III) with L occupying cis-coordination positions (3). They thus provide a striking illustration of the adaptability of L to a variety of coordination numbers and oxidation states. 30 refs., 3 figs., 8 tabs.

  14. (C-meso-N-meso-5,12-Dimethyl-7,14-diphenyl-1,4,8,11-tetra­aza­cyclo­tetra­deca-4,11-diene)copper(II) bis­[O,O′-bis­(4-methyl­phen­yl)dithio­phosphate

    PubMed Central

    Zou, Li-Ke; Xie, Bin; Feng, Jian-Shen; Lai, Chuan

    2010-01-01

    In the title compound, [Cu(C24H32N4)](C14H14O2PS2)2, the CuII atom lies on an inversion center and is chelated by the macrocyclic ligand in a distorted CuN4 square-planar geometry. Two O,O′-bis­(4-methyl­phen­yl)dithio­phosphate anions occupy the axial positions with long Cu⋯S distances of 3.0090 (8) Å. Inter­molecular N—H⋯S and C—H⋯S hydrogen bonding is present between the anions and the cation. PMID:21589275

  15. Crystal structure of chlorido­(2-{1-[2-(4-chloro­phen­yl)hydrazin-1-yl­idene-κN]eth­yl}pyridine-κN)(η5-penta­methyl­cyclo­penta­dien­yl)rhodium(III) chloride

    PubMed Central

    Devika, Neelakandan; Raja, Nandhagopal; Ananthalakshmi, Subbiah; Therrien, Bruno

    2015-01-01

    The cation of the title compound, [Rh(η5-C5Me5)Cl(C13H12ClN3)]Cl, adopts a typical piano-stool geometry. The complex is chiral at the metal and crystallizes as a racemate. Upon coordination, the hydrazinyl­idene­pyridine ligand is non-planar, an angle of 54.42 (7)° being observed between the pyridine ring and the aromatic ring of the [2-(4-chloro­phen­yl)hydrazin-1-yl­idene]ethyl group. In the crystal, a weak inter­ionic N—H⋯Cl hydrogen bond is observed. PMID:25844178

  16. Crystal structure of chlorido­(2-{[2-(4-chloro­phen­yl)hydrazin-1-yl­idene-κN 1](phen­yl)meth­yl}pyridine-κN)(η5-penta­methyl­cyclo­penta­dien­yl)iridium(III) tetra­phenyl­borate

    PubMed Central

    Devika, Neelakandan; Raja, Nandhagopal; Ananthalakshmi, Subbiah; Therrien, Bruno

    2015-01-01

    The title compound, [Ir(η5-C5Me5)Cl(C18H14ClN3)]B(C6H5)4, is chiral at the metal center and crystallizes as a racemate. In the cation, the hydrazinyl­idene­pyridine ligand is N,N-coordinated through the N-pyridyl and N-hydrazinyl­idene groups forming a five-membered metallacycle. An intra­molecular C—H⋯Cl hydrogen bond is observed. In the crystal, centrosymmetrically-related cations are connected by C—Cl⋯π inter­actions, forming a dimeric structure. The crystal packing is further stabilized by weak inter­ionic C—H⋯π inter­actions. PMID:25844211

  17. Bis[1,2-bis-(meth-oxy-carbon-yl)ethene-1,2-dithiol-ato-κ(2) S,S']bis-(η(5)-penta-methyl-cyclo-penta-dien-yl)tetra-μ3-sulfido-tetra-iron(4 Fe-Fe) hexa-fluoridophosphate.

    PubMed

    Inomata, Shinji; Ito, Shohei; Takase, Tsugiko

    2013-04-01

    The asymmetric unit of the title compound, [Fe4(C6H6O4S2)2(C10H15)2S4]PF6, contains two different complex cations and two PF6 (-) anions. The two complex cations have similar conformations with the butterfly-like Fe4S4 core surrounded by two penta-methyl-cyclo-penta-dienyl ligands and the S atoms of two dithiol-ate ligands. In each Fe4S4 core, there are four short Fe-Fe and two long Fe⋯Fe contacts, suggesting bonding and non-bonding inter-actions, respectively. The Fe-S distances range from 2.1287 (13) to 2.2706 (16) Å for one and from 2.1233 (13) to 2.2650 (16) Å for the other Fe4S4 core. The Fe-S distances involving the dithiol-ate ligands are in a more narrow range [2.1764 (16)-2.1874 (13) Å for one and 2.1743 (14)-2.1779 (16) Å for the other cation]. There are no significant inter-actions between cations and anions.

  18. Bis[1,2-bis­(eth­oxy­carbon­yl)ethene-1,2-dithiol­ato-κ2 S,S′]bis­(η5-penta­methyl­cyclo­penta­dien­yl)tetra-μ3-sulfido-diiron(IV)diiron(III)(3 Fe—Fe)

    PubMed Central

    Ito, Shohei; Hisamichi, Nozomu; Takase, Tsugiko; Inomata, Shinji

    2013-01-01

    The title compound, [Fe4(C10H15)2(C8H10O4S2)2S4], contains a twisted Fe4S4 cubane-like core. A twofold rotation axis passes through the Fe4S4 core, completing the coordination of the four Fe atoms with two penta­methyl­cyclo­penta­dienyl ligands and two chelating dithiol­ate ligands. There are three short Fe—Fe and three long Fe⋯Fe contacts in the Fe4S4 core, suggesting bonding and non-bonding inter­actions, respectively. The Fe—S bonds in the Fe4S4 core range from 2.1523 (5) to 2.2667 (6) Å and are somewhat longer than the Fe—S bonds involving the dithiol­ate ligand. PMID:23633986

  19. Bis[1,2-bis­(meth­oxy­carbon­yl)ethene-1,2-dithiol­ato-κ2 S,S′]bis­(η5-penta­methyl­cyclo­penta­dien­yl)tetra-μ3-sulfido-tetra­iron(4 Fe–Fe) hexa­fluoridophosphate

    PubMed Central

    Inomata, Shinji; Ito, Shohei; Takase, Tsugiko

    2013-01-01

    The asymmetric unit of the title compound, [Fe4(C6H6O4S2)2(C10H15)2S4]PF6, contains two different complex cations and two PF6 − anions. The two complex cations have similar conformations with the butterfly-like Fe4S4 core surrounded by two penta­methyl­cyclo­penta­dienyl ligands and the S atoms of two dithiol­ate ligands. In each Fe4S4 core, there are four short Fe—Fe and two long Fe⋯Fe contacts, suggesting bonding and non-bonding inter­actions, respectively. The Fe—S distances range from 2.1287 (13) to 2.2706 (16) Å for one and from 2.1233 (13) to 2.2650 (16) Å for the other Fe4S4 core. The Fe—S distances involving the dithiol­ate ligands are in a more narrow range [2.1764 (16)–2.1874 (13) Å for one and 2.1743 (14)–2.1779 (16) Å for the other cation]. There are no significant inter­actions between cations and anions. PMID:23634019

  20. Bis(μ-2-tert-butyl­phenyl­imido-1:2κ2 N:N)chlorido-2κCl-(diethyl ether-1κO)(2η5-penta­methyl­cyclo­penta­dien­yl)lithiumtantalum(V)

    PubMed Central

    Cole, Jacqueline M.; Chan, Michael C. W.; Gibson, Vernon C.; Howard, Judith A. K.

    2011-01-01

    In the title compound, [LiTa(C10H15)(C10H13N)2Cl(C4H10O)], the TaV atom is coordinated by a η5-penta­methyl­cyclo­penta­dienyl (Cp*) ligand, a chloride ion and two N-bonded 2-tert-butyl­phenyl­imide dianions. With respect to the two N atoms, the chloride ion and the centroid of the Cp* ring, the tantalum coordination geometry is approximately tetra­hedral. The lithium cation is bonded to both the 2-tert-butyl­phenyl­imide dianions and also a diethyl ether mol­ecule, in an approximate trigonal planar arrangement. The Ta⋯Li separation is 2.681 (15) Å. In the crystal, a weak C—H⋯Cl inter­action links the mol­ecules. When compared to the 2,6-diisopropyl­phenyl­imide analogue (‘the Wigley derivative’) of the title compound, the two structures are conformationally matched with an overall r.m.s. difference of 0.461Å. PMID:21754594

  1. Bis[1,2-bis-(eth-oxy-carbon-yl)ethene-1,2-dithiol-ato-κ(2) S,S']bis-(η(5)-penta-methyl-cyclo-penta-dien-yl)tetra-μ3-sulfido-diiron(IV)diiron(III)(3 Fe-Fe).

    PubMed

    Ito, Shohei; Hisamichi, Nozomu; Takase, Tsugiko; Inomata, Shinji

    2013-04-01

    The title compound, [Fe4(C10H15)2(C8H10O4S2)2S4], contains a twisted Fe4S4 cubane-like core. A twofold rotation axis passes through the Fe4S4 core, completing the coordination of the four Fe atoms with two penta-methyl-cyclo-penta-dienyl ligands and two chelating dithiol-ate ligands. There are three short Fe-Fe and three long Fe⋯Fe contacts in the Fe4S4 core, suggesting bonding and non-bonding inter-actions, respectively. The Fe-S bonds in the Fe4S4 core range from 2.1523 (5) to 2.2667 (6) Å and are somewhat longer than the Fe-S bonds involving the dithiol-ate ligand.

  2. Crystal structure of bis­{μ2-[(2-imino­cyclo­pentyl­idene)methyl­idene]aza­nido-κ2 N:N′}bis­[(η5-penta­methyl­cyclo­penta­dien­yl)zirconium(IV)] hexane monosolvate

    PubMed Central

    Becker, Lisanne; Spannenberg, Anke; Arndt, Perdita; Rosenthal, Uwe

    2015-01-01

    The title compound, [Zr2(C10H15)4(C6H6N2)2]·C6H14, was obtained by the stoichiometric reaction of adipo­nitrile with [Zr(C10H15)2(η2-Me3SiC2SiMe3)]. Intra­molecular nitrile–nitrile couplings and deprotonation of the substrate produced the (1-imino-2-enimino)­cyclo­pentane ligand, which functions as a five-membered bridge between the two metal atoms. The ZrIV atom exhibits a distorted tetra­hedral coordination sphere defined by two penta­methyl­cyclo­penta­dienyl ligands, by the imino unit of one (1-imino-2-enimino)­cyclo­pentane and by the enimino unit of the second (1-imino-2-enimino)­cyclo­pentane. The cyclo­pentane ring of the ligand shows an envelope conformation. The asymmetric unit contains one half of the complex and one half of the hexane solvent mol­ecule, both being completed by the application of inversion symmetry. One of the penta­methyl­cyclo­penta­dienyl ligands is disordered over two sets of sites with a refined occupancy ratio of 0.8111 (3):0.189 (3). In the crystal, the complex mol­ecules are packed into rods extending along [100], with the solvent mol­ecules located in between. The rods are arranged in a distorted hexa­gonal packing. PMID:26870433

  3. Dicarbon­yl(hexa­methyl­ene-1,3,5,7-tetra­mine-κN 1)(η5-penta­methyl­cyclo­penta­dien­yl)iron(II) tetra­fluoridoborate

    PubMed Central

    M’thiruaine, Cyprian M.; Friedrich, Holger B.; Changamu, Evans O.; Fernandes, Manuel A.

    2012-01-01

    In the title compound, [Fe(C10H15)(C6H12N4)(CO)2]BF4, the arrangement around the FeII atom corresponds to a three-legged piano stool. The penta­methyl­cyclo­penta­dienyl (Cp*) ligand occupies three coordination sites, while two CO ligands and one N atom of the hexa­methyl­ene­tetra­mine ligand occupy the remaining coordination sites, completing a pseudo-octahedral geometry. Both the complex cation and the BF4 − anion reside on crystallographic mirror planes. The Fe—N bond length is 2.069 (2) and the Fe—Cp*(centroid) distance is 1.7452 (3) Å. PMID:22807762

  4. Naval Forces, Vietnam Monthly Historical Summary for January 1966

    DTIC Science & Technology

    1966-01-01

    innocent when inspected» At * other times personnel were detained because they lacked proper credentials. ,80010 of these people were later identified...Phu Quoc Island, having as its . • first objective the survey of Fausse Poulo Obi Island to find suitable anchorages in case of bad weather« When this...8217decrease was not determined. The American rationalization that the holiday mood of the people during Tet caused the reduced patrol effort could not be

  5. Southeast Asia, Report No. 1298.

    DTIC Science & Technology

    1983-06-10

    recycled nearly 3,000 tons of used oil , purchased 52,000 tons of scrap steel, etc. In 1982, the collection, restoration, and reprocessing of such old...its recovery is well organized and if it is processed well, used lubricating oil could meet one-fifth of the planned needs every year. 29 Another...Hoa in Vinh Phu Province, or forested lowland district (such as a number of cajeput and mangrove forests in the south). There is the type of

  6. Food composition and acid-base balance: alimentary alkali depletion and acid load in herbivores.

    PubMed

    Kiwull-Schöne, Heidrun; Kiwull, Peter; Manz, Friedrich; Kalhoff, Hermann

    2008-02-01

    Alkali-enriched diets are recommended for humans to diminish the net acid load of their usual diet. In contrast, herbivores have to deal with a high dietary alkali impact on acid-base balance. Here we explore the role of nutritional alkali in experimentally induced chronic metabolic acidosis. Data were collected from healthy male adult rabbits kept in metabolism cages to obtain 24-h urine and arterial blood samples. Randomized groups consumed rabbit diets ad libitum, providing sufficient energy but variable alkali load. One subgroup (n = 10) received high-alkali food and approximately 15 mEq/kg ammonium chloride (NH4Cl) with its drinking water for 5 d. Another group (n = 14) was fed low-alkali food for 5 d and given approximately 4 mEq/kg NH4Cl daily for the last 2 d. The wide range of alimentary acid-base load was significantly reflected by renal base excretion, but normal acid-base conditions were maintained in the arterial blood. In rabbits fed a high-alkali diet, the excreted alkaline urine (pH(u) > 8.0) typically contained a large amount of precipitated carbonate, whereas in rabbits fed a low-alkali diet, both pH(u) and precipitate decreased considerably. During high-alkali feeding, application of NH4Cl likewise decreased pH(u), but arterial pH was still maintained with no indication of metabolic acidosis. During low-alkali feeding, a comparably small amount of added NH4Cl further lowered pH(u) and was accompanied by a significant systemic metabolic acidosis. We conclude that exhausted renal base-saving function by dietary alkali depletion is a prerequisite for growing susceptibility to NH4Cl-induced chronic metabolic acidosis in the herbivore rabbit.

  7. Project CHECO Southeast Asia Report. Air Defense in Southeast Asia 1945 - 1971

    DTIC Science & Technology

    1973-01-17

    13th AF Second Advanced Echelon (Det 7, 2 ADVON) 2 / was organized at TSN Airport , with Brigadier General Rollen H. Anthis, Deputy 3 Commander 13th Air...enroute flight requirements of tactical aircraft deployed to Don Muang Airport , Thai land. I 4. Conducting air defense training. 5. Assisting in the...deactivated.- Another radar equipped FACP was to have a short existence at Duong Dong Airport on Phu Quoc Island covering southern Cambodia, the Gulf of

  8. Learning Non-Local Dependencies

    ERIC Educational Resources Information Center

    Kuhn, Gustav; Dienes, Zoltan

    2008-01-01

    This paper addresses the nature of the temporary storage buffer used in implicit or statistical learning. Kuhn and Dienes [Kuhn, G., & Dienes, Z. (2005). Implicit learning of nonlocal musical rules: implicitly learning more than chunks. "Journal of Experimental Psychology-Learning Memory and Cognition," 31(6) 1417-1432] showed that people could…

  9. Triterpenoids from Arctium lappa.

    PubMed

    Jeelani, S; Khuroo, M A

    2012-01-01

    Phytochemical investigation of the leaves of Arctium lappa led to the isolation of two triterpenoids, characterised by NMR, IR and MS as 3α-hydroxylanosta-5,15-diene and 3α-acetoxy-hop-22(29)-ene. 3α-hydroxylanosta-5,15-diene is a new triterpenoid and is isolated for the first time from this genus.

  10. Bromine radical-mediated sequential radical rearrangement and addition reaction of alkylidenecyclopropanes.

    PubMed

    Kippo, Takashi; Hamaoka, Kanako; Ryu, Ilhyong

    2013-01-16

    Bromine radical-mediated cyclopropylcarbinyl-homoallyl rearrangement of alkylidenecyclopropanes was effectively accomplished by C-C bond formation with allylic bromides, which led to the syntheses of 2-bromo-1,6-dienes. A three-component coupling reaction comprising alkylidenecyclopropanes, allylic bromides, and carbon monoxide also proceeded well to give 2-bromo-1,7-dien-5-ones in good yield.

  11. Enantioselective synthesis of helicenequinones and -bisquinones.

    PubMed

    Urbano, Antonio; Carreño, M Carmen

    2013-02-07

    A convergent approach based on Diels-Alder reactions between polycyclic dienes and benzoquinones has emerged as a powerful tool for the construction of helicenequinones and bisquinones. Chemical resolution and asymmetric Diels-Alder reactions with sulfinyl quinones provide direct access to enantiopure derivatives. Biaryl or ferrocenyl dienes can be resolved leading to helicenequinones having additional axial or planar chirality.

  12. Comparing utilitarian and hedonic usefulness to user intention in multipurpose information systems.

    PubMed

    Gu, Ja-Chul; Fan, Liu; Suh, Yung Ho; Lee, Sang-Chul

    2010-06-01

    This research studies the differences between productivity-oriented (or utilitarian) and entertainment-oriented (or hedonic) usefulness for a multipurpose information system in user acceptance models, as information systems can be high or low in both hedonic and utilitarian attributes. Accordingly, perceived usefulness (PU) is divided into perceived utilitarian usefulness (PUU) and perceived hedonic usefulness (PHU) to provide a better understanding of users' intention for accepting IT. To test the proposed model more effectively, this research targets instant messaging (IM), which is an extremely popular and increasingly important communication system, both utilitarian and hedonic in nature. This research compares the difference across two groups: students for hedonic purpose and employees for utilitarian purpose. We conclude that the proposed model, which distinguishes between utilitarian and hedonic usefulness, is more effective than previous models in which the usefulness was not distinguished. Both PUU and PHU have an effect on intention to use. Employees consider PUU more important in their intention to use IM, while students are more influenced by PHU.

  13. Genetic polymorphism of the CAPN1 gene is associated with meat quality traits in Japanese quail.

    PubMed

    Rasouli, Z; Zerehdaran, S; Azari, M A; Shargh, M S

    2013-01-01

    1. The objective of the study was to investigate the polymorphisms in two regions of the calpain 1 (CAPN1) gene and their association with breast and thigh meat quality in Japanese quail (ultimate pH (pHu), lightness, redness, yellowness, drip loss, thawing-cooking loss, water holding capacity and shear force, SF). 2. Blood samples were collected randomly from 100 birds and DNA was extracted using a commercial kit. Genotypes were determined by PCR amplification followed by single-strand conformation polymorphism (SSCP) analysis. The effect of CAPN1 genotypes on meat quality traits were analysed using a general linear model (GLM) procedure. 3. Genotypes of the CAPN1 gene in the first region (217-bp) analysed were significantly associated with yellowness and SF. The TT genotype showed significantly higher yellowness and lower shear force (more tenderness) than CT and CC genotypes. Genotypes of the second region of the gene (intron 4, 800-bp) were significantly associated with pHu, redness and SF of the breast meat. The BB genotype showed significantly lower pHu and redness and higher SF (lower tenderness) than other genotypes. 4. Information on polymorphisms of the CAPN1 gene will eventually provide useful information for improving meat quality of Japanese quail through marker-assisted selection.

  14. A bacteriophage tubulin harnesses dynamic instability to center DNA in infected cells.

    PubMed

    Erb, Marcella L; Kraemer, James A; Coker, Joanna K C; Chaikeeratisak, Vorrapon; Nonejuie, Poochit; Agard, David A; Pogliano, Joe

    2014-11-27

    Dynamic instability, polarity, and spatiotemporal organization are hallmarks of the microtubule cytoskeleton that allow formation of complex structures such as the eukaryotic spindle. No similar structure has been identified in prokaryotes. The bacteriophage-encoded tubulin PhuZ is required to position DNA at mid-cell, without which infectivity is compromised. Here, we show that PhuZ filaments, like microtubules, stochastically switch from growing in a distinctly polar manner to catastrophic depolymerization (dynamic instability) both in vitro and in vivo. One end of each PhuZ filament is stably anchored near the cell pole to form a spindle-like array that orients the growing ends toward the phage nucleoid so as to position it near mid-cell. Our results demonstrate how a bacteriophage can harness the properties of a tubulin-like cytoskeleton for efficient propagation. This represents the first identification of a prokaryotic tubulin with the dynamic instability of microtubules and the ability to form a simplified bipolar spindle.

  15. Diterpenoids from the freshwater green algae Rhizoclonium hieroglyphicum with antibacterial activity.

    PubMed

    Perez Gutierrez, Rosa Martha; Garcia Baez, Efren

    2011-10-01

    Three new isopimarane diterpenes 7β-hydroxy-19α-methylmalonyloxy-isopimara-8(14),15-diene (1), 7β-hydroxy-14-oxo-isopimara-8(9),15-dien-19oic acid (2), and 7β-hydroxy-14-oxo-19α-methylmalonyloxy-isopimara-9(11),15-diene (3) in addition to the known compounds isopimaric acid (4), 7oxo-13-epi-pimara-14,15-dien-18oic acid (5), 7oxo-13-epi-pimara-8,15-dien-18oic acid (6), and 6β-hydroxyisopimaric acid (7) were isolated from the hexane extract of Rhizoclonium hieroglyphicum. The structures of compounds 1-7 were established by 1D and 2D NMR techniques. The isolated diterpenoids were screened for antimicrobial activity against gram-positive and gram-negative bacteria and yeast strains.

  16. Polar Diels-Alder reactions using electrophilic nitrobenzothiophenes. A combined experimental and DFT study

    NASA Astrophysics Data System (ADS)

    Della Rosa, Claudia D.; Mancini, Pedro M. E.; Kneeteman, Maria N.; Lopez Baena, Anna F.; Suligoy, Melisa A.; Domingo, Luis R.

    2015-01-01

    The reactions between 2- and 3-nitrobenzothiophenes with three dienes of different nucleophilicity, 1-methoxy-3-trimethylsilyloxy-1,3-butadiene, 1-trimethylsilyloxy-1,3-butadiene and isoprene developed in anhydrous benzene and alternative under microwave irradiation with molecular solvents or in free solvent conditions, respectively, for produce dibenzothiophenes permit to conclude that both nitroheterocycles act as electrophile with the cited dienes. In the cases of the dienes 1-methoxy-3-trimethylsilyloxy-1,3-butadiene and 1-trimethylsilyloxy-1,3-butadiene which posses major nucleophilicity the observed product is the normal cycloaddition one. However when the diene is isoprene the product with both electrophiles follow the hetero Diels-Alder way. These reactions are considered polar cycloaddition reactions and the yields are reasonables. Moreover the polar Diels-Alder reactions of nitrobenzothiophenes with electron rich dienes 1-trimethylsilyloxy-1,3-butadiene have been theoretically studied using DFT methods.

  17. Biotransformation of dianabol with the filamentous fungi and β-glucuronidase inhibitory activity of resulting metabolites.

    PubMed

    Khan, Naik T; Zafar, Salman; Noreen, Shagufta; Al Majid, Abdullah M; Al Othman, Zeid A; Al-Resayes, Saud Ibrahim; Atta-ur-Rahman; Choudhary, M Iqbal

    2014-07-01

    Biotransformation of the anabolic steroid dianabol (1) by suspended-cell cultures of the filamentous fungi Cunninghamella elegans and Macrophomina phaseolina was studied. Incubation of 1 with C. elegans yielded five hydroxylated metabolites 2-6, while M. phaseolina transformed compound 1 into polar metabolites 7-11. These metabolites were identified as 6β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (2), 15α,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (3), 11α,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (4), 6β,12β,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (5), 6β,15α,17β-trihydroxy-17α-methylandrost-1,4-dien-3-one (6), 17β-hydroxy-17α-methylandrost-1,4-dien-3,6-dione (7), 7β,17β,-dihydroxy-17α-methylandrost-1,4-dien-3-one (8), 15β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (9), 17β-hydroxy-17α-methylandrost-1,4-dien-3,11-dione (10), and 11β,17β-dihydroxy-17α-methylandrost-1,4-dien-3-one (11). Metabolite 3 was also transformed chemically into diketone 12 and oximes 13, and 14. Compounds 6 and 12-14 were identified as new derivatives of dianabol (1). The structures of all transformed products were deduced on the basis of spectral analyses. Compounds 1-14 were evaluated for β-glucuronidase enzyme inhibitory activity. Compounds 7, 13, and 14 showed a strong inhibition of β-glucuronidase enzyme, with IC50 values between 49.0 and 84.9 μM.

  18. Synthesis, structural and electrochemical properties of nickel(II) sulfamethazine complex with diethylenetriamine ligand.

    PubMed

    Bulut, İclal; Öztürk, Filiz; Bulut, Ahmet

    2015-03-05

    In this study, [Ni(dien)2]⋅smz2⋅(Hsmz: sulfamethazine and dien: diethylenetriamine) complex has been synthesized and its crystal structure has been determined by X-ray diffraction technique. The title complex crystallizes in orthorhombic system with space group Pbnb [a=8.556(5), b=16.228(5), c=28.209(5)Å, V=3917(3)Å(3) and Z=4]. The nickel(II) ion has distorted octahedral coordination geometry. The metal atom, which rides on a crystallographic center of symmetry, is coordinated by six nitrogen atoms of two dien ligands to form a discrete [Ni(dien)2](2+) unit, which captures two sulfamethazine ions, each through intermolecular hydrogen bonds. The powder EPR spectrum of Cu(2+) doped Ni(II) complex was recorded at room temperature. The vibrational investigation has been carried out by considering the characteristic bands related to the functional groups of the complex. The electrochemical behavior of Ni(II) ions in the presence and in the absence of smz and dien were studied by square wave and cyclic voltammetry. A well-defined irreversible peak at -1.112V different from those of the Ni(II)-smz (-0.876V) and the Ni(II)-dien complex (-1.064V) was observed in the solution containing Ni(II) ions, which was attributed to the formation of the new mixed ligand complex of Ni(II) with smz and dien.

  19. Structure-Activity Relationships for Some Diamine, Triamine and Schiff Base Derivatives and Their Copper(II) Complexes

    PubMed Central

    Bolos, C. A.; Nikolov, G. St.; Ekateriniadou, L.; Kortsaris, A.; Kyriakidis, D. A.

    1998-01-01

    Ethylenediamine (en), putrescine (pu), diethylenetriamine (dien), dipropylenetriamine (dpta), spermidine (spmd) and their CuII compounds as well as the Schiff bases with 2-furaldehyde (dienOO), 2- thiophenecarboxaldehyde (dienSS) and pyrrole-2-carboxaldehyde (dienNN) of dien and that of dpta with 2- thiophenecarboxaldehyde (dptaSS), were prepared and characterised. They were tested against Bacillus substilis, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Proteus vulgaris and Xanthomonas campestris as antibacterial reagents, the highest activity being exhibited by Cu(dptaSS)(NO3)2 complex, which acts as antibiotic. In the antiproliferative tests (vs. T47D,L929 and BHK21/c13 cell lines) the best results were obtained with Cu(dptaSS)2+ and Cu(dienSS)2+. Electronic structure calculations gave for dptaSS and dienSS the higher negative charges on the N atoms. The counter-ions (Br-, NO3- and SO42-) play an important role by modulating the reagent's selectivity versus the bacteria [Gram(+) or Gram(-)], but they have no effect on the antiproliferative activity. PMID:18475868

  20. Volatile components from European liverworts Marsupella emarginata, M. aquatica and M. alpina.

    PubMed

    Adio, Adewale Martins; Paul, Claudia; König, Wilfried A; Muhle, Hermann

    2002-09-01

    The hydrodistillation products of the liverworts Marsupella emarginata, M. aquatica and M. alpina were investigated by spectroscopic methods. A number of new compounds could be isolated by preparative gas chromatography (GC) and identified by spectroscopic techniques including GC-mass spectrometry, NMR and chemical correlations in conjunction with enantioselective GC. From M. emarginata, in addition to many known compounds, the sesquiterpene hydrocarbon (-)-7-epi-eremophila-1(10),8,11-triene (1) and the sesquiterpene derivatives (-)-4-epi-marsupellol (2), (-)-marsupellol acetate (18), (-)-4-epi-marsupellol acetate (4), (+)-5-hydroxymarsupellol acetate (5) and (-)-9-acetoxygymnomitr-8(12)-ene (24) could be identified. In M. aquatica the sesquiterpene hydrocarbons (-)-myltayl-8(12)-ene (7), ent-(+)-amorpha-4,11-diene (8), (-)-amorpha-4,7(11)-diene (9), the sesquiterpene alcohol (+)-9-hydroxyselina-4,11-diene (10) and (-)-2-acetoxyamorpha-4,7(11)-diene (11) were identified. In M. alpina (-)-trans-selina-4(15),11-dien-5-ol (12), (+)-8,9-epoxyselina-4,11-diene (13) and (+)-cis-selina-4(15),11-dien-5-ol (14) were found as new natural products.

  1. A non-calcemic sulfone version of the vitamin D(3) analogue seocalcitol (EB 1089): chemical synthesis, biological evaluation and potency enhancement of the anticancer drug adriamycin.

    PubMed

    Posner, G H; Crawford, K R; Peleg, S; Welsh, J E; Romu, S; Gewirtz, D A; Gupta, M S; Dolan, P; Kensler, T W

    2001-09-01

    Novel side-chain diene sulfones 5, analogues of the natural hormone 1alpha,25-dihydroxyvitamin D(3) (calcitriol, 1), were designed to incorporate some of the therapeutically most favorable structural features of the Leo Pharmaceutical Company's drug candidate diene EB 1089 (seocalcitol, 4) and of the Hopkins' non-calcemic side-chain sulfone analogues 2 and 3. Synthesis of diene sulfones 5 features selective Swern oxidation of a primary silyl ether in the presence of a secondary silyl ether (9-->10) and Horner-Wadsworth-Emmons aldehyde addition by a 1-phosphonyl-3-sulfonyl stabilized carbanion regiospecifically at the 1-position to form E,E-diene sulfone 11. Sulfone diene analogue 5a with natural 1alpha,3beta-diol functionality, but not its diastereomer 5b with unnatural A-ring stereochemistry, is antiproliferative in vitro toward murine keratinocytes and malignant melanoma cells, as well as toward MCF-7 human breast cancer cells. Combining diene sulfone 5a with the currently used anticancer drug adriamycin (ADR) caused a noteworthy 3-fold enhancement of ADR antiproliferative potency in MCF-7 cells. Sulfone diene analogue 5a is weakly active transcriptionally in MCF-7 and ROS 17/2.8 cells, binds poorly but measurably to the vitamin D receptor (VDR), and desirably is non-calcemic in vivo at a daily dose (7 days) of 10 microg/kg of rat body weight.

  2. Utilization of services provided by village based ethnic minority midwives in mountainous villages of Vietnam

    PubMed Central

    Doan, Duong Thi Thuy; Bui, Ha Thi Thu; Le, Thi Minh; Duong, Duc Minh; Luu, Hong Thi; Dinh, Tuan Anh; Mirzoev, Tolib

    2016-01-01

    Introduction Since 2011, the Vietnam’s Ministry of Health implemented the ethnic minority midwives (EMMs) scheme in order to increase the utilization of maternal health services by women from ethnic minorities and those living in hard-to-reach mountainous areas. This paper analyzes the utilization of antenatal, delivery, and postpartum care provided by EMMs and reports the key determinants of utilization of EMM services as perceived by service users. Methods A structured questionnaire was administered in 2015 to all mothers (n=320) who gave birth to a live-born during a 1-year period in 31 villages which had EMM in two provinces, Dien Bien and Kon Tum. A multivariate logistic regression model was used to examine the association between all potential factors and the use of services provided by EMMs. Results We found that EMMs provided more antenatal care and postnatal care as compared with delivery services, which corresponded to their job descriptions. The results also showed that utilization of antenatal care provided by EMMs was lower than that of postnatal care. The proportion of those who never heard about EMM was high (24%). Among the mothers who knew about EMM services, 33.4% had antenatal checkups, 20.1% were attended during home deliveries, and 57.3% had postnatal visits by an EMM. Key factors that determined the use of EMM services included knowledge of the location of EMM’s house, being aware about EMMs by health workers, trust in services provided by EMMs, and perception that many others mothers in a village also knew about EMM services. Conclusion EMM seems to be an important mechanism to ensure assistance during home births and postnatal care for ethnic minority groups, who are often resistant to attend health facilities. Building trust and engaging with communities are the key facilitators to increase the utilization of services provided by EMMs. Communication campaigns to raise awareness about EMMs and to promote their services in the village

  3. Synthesis of (+)-Discodermolide by Catalytic Stereoselective Borylation Reactions**

    PubMed Central

    Yu, Zhiyong; Ely, Robert J.

    2014-01-01

    The marine natural product (+)-discodermolide was first isolated in 1990 and, to this day, remains a compelling synthesis target. Not only does the compound possess fascinating biological activity, but it also presents an opportunity to test current methods for chemical synthesis and provides a forum for the inspiration of new reaction development. In this manuscript, we present a synthesis of discodermolide that employs a previously undisclosed stereoselective catalytic diene hydroboration and also establishes a strategy for chiral enolate alkylation. In addition, this synthesis of discodermolide provides the first examples of diene 1,4-diboration and borylative diene-aldehyde couplings in complex molecule synthesis. PMID:25045037

  4. Cucurbitane-type triterpenoids from the fruit pulp of Momordica charantia.

    PubMed

    Liao, Yun-Wen; Chen, Chiy-Rong; Kuo, Yueh-Hsiung; Hsu, Jue-Liang; Shih, Wen-Ling; Cheng, Hsueh-Ling; Huang, Tzou-Chi; Chang, Chi-I

    2012-12-01

    Three new cucurbitane-type triterpenoids, 5beta,19-epoxy-23(R)-methoxycucurbita-6,24-dien-3beta-ol (1), 5beta,19-epoxy-23(S)-methoxycucurbita-6,24-dien-3beta-ol (2), and 3beta-hydroxy-23(R)-methoxycucurbita-6,24-dien-5beta,19-olide (3), were isolated from the fruit pulp of Momordica charantia. Their structures were established on the basis of extensive NMR (1H, 13C, COSY, HMQC, HMBC, and NOESY) and EI-MS studies. Compound 1 exhibited cytotoxic activity against the SK-Hep 1 cell line.

  5. Three new triterpene glycosides from Ilex asprella.

    PubMed

    Zhang, Zhen-Xia; Fu, Qiang; Zheng, Ken Yu-Zhong

    2013-01-01

    Three new sulfated triterpene glycosides, asprellanosides C-E (1-3), were isolated from the roots of Ilex asprella. Their structures were elucidated as 3β-[(2-O-sulfo-β-d-xylopyranosyl)oxy]urs-12,19(29)-diene-28-oic acid 28-β-d-glucopyranoside (1), 3β-[(2-O-sulfo-β-d-xylopyranosyl)oxy]urs-12,19-diene-28-oic acid 28-β-d-glucopyranoside (2), and 3β-[(2-O-sulfo-β-d-xylopyranosyl)oxy]urs-12,19-diene-28-oic acid (3) on the basis of the spectral and chemical methods.

  6. Analyse des facteurs prédictifs de malignité des goitres nodulaires : à propos de 500 cas

    PubMed Central

    Bouaity, Brahim; Darouassi, Youssef; Chihani, Mehdi; Touati, Mohamed Mliha; Ammar, Haddou

    2016-01-01

    Les nodules thyroïdiens sont très fréquents et moins de 10% d'entre eux sont malin. Ils posent un véritable problème diagnostique et thérapeutique surtout par rapport à leur nature bénigne ou maligne. L’étude de certains facteurs cliniques et paracliniques de présomption de malignité permet de bien codifier la stratégie thérapeutique. Le but de ce travail est d’étudier les facteurs prédictifs de malignité des goitres nodulaires et comparer nos résultats à ceux de la littérature. Il s'agit d'une étude rétrospective à propos de 500 cas de goitres nodulaires opérés au service d'Oto-rhino-laryngologie (ORL) et Chirurgie cervico-faciale (CCF) de l'hôpital militaire Avicenne de Marrakech entre 2006 et 2012. Le pourcentage de cancers a été de 6,8%. L’âge moyen de nos patients était de 46 ans, avec une sex-ratio de 5 (F/H). A la palpation cervicale; le caractère dure du nodule a été constaté dans 94,4% des cas de cancer, avec des limites irrégulières dans 64,70% des cas de cancer. Trois nodules étaient fixes et ils étaient tous malins. Les adénopathies cervicales ont été constatées chez 8 malades dont 7 présentaient des cancers. A l’échographie, 61,8% des nodules malins présentaient un aspect hypoéchogène, avec des contours flous dans 88,24% des cas. La vascularisation intra nodulaire était présente dans 35,3% de ces cas des cancers avec des microcalcifications chez 55,9% d'entre eux. Le halo hypoéchogene périnodulaire était incomplet dans 73,5% des cas de cancer. Nos patients étaient en euthyroïdie dans 84,6% des cas. Les facteurs prédictifs de malignité d'un goitre nodulaire, étaient donc dans notre étude d'abord cliniques: l’âge supérieur à 60 ans, la consistance dure du nodule, sa fixité, son caractère irrégulier et mal limité à la palpation, ainsi que la présence d'adénopathie(s) cervicale(s) à l'examen; et échographiques: le caractère hypoéchogène, les limites floues, la présence de

  7. Di-μ-hydroxido-κ4 O:O-μ-trifluoro­methane­sulfonato-κ2 O:O′-bis­[(5,5′-dimethyl-2,2-bipyridine-κ2 N,N′)(η5-penta­methyl­cyclo­penta­dien­yl)ytterbium(III)] tetra­phenyl­borate 5,5′-dimethyl-2,2-bipyridine

    PubMed Central

    Kazhdan, Daniel

    2008-01-01

    The title compound, [Yb2(CF3O3S)(C10H15)2(OH)2(C12H12N2)2](C24H20B)·C12H12N2, crystallizes as a half-sandwich complex with a bridging trifluoro­methane­sulfonate as well as two bridging hydroxide groups. The bound bipyridine ligands have N—C—C—N torsion angles of 13.1 (9) and −12.1 (8)°. The structure also contains an uncoordinated 5,5′-dimethyl-2,2′-bipyridine molecule with an N—C—C—N torsion angle of 169.5 (7)°. The triply bridged Yb centers are 3.5990 (4) Å apart. The Yb—N bond lengths are in the range 2.389 (6)–2.424 (5) Å. PMID:21201376

  8. Crystal structure of μ-carbonyl-1:2κ2 C:C-carbonyl-1κC-(1η5-cyclo­penta­dien­yl)iodido-2κI-[μ-2-(pyridin-2-yl)ethene-1,1-diyl-1κC 1:2κ2 N,C 1]ironpalladium(Fe—Pd) benzene monosolvate

    PubMed Central

    Verpekin, Victor V.; Kreindlin, Arkadii Z.; Semeikin, Oleg V.; Smol’yakov, Alexander F.; Dolgushin, Fedor M.; Chudin, Oleg S.; Ustynyuk, Nikolai A.

    2017-01-01

    The reaction of Cp(CO)2FeI with 2-ethynyl­pyridine under Sonogashira conditions [5% PdCl2(PPh3)2, 10% CuI, THF–NEt3 (2:1)] afforded the title binuclear μ-pyridyl­vinyl­idene FePd complex (FePd1) as a benzene solvate, [FePd(C5H5)(C7H5N)I(CO)2]·C6H6, in a very low yield rather than the expected iron o-pyridyl­ethynyl complex Cp(CO)2Fe—C≡C-(2-C5H4N). The Fe and Pd atoms in FePd1 are bridged by carbonyl and pyridyl­vinyl­idene ligands, the pyridyl N atom being bonded to the palladium atom. The use of equimolar amounts of PdCl2 increases the yield of FePd1 to 12%. The reaction pathway leading to FePd1 is proposed. PMID:28083139

  9. Crystal structure of μ-1κC:2(η2)-carbonyl-carbonyl-1κC-chlorido-2κCl-μ-chlorido­borylene-1:2κ2 B:B-[1(η5)-penta­methyl­cyclo­penta­dien­yl](tri­cyclo­hexyl­phosphane-2κP)iron(II)platinum(II) benzene monosolvate

    PubMed Central

    Braunschweig, Holger; Kramer, Thomas

    2014-01-01

    In the mol­ecular structure of the dinuclear title compound [η5-(C5(CH3)5)(CO)Fe{(μ-BCl)(μ-CO)}PtCl(P(C6H11)3)]·C6H6, the two metal atoms, iron(II) and platinum(II), are bridged by one carbonyl (μ-CO) and one chlorido­borylene ligand (μ-BCl). The PtII atom is additionally bound to a chloride ligand situated trans to the bridging borylene, and a tri­cyclo­hexyl­phosphane ligand (PCy3) trans to the carbonyl ligand, forming a distorted square-planar structural motif at the PtII atom. The FeII atom is bound to a penta­methyl­cyclo­penta­dienyl ligand [η5-C5(CH3)5] and one carbonyl ligand (CO), forming a piano-stool structure. Additionally, one benzene solvent mol­ecule is incorporated into the crystal structure, positioned staggered relative to the penta­methyl­cyclo­penta­dienyl ligand at the FeII atom, with a centroid–centroid separation of 3.630 (2) Å. PMID:25484763

  10. Crystal structure of μ-oxido-1,1′κ2 O:O-bis{tetra-μ-oxido-1:2κ2 O:O;1:3κ2 O:O;2:3κ4 O:O-tris[1,2,3(η5)-penta­methyl­cyclo­penta­dien­yl]-trianglo-trititanium(IV)}

    PubMed Central

    Pérez-Redondo, Adrián; Martín, Avelino

    2015-01-01

    The title polynuclear organometallic titanium(IV) oxide, [{Ti3(η5-C5Me5)3(μ-O)4}2(μ-O)], exhibits two Ti3O4 cores bridged by an O atom located on a twofold axis. All metal centres present the typical three-legged piano-stool coordination environment, where one site is occupied by a penta­methyl­cyclo­penta­dienyl ligand linked in an η5-coordination fashion, while three bridging O atoms fill the other three sites. PMID:26029420

  11. Synthesis of tetrasubstituted 1-silyloxy-3-aminobutadienes and chemistry beyond Diels–Alder reactions

    PubMed Central

    Li, Xijian; Peng, Siyu; Li, Li; Huang, Yong

    2015-01-01

    Electron-rich dienes have revolutionized the synthesis of complex compounds since the discovery of the legendary Diels–Alder cycloaddition reaction. This highly efficient bond-forming process has served as a fundamental strategy to assemble many structurally formidable molecules. Amino silyloxy butadienes are arguably the most reactive diene species that are isolable and bottleable. Since the pioneering discovery by Rawal, 1-amino-3-silyloxybutadienes have been found to undergo cycloaddition reactions with unparalleled mildness, leading to significant advances in both asymmetric catalysis and total synthesis of biologically active natural products. In sharp contrast, this class of highly electron-rich conjugated olefins has not been studied in non-cycloaddition reactions. Here we report a simple synthesis of tetrasubstituted 1-silyloxy-3-aminobutadienes, a complementarily substituted Rawal's diene. This family of molecules is found to undergo a series of intriguing chemical transformations orthogonal to cycloaddition reactions. Structurally diverse polysubstituted ring architectures are established in one step from these dienes. PMID:25898310

  12. Click and Patterned Functionalization of Graphene by Diels-Alder Reaction.

    PubMed

    Li, Jing; Li, Meng; Zhou, Li-Li; Lang, Shuang-Yan; Lu, Hai-Yan; Wang, Dong; Chen, Chuan-Feng; Wan, Li-Jun

    2016-06-22

    Chemical functionalization is a promising approach to controllably manipulate the characteristics of graphene. Here, we designed cis-dienes, featuring two dihydronaphthalene backbones, to decorate a graphene surface via Diels-Alder (DA) click reaction. The installation of a diene moiety into a nonplanar molecular structure to form cis-conformation enables a rapid (∼5 min) DA reaction between graphene and diene groups. Patterned graphene of sub-micrometer resolution can be obtained by easily soaking poly(methyl methacrylate)-masked graphene in solution of hydroxyl-substituted cis-diene at room temperature. The functionalization degree can be further controlled by carrying out the reaction at higher temperature. The present result gives important insight into the effect of molecular conformation on the graphene functionalization process, and provides an effective and facile method for graphene functionalization.

  13. Fluorinated 5- and 7-membered carbacycle motifs by reaction of difluorocarbene with acetylene ethers.

    PubMed

    Chia, Poh Wai; Bello, Davide; Slawin, Alexandra M Z; O'Hagan, David

    2013-03-18

    The reaction of acetylene ethers with difluorocarbene (CF(2)), generated from the Ruppert-Prakash reagent, unexpectedly gave rise to co-produced fluorinated bicyclic [2.1.1]-hex-2-ene and cyclohepta-1,4-diene ring products.

  14. Kinetics and mechanism of the oxidation of alkenes and silanes by hydrogen peroxide catalyzed by methylrhenium trioxide (MTO) and a novel application of electrospray mass spectrometry to study the hydrolysis of MTO

    SciTech Connect

    Tan, Haisong

    1999-11-08

    Conjugated dienes were oxidized by hydrogen peroxide with methylrhenium trioxide (MTO) as catalyst. Methylrhenium bis-peroxide was the major reactive catalyst present. Hydroxyalkenes and trisubstituted silane were also tested. Mechanisms for each of these reactions are presented.

  15. Asymmetric synthesis of gem-diaryl substituted cyclic sulfamidates and sulfamides by rhodium-catalyzed arylation of cyclic ketimines.

    PubMed

    Nishimura, Takahiro; Ebe, Yusuke; Fujimoto, Hiroto; Hayashi, Tamio

    2013-06-18

    Asymmetric addition of arylboronates to aryl-substituted cyclic ketimines proceeded in the presence of a rhodium catalyst coordinated with a chiral diene ligand to give high yields of sulfamidates and sulfamides with high enantioselectivity (up to 99% ee).

  16. NMR spectroscopy for assessment of lipid oxidation during frying

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Except for total polar compounds (TPC), polymerized triacylglycerols (PTAG) and fatty acid composition, most other current standard methods for lipid oxidation detect very small amounts of oxidation products such as hydroperoxides, conjugated dienes, aldehydes, and epoxides. Therefore, amounts of th...

  17. Technology & Mechanics Overview of Air-Inflated Fabric Structures

    DTIC Science & Technology

    2006-12-04

    moisture, fire, chemicals, etc. Coating materials such as urethane, PVC (poly vinyl chloride ), neoprene, EPDM (ethylene propylene diene monomer ) are...Compressibility Drop-Stitched Fabric Inflatable Wings Textile Architectures Optional Rigidification High Performance Fibers 16. PRICE CODE Seamless

  18. Manipulatives Make Math Meaningful for Middle Schoolers.

    ERIC Educational Resources Information Center

    Scheer, Janet K.

    1985-01-01

    Narrates an account of teaching mathematical concepts to junior high school students using manipulative materials and small and large group games. The following concepts are explained through game descriptions using numeration or Dienes blocks: regrouping decimals, and place value. (DST)

  19. New domino transposition/intramolecular Diels-Alder reaction in monocyclic allenols: a general strategy for tricyclic compounds.

    PubMed

    Alcaide, Benito; Almendros, Pedro; Aragoncillo, Cristina; Redondo, María C

    2002-07-21

    A novel and direct synthetic strategy to prepare fused tricycles has been developed from monocyclic allenols, masked functionalized dienes, which underwent a domino allenol transposition/intramolecular Diels-Alder reaction.

  20. Mannich-Michael versus formal aza-Diels-Alder approaches to piperidine derivatives.

    PubMed

    Girling, P Ricardo; Kiyoi, Takao; Whiting, Andrew

    2011-05-07

    A review into the aza-Diels-Alder reaction, mainly concentrating on literature examples that form piperidin-4-ones from the reaction of imines and electron rich dienes or enones, either through a Lewis acidic/Brønsted acid approach or through the use of an organocatalyst. This review questions whether the mechanism of the aza-Diels-Alder reaction is step wise as opposed to concerted when using oxygenated dienes.

  1. Hydrazones as substrates for cycloaddition reactions

    NASA Astrophysics Data System (ADS)

    Belskaya, N. P.; Eliseeva, A. I.; Bakulev, V. A.

    2015-12-01

    The [2+2]-, [4+2]- and [3+2]-cycloaddition reactions of hydrazones and 1,2-diazabuta-1,3-dienes, azomethine imines, nitrile imines and azomethine ylides formed upon hydrazone transformations with dienophiles, dipolarophiles and dienes are considered. The principal issues of structure and reactivity of active substrates and the influence of the reaction conditions and catalysts on the reaction regioselectivity and efficiency are discussed. The bibliography includes 288 references.

  2. A new 28-noroleanane triterpenoid from the aerial parts of Lantana camara Linn.

    PubMed

    Begum, Sabira; Zehra, Syeda Qamar; Ayub, Anjum; Siddiqui, Bina Shaheen

    2010-08-01

    A new 28-norolean-12,17-diene triterpene lantigdienone (1) oxidised at C-11 and C-22 has been isolated from the aerial parts of Lantana camara, along with two known compounds, camarinin (2) and camangeloyl acid (3). The structure of compound 1 was elucidated as 3,25-epoxy-3alpha-hydroxy-22beta-[beta,betadimethylacryloyloxy]-11-oxo-28-norolean-12,17-diene, with the help of spectral studies.

  3. Rh(I)-catalyzed intramolecular carbonylative [2+2+1] cycloaddition reaction: preparation of bicyclo[5.3.0]decadienones with substituted cyclopentenone frameworks.

    PubMed

    Mukai, Chisato; Takahashi, Yasuhito; Ogawa, Kumiko; Hayashi, Yujiro; Inagaki, Fuyuhiko

    2014-01-01

    The [RhCl(CO)2]2-catalyzed [2+2+1] cycloaddition of bis(allene)s, which have a substituent at the allenic terminus, produced the 8-substituted bicyclo[5.3.0]deca-1(10),6-dien-9-one frameworks. The synthesis of 8,10-dimethylbicyclo[5.3.0]deca-1(10),6-dien-9-one could also be achieved from the bis(1,1,3-trisubstituted-allene).

  4. Synthesis of the C1-C18 fragment of rhizopodin: late-state introduction of the oxazole.

    PubMed

    Bender, Tobias; Loits, Darran; White, Jonathan M; Rizzacasa, Mark A

    2014-03-07

    The synthesis of the C1-C18 fragment of the myxobacteria metabolite rhizopodin is described. Initial attempts at installing the E,E-diene via cross coupling with an oxazole fragment gave poor results. An alternative approach, in which the diene was formed prior and the oxazole introduced by an acylation/O,N-shift protocol, gave the C1-C18 fragment 2 of rhizopodin (1).

  5. Intramolecular 1,1-carboboration versus intermolecular FLP addition in reactions of boranes and bis(phenylethynyl)telluroether.

    PubMed

    Tsao, Fu An; Lough, Alan J; Stephan, Douglas W

    2015-03-11

    Reactions of boranes with Te(CCPh)2 proceed via initial intermolecular 1,1-carboboration followed by either an intramolecular carboboration or an FLP addition to a second molecule of the intermediate, yielding 1-bora-4-tellurocyclohexa-2,5-diene heterocycles or tricylic derivatives of 1,4-ditellurocyclohexa-2,5-diene, respectively. The latter species is also shown to convert to the former upon heating.

  6. Two new triterpenoid saponins from Dianthus superbus L.

    PubMed

    Chen, Xia; Luo, Jian-Guang; Kong, Ling-Yi

    2010-06-01

    Two new triterpenoid saponins (1 and 2) were isolated from the dried aerial parts of Dianthus superbus L. (Caryophyllaceae). Their structures were elucidated on the basis of spectral data to be 3-O-beta-D-glucopyranosyl olean-9(11),12-diene-23,28-dioic acid 28-O-beta-D-glucopyranoside (1) and 3-O-beta-D-glucopyranosyl olean-11,13(18)-diene-23,28-dioic acid 28-O-beta-D-glucopyranoside (2).

  7. Thermal rearrangements in 1,2-poly/1,4-hexadiene/s

    NASA Technical Reports Server (NTRS)

    Golub, M. A.

    1978-01-01

    The work described was carried out to study the thermal rearrangements of two unsaturated diene polymers - 1,2-poly(cis-1,4-hexadiene) (CHD) and 1,2-poly(trans-1.4-hexadiene) (THD). It is shown that both CHD and THD have a predominatly 1,8 diene structure and seem to cyclize mainly by the (2 + 2) thermal cycloaddition of double bonds, and to a small extent also by sigmatropic rearrangement with hydrogen shift.

  8. Physalindicanols, New Biogenetic Precursors of C28-Steroidal Lactones from Physalis minima var. indica.

    PubMed

    Sinha, S C; Ali, A; Bagchi, A; Sahai, M; Ray, A B

    1987-02-01

    The structures of two isomeric C (28)-sterols isolated from PHYSALIS MINIMA Linn. var. INDICA were elucidated as ergosta-5,25-dien-3beta,24zeta,-diol and ergosta-5,24(28)-dien-3beta,25-diol on the basis of detailed spectral analysis. The isolated sterols are regarded as precursors in the elaboration of complex C (28)-steroidal lactones, native in this plant and related species.

  9. Identification of (+)-phyllocladene, (--)-sandaracopimaradiene, and (+)-kaurene as new fungal metabolites from fusicoccin-producing Phomopsis amygdali F6.

    PubMed

    Kenmoku, Hiromichi; Tanaka, Mio; Ogiyama, Koichi; Kato, Nobuo; Sassa, Takeshi

    2004-07-01

    A chemical analysis of the diterpene hydrocarbons produced by fusicoccin-producing fungus Phomopsis amygdali F6 identified five phyllocladene-related tri- and tetracyclic diterpene hydrocarbons. The presence of (+)-phyllocladene, (--)-sandaracopimaradiene, (+)-isopimara-8,15-diene, and (+)-pimara-8(14),15-diene in the fungus was demonstrated by GC-MS, 1H-NMR, and [alpha]D measurements. (+)-Kaurene was also identified by GC-MS and chiral capillary GC. The possible biosynthetic relationship of these metabolites is discussed.

  10. Layaway Procedures for U.S. Army Facilities. Volume 2. Inspection and Maintenance and Repair Checklists

    DTIC Science & Technology

    1991-07-01

    EPDM ethylone-propylene.diene monomer EPRI Electrical Power Research Institute ETAC US. Force Environmental Technical Applications Center EUAC...inspections for ethylene-propylene-diene monomer ( EPDM ) single-ply roofs should be performed in accordance with the previously mentioned USACERL draft...Debris and Vegetation Improper Equipment Supports B13 "I? SINGLE-PLY EPDM - MAINTENANCE AND REPAIR NOTE: D = Deactivation Pfr - Preferred P - Periodic

  11. ENSO and anthropogenic impacts on phytoplankton diversity in tropical coastal waters

    NASA Astrophysics Data System (ADS)

    Doan-Nhu, Hai; Nguyen-Ngoc, Lam; Nguyen, Chi-Thoi

    2016-01-01

    16-year phytoplankton data were analysed to assess ENSO and anthropogenic impacts on biodiversity and community structure at 3 locations (Nha-Trang and Phan-Thiet Bays and near Phu-Qui Island) in South Centre Viet Nam to understand (1) the primary scales of change in phytoplankton community structure, and traditional and taxonomic diversity indices; (2) the significance of environmental changes and/or climate variability on phytoplankton diversity; and (3) the usefulness of these long-term data for analysing future impacts of anthropogenic and climate changes. Traditional and taxonomic diversity indices were compared and tested in linkage with environmental conditions and ENSO. Nutrient data indicated stronger environmental impacts in Phan-Thiet Bay, milder in Nha-Trang Bay and less noticeable near Phu-Qui Island. There were measurable impacts of both anthropogenic and ENSO on phytoplankton at different locations in various parameters, e.g. species number, diversity and community structures. The lowest diversity was recorded in the most anthropogenically impacted site, Phan-Thiet Bay. Although a stronger impact on phytoplankton was recorded in ENSO year in Phan Thiet Bay, quantitative separation between anthropogenic and ENSO impacts using phytoplankton biodiversity indices was impossible. In the waters with less anthropogenic impacts, ENSO effects on taxonomic diversity was better indicated by negative phytoplankton responses to the ONI index (Nha-Trang Bay) and recovery of phytoplankton after the ENSO events (near Phu-Qui Island). Among the diversity indices, the taxonomic diversity indices (e.g. Δ+ and Λ+) better described impacts of ENSO than the traditional ones.

  12. Measles prevention in adolescents: lessons learnt from implementing a high school catch-up vaccination programme in New South Wales, Australia, 2014–2015

    PubMed Central

    Seale, Holly; Sheppeard, Vicky; Campbell-Lloyd, Sue

    2016-01-01

    Introduction In response to a significant increase of measles cases and a high percentage of unvaccinated adolescents in New South Wales, Australia, a measles high school catch-up vaccination programme was implemented between August and December 2014. This study aimed to explore the factors affecting school-based supplementary immunization activities (SIAs) and to inform future SIA and routine school-based vaccination programme implementation and service provision. Methods Focus group analysis was conducted among public health unit (PHU) staff responsible for implementing the SIA catch-up programme. Key areas discussed were pre-programme planning, implementation, resources, consent materials, media activity and future directions for school vaccination programme delivery. Sessions were audio recorded, transcribed verbatim and reviewed. Thematic analysis was conducted to identify the major themes. Results Two independent focus groups with 32 participants were conducted in January 2015. Barriers to the SIA implementation included lead time, consent processes, interagency collaboration, access to the targeted cohort and the impact of introducing a SIA to an already demanding curriculum and school programme immunization schedule. A positive PHU school coordinator rapport and experience of PHU staff facilitated the implementation. Consideration of different approaches for pre-clinic vaccination status checks, student involvement in the vaccination decision, online consent, workforce sharing between health districts and effective programme planning time were identified for improving future SIA implementation. Conclusion Although many barriers to school programme implementation have been identified in this study, with adequate resourcing and lead time, SIAs implemented via a routine school vaccination programme are an appropriate model to target adolescents. PMID:27757258

  13. Constituents of south Indian vetiver oils.

    PubMed

    Mallavarapu, Gopal Rao; Syamasundar, Kodakandla V; Ramesh, S; Rao, Bhaskaruni R Rajeswara

    2012-02-01

    The essential oils isolated from vetiver [Vetiveria zizanioides (L.) Nash.] roots collected from four locations in south India were analyzed by GC-FID and GC-MS. Eighty constituents, representing 94.5-97.8% of the oils, have been identified. The oils from Bangalore, Hyderabad, Kundapur, and Mettupalayam were rich in sesquiterpenes and oxygenated sesquiterpenes with cedrane, bisabolane, eudesmane, eremophilane, and zizaane skeletons. The main components of the four essential oils were: eudesma-4,6-diene (delta-selinene) + beta-vetispirene (3.9-6.1%), beta-vetivenene (0.9-9.4%), 13-nor-trans-eudesma-4(15),7-dien-11-one + amorph-4-en-10-ol (5.0-6.4%), trans-eudesma-4(15),7-dien-12-ol (vetiselinenol) + (E)-opposita-4(15),7(11)-dien-12-ol (3.7-5.9%), eremophila-1 (10),11-dien-2alpha-ol (nootkatol) + ziza-6(13)-en-12-ol (khusimol) (16.1-19.2%), and eremophila-1(10),7(11)-dien-2alpha-ol (isonootkatol) + (E)-eremophila-1(10),7(11)-12-ol (isovalencenol) (5.6-6.9%). The important compounds that impart the characteristic vetiver odor are: khusimene, delta-selinene, beta-vetivenene, cyclocopacamphan-12-ol (epimers A and B), vetiselinenol, khusimol, isovalencenol, khusimone, alpha-vetivone, and beta-vetivone. The chemical profiles of the oils are comparable to Haitian vetiver oil.

  14. Source identification and distribution reveals the potential of the geochemical Antarctic sea ice proxy IPSO25

    PubMed Central

    Belt, S. T.; Smik, L.; Brown, T. A.; Kim, J.-H.; Rowland, S. J.; Allen, C. S.; Gal, J.-K.; Shin, K.-H.; Lee, J. I.; Taylor, K. W. R.

    2016-01-01

    The presence of a di-unsaturated highly branched isoprenoid (HBI) lipid biomarker (diene II) in Southern Ocean sediments has previously been proposed as a proxy measure of palaeo Antarctic sea ice. Here we show that a source of diene II is the sympagic diatom Berkeleya adeliensis Medlin. Furthermore, the propensity for B. adeliensis to flourish in platelet ice is reflected by an offshore downward gradient in diene II concentration in >100 surface sediments from Antarctic coastal and near-coastal environments. Since platelet ice formation is strongly associated with super-cooled freshwater inflow, we further hypothesize that sedimentary diene II provides a potentially sensitive proxy indicator of landfast sea ice influenced by meltwater discharge from nearby glaciers and ice shelves, and re-examination of some previous diene II downcore records supports this hypothesis. The term IPSO25—Ice Proxy for the Southern Ocean with 25 carbon atoms—is proposed as a proxy name for diene II. PMID:27573030

  15. Project CHECO Southeast Asia Report. Visual Reconnaissance in I Corps

    DTIC Science & Technology

    1968-09-30

    Air Force FAC Assets in I Corps 1. Dong Ha (USMC-3700 alum, 0-1/0-2) Special Project THOR: 2 0-2s, 4 FACs (COVEY) 2. Mai Loc (SF-1500 laterite , 0-1...Da Nang 3 11. LZ Sally (USA-1300 laterite , 0-1) 2d Bde/lOlst Abn Div: Bde TACP; 2 0-1s, 3 FACs (BILK) i 12. Hue-Phu Bai (USMC-5600 hard, 0-1/0-2) 1st

  16. U. S. Naval Forces, Vietnam Monthly Historical Supplement for February 1967

    DTIC Science & Technology

    1967-04-16

    DIA (DIAAP-1) LESS PHOTOGRAPHS NAVFORVINST 5215 .IB Ust I; List II B, Kj list III C(12), D(8)j List IV B, 0(5), D(l) List V A(l), B(l), D(l), N...One sailor is killed, another is wounded, p. 11, - USCGC POINT CLEAR provides gunfire support and escort assistance during Operation MUERTO DOS...Zone, 2, Operation MUERTO DOS, from 3 through 7 February on Phu Quoc Island in the Fourth Coastal Zone, 3, Operation PERSKENG, from 12 February

  17. Archaeological Investigations in the Gainesville Lake Area of the Tennessee-Tombigbee Waterway. Volume I. The Gainesville Lake Area Excavations.

    DTIC Science & Technology

    1981-01-01

    Late Archaic or Possible prepared clay hearth Leoel I Fired Clay Loam Broken Pumpkin Concentrat ion Creek Phase 2 44 ’NIIOU Bowl 3.bx3.bx2.5 Dark...LeoL 2 Fired c.loy Loam Clay. Charcoal Broken Pumpkin "ncool rat Lo Creek Phu.e S 1o0U.NOO ,traignt I.7.2.4.4.u Mdtum ’ark Brown Ceramics. Llthlcs...artifacts. Zone C contained an array of cultural material repre- senting all the above components as well as Middle Gulf Formational Broken Pumpkin Creek

  18. Naval Advisory Group Activities Historical Review for December 1965

    DTIC Science & Technology

    1965-12-01

    An Thoi on Phu Quoc Island, there were fewer Viet Cong actions against USN and MM installations, Interdiction of small boat coastal traffic...4j •-•. ^’. -.-..-..ViJ ^^TT^/^^r "v ’ yimmmmi^mwrnymim-wmm^WWim^ mymv » ^vtm wm (■■ |_- -^mDLiuiAi. UNCaSSIEIEG Konaoon curtftilcd junk...V-i’-’.--" .-■ .-• -v A.--V».> - . . -V -u-^^n-.--■■■.--.•. ..• .-- •■’- ■• --•’.■-■.’■■. --■.;■ \\ ■-■■■ : .--. •.-". mm

  19. An Operational TWSTT Monitoring System

    DTIC Science & Technology

    1997-12-01

    29th Annual Precise Time and Time Interval (PTTI) Meeting AN OPERATIONAL TWSTT MONITORING SYSTEM I?. Mai and J. A. DeYoung U.S. Naval Observatory... Time Service Department 3450 Massachusetts Avenue NW Washington, DC 20392-5240 USA phu@simon.usno .navy .mil dey@herschel.usno .navy .mil The...US. Naval Ohmamy (USNO) Time %vice (TS) uses the AOA TWT-100 AtIantis Modem J&r its most important Taw-Way SateEte Time Transfer (TWSTlJ appkcations

  20. Within-host evolution of Pseudomonas aeruginosa reveals adaptation toward iron acquisition from hemoglobin.

    PubMed

    Marvig, Rasmus Lykke; Damkiær, Søren; Khademi, S M Hossein; Markussen, Trine M; Molin, Søren; Jelsbak, Lars

    2014-05-06

    ABSTRACT Pseudomonas aeruginosa airway infections are a major cause of mortality and morbidity of cystic fibrosis (CF) patients. In order to persist, P. aeruginosa depends on acquiring iron from its host, and multiple different iron acquisition systems may be active during infection. This includes the pyoverdine siderophore and the Pseudomonas heme utilization (phu) system. While the regulation and mechanisms of several iron-scavenging systems are well described, it is not clear whether such systems are targets for selection during adaptation of P. aeruginosa to the host environment. Here we investigated the within-host evolution of the transmissible P. aeruginosa DK2 lineage. We found positive selection for promoter mutations leading to increased expression of the phu system. By mimicking conditions of the CF airways in vitro, we experimentally demonstrate that increased expression of phuR confers a growth advantage in the presence of hemoglobin, thus suggesting that P. aeruginosa evolves toward iron acquisition from hemoglobin. To rule out that this adaptive trait is specific to the DK2 lineage, we inspected the genomes of additional P. aeruginosa lineages isolated from CF airways and found similar adaptive evolution in two distinct lineages (DK1 and PA clone C). Furthermore, in all three lineages, phuR promoter mutations coincided with the loss of pyoverdine production, suggesting that within-host adaptation toward heme utilization is triggered by the loss of pyoverdine production. Targeting heme utilization might therefore be a promising strategy for the treatment of P. aeruginosa infections in CF patients. IMPORTANCE Most bacterial pathogens depend on scavenging iron within their hosts, which makes the battle for iron between pathogens and hosts a hallmark of infection. Accordingly, the ability of the opportunistic pathogen Pseudomonas aeruginosa to cause chronic infections in cystic fibrosis (CF) patients also depends on iron-scavenging systems. While

  1. Hand-held lactate analyzer as a tool for the real-time measurement of physical fatigue before slaughter and pork quality prediction.

    PubMed

    Rocha, L M; Dionne, A; Saucier, L; Nannoni, E; Faucitano, L

    2015-04-01

    The objectives of this study were to assess the relationship between blood lactate variation measured at the plant, and pork quality variation on a large sample size and under commercial preslaughter handling conditions. A total of 600 pigs were randomly chosen on arrival at a commercial slaughter plant and blood samples taken from the ear vein at unloading (UN), after lairage (LA), in the restrainer (RE; before stunning) and at exsanguination (EX) were analysed for lactate content using a Lactate Scout Analyzer (LSA). In order to have a large range of measures, pigs were distributed into two groups; one kept in lairage overnight (G1) and the other for 2 to 3 h (G2) before slaughter. Meat quality was assessed in the Longissimus thoracis (LT), Semimembranosus (SM) and Adductor (AD) muscles by measuring the pH 30 min postmortem (pH1) and at 24 h postmortem (pHu), the colour and the drip loss. Blood lactate levels did not differ between G1 and G2 (P>0.05). A reduced muscle lactate and glucose contents (P=0.02 and P=0.004, respectively) resulting in a lower (P<0.001) glycolytic potential (GP) was observed in the LT muscle of G1 pigs when compared with G2 loins. In the LT muscle of G1 pigs, the lower GP resulted in an increased pHu (r=-0.67; P<0.001), decreased drip loss (r=0.57; P<0.001) and darker colour (r=0.50; P<0.001) compared with G2. In both G1 and G2 pigs, the lower GP was correlated to higher pHu value in the SM and AD muscles (r=-0.73; P<0.001). The greatest correlation was observed in G2 between blood lactate levels at LA and pHu value of the SM and AD muscles (r=0.46 and r=0.44, respectively; P<0.001 for both muscles). The second greatest correlation was found between blood lactate levels at EX and pH1 value in the SM muscle in both groups (r=-0.37 and r=-0.41, respectively; P<0.001 for both groups). Based on the results of this study, it appears that blood lactate levels, as measured by the LSA, reliably reflect the physiological response of pigs to

  2. [Community vegetable gardens as a health promotion activity: an experience in Primary Healthcare Units].

    PubMed

    Costa, Christiane Gasparini Araújo; Garcia, Mariana Tarricone; Ribeiro, Silvana Maria; Salandini, Marcia Fernanda de Sousa; Bógus, Cláudia Maria

    2015-10-01

    Urban and peri-urban agriculture (UPA) is being practiced in different settings, contributing to the improvement of health in communities and healthier environments. In order to identify the meanings and implications of the practice of UPA in Primary Healthcare Units (PHU) as an activity of health promotion (HP), and to what extent its therapeutic dimension characterizes it as an activity aligned with complementary and integrative practices (CIP), a qualitative cross-sectional study was performed in Embu das Artes, State of São Paulo. From the analysis, the following main themes arose: health concept, health outcomes, the return to traditional practices and habits and the reorientation of health services. It was possible to identify the close link between the cultivation of vegetable gardens and HP guidelines and fields of action, such as creating healthier environments, boosting community actions, developing personal skills, stimulating autonomy and empowerment and demands for the reorientation of services. The garden activities, set up in PHU areas, proved to be an implementation strategy of CIP. The conclusion reached is that vegetable gardening activities in community gardens are seen to be health promotion practices that integrate key elements of CIP.

  3. Activities of some stress enzymes as indicators of slaughter cattle welfare and their relationship with physico-chemical characteristics of beef.

    PubMed

    Chulayo, A-Y; Muchenje, V

    2017-02-20

    The study determined the activities of creatine kinase (CK) and lactate dehydrogenase (LDH) in transported cattle as indicators of welfare and how they relate to beef quality. A total of 219 (n=219) (85 Beefmaster, 48 Charolaise, 32 Holstein-Friesian and 54 nondescript) cattle brought to the abattoir for slaughter were used in the study. Disposable vacutainer tubes with anticoagulant (ethylenediaminetetraacetic acid) were used to collect 4 ml of blood samples to determine the activities of CK and LDH. The measurements of pHu and colour coordinates (L*, a* and b*) were carried out at 48 h after slaughter on the representative samples of muscularis longissimuss thoracis et. lumborum (LTL). Longer distance travelled by cattle had a significant effect (P3000 to 5000) and those that travelled for 1263 km had lower CK activities (1000). The activities of LDH were observed in cattle that travelled for 366 and 1012 km (7000) and for those that travelled for 877 and 922 km (6000). Results of the principal component analysis showed that the first three principal components (PCs) explained about 53% of the total variability. The first PC was correlated with meat quality attributes (pHu, Tm, a* and b* values). The activities of CK and LDH were related and useful to define the second PC. However, CK and LDH were not related to beef quality. Therefore, CK and LDH can be used as indicators of welfare in slaughter cattle but cannot be used to predict the quality of meat.

  4. Predicting meat quality traits of ovine m. semimembranosus, both fresh and following freezing and thawing, using a hand held Raman spectroscopic device.

    PubMed

    Fowler, Stephanie M; Schmidt, Heinar; van de Ven, Remy; Wynn, Peter; Hopkins, David L

    2015-10-01

    Complementary studies were conducted to determine the potential for a Raman spectroscopic hand held device to predict meat quality traits of fresh lamb m. semimembranosus (topside) after ageing and freezing/thawing. Spectra were collected from 80 fresh muscles at 24h and 5d PM, another 80 muscles were measured at 24h, 5d and following freezing/thawing. Shear force, cooking loss, sarcomere length, colour, particle size, collagen content, pH24, pHu, purge and thaw loss were also measured. Results indicated a potential to predict pHu (R(2)cv=0.59), pH24 (R(2)cv=0.48) and purge (R(2)cv=0.42) using spectra collected 24h PM. L* could be predicted using spectra collected 24h (R(2)cv=0.33) or 5d PM (R(2)cv=0.33). This suggests that Raman spectroscopy is suited to identifying carcases which deviate from the normal metabolic processes and related meat quality traits.

  5. Cloning and characterization of hydrogen uptake genes from Rhizobium leguminosarum.

    PubMed Central

    Leyva, A; Palacios, J M; Mozo, T; Ruiz-Argüeso, T

    1987-01-01

    A gene library of genomic DNA from the hydrogen uptake (Hup)-positive strain 128C53 of Rhizobium leguminosarum was constructed by using the broad-host-range mobilizable cosmid vector pLAFR1. The resulting recombinant cosmids contained insert DNA averaging 21 kilobase pairs (kb) in length. Two clones from the above gene library were identified by colony hybridization with DNA sequences from plasmid pHU1 containing hup genes of Bradyhizobium japonicum. The corresponding recombinant cosmids, pAL618 and pAL704, were isolated, and a region of about 28 kb containing the sequences homologous to B. japonicum hup-specific DNA was physically mapped. Further hybridization analysis with three fragments from pHU1 (5.9-kb HindIII, 2.9-kb EcoRI, and 5.0-kb EcoRI) showed that the overall arrangement of the R. leguminosarum hup-specific region closely parallels that of B. japonicum. The presence of functional hup genes within the isolated cosmid DNA was demonstrated by site-directed Tn5 mutagenesis of the 128C53 genome and analysis of the Hup phenotype of the Tn5 insertion strains in symbiosis with peas. Transposon Tn5 insertions at six different sites spanning 11 kb of pAL618 completely suppressed the hydrogenase activity of the pea bacteroids. Images PMID:2822654

  6. Orthogonius species and diversity in Thailand (Coleoptera, Caraboidea, Orthogoniini), a result from the TIGER project.

    PubMed

    Tian, Mingyi; Deuve, Thierry; Felix, Ron

    2012-01-01

    The carabid genus Orthogonius MacLeay is treated, based mainly on materials collected in Thailand through the TIGER project (the Thailand Inventory Group for Entomological Research). Among 290 specimens, 20 species are identified in total, 10 of them are new species: Orthogonius taghavianaesp. n. (Nakhon Nayok: Khao Yai National Park), Orthogonius coomanioidessp. n. (Phetchabun: Thung Salaeng Luang National Park), Orthogonius similarissp. n. (Phetchabun: Thung Salaeng Luang National Park; Loei: Phu Kradueng National Park), Orthogonius setosopalpigersp. n. (Phetchabun: Thung Salaeng Luang National Park), Orthogonius gracililamellasp. n. (Loei: Phu Kradueng National Park; Chaiyaphum: Tat Tone National Park), Orthogonius pseudochaudoirisp. n. (Phetchabum: Thung Salaeng Luang National Park; Nakhon Nayok: Khao Yai National Park), Orthogonius constrictussp. n. (Phetchabum: Thung Salaeng Luang National Park), Orthogonius pinophilussp. n. (Phetchabum: Thung Salaeng Luang National Park), Orthogonius varisp. n. (Cambodia: Siem Reap; Thailand: Ubon Ratchathani: Pha Taem National Park; Phetchabun: Thung Salaeng Luang National Park) and Orthogonius variabilissp. n. (Thailand: Phetchabun: Thung Salaeng Luang National Park; Nakhon Nayok: Khao Yai National Park; Phetchabun: Nam Nao National Park; China: Yunnan). In addition, Orthogonius mouhoti Chaudoir, 1871 and Orthogonius kirirom Tian & Deuve, 2008 are recorded in Thailand for the first time. In total, 30 species of Orthogonius have been recorded from Thailand, indicating that Thailand holds one of the richest Orthogonius faunas in the world. A provisional key to all Thai species is provided. A majority of Thai Orthogonius species are endemic. Among the ten national parks in which orthogonine beetles were collected, Thung Salaeng Luang holds the richest fauna, including 16 species.

  7. Exploring the potential energy surface for the interaction of sterically hindered trichloro(diethylenetriamine)gold(III) complexes with water.

    PubMed

    Dos Santos, Hélio F; Paschoal, Diego; Burda, Jaroslav V

    2012-11-15

    The reactivity of gold(III) complexes is analyzed for a series of derivatives of 3-azapentane-1,5-diamine (dien) tridentate ligand that can contain some bulky substituents. Two distinct series of compounds are considered where the dien ligand is either deprotonated (R-dien-H) or protonated (R-dien) at the secondary amine where R = ethyl (Et) or methyl (Me). While the deprotonated species will occur in neutral and basic solutions, the protonated forms are likely to be present in acidic environment. Hydration reaction (water/Cl(-) ligand exchange) of 14 complexes is modeled with quantum chemical calculations. Our calculations predict that the reactivity decreases with the increase in the molecular volume of the substituted dien ligand, and the calculated rate constants are in satisfactory agreement with experimental results. In addition, quantitative structure/reactivity models are proposed where the angle between the entering and leaving groups in the transition state structure (the reactivity angle) is used as a molecular descriptor. These models explain the trend of the relative reactivity of these complexes and can be used to design new ligands for gold(III) complexes aiming to adjust the reactivity of the complex.

  8. Evaluation of the water-treatment ability of silica-doped titanium dioxide-coated glass plates using a cationic coupling reagent based on a flow analytical system.

    PubMed

    Sugita, Tsuyoshi; Mori, Masanobu; Mase, Akinori; Noguchi, Shin-nosuke; Tokutome, Toru; Fujii, Kengo; Hara, Chisato; Katayama, Kenji; Iwamoto, Shinji; Itabashi, Hideyuki

    2015-01-01

    In this study, a photocatalytic plate bound to highly dispersible silica-doped titanium dioxide (SiT) on a trimethoxysilyl-propyldiethylenetriamine (dien)-coated glass plate (dien-plate) was newly synthesized, and was evaluated by a flow analytical (FA) system, which consists of a photocatalytic reactor and a spectrophotometer, to continuously monitor the absorbance of tested chemicals. The method was not required to collect any sample solution at a constant period. The SiT-dien-plate facilitated the photodecomposition of methylene blue (MB) and indigo carmine (InC) in aqueous solutions. Notably, MB was quantitatively photo-decomposed following 18 h of UV-light irradiation, related to the electrostatic adsorption of surface-bound particles. A water-treatment ability of visible-light-responsive vanadium-modified nitrogen/silica co-doped titanium dioxide fixed on the dien-plate was also evaluated by the FA system. It clarified to decompose MB and InC under visible-light irradiation. Finally, the decomposition of a humic substance dissolved from Middle West China peaty soils by the SiT-dien-plate under UV-irradiation was assessed as applying the FA system with a photocatalytic plate.

  9. N7-platinated ribonucleotides are not incorporated by RNA polymerases. New perspectives for a rational design of platinum antitumor drugs.

    PubMed

    Benedetti, Michele; Romano, Alessandro; De Castro, Federica; Girelli, Chiara R; Antonucci, Daniela; Migoni, Danilo; Verri, Tiziano; Fanizzi, Francesco P

    2016-10-01

    In this work, we assessed the capacity of RNA polymerases to use platinated ribonucleotides as substrates for RNA synthesis by testing the incorporation of the model compound [Pt(dien)(N7-5'-GTP)] (dien=diethylenetriamine; GTP=5'-guanosine triphosphate) into a natural RNA sequence. The yield of in vitro transcription operated by T7 RNA polymerase, on the LacZ (Escherichia coli gene encoding for β-galactosidase) sequence, decreases progressively with decreasing the concentration of natural GTP, in favor of the platinated nucleotide, [Pt(dien)(N7-5'-GTP)]. Comparison of the T7 RNA polymerase transcription activities for [Pt(dien)(N7-5'-GTP)] compound incorporation reaction test, with respect to the effect of a decreasing concentration of natural GTP, showed no major differences. A specific inhibitory effect of compound [Pt(dien)(N7-5'-GTP)] (which may pair the complementary base on the DNA strand, without being incorporated in the RNA by the T7 RNA polymerase) was evidenced. Our findings therefore suggest that RNA polymerases, unlike DNA polymerases, are unable to incorporate N7-platinated nucleotides into newly synthesized nucleic acids. In this respect, specifically designed N7-platinated nucleotides based compounds could be used in alternative to the classical platinum based drugs. This approach may offer a possible strategy to target specifically DNA, without affecting RNA, and is potentially able to better modulate pharmacological activity.

  10. Sesquiterpene constituents from the essential oils of the liverworts Mylia taylorii and Mylia nuda.

    PubMed

    von Reuss, Stephan H; Wu, Chia-Li; Muhle, Hermann; König, Wilfried A

    2004-08-01

    The essential oils and extracts of Mylia taylorii and M. nuda were investigated by gas chromatography, mass spectrometry, NMR spectroscopy and chemical correlations. Beside several known compounds 13 new constituents including three new carbon skeletons could be identified. Four hydrocarbons with a molecular formula of C15H22 (m/z 202) were identified as myli-4(15)-ene (1), aromadendra-1(10),4(15)-diene (19), aromadendra-4,10(14)-diene (20) and aromadendra-4,9-diene (21). Three oxaspiro-compounds were identified as 7-epi-bourbon-3-en-5,11-oxide (22), guai-3,10(14)-dien-5,11-oxide (23) and guai-3,9-dien-5,11-oxide (24). The absolute configuration of myli-4(15)-en-3-one (5) could be established by chemical correlation. Together with alpha-taylorione (7) the corresponding 6,11-seco-compound taylopyran (25) with a new carbon skeleton was identified which serves as a precursor to taylocyclane (26) and taylofuran (27). Taynudol (28) contains a new carbon skeleton with a cyclobutenyl structure.

  11. Cluster synthesis. 38. Formation of high-nuclearity platinum-osmium cluster complexes. Synthesis, structural characterizations, and interrelationships of Pt[sub 4]Os[sub 6](CO)[sub 22](COD), Pt[sub 5]Os[sub 6](CO)[sub 21](COD)[sub 2], Pt[sub 4]Os[sub 6](CO)[sub 19](COD)[sub 2], and Pt[sub 7]Os[sub 6](CO)[sub 21](COD)[sub 2] (COD = cycloocta-1,5-diene)

    SciTech Connect

    Adams, R.D.; Jauching Lii; Wengan Wu )

    1992-06-10

    The chemistry of heteronuclear cluster complexes containing Pt has attracted a great deal of interest becasue of the importance of Pt alloys to the process of catalytic petroleum reforming. Three new high-nuclearity Pt-Os carbonyl cluster complexes Pt[sub 4]Os[sub 6](CO)[sub 22](COD) (2), Pt[sub 5]Os[sub 6](CO)[sub 21](COD)[sub 2] (3), and Pt[sub 4]Os[sub 6](CO)[sub 19](COD)[sub 2] (4) were obtained in 17%, 13%, and 9% yields, respectively, from the pyrolysis of Pt[sub 2]Os[sub 3](CO)[sub 10](COD)[sub 2] (1) under a CO atmosphere at 128C. Compounds 2-4 were characterized by IR, [sup 1]H NMR, and single-crystal X-ray diffraction analyses. Compound 2 consists of two Pt[sub 3]Os[sub 3] octahedra sharing a Pt[sub 3] triangular face. A Pt(COD) group caps one of the Os[sub 3] triangular faces. Compound 3 is structurally similar to compound 2 but has an additional Pt(COD) group capping one of the PtOs[sub 2] triangular faces. The cluster of compound 4 can be viewed as a meta-bicapped Pt[sub 2]Os[sub 4] octahedron with an additional Pt(COD) group capping a PtOs[sub 2] traingle to one of the capping groups on the octahedron and a Pt(COD) group bridging the Pt-Pt edge of the octahedron. Compound 2 was converted to 4 in 65% yield, when it was irradiated in the presence of COD. When compound 2 was treated with 1 equiv of trimethylamine N-oxide and 2 equiv of Pt(COD)[sub 2], compound 3 and a new higher nuclearity platinum-osmium carbonyl complex Pt[sub 7]Os[sub 6](CO)[sub 21](COD)[sub 2] (5; 8% yeild) were obtained. Compound 5 was characterized by a single-crystal X-ray diffraction analysis. It was formed by the loss of one CO from 2 and the addition of three Pt atoms and one COD ligand. Compound 2 was converted to the known compound Pt[sub 4]Os[sub 6](CO)[sub 21](COD)([mu]-H)[sub 2] in good yield (79%) by reacting with trimethylamine N-oxide and hydrogen.

  12. Cluster synthesis. 39. New platinum-ruthenium carbonyl cluster complexes with bridging hydride ligands. Synthesis and structural characterizations of Ru sub 4 Pt(CO) sub 13 (COD)(. mu. -H) sub 2 , Ru sub 3 Pt(CO) sub 9 (. mu. -CO)(COD)(. mu. -H) sub 2 , Ru sub 4 Pt sub 2 (CO) sub 11 (COD) sub 2 (. mu. sub 3 -H) sub 2 , and Ru sub 5 Pt sub 5 (CO) sub 18 (COD) sub 2 (. mu. -H) sub 2 , COD = Cycloocta-1,5-diene

    SciTech Connect

    Adams, R.D.; Zhaoyang Li; Jauching Lii; Wengan Wu )

    1992-08-05

    The reaction of Ru{sub 4}(CO){sub 13}({mu}-H){sub 2} (1) with Pt(COD){sub 2} at 25 C yielded four new platinum-ruthenium carbonyl cluster complexes Ru{sub 4}Pt(CO){sub 13}(COD)({mu}-H){sub 2} (2) (37%), Ru{sub 3}Pt(CO){sub 9}({mu}-CO)(COD)({mu}-H){sub 2} (3) (10%), Ru{sub 4}Pt{sub 2}-(CO){sub 11}(COD){sub 2}({mu}{sub 3}-H){sub 2} (4) (2.5%), and Ru{sub 5}Pt{sub 5}(CO){sub 18}(COD){sub 2}({mu}{sub 3}-H){sub 2} (5) (1%). All compounds were characterized by IR, {sup 1}H NMR, and single-crystal X-ray diffraction analyses. The cluster of compound 2 consists of a butterfly tetrahedron of four ruthenium atoms with one triangular face capped by a Pt(COD) grouping. Compound 3 consists of a cluster of three ruthenium atoms and one platinum atom in a tetrahedral arrangement. Compound 4 consists of a tetrahedral cluster of four ruthenium atoms with two of the triangular faces capped by Pt(COD) groupings. The other two triangular faces have triply bridging hydride ligands. In the cluster of compound 5, the five ruthenium and four of the platinum atoms are arranged in the form of a face-shared bioctahedron. The shared face consists of three of the platinum atoms. The fifth platinum atom is a cap on one of the Ru{sub 2}Pt triangles. Two hydride ligands are believed to bridge metals of the triangular faces on the opposite ends of the bioctahedron.

  13. Indolizinones as synthetic scaffolds: fundamental reactivity and the relay of stereochemical information†

    PubMed Central

    Hardin Narayan, Alison R.

    2012-01-01

    Indolizinones are under-explored N-heterocycles that react with exquisite chemo- and stereoselectivity. An exploration of the fundamental reactivity of these azabicycles demonstrates the potential to relay stereochemical information from the ring-fusion to newly formed stereocenters on the bicyclic core. The indolizinone diene undergoes selective hydrogenation and readily participates in Diels–Alder cycloadditions as well as ene reactions. The vinylogous amide embedded in the five-membered ring is resistant to reaction when the diene is in place. However, removal of the diene allows for diastereoselective hydrogenation of, and 1,4-additions to, the vinylogous amide. These fundamental reactions with indolizinones have provided a structurally diverse array of products that hold promise in the context of natural product synthesis. PMID:22072189

  14. Kinetic modeling of ethene and propene aromatization over HZSM-5 and GaHZSM-5

    SciTech Connect

    Lukyanov, D.B.; Gnep, N.S.; Guisnet, M.R. . Catalyse en Chimie Organique)

    1994-02-01

    A kinetic model for ethene and propene aromatization over HZSM-5 and GaHZSM-5 is developed. This model describes olefin oligomerization and cracking on zeolite catalytic sites (ZCS), diene formation via hydrogen transfer on ZCS and via dehydrogenation on gallium species, diene cyclization on ZCS, and formation of cyclic diolefins and aromatics via hydrogen transfer on ZCS and via dehydrogenation on gallium species. The rate constants of various reaction steps are compared, and the contribution of gallium in formation of dienes and aromatics is estimated. It is shown that aromatics formation accelerates olefin conversion due to the olefin consumption, on one hand, and inhibits olefin conversion due to the partial blocking of the zeolite catalytic sites, on the other hand. Because of this, both the increase and the decrease in olefin conversion over GaHZSM-5 can be observed (in comparison with HZSM-5), depending on the feed olefin and on the reaction conditions.

  15. μ-2,2',6,6'-Tetramethyl-4,4'-bipyridine-κ2N1:N1'-bis[(diethylenetriamine-κ3N,N',N'')palladium(II)] tetranitrate.

    PubMed

    Seidel, Rüdiger W; Oppel, Iris M

    2011-06-01

    The title compound, [Pd(2)(C(4)H(13)N(3))(2)(C(14)H(16)N(2))](NO(3))(4), comprises discrete tetracationic dumbbell-type dinuclear complex molecules and noncoordinating nitrate anions. Two Pd(dien)(2+) moieties (dien is diethylenetriamine) are joined by the rigid linear exo-bidentate bridging 2,2',6,6'-tetramethyl-4,4'-bipyridine ligand to form the dinuclear complex, which lies across a centre of inversion in the space group P2(1)/n, so that the rings in the 2,2',6,6'-tetramethyl-4,4'-bipyridine bridging ligand are parallel. In the crystal, the primary and secondary amino groups of the dien ligand act as hydrogen-bond donors towards the nitrate anions to form a three-dimensional hydrogen-bond network.

  16. Exclusive selectivity in the one-pot formation of C-C and C-Se bonds involving Ni-catalyzed alkyne hydroselenation: optimization of the synthetic procedure and a mechanistic study.

    PubMed

    Orlov, Nikolay V; Chistyakov, Igor V; Khemchyan, Levon L; Ananikov, Valentine P; Beletskaya, Irina P; Starikova, Zoya A

    2014-12-19

    A unique Ni-catalyzed transformation is reported for the one-pot highly selective synthesis of previously unknown monoseleno-substituted 1,3-dienes starting from easily available terminal alkynes and benzeneselenol. The combination of a readily available catalyst precursor, Ni(acac)2, and an appropriately tuned phosphine ligand, PPh2Cy, resulted in the exclusive assembly of the s-gauche diene skeleton via the selective formation of C-C and C-Se bonds. The unusual diene products were stable under regular experimental conditions, and the products maintained the s-gauche geometry both in the solid state and in solution, as confirmed by X-ray analysis and NMR spectroscopy. Thorough mechanistic studies using ESI-MS revealed the key Ni-containing species involved in the reaction.

  17. Three new triterpenoid saponins from Ilex pubescens.

    PubMed

    Li, Ling; He, Yu-Xin; Gou, Mei-Ling; Dai, Chun

    2012-01-01

    Three new triterpene saponins, ilexsaponins D-F (1-3), were isolated from the roots of Ilex pubescens. Their structures were elucidated as 3-O-β-D-glucopyranosyl(1 → 3)-α-L-arabinopyranosyl urs-12,18-diene-24,28-dioic acid 28-O-β-D-glucopyranoside (1), 3-O-β-D-glucopyranosyl(1 → 3)-α-L-arabinopyranosyl urs-12,18-diene-24,28-dioic acid (2), and 3-O-β-D-glucopyranosyl(1 → 3)-α-L-arabinoyranosyl-30-hydroxyurs-12,19-diene-24,28-dioic acid 28-O-β-D-glucopyranoside (3) on the basis of the chemical and spectroscopic evidence.

  18. [Studies on the constituents of Scutellaria species. XV. On the diterpenoid constituents of the leaves of Scutellaria alpina L].

    PubMed

    Miyaichi, Y; Kizu, H; Yamaguchi, Y; Tomimori, T

    1994-04-01

    From the leaves of Scutellaria alpina L., four new neo-clerodane diterpenes (1-4) were isolated. The structures of 1-4 were shown to be (4S)-19-acetoxy-8 beta-hydroxy-6 alpha-benzoyloxy-4,18-epoxy-neo-cleroda-11,13- dien-15,16-olide, (4S)-19-acetoxy-8 beta-hydroxy-6 alpha-tigloyloxy-4,18-epoxy-neo-cleroda-11,13- dien-15,16-olide, (4S, 11S)-11-acetoxy-8 beta,19-dihydroxy-6 alpha-tigloyloxy-4,18-epoxy-neo- clerod-13-en-15,16-olide, and (4S)-19-acetoxy-8 beta-hydroxy-6 alpha, 7 beta-dibenzoyloxy-4,18-epoxy-neo- cleroda-11,13-dien-15,16-olide, respectively, by the chemical and spectral data.

  19. A molecular symmetry analysis of the electronic states and transition dipole moments for molecules with two torsional degrees of freedom

    SciTech Connect

    Obaid, R.; Leibscher, M.

    2015-02-14

    We present a molecular symmetry analysis of electronic states and transition dipole moments for molecules which undergo large amplitude intramolecular torsions. The method is based on the correlation between the point group of the molecule at highly symmetric configurations and the molecular symmetry group. As an example, we determine the global irreducible representations of the electronic states and transition dipole moments for the quinodimethane derivative 2-[4-(cyclopenta-2,4-dien-1-ylidene)cyclohexa-2,5-dien-1-ylidene]-2H-1, 3-dioxole for which two torsional degrees of freedom can be activated upon photo-excitation and construct the resulting symmetry adapted transition dipole functions.

  20. An unexpected double Diels-Alder reaction of (E)-2-bromo-4-aryl-1,3-pentadiene involving [1,5]-hydrogen migration and HBr elimination: synthesis of bicyclo[2.2.2]octene derivatives.

    PubMed

    Huang, Pingping; Liu, Lingyan; Chang, Weixing; Li, Jing

    2015-03-01

    An unexpected double Diels-Alder (DDA) reaction of (E)-2-bromo-4-aryl-1,3-pentadiene was developed and resulted in a series of "butterfly-like" bicyclo[2.2.2]octene derivatives in moderate to good yields without the need for a metal catalyst. The proposed mechanism involves a [1,5]-sigmatropic hydrogen migration and HBr elimination. Through this decisive [1,5]-hydrogen shift step, the electronic properties and steric hindrance of the conjugated diene substrate are completely altered and the DDA reaction of this potential diene synthon is successfully achieved.

  1. Isolation and Identification of Homologues of Ajoene and Alliin from Bulb-Extracts of Allium ursinum.

    PubMed

    Sendl, A; Wagner, H

    1991-08-01

    From the chloroform extract of ALLIUM URSINUM L. (Liliaceae) bulbs, in addition to other sulfur-containing constituents ( E/Z)-4,5,9-trithiadeca-1,6,11-dien-9-oxide [= methylajoene) and ( E/Z)-4,5,9-trithiaocta-1,6-dien-9-oxide (= dimethylajoene) were isolated and identified by NMR and mass spectroscopy. These two compounds were also found in A. SATIVUM but in lower amounts. The higher contents of the corresponding precursors (+)- S-methyl- L-cysteine sulfoxide (MCSO) and methylallyl/allylmethy] thiosulfmate in A. URSINUM water/methanol extracts correspond with the higher amounts of ajoene homologues.

  2. Decarboxylative and dehydrative coupling of dienoic acids and pentadienyl alcohols to form 1,3,6,8-tetraenes

    PubMed Central

    Hyatt, I F Dempsey; Nagy, Emma E; Gettys, Kristen E; Sayed, Sommayah S; Joliat, Christine M; Daniel, Paige E; Vummalaneni, Rupa M; Morehead, Andrew T; Sargent, Andrew L

    2017-01-01

    Dienoic acids and pentadienyl alcohols are coupled in a decarboxylative and dehydrative manner at ambient temperature using Pd(0) catalysis to generate 1,3,6,8-tetraenes. Contrary to related decarboxylative coupling reactions, an anion-stabilizing group is not required adjacent to the carboxyl group. Of mechanistic importance, it appears that both the diene of the acid and the diene of the alcohol are required for this reaction. To further understand this reaction, substitutions at every unique position of both coupling partners was examined and two potential mechanisms are presented. PMID:28382176

  3. Reactions of 1,3-Dibromo-1,1-difluoro Compounds with 1,8-Diazabicyclo[5.4.0]undec-7-ene.

    PubMed

    Elsheimer, Seth; Foti, Christopher J.; Bartberger, Michael D.

    1996-09-06

    Difluorodienes result from the double dehydrobromination of 4-aryl-1,3-dibromo-1,1-difluorobutanes with DBU. Attempted syntheses of analogous 4-alkyl or 4-alkoxy dienes yield monoelimination products under mild conditions and unexpected trifluoro compounds under more vigorous conditions. 4-Aryl-1,1-difluoro-1,3-butadienes react rapidly with 4-phenyl-1,2,4-triazoline-3,5-dione in Diels-Alder reactions, but these dienes are unreactive toward several other electron-deficient and electron-rich dienophiles.

  4. Systematic studies of morphological changes of precision polyethylene.

    PubMed

    Few, Chip S; Wagener, Kenneth B; Thompson, Donovan L

    2014-01-01

    The morphological changes of polyethylenes bearing precisely spaced "defects" are reviewed, focusing on the effects of defect frequency, size, and functionality on crystallization and crystalline structure. The precise defect interval is imparted through acyclic diene metathesis polymerization of structurally symmetric diene monomers. Studies have included structural characterization by differential scanning calorimetry, wide-angle X-ray scattering, small-angle X-ray scattering (SAXS), and infrared spectroscopy. The collective results are presented separately for functionalized polyethylenes and for those containing alkyl chain branches, as these two classes of polymers vary greatly in morphology.

  5. A new glucoceramide from the watermelon Begonia, Pellionia repens.

    PubMed

    Luo, Yinggang; Liu, Yan; Qi, Huayi; Zhang, Guolin

    2004-10-01

    A new glucoceramide named pellioniareside (1) was isolated from the aqueous ethanolic extract of whole plants of Pellionia repens, together with lupeol (2), uracil (3), (22E,20S,24R)-5alpha,8alpha-epidioxyergosta-6,22-dien-3-beta-ol (4), and daucosterol (5). The structure and relative configurations of pellioniareside were identified as (2S,3S,4R,6E,8E)-1-O-beta-D-glucopyranosyl-2-[(2 R)-2-hydroxytetracosanoylamino]-1,3,4-octadecanetriol-6,8-diene by analysis of spectral data and by chemical evidence.

  6. Stepwise acid-promoted double-Michael process: an alternative to Diels-Alder cycloadditions for hindered silyloxydiene-dienophile pairs.

    PubMed

    Jung, Michael E; Ho, David G

    2007-01-18

    The hindered diene 1 reacts with 3-methylcyclohexenone 6 catalyzed by triflimide to produce the Mukaiyama Michael product 7 (low-temperature quenching) or the [4+2] cycloadduct 8 (quenching at 0 degrees C). Reaction of the hindered diene 23 with 2-methylcyclohexenone 12 with 5:1 AlBr3:AlMe3 afforded a 71% yield of a 1.9:1 mixture of two cycloadducts. Hydrolysis of the major isomer gave the dione 27', a model for the BCD ring system of pentacyclic triterpenes. [reaction: see text].

  7. Anti-oxidant effects of cinnamon (Cinnamomum verum) bark and greater cardamom (Amomum subulatum) seeds in rats fed high fat diet.

    PubMed

    Dhuley, J N

    1999-03-01

    In order to gain insight into the antioxidant effect of cinnamon (Cinnamomum verum; Lauraceae) and cardamom (Amomum subulatum; Zingiberaceae) hepatic and cardiac antioxidant enzymes, glutathione (GSH) content and lipid conjugated dienes were studied in rats fed high fat diet along with cinnamon or cardamom. The antioxidant enzyme activities were found to be significantly enhanced whereas GSH content was markedly restored in rats fed a fat diet with spices. In addition, these spices partially counteracted increase in lipid conjugated dienes and hydroperoxides, the primary products of lipid peroxidation. Thus, it appears that these spices exert antioxidant protection through their ability to activate the antioxidant enzymes.

  8. Addition of carboxyalkyl radicals to alkenes through a catalytic process, using a Mn(II)/Co(II)/O2 redox system.

    PubMed

    Hirase, Koji; Sakaguchi, Satoshi; Ishii, Yasutaka

    2003-07-25

    A novel strategy for production of mono- and dicarboxylic acids by the addition of carboxyalkyl radicals to alkenes and dienes, respectively, was successfully developed through a catalytic process with use of Mn(II)/Co(II)/O(2) system. Thus, a variety of carboxylic acids were prepared by the reaction of alkenes and dienes with acid anhydrides in the presence of a very small amount of Mn(OAc)(2) (0.5 mol %) and Co(OAc)(2) (0.1 mol %) under dilute dioxygen.

  9. Reversible Thermoset Adhesives

    NASA Technical Reports Server (NTRS)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  10. One-Pot Synthesis of Imidazole-4-Carboxylates by Microwave-Assisted 1,5-Electrocyclization of Azavinyl Azomethine Ylides

    PubMed Central

    Preti, Lisa; Attanasi, Orazio A.; Caselli, Emilia; Favi, Gianfranco; Ori, Claudia; Davoli, Paolo; Felluga, Fulvia

    2013-01-01

    Diversely functionalized imidazole-4-carboxylates were synthesized by microwave-assisted 1,5-eletrocyclization of 1,2-diaza-1,3-diene-derived azavinyl azomethine ylides. 1,2-Diaza-1,3-dienes were treated with primary aliphatic or aromatic amines and subjected to microwave irradiation in the presence of aldehydes. 3-Alkyl- and 3-arylimidazole-4-carboxylates were prepared in good yields through a one-pot multicomponent procedure. Modulation of the substituents at C-2, N-3 and C-5 was possible, and 2-unsubstituted imidazoles were obtained when paraformaldehyde was used. PMID:24273445

  11. Sequential aza-Baylis-Hillman/ring closing metathesis/aromatization as a novel route for the synthesis of substituted pyrroles.

    PubMed

    Declerck, Valérie; Ribière, Patrice; Martinez, Jean; Lamaty, Frédéric

    2004-11-26

    A new route to diverse 2-substituted-3-methoxycarbonyl pyrroles has been developed. Diverse SES protected alpha-methylene beta-aminoesters were obtained by a 3-component aza-Baylis-Hillman reaction. Diversity arose from the aryl aldehydes which can be used in this reaction. N-Alkylation with allyl bromide under mild conditions provided the corresponding dienes. These substituted dienes were cyclized by ring closing metathesis at room temperature or under microwave-activation with Grubbs-type II catalyst to yield SES-protected pyrroline intermediates. The final pyrroles were obtained by base-promoted dehydrodesulfinylation/aromatization. The scope of each of these reactions was explored.

  12. (3S*,4S*,E)-tert-Butyl 3,4-dibromo-5-oxo­cyclo­oct-1-ene­carboxyl­ate

    PubMed Central

    Blanco, Magda; Garrido, Narciso M.; Sanz, Francisca; Diez, David

    2012-01-01

    The title compound, C13H18Br2O3, was prepared by a bromination reaction of (1E,3Z)-methyl 5-oxocyclo­octa-1,3-diene­carboxyl­ate, which was obtained by an ep­oxy­dation reaction of tert-butyl cyclo­oct-1,3-diene­carboxyl­ate. The crystal structure confirms unequivocally the absolute configuration of both chiral centres to be S. In the crystal, C—H⋯O inter­actions link the mol­ecules into chains running along the c axis. PMID:22259514

  13. JPRS Report, East Asia, Southeast Asia.

    DTIC Science & Technology

    2007-11-02

    mine, Dien Cong port, Hon Gai , Ha Tu, and rail lines in the Cam Pha area. Now the Vang Danh-Dien Cong rail line not only ensures transport of all...saving hundreds of tons of fuel and dozens of vehicles. The Ha Tu-Hon Gai rail line was strengthened in 1987 and transports all the coal of the Ha...number of sorters in Cua Ong, Hong Gai , Vang Danh, and Mao Khe. Thanks to this, the quality of coal has gotten better. JPRS-SEA-88-047 30 November

  14. Modulating TRAIL-Mediated Apoptosis in Prostate Cancer Using Synthetic Triterpenoids

    DTIC Science & Technology

    2005-01-01

    AD Award Number: W81XWH-04-1-0052 TITLE: Modulating TRAIL-Mediated Apoptosis in Prostate Cancer Using Synthetic Triterpenoids PRINCIPAL INVESTIGATOR...Modulating TRAIL-Mediated Apoptosis in Prostate Cancer W81XWH-04-1-0052 Using Synthetic Triterpenoids 6. AUTHOR(S) Marc L. Hyer, Ph.D. 7. PERFORMING...dien-28-oic acid (CDDO) and its derivative 1-(2-cyano-3,12-dioxooleana-1,9-dien-28-oyl) imidazole (CDDO-Im), which induce apoptosis in breast and

  15. Three new multiflorane-type triterpenes from pumpkin (Cucurbita maxima) seeds.

    PubMed

    Kikuchi, Takashi; Takebayashi, Mika; Shinto, Mayumi; Yamada, Takeshi; Tanaka, Reiko

    2013-05-14

    Three new multiflorane-type triterpenes; 7a-methoxymultiflor-8-ene-3a,29-diol 3-acetate-29-benzoate (1), 7-oxomultiflor-8-ene-3a,29-diol 3-acetate-29-benzoate (2), and multiflora-7,9(11)-diene-3a,29-diol 3-p-hydroxybenzoate-29-benzoate (3), were isolated from seeds of Cucurbita maxima, along with three known compounds. Compound 3 and multiflora-7,9(11)-diene-3a-29-diol 3-benzoate (5) exhibited potent inhibitory effects on melanogenesis, with low cytotoxicities, and 2 exhibited single-digit micromolar cytotoxicity against HL-60 and P388 cells.

  16. Cucurbitane-type triterpenes from Citrullus lanatus (watermelon) seeds.

    PubMed

    Kikuchi, Takashi; Okada, Rina; Harada, Yu; Ikushima, Kenji; Yamakawa, Takahiro; Yamada, Takeshi; Tanaka, Reiko

    2013-10-01

    Two new cucurbitane-type triterpenes, 24-hydroperoxycucurbita-5,25-dien-3beta-ol (1) and 25-hydroperoxycucurbita-5,23-dien-3beta-ol (2), were isolated from a MeOH extract of Citrullus lanatus seeds. Compounds 1 and 2 exhibited moderate cytotoxic activities with IC50 values of 33.4-52.4 microM against HL-60 (human leukemia), P388 (murine leukemia), and L1210 (murine leukemia) cells. Compound 1 showed melanogenesis inhibitory activity (melanin content 80.0 %) with low cytotoxicity (cell viability 97.6%) at a low concentration (10 microM).

  17. New Triterpenoids with Cytotoxic Activity from Actinidia Valvata

    PubMed Central

    Qu, Li-Ping; Zheng, Guo-Yin; Su, Yong-Hua; Zhang, Hui-Qing; Yang, Yan-Long; Xin, Hai-Liang; Ling, Chang-Quan

    2012-01-01

    Two new triterpenoids, 30-O-β-d-glucopyranosyloxy-2α,3α,24-trihydroxyurs-12, 18-diene-28-oic acid O-β-d-glucopyranosyl ester (1) and 2α,3β,3,30-tetrahydroxyurs-12, 18-diene-28-oic acid O-β-d-glucopyranosyl ester (2) were isolated from roots of Actinidia valvata Dunn. Their structures were elucidated by means of extensive spectroscopic studies. Both these two new compounds showed moderate cytotoxic activity in vitro against BEL-7402 and SMMC-7721 tumor cell line. PMID:23203098

  18. Alienusolin, a new 4α-deoxyphorbol ester derivative, and crotonimide C, a new glutarimide alkaloid from the Kenyan Croton alienus.

    PubMed

    Ndunda, Beth; Langat, Moses K; Wanjohi, John M; Midiwo, Jacob O; Kerubo, Leonidah O

    2013-12-01

    Two novel compounds, alienusolin, a 4α-deoxyphorbol ester (1), crotonimide C, a glutarimide alkaloid derivative (2), and ten known compounds, julocrotine (3), crotepoxide (4), monodeacetyl crotepoxide (5), dideacetylcrotepoxide, (6), β-senepoxide (7), α-senepoxide (8), (+)-(2S,3R-diacetoxy-1-benzoyloxymethylenecyclohex-4,6-diene (9), benzyl benzoate (10), acetyl aleuritolic (11), and 24-ethylcholesta-4,22-dien-3-one (12) were isolated from the Kenyan Croton alienus. The structures of the compounds were determined using NMR, GCMS, and HRESIMS studies.

  19. New triterpenoids from Morus alba L. stem bark.

    PubMed

    Ali, Abuzer; Ali, Mohd

    2013-01-01

    Two lupeol-type pentacyclic triterpenoids characterised as lup-20(29)-en-3β-ol-27-oic acid (moruslupenoic acid A) and lup-12, 20(29)-dien-3β-ol-26-oic acid (moruslupenoic acid B) and lanst-5, 24-dien-3β-yl acetate (moruslanosteryl acetate) along with the known triterpenoidal phytoconstituents α-amyrin acetate, β-amyrin-β-D-glucopyranoside and betulinic acid have been isolated from the stem bark of Morus alba L. (Moraceae). The structures of the isolated phytoconstituents were established on the basis of spectral data analysis and chemical means.

  20. Diels-Alder cycloadditions in water for the straightforward preparation of peptide–oligonucleotide conjugates

    PubMed Central

    Marchán, Vicente; Ortega, Samuel; Pulido, Daniel; Pedroso, Enrique; Grandas, Anna

    2006-01-01

    The Diels-Alder reaction between diene-modified oligonucleotides and maleimide-derivatized peptides afforded peptide–oligonucleotide conjugates with high purity and yield. Synthesis of the reagents was easily accomplished by on-column derivatization of the corresponding peptides and oligonucleotides. The cycloaddition reaction was carried out in mild conditions, in aqueous solution at 37°C. The speed of the reaction was found to vary depending on the size of the reagents, but it can be completed in 8–10 h by reacting the diene-oligonucleotide with a small excess of maleimide-peptide. PMID:16478710

  1. Incidence, distribution, seasonality, and demographic risk factors of Salmonella Enteritidis human infections in Ontario, Canada, 2007–2009

    PubMed Central

    2013-01-01

    Background In Canada, surveillance systems have highlighted the increasing trend of Salmonella enterica serovar Enteritidis (S. Enteritidis) human infections. Our study objectives were to evaluate the epidemiology of S. Enteritidis infections in Ontario using surveillance data from January 1, 2007 through December 31, 2009. Methods Annual age-and-sex-adjusted incidence rates (IRs), annual and mean age-adjusted sex-specific IRs, and mean age-and-sex-adjusted IRs by public health unit (PHU), were calculated for laboratory-confirmed S. Enteritidis cases across Ontario using direct standardization. Multivariable Poisson regression with PHU as a random effect was used to estimate incidence rate ratios (IRRs) of S. Enteritidis infections among years, seasons, age groups, and sexes. Results The annual age-and-sex-adjusted IR per 100,000 person-years was 4.4 [95% CI 4.0-4.7] in 2007, and 5.2 [95% CI 4.8-5.6] in both 2008 and 2009. The annual age-adjusted sex-specific IRs per 100,000 person-years ranged from 4.5 to 5.5 for females and 4.2 to 5.2 for males. The mean age-adjusted sex-specific IR was 5.1 [95% CI 4.8-5.4] for females and 4.8 [95% CI 4.5-5.1] for males. High mean age-and-sex-adjusted IRs (6.001-8.10) were identified in three western PHUs, one northern PHU, and in the City of Toronto. Regression results showed a higher IRR of S. Enteritidis infections in 2009 [IRR = 1.18, 95% CI 1.06-1.32; P = 0.003] and 2008 [IRR = 1.17, 95% CI 1.05-1.31; P = 0.005] compared to 2007. Compared to the fall season, a higher IRR of S. Enteritidis infections was observed in the spring [IRR = 1.14, 95% CI 1.01-1.29; P = 0.040]. Children 0–4 years of age (reference category), followed by children 5–9 years of age [IRR = 0.64, 95% CI 0.52-0.78; P < 0.001] had the highest IRRs. Adults ≥ 60 years of age and 40–49 years of age [IRR = 0.31, 95% CI 0.26-0.37; P < 0.001] had the lowest IRRs. Conclusions The study findings suggest that there was an increase in the incidence of S

  2. A Concept for Directing Combat Air Operations

    DTIC Science & Technology

    2014-08-01

    within its inventory to meet this new requirement. However, by borrowing from the U.S. Army, a force of O-1 aircraft was assembled at Bien Hoa in July...1967, when an off-the-shelf commercial aircraft, the O-2, began service. Five years after the activation of the Bien Hoa O-1 squadron, and roughly a

  3. Summary of Rand Interviews of Captured North Vietnamese That Deal With the Effectiveness of Air Power in Southeast Asia

    DTIC Science & Technology

    1969-08-04

    persona illy observed the following damage to bridges in North Vietnam: Bridge Location Date Observed Damage Repair Time Long Bien Hanoi 1967 1007...April 25, 1968. While on leave on February 6, 1968, he observed the destroyed Long Bien Bridge on Route Number 5. It was no longer being repaired

  4. A New Representative of Star-Shaped Fungi: Astraeus sirindhorniae sp. nov. from Thailand

    PubMed Central

    Phosri, Cherdchai; Watling, Roy; Suwannasai, Nuttika; Wilson, Andrew; Martín, María P.

    2014-01-01

    Phu Khieo Wildlife Sanctuary (PKWS) is a major hotspot of biological diversity in Thailand but its fungal diversity has not been thouroughly explored. A two-year macrofungal study of this remote locality has resulted in the recognition of a new species of a star-shaped gasteroid fungus in the genus Astraeus. This fungus has been identified based on a morphological approach and the molecular study of five loci (LSU nrDNA, 5.8S nrDNA, RPB1, RPB2 and EF1-a). Multigene phylogenetic analysis of this new species places it basal relative to other Astraeus, providing additional evidence for the SE Asian orgin of the genus. The fungus is named in honour of Her Majesty Princess Sirindhorn on the occasion the 84th birthday of her father, who have both been supportive of natural heritage studies in Thailand. PMID:24806455

  5. White-toothed shrews (Mammalia, Soricomorpha, Crocidura) of coastal islands of Vietnam

    PubMed Central

    Abramov, Alexei V.; Bannikova, Anna A.; Rozhnov, Viatcheslav V.

    2012-01-01

    Abstract New findings of the white-toothed shrews (Crocidura spp.) from offshore islands of Vietnam are reported. The species identifications have been confirmed by the analysis of complete mitochondrial cytochrome b gene (1140 bp). Crocidura phuquocensis is the only species found in the Phu Quoc Island. Crocidura fuliginosa has been recorded from two islands of the Con Dao Archipelago (Con Son and Bai Canh). The occurrence of Crocidura fuliginosa in Vietnam has been genetically confirmed for the first time. Crocidura attenuata has been collected from the Cat Ba Island for the first time, and this finding corresponds well with the proposal that the species’ distribution is confined to the north and east of the Red River only. PMID:22855639

  6. A new representative of star-shaped fungi: Astraeus sirindhorniae sp. nov. from Thailand.

    PubMed

    Phosri, Cherdchai; Watling, Roy; Suwannasai, Nuttika; Wilson, Andrew; Martín, María P

    2014-01-01

    Phu Khieo Wildlife Sanctuary (PKWS) is a major hotspot of biological diversity in Thailand but its fungal diversity has not been thouroughly explored. A two-year macrofungal study of this remote locality has resulted in the recognition of a new species of a star-shaped gasteroid fungus in the genus Astraeus. This fungus has been identified based on a morphological approach and the molecular study of five loci (LSU nrDNA, 5.8S nrDNA, RPB1, RPB2 and EF1-a). Multigene phylogenetic analysis of this new species places it basal relative to other Astraeus, providing additional evidence for the SE Asian origin of the genus. The fungus is named in honour of Her Majesty Princess Sirindhorn on the occasion the 84th birthday of her father, who have both been supportive of natural heritage studies in Thailand.

  7. Ebola infection control in Sierra Leonean health clinics: A large cross-agency cooperative project.

    PubMed

    Levy, Benjamin; Rao, Carol Y; Miller, Laura; Kennedy, Ngozi; Adams, Monica; Davis, Rosemary; Hastings, Laura; Kabano, Augustin; Bennett, Sarah D; Sesay, Momodu

    2015-07-01

    The Ebola virus disease outbreak occurring in West Africa has resulted in at least 199 cases of Ebola in Sierra Leonean health care workers, many as a result of transmission occurring in health facilities. The Ministry of Health and Sanitation of Sierra Leone recognized that improvements in infection prevention and control (IPC) were necessary at all levels of health care delivery. To this end, the U.S. Centers for Disease Control and Prevention, United Nations Children's Fund, and multiple nongovernmental organizations implemented a national IPC training program in 1,200 peripheral health units (PHUs) in Sierra Leone. A tiered training of trainers program was used. Trainers conducted multiday trainings at PHUs and coordinated the delivery of personal protective equipment (gloves, gowns, masks, boots) and infection control supplies (chlorine, buckets, disposable rags, etc) to all PHU staff. Under the ongoing project, 4,264 health workers have already been trained, and 98% of PHUs have received their first shipment of supplies.

  8. Assessment of the meat quality of lamb M. longissimus thoracis et lumborum and M. triceps brachii following three different Halal slaughter procedures.

    PubMed

    Danso, A S; Richardson, R I; Khalid, R

    2017-05-01

    A total of fifteen male and fifteen female lambs were allocated to three groups of ten animals and subjected to: traditional Halal slaughter without stunning (TNS); slaughter following electric head-only stunning (EHOS) or; post-cut electric head-only stun (PCEHOS) and their meat quality was determined. Instrumental and sensory analyses were carried out on two muscles; M. longissimus thoracis et lumborum (LTL) and M. triceps brachii (TB). Additionally, the effects of sex and muscle type were also assessed. No differences were found among slaughter methods for pH, drip loss and shear force. TB had a higher pHu and was more tender than LTL. Muscles from EHOS and PCEHOS lambs discoloured more quickly than TNS muscles. There were no differences in the measured sensory attributes, with the exception of EHOS meat being tougher than PCEHOS and TNS meat. This study showed that the three slaughter methods had no substantial effect on lamb meat quality.

  9. A simple rule based model for scheduling farm management operations in SWAT

    NASA Astrophysics Data System (ADS)

    Schürz, Christoph; Mehdi, Bano; Schulz, Karsten

    2016-04-01

    For many interdisciplinary questions at the watershed scale, the Soil and Water Assessment Tool (SWAT; Arnold et al., 1998) has become an accepted and widely used tool. Despite its flexibility, the model is highly demanding when it comes to input data. At SWAT's core the water balance and the modeled nutrient cycles are plant growth driven (implemented with the EPIC crop growth model). Therefore, land use and crop data with high spatial and thematic resolution, as well as detailed information on cultivation and farm management practices are required. For many applications of the model however, these data are unavailable. In order to meet these requirements, SWAT offers the option to trigger scheduled farm management operations by applying the Potential Heat Unit (PHU) concept. The PHU concept solely takes into account the accumulation of daily mean temperature for management scheduling. Hence, it contradicts several farming strategies that take place in reality; such as: i) Planting and harvesting dates are set much too early or too late, as the PHU concept is strongly sensitivity to inter-annual temperature fluctuations; ii) The timing of fertilizer application, in SWAT this often occurs simultaneously on the same date in in each field; iii) and can also coincide with precipitation events. Particularly, the latter two can lead to strong peaks in modeled nutrient loads. To cope with these shortcomings we propose a simple rule based model (RBM) to schedule management operations according to realistic farmer management practices in SWAT. The RBM involves simple strategies requiring only data that are input into the SWAT model initially, such as temperature and precipitation data. The user provides boundaries of time periods for operation schedules to take place for all crops in the model. These data are readily available from the literature or from crop variety trials. The RBM applies the dates by complying with the following rules: i) Operations scheduled in the

  10. Prevalence of Opisthorchis viverrini-Like Fluke Infection in Ducks in Binh Dinh Province, Central Vietnam.

    PubMed

    Dao, Thanh Thi Ha; Abatih, Emmanuel Nji; Nguyen, Thanh Thi Giang; Tran, Ha Thi Lam; Gabriël, Sarah; Smit, Suzanne; Le, Phap Ngoc; Dorny, Pierre

    2016-06-01

    Following the first report of Opisthorchis viverrini infection in a domestic duck in Phu My District of Binh Dinh Province, Central Vietnam, many other cases were observed in the province. We determined the infection rate and intensity of O. viverrini infection in ducks in 4 districts of the province. A total of 178 ducks were randomly selected from 34 farms for examination of flukes in the liver and gall bladder. An infection rate of 34.3% (range 20.7-40.4% among districts) was found; the intensity of infection was 13.8 worms per infected duck (range 1-100). These findings show the role of ducks as a host for O. viverrini, duck genotype, which is sympatric with the human O. viverrini genotype in this province. It also stresses the need for investigations on the zoonotic potential and the life cycle of this parasite.

  11. Prevalence of Opisthorchis viverrini-Like Fluke Infection in Ducks in Binh Dinh Province, Central Vietnam

    PubMed Central

    Dao, Thanh Thi Ha; Abatih, Emmanuel Nji; Nguyen, Thanh Thi Giang; Tran, Ha Thi Lam; Gabriël, Sarah; Smit, Suzanne; Le, Phap Ngoc; Dorny, Pierre

    2016-01-01

    Following the first report of Opisthorchis viverrini infection in a domestic duck in Phu My District of Binh Dinh Province, Central Vietnam, many other cases were observed in the province. We determined the infection rate and intensity of O. viverrini infection in ducks in 4 districts of the province. A total of 178 ducks were randomly selected from 34 farms for examination of flukes in the liver and gall bladder. An infection rate of 34.3% (range 20.7-40.4% among districts) was found; the intensity of infection was 13.8 worms per infected duck (range 1-100). These findings show the role of ducks as a host for O. viverrini, duck genotype, which is sympatric with the human O. viverrini genotype in this province. It also stresses the need for investigations on the zoonotic potential and the life cycle of this parasite. PMID:27417094

  12. Gallium-Protoporphyrin IX Inhibits Pseudomonas aeruginosa Growth by Targeting Cytochromes

    PubMed Central

    Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

    2017-01-01

    Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti-Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa. Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu, primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration. PMID:28184354

  13. A calibration procedure to improve global rice yield simulations with EPIC

    SciTech Connect

    Xiong, Wei; Balkovic, Juraj; van der Velde, M.; Zhang, Xuesong; Izaurralde, Roberto C.; Skalsky, Rastislav; Lin, Erda; Mueller, Nathan; Obersteiner, Michael

    2014-02-01

    Crop models are increasingly used to assess impacts of climate change/variability and management practices on productivity and environmental performance of alternative cropping systems. Calibration is an important procedure to improve reliability of model simulations, especially for large area applications. However, global-scale crop model calibration has rarely been exercised due to limited data availability and expensive computing cost. Here we present a simple approach to calibrate Environmental Policy Integrated Climate (EPIC) model for a global implementation of rice. We identify four parameters (potential heat unit – PHU, planting density – PD, harvest index – HI, and biomass energy ratio – BER) and calibrate them regionally to capture the spatial pattern of reported rice yield in 2000. Model performance is assessed by comparing simulated outputs with independent FAO national data. The comparison demonstrates that the global calibration scheme performs satisfactorily in reproducing the spatial pattern of rice yield, particularly in main rice production areas. Spatial agreement increases substantially when more parameters are selected and calibrated, but with varying efficiencies. Among the parameters, PHU and HI exhibit the highest efficiencies in increasing the spatial agreement. Simulations with different calibration strategies generate a pronounced discrepancy of 5–35% in mean yields across latitude bands, and a small to moderate difference in estimated yield variability and yield changing trend for the period of 1981–2000. Present calibration has little effects in improving simulated yield variability and trends at both regional and global levels, suggesting further works are needed to reproduce temporal variability of reported yields. This study highlights the importance of crop models’ calibration, and presents the possibility of a transparent and consistent up scaling approach for global crop simulations given current availability of

  14. Conserved Plasmid Hydrogen-Uptake (hup)-Specific Sequences within Hup+Rhizobium leguminosarum Strains

    PubMed Central

    Leyva, Antonio; Palacios, José M.; Ruiz-Argüeso, Tomás

    1987-01-01

    Thirteen Rhizobium leguminosarum strains previously reported as H2-uptake hydrogenase positive (Hup+) or negative (Hup−) were analyzed for the presence and conservation of DNA sequences homologous to cloned Bradyrhizobium japonicum hup-specific DNA from cosmid pHU1 (M. A. Cantrell, R. A. Haugland, and H. J. Evans, Proc. Natl. Acad. Sci. USA 80:181-185, 1983). The Hup phenotype of these strains was reexamined by determining hydrogenase activity induced in bacteroids from pea nodules. Five strains, including H2 oxidation-ATP synthesis-coupled and -uncoupled strains, induced significant rates of H2-uptake hydrogenase activity and contained DNA sequences homologous to three probe DNA fragments (5.9-kilobase [kb] HindIII, 2.9-kb EcoRI, and 5.0-kb EcoRI) from pHU1. The pattern of genomic DNA HindIII and EcoRI fragments with significant homology to each of the three probes was identical in all five strains regardless of the H2-dependent ATP generation trait. The restriction fragments containing the homology totalled about 22 kb of DNA common to the five strains. In all instances the putative hup sequences were located on a plasmid that also contained nif genes. The molecular sizes of the identified hup-sym plasmids ranged between 184 and 212 megadaltons. No common DNA sequences homologous to B. japonicum hup DNA were found in genomic DNA from any of the eight remaining strains showing no significant hydrogenase activity in pea bacteroids. These results suggest that the identified DNA region contains genes essential for hydrogenase activity in R. leguminosarum and that its organization is highly conserved within Hup+ strains in this symbiotic species. Images PMID:16347471

  15. Bruising in slaughter cattle and its relationship with creatine kinase levels and beef quality as affected by animal related factors.

    PubMed

    Mpakama, T; Chulayo, A Y; Muchenje, V

    2014-05-01

    The objective of the study was to determine the effects of animal related factors on bruising in slaughter cattle, creatine kinase (CK) and beef quality. Three hundred and twenty one cattle from three breeds (108 Bonsmara, 130 Beefmaster and 83 Brahman) were used in this study. The animals were grouped as follows: Group 1 (16 months old), Group 2 (18 months old) and Group 3 (24 months old). At exsanguinations, blood samples for CK determination were collected using disposable vacutainer tubes. Muscularis longissimus thoracis et lumborum (LTL) was collected 24 h after slaughter to determine the colour (L*, a*, and b*) and ultimate pH (pHu) of beef. Breed, sex and age had significant effects (p<0.05) on bruising score, CK levels and beef quality. Bonsmara breed had the highest (80%) bruising score percentage, CK (705.3±80.57 U/L) and pHu (6.3±0.05) values while the Bonsmara had the highest L* (24.8±0.78) a* (17.5±0.53) and b* (12.8±0.53) values. Higher CK levels were also observed in winter compared to summer, spring and autumn respectively. Therefore, animal factors (sex, breed and animal age at slaughter) contribute to the development of bruises and have an effect on the levels of CK and meat quality. It was also concluded that there is no significant relationship between meat parameters (L,* a*, and b*) and CK levels.

  16. Sequence Diversity in Coding Regions of Candidate Genes in the Glycoalkaloid Biosynthetic Pathway of Wild Potato Species

    PubMed Central

    Manrique-Carpintero, Norma C.; Tokuhisa, James G.; Ginzberg, Idit; Holliday, Jason A.; Veilleux, Richard E.

    2013-01-01

    Natural variation in five candidate genes of the steroidal glycoalkaloid (SGA) metabolic pathway and whole-genome single nucleotide polymorphism (SNP) genotyping were studied in six wild [Solanum chacoense (chc 80-1), S. commersonii, S. demissum, S. sparsipilum, S. spegazzinii, S. stoloniferum] and cultivated S. tuberosum Group Phureja (phu DH) potato species with contrasting levels of SGAs. Amplicons were sequenced for five candidate genes: 3-hydroxy-3-methylglutaryl coenzyme A reductase 1 and 2 (HMG1, HMG2) and 2.3-squalene epoxidase (SQE) of primary metabolism, and solanidine galactosyltransferase (SGT1), and glucosyltransferase (SGT2) of secondary metabolism. SNPs (n = 337) producing 354 variations were detected within 3.7 kb of sequenced DNA. More polymorphisms were found in introns than exons and in genes of secondary compared to primary metabolism. Although no significant deviation from neutrality was found, dN/dS ratios < 1 and negative values of Tajima’s D test suggested purifying selection and genetic hitchhiking in the gene fragments. In addition, patterns of dN/dS ratios across the SGA pathway suggested constraint by natural selection. Comparison of nucleotide diversity estimates and dN/dS ratios showed stronger selective constraints for genes of primary rather than secondary metabolism. SNPs (n = 24) with an exclusive genotype for either phu DH (low SGA) or chc 80-1 (high SGA) were identified for HMG2, SQE, SGT1 and SGT2. The SolCAP 8303 Illumina Potato SNP chip genotyping revealed eight informative SNPs on six pseudochromosomes, with homozygous and heterozygous genotypes that discriminated high, intermediate and low levels of SGA accumulation. These results can be used to evaluate SGA accumulation in segregating or association mapping populations. PMID:23853090

  17. Gallium-Protoporphyrin IX Inhibits Pseudomonas aeruginosa Growth by Targeting Cytochromes.

    PubMed

    Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

    2017-01-01

    Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti-Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa. Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu, primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration.

  18. Bruising in Slaughter Cattle and Its Relationship with Creatine Kinase Levels and Beef Quality as Affected by Animal Related Factors

    PubMed Central

    Mpakama, T.; Chulayo, A. Y.; Muchenje, V.

    2014-01-01

    The objective of the study was to determine the effects of animal related factors on bruising in slaughter cattle, creatine kinase (CK) and beef quality. Three hundred and twenty one cattle from three breeds (108 Bonsmara, 130 Beefmaster and 83 Brahman) were used in this study. The animals were grouped as follows: Group 1 (16 months old), Group 2 (18 months old) and Group 3 (24 months old). At exsanguinations, blood samples for CK determination were collected using disposable vacutainer tubes. Muscularis longissimus thoracis et lumborum (LTL) was collected 24 h after slaughter to determine the colour (L*, a*, and b*) and ultimate pH (pHu) of beef. Breed, sex and age had significant effects (p<0.05) on bruising score, CK levels and beef quality. Bonsmara breed had the highest (80%) bruising score percentage, CK (705.3±80.57 U/L) and pHu (6.3±0.05) values while the Bonsmara had the highest L* (24.8±0.78) a* (17.5±0.53) and b* (12.8±0.53) values. Higher CK levels were also observed in winter compared to summer, spring and autumn respectively. Therefore, animal factors (sex, breed and animal age at slaughter) contribute to the development of bruises and have an effect on the levels of CK and meat quality. It was also concluded that there is no significant relationship between meat parameters (L,* a*, and b*) and CK levels. PMID:25050007

  19. Orthogonius species and diversity in Thailand (Coleoptera, Caraboidea, Orthogoniini), a result from the TIGER project

    PubMed Central

    Tian, Mingyi; Deuve, Thierry; Felix, Ron

    2012-01-01

    Abstract The carabid genus Orthogonius MacLeay is treated, based mainly on materials collected in Thailand through the TIGER project (the Thailand Inventory Group for Entomological Research). Among 290 specimens, 20 species are identified in total, 10 of them are new species: Orthogonius taghavianae sp. n. (Nakhon Nayok: Khao Yai National Park), Orthogonius coomanioides sp. n. (Phetchabun: Thung Salaeng Luang National Park), Orthogonius similaris sp. n. (Phetchabun: Thung Salaeng Luang National Park; Loei: Phu Kradueng National Park), Orthogonius setosopalpiger sp. n. (Phetchabun: Thung Salaeng Luang National Park), Orthogonius gracililamella sp. n. (Loei: Phu Kradueng National Park; Chaiyaphum: Tat Tone National Park), Orthogonius pseudochaudoiri sp. n. (Phetchabum: Thung Salaeng Luang National Park; Nakhon Nayok: Khao Yai National Park), Orthogonius constrictus sp. n. (Phetchabum: Thung Salaeng Luang National Park), Orthogonius pinophilus sp. n. (Phetchabum: Thung Salaeng Luang National Park), Orthogonius vari sp. n. (Cambodia: Siem Reap; Thailand: Ubon Ratchathani: Pha Taem National Park; Phetchabun: Thung Salaeng Luang National Park) and Orthogonius variabilis sp. n. (Thailand: Phetchabun: Thung Salaeng Luang National Park; Nakhon Nayok: Khao Yai National Park; Phetchabun: Nam Nao National Park; China: Yunnan). In addition, Orthogonius mouhoti Chaudoir, 1871 and Orthogonius kirirom Tian & Deuve, 2008 are recorded in Thailand for the first time. In total, 30 species of Orthogonius have been recorded from Thailand, indicating that Thailand holds one of the richest Orthogonius faunas in the world. A provisional key to all Thai species is provided. A majority of Thai Orthogonius species are endemic. Among the ten national parks in which orthogonine beetles were collected, Thung Salaeng Luang holds the richest fauna, including 16 species. PMID:22328852

  20. Genetic structure of the threatened Dipterocarpus costatus populations in lowland tropical rainforests of southern Vietnam.

    PubMed

    Duc, N M; Duy, V D; Xuan, B T T; Thang, B V; Ha, N T H; Tam, N M

    2016-10-24

    Dipterocarpus costatus is an endangered species restricted to the lowland forests of southern Vietnam. Habitat loss and over-exploitation of D. costatus wood are the major threats to this species. We investigated the level of genetic variability within and among populations of D. costatus in order to provide guidelines for the conservation, management, and restoration of this species to the Forest Protection Department, Vietnam. Nine microsatellite markers were used to analyze 114 samples from four populations representing the natural range of D. costatus in southeast Vietnam. We indicated the low allelic diversity (NA = 2.3) and low genetic diversities with an average observed and expected heterozygosity of 0.130 and 0.151, respectively, in the lowland forests of southeast Vietnam. The low genetic diversity might be a consequence of inbreeding within the small and isolated populations of D. costatus owing to its habitat loss and over-exploitation. All populations deviated from Hardy-Weinberg equilibrium showing reduced heterozygosity. Alleles were lost from the populations by genetic drift. Genetic differentiation among populations was high (average pairwise FST = 0.405), indicating low gene flow (<1) and isolated populations due to its destructed habitat and large geographical distances (P < 0.05) among populations. Heterozygosity excess tests (except of Bu Gia Map only under infinite allele model) were negative. The high genetic variation (62.7%) was found within populations. The STRUCTURE and neighbor joining tree results suggest strong differentiation among D. costatus populations, with the three genetic clusters, Phu Quoc, Tan Phu and Bu Gia Map, and Lo Go-Xa Mat due to habitat fragmentation and isolation. The threatened status of D. costatus was related to a lack of genetic diversity, with all its populations isolated in small forest patches. We recommend the establishment of an ex situ conservation site for D. costatus with a new big population comprising

  1. Enantioselective rhodium-catalyzed arylation of cyclic N-sulfamidate alkylketimines: a new access to chiral β-alkyl-β-aryl amino alcohols.

    PubMed

    Chen, Ya-Jing; Chen, Ya-Heng; Feng, Chen-Guo; Lin, Guo-Qiang

    2014-06-20

    The enantioselective rhodium-catalyzed 1,2-addition of arylboronates to cyclic N-sulfamidate alkylketimines was developed. With a rhodium/diene complex as catalyst, high enantioselectivity and broad functional group tolerance were observed. The resulting sulfamidates can easily be converted into chiral β-alkyl-β-aryl amino alcohols.

  2. Cytotoxic pregnane steroids from the seeds of Cipadessa baccifera (Roth.) Miq.

    PubMed

    Zhao, Lei; Zhang, Ping; Su, Xiao-Jie; Zhang, Bing

    2017-03-01

    A chemical investigation of the 80% ethanol extract of the seeds of Cipadessa baccifera (Roth.) Miq. led to the isolation of five new pregnane steroids, 17α,18,20S-trihydroxy-pregn-4-en-3,16-dione (1), 18-hydoxy-pregn-4,17(20)-trans-dien-3,16-dione (2), 3β,18-dihydroxy-pregn-5,17(20)-trans-dien-16-one (3), 2α,3β,4β,18-tetrahydroxy-pregn-5,17(20)-trans-dien-16-one (4), and 2α,3β,4β,17α,18,20S-hexahydroxy-pregn-5-en-16-one (5), along with two known compounds, 17α,20S-dihydroxy-pregn-4-en-3,16-dione (6) and 3β-hydroxy-pregn-5,17-dien-16-one (7). Structural elucidation of all the compounds was accomplished by spectral methods such as 1D and 2D NMR, IR, UV, and HRESIMS. The isolated compounds were tested in vitro for cytotoxic activities against seven tumor cell lines. As a result, pregnane-type steroids 1, 5 and 6 exhibited cytotoxicity with IC50 values <20μM against all tested tumor cell lines except meningioma cells (BEN-MEN-1).

  3. Antimicrobial effect of the Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (higher Basidiomycetes) and its main compounds.

    PubMed

    Vazirian, Mahdi; Faramarzi, Mohammad Ali; Ebrahimi, Seyed Esmaeil Sadat; Esfahani, Hamid Reza Monsef; Samadi, Nasrin; Hosseini, Seyed Aboulfazl; Asghari, Ali; Manayi, Azadeh; Mousazadeh, Ali; Asef, Mohammad Reza; Habibi, Emran; Amanzadeh, Yaghoub

    2014-01-01

    Mushrooms are considered one of the richest sources of natural antibiotics, and various species of them inhibit the growth of a wide diversity of microorganisms. Ganoderma lucidum, a well-known medicinal mushroom. has many pharmacological and biological activities including an antimicrobial effect, although few studies have investigated the antibacterial and antifungal effects of its purified compounds. The chemical structure of the purified compounds from the hexane fraction was elucidated as ergosta-7,22-dien-3β-yl acetate, ergosta-5,7,22-trien-3β-yl acetate (isopyrocalciferol acetate), ergosta-7,22-dien-3-one, ergosta-7,22-dien-3β-ol, and ergosta-5,7,22-trien-3β-ol (ergostrol). In addition, the structure of ganodermadiol was demonstrated after purification from the chloroform fraction. The fractions inhibited Gram-positive bacteria and yeast, with minimum inhibitory concentration values of 6.25 mg/mL, but were ineffective against Gram-negative bacteria in the tested concentrations. The results were comparable for isolated compounds, whereas the mixture of ergosta-7,22-dien-3β-yl acetate and isopyrocalciferol acetate was weakly effective against Escherichia coli (minimum inhibitory concentration, 10 mg/mL). It could be assumed that the antimicrobial effect of crude fractions is the consequence of mixing triterpenoid and steroid compounds.

  4. Microbial degradation of steroid alkaloids. Effect of nitrogen atom in the side-chain on the microbial degradation of steroid alkaloids.

    PubMed

    Belic, I; Socic, H

    1975-01-01

    The microbial dehydrogenation of steroid alkaloids follows the dehydrogenation pattern of steroids until the 3-keto-1,4-diene stage. No side-chain cleavage or degradation of the steroid nucleus is observed. Side-chain cleavage of tomatidine is achieved only by previous induction of side-chain splitting enzymes.

  5. 7alpha,11beta-Dimethyl-19-nortestosterone: a potent and selective androgen response modulator with prostate-sparing properties.

    PubMed

    Cook, C Edgar; Kepler, John A

    2005-02-15

    7alpha,11beta-Dimethyl-19-nortestosterone, made by 1,6-methyl addition to 17beta-acetoxy-11beta-methylestra-4,6-dien-3-one, was a highly potent and selective androgen response modulator, with enhanced androgen receptor binding, androgenic activity and anabolic:androgenic ratio over its two monomethyl homologs.

  6. Asymmetric synthesis of dihydropyranones from ynones by sequential copper(I)-catalyzed direct aldol and silver(I)-catalyzed oxy-Michael reactions.

    PubMed

    Shi, Shi-Liang; Kanai, Motomu; Shibasaki, Masakatsu

    2012-04-16

    Ynones as diene surrogates: the asymmetric synthesis of enantiomerically enriched substituted dihydropyranones is described. The products are obtained in two steps by a copper(I)-catalyzed direct aldol reaction of ynones followed by a silver-catalyzed oxy-Michael reaction. This easy method is compatible with both aromatic and aliphatic substrates, and provides excellent chemoselectivity under mild reaction conditions.

  7. Identification of the 187 bp EphA7 Genomic DNA as the Dorsal Midline-Specific Enhancer of the Diencephalon and Mesencephalon

    PubMed Central

    Kim, Yujin; Park, Eunjeong; Park, Soochul

    2015-01-01

    EphA7 is a key molecule in regulating the development of the dien- and mesencephalon. To get insight into the mechanism of how EphA7 gene expression is regulated during the dorsal specification of the dien- and mesencephalon, we investigated the cis-acting regulatory sequence driving EphA7 to the dorsal midline of the dien- and mesencephalon. Transgenic LacZ reporter analysis, using overlapping EphA7 BACs, was used to narrow down the dorsal midline-specific enhancer, revealing the 25.3 kb genomic region as the enhancer candidate. Strikingly, this genomic DNA was located far downstream of the EphA7 transcription start site, +302.6 kb to +327.9 kb. Further enhancer mapping, using comparative genomic analysis and transgenic methods, showed that the 187 bp genomic DNA alone, approximately 305 kb downstream of the EphA7 transcription start site, was sufficient to act as the dorsal midline-specific enhancer of EphA7. Importantly, our results indicate that the 187 bp dorsal midline-specific enhancer is critically regulated by homeobox transcription factors during the development of the dien- and mesencephalon. PMID:26537192

  8. [Constituents of essential oil of imported myrrh and gum opoponax].

    PubMed

    Tian, J; Shi, S

    1996-04-01

    The constitutents of essential oil in two kinds of Myrrha were analyzed by GC-MS. Fifteen compounds in Myrrh and thirty-three compounds in Gum opoponax were identified with their percent contents given. The main constituent of Myrrh is furanoeudesma-1,3-diene, and the main constituent of Gum opoponax is beta-trans-ocimene.

  9. Catalyst-controlled formal [4 + 3] cycloaddition applied to the total synthesis of (+)-barekoxide and (-)-barekol.

    PubMed

    Lian, Yajing; Miller, Laura C; Born, Stephen; Sarpong, Richmond; Davies, Huw M L

    2010-09-08

    The tandem cyclopropanation/Cope rearrangement between bicyclic dienes and siloxyvinyldiazoacetate, catalyzed by the dirhodium catalyst Rh(2)(R-PTAD)(4), effectively accomplishes enantiodivergent [4 + 3] cycloadditions. The reaction proceeds by a cyclopropanation followed by a Cope rearrangement of the resulting divinylcyclopropane. This methodology was applied to the synthesis of (+)-barekoxide (1) and (-)-barekol (2).

  10. Face-selective Diels-Alder reactions between unsymmetrical cyclohexadienes and symmetric trans-dienophile: an experimental and computational investigation.

    PubMed

    Lahiri, Saswati; Yadav, Somnath; Banerjee, Srirupa; Patil, Mahendra P; Sunoj, Raghavan B

    2008-01-18

    A combined experimental and theoretical study of the Diels-Alder reactions between 2-trimethylsiloxy-1,3-cyclohexadienes (2-11) and (E)-1,4-diphenylbut-2-ene-1,4-dione (1) is reported. Two diastereomeric products, 5-endo-6-exo- (nx) and 5-exo-6-endo- (xn) dibenzoyl derivatives, are possible with symmetric trans-dienophile (1). While in many cases 5-endo-6-exo product is preferred over the corresponding 5-exo-6-endo product, the product ratio nx:xn is found to vary with the position of substituents on the diene. The density functional theory studies with the mPW1PW91/6-31G* as well as the B3LYP/6-31G* levels reveal that the electrostatic repulsion between the oxygen lone pairs on the diene and the dienophile is critical to the observed product selectivities. The optimized transition state geometries though appeared to involve secondary orbital interactions, careful examination of the frontier Kohn-Sham orbitals as well as calculations with the natural bond orbital (NBO) analyses confirm the absence of SOI in these transition states. In the case of methyl-substituted dienes, a cumulative effect of steric and electrostatic interactions between the diene and the dienophile is found to be the controlling element toward the observed selectivity.

  11. Allylic oxidation of steroidal olefins by vanadyl acetylacetonate and tert-butyl hydroperoxide.

    PubMed

    Grainger, Wendell S; Parish, Edward J

    2015-09-01

    Readily available vanadyl acetylacetonate was found to oxidize the allylic sites of Δ(5) steroidal alcohols without protection of hydroxyl groups. Cholesterol, dehydroepiandrosterone, cholesterol benzoate, cholesterol acetate, pregnenolone, and 5-pregnen-3,20-diene were oxidized to 7-keto products using vanadyl acetylacetonate in one pot reactions at room temperature in the presence of oxygen and water.

  12. Why a Proximity-Induced Diels–Alder Reaction is So Fast

    PubMed Central

    Krenske, Elizabeth H.; Perry, Emma W.; Jerome, Steven V.; Maimone, Thomas J.; Baran, Phil S.; Houk, K. N.

    2012-01-01

    Unlike normal Diels–Alder reactions of acyclic alkadienes with alkenes, the vinylbicyclo[2.2.2]octene employed in the Baran total synthesis of vinigrol undergoes quantitative Diels–Alder reaction with a tethered alkene at room temperature. Density functional theory calculations reveal that this unprecedented reactivity originates from a combination of preorganization, diene strain, and tether stabilization. PMID:22630569

  13. Synthesis of cyclic sulfones by ring-closing metathesis.

    PubMed

    Yao, Qingwei

    2002-02-07

    A general and highly efficient synthesis of cyclic sulfones based on ring-closing metathesis has been developed. The synthetic utility of the resulting cyclic sulfones was demonstrated by their participation in stereoselective Diels-Alder reactions and transformation to cyclic dienes by the Ramberg-Bäcklund reaction.

  14. Structure of the interfacial layer in blends of elastomers with different polarities and ozone resistance

    NASA Astrophysics Data System (ADS)

    Livanova, N. M.; Popov, A. A.; Shershnev, V. A.; Zaikov, G. E.

    2014-05-01

    The effects of isomers of butadiene units, the ratio of comonomers in ethylene-propylene-diene terpolymers, and the degree of isotacticity of propylene units on the intensity of interfacial interaction in blends and ozone resistence of covulcanisates with butadiene-nitrile rubbers have been analyzed.

  15. A Concise Asymmetric Total Synthesis of (+)-Brevisamide

    PubMed Central

    Herrmann, Aaron T.; Martinez, Steven R.; Zakarian, Armen

    2012-01-01

    A new protecting-group-free synthesis of the marine monocyclic ether (+)-brevisamide is reported. The enantioselective synthesis utilizes a key asymmetric Henry reaction and an Achmatowicz rearrangement for the formation of the tetrahydropyran ring. A penultimate Stille cross-coupling allows for an efficient installation of the conjugated (E,E)-diene side chain ultimately delivering (+)-brevisamide. PMID:21678904

  16. Fluorescence Studies Of A Cholesterol-Analogue Probe

    NASA Astrophysics Data System (ADS)

    Drew, Jacinta; Szabo, Arthur G.; Morand, Peter

    1988-06-01

    A novel cholesterol-analogue probe1,2 with a diene-(2-naphthyl) fluorophore in the sidechain (Figure 1), hereafter referred to as DN-Chol, has had its steady-state and time-resolved fluorescence properties characterized in solvents and in various viscosity mineral oils.

  17. Remendable Polymeric Materials Using Reversible Covalent Bonds

    DTIC Science & Technology

    2008-12-01

    Novel Polymeric Dienes and Dienophiles: Synthesis of Reversibly Cross- Linked Elastomers . Macromolecules, 35, 7246- 7253. Goiti, E., M. Huglin, and J...Materials and Nanotechnology in Engineering. Edited by Du, 6423, 112. Liu, Y., and Y. Chen, 2007: Thermally Reversible Cross- Linked Polyamides with...High Toughness and Self- Repairing Ability from Maleimide- and Furan- Functionalized Aromatic Polyamides . Macromolecular Chemistry and Physics, 208

  18. Experimental and Computational Studies of the Macrocyclic Effect of an Auxiliary Ligand on Electron and Proton Transfers Within Ternary Copper(II)–Histidine Complexes

    SciTech Connect

    Song, Tao; Lam, Corey; Ng, Dominic C.; Orlova, G.; Laskin, Julia; Fang, De-Cai; Chu, Ivan K.

    2009-06-01

    The dissociation of [CuII(L)His]•2+ complexes [L = diethylenetriamine (dien) or 1,4,7-triazacyclononane (9-aneN3)] bears a strong resemblance to the previously reported behavior of [CuII(L)GGH]•2+ complexes. We have used low energy collision-induced dissociation experiments and density functional theory (DFT) calculations at the B3LYP/6-31+G(d) level to study the macrocyclic effect of the auxiliary ligands on the formation of His•+ from prototypical [CuII(L)His]•2+ systems. DFT revealed that the relative energy barriers of the same electron transfer (ET) dissociation pathways of [CuII(9-aneN3)His]•2+ and [CuII(dien)His]•2+ are very similar, with the ET reactions of [CuII(9-aneN3)His]•2+ leading to the generation of two distinct His•+ species; in contrast, the proton transfer (PT) dissociation pathways of [CuII(9-aneN3)His]•2+ and [CuII(dien)His]•2+ differ considerably. The PT reactions of [CuII(9-aneN3)His]•2+ are associated with substantially higher barriers (>13 kcal/mol) than those of [CuII(dien)His]•2+. Thus, the sterically encumbered auxiliary 9-aneN3 ligand facilitates ET reactions while moderating PT reactions, allowing the formation of hitherto non-observable histidine radical cations.

  19. Antiparasitic, Nematicidal and Antifouling Constituents from Juniperus Berries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A bioassay-guided fractionation of Juniperus procera berries yielded antiparasitic, nematicidal and antifouling constituents, including a wide range of known abietane, pimarane and labdane diterpenes. Among these, abieta-7,13-diene (1) demonstrated in vitro antimalarial activity against Plasmodium f...

  20. D:C-friedooleanane-type triterpenoids from Lagenaria siceraria and their cytotoxic activity.

    PubMed

    Chen, Chiy-Rong; Chen, Hung-Wei; Chang, Chi-I

    2008-03-01

    Four new D:C-friedooleanane-type triterpenes, 3 beta-O-(E)-feruloyl-D:C-friedooleana-7,9(11)-dien-29-ol (1), 3 beta-O-(E)-coumaroyl-D:C-friedooleana-7,9(11)-dien-29-ol (2), 3 beta-O-(E)-coumaroyl-D:C-friedooleana-7,9(11)-dien-29-oic acid (3), and methyl 2 beta,3 beta-dihydroxy-D:C-friedoolean-8-en-29-oate (6), together with five known triterpenes with the same skeleton, 3-epikarounidiol (4), 3-oxo-D:C-friedoolena-7,9(11)-dien-29-oic acid (5), bryonolol (7), bryononic acid (8), and 20-epibryonolic acid (9), were isolated from the methanol extract of the stems of Lagenaria siceraria. The structures of those compounds were elucidated using spectroscopic methods. Compounds 3 and 9 showed significant cytotoxic activity against the SK-Hep 1 cell line with IC50 values of 4.8 and 2.1 microg/ml, respectively. Based on these initially promising results, the two D:C-friedooleanane triterpenes merit further study as potential anticancer agents.