Divergent strategy for the synthesis of alpha-aryl-substituted fosmidomycin analogues.

PubMed

Devreux, Vincent; Wiesner, Jochen; Jomaa, Hassan; Rozenski, Jef; Van der Eycken, Johan; Van Calenbergh, Serge

2007-05-11

Fosmidomycin is the first representative of a new class of antimalarial drugs acting through inhibition of 1-deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase (DXR), an essential enzyme in the non-mevalonate pathway for the synthesis of isoprenoids. This work describes a divergent strategy for the synthesis of a series of alpha-aryl-substituted fosmidomycin analogues, featuring a palladium-catalyzed Stille coupling as the key step. An alpha-(4-cyanophenyl)fosmidomycin analogue emerged as the most potent analogue in the present series. Its antimalarial activity clearly surpasses that of the reference compound fosmidomycin.

A novel dihydropyridine with 3-aryl meta-hydroxyl substitution blocks L-type calcium channels in rat cardiomyocytes.

PubMed

Galvis-Pareja, David; Zapata-Torres, Gerald; Hidalgo, Jorge; Ayala, Pedro; Pedrozo, Zully; Ibarra, Cristián; Diaz-Araya, Guillermo; Hall, Andrew R; Vicencio, Jose Miguel; Nuñez-Vergara, Luis; Lavandero, Sergio

2014-08-15

Dihydropyridines are widely used for the treatment of several cardiac diseases due to their blocking activity on L-type Ca(2+) channels and their renowned antioxidant properties. We synthesized six novel dihydropyridine molecules and performed docking studies on the binding site of the L-type Ca(2+) channel. We used biochemical techniques on isolated adult rat cardiomyocytes to assess the efficacy of these molecules on their Ca(2+) channel-blocking activity and antioxidant properties. The Ca(2+) channel-blocking activity was evaluated by confocal microscopy on fluo-3AM loaded cardiomyocytes, as well as using patch clamp experiments. Antioxidant properties were evaluated by flow cytometry using the ROS sensitive dye 1,2,3 DHR. Our docking studies show that a novel compound with 3-OH substitution inserts into the active binding site of the L-type Ca(2+) channel previously described for nitrendipine. In biochemical assays, the novel meta-OH group in the aryl in C4 showed a high blocking effect on L-type Ca(2+) channel as opposed to para-substituted compounds. In the tests we performed, none of the molecules showed antioxidant properties. Only substitutions in C2, C3 and C5 of the aryl ring render dihydropyridine compounds with the capacity of blocking LTCC. Based on our docking studies, we postulate that the antioxidant activity requires a larger group than the meta-OH substitution in C2, C3 or C5 of the dihydropyridine ring. Copyright © 2014 Elsevier Inc. All rights reserved.

Understanding the properties of chitosan aryl substituted thioureas in their role and potential as antibacterial agents

NASA Astrophysics Data System (ADS)

Khairul, Wan M.; Daud, Adibah Izzati; Ismail, Noraznawati

2018-02-01

In this study, the effort was to design and synthesize a series of thiourea-chitosan derivatives featuring five aryl substituted members namely N-chitosan-N'-(4-nitrobenzoyl) thiourea (1), N-chitosan-N'-(4-chlorobenzoyl) thiourea (2), N-chitosan-N'-(4-methylbenzoyl) thiourea (3), N-chitosan-N'-(2-iodobenzoyl) thiourea (4), and N-chitosan-N'-(2-methylbenzoyl) thiourea (5) via SN2 reaction pathway having different donating and withdrawing groups. Their molecular structures were then characterised by FT-IR, UV-Vis, and thermogravimetric analysis (TGA). The antimicrobial activities of these derivatives against four species bacteria Bacillus cereus, Staphylococcus aureus, Salmonella typhi, and Escherichia coli of both Gram-positive and Gram-negative type bacteria at minimum concentration 6mg/ml were carried out to investigate their potential as antibacterial agents. Compound 1 exhibited specific activity as it can only inhibit Gram-positive bacteria while other compounds 2-5 showed broad range spectrum activity as they were able to inhibit both Gram-positive and Gram-negative bacteria. Therefore, 1-5 showed good antibacterial activity and have high potential to be further developed as active materials in pharmaceutical interests.

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles.

PubMed

Kostyuchenko, Anastasia Sergeevna; Zheleznova, Tatyana Yu; Stasyuk, Anton Jaroslavovich; Kurowska, Aleksandra; Domagala, Wojciech; Pron, Adam; Fisyuk, Alexander S

2017-01-01

New photoluminescent donor-acceptor-donor (DAD) molecules, namely 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles were prepared by palladium-catalyzed coupling from readily available compounds such as ethyl 3-decyl-2,2'-bithiophene-5-carboxylate and aryl halides. The obtained compounds feature increasing bathochromic shifts in their emission spectra with increasing aryl-substituent size yielding blue to bluish-green emissions. At the same time, their absorption spectra are almost independent from the identity of the terminal substituent with λ max values ranging from 395 to 405 nm. The observed trends are perfectly predicted by quantum chemical DFT/TDDFT calculations carried out for these new molecules.

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

PubMed Central

Kostyuchenko, Anastasia Sergeevna; Zheleznova, Tatyana Yu; Stasyuk, Anton Jaroslavovich; Kurowska, Aleksandra; Domagala, Wojciech

2017-01-01

New photoluminescent donor–acceptor–donor (DAD) molecules, namely 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles were prepared by palladium-catalyzed coupling from readily available compounds such as ethyl 3-decyl-2,2'-bithiophene-5-carboxylate and aryl halides. The obtained compounds feature increasing bathochromic shifts in their emission spectra with increasing aryl-substituent size yielding blue to bluish-green emissions. At the same time, their absorption spectra are almost independent from the identity of the terminal substituent with λmax values ranging from 395 to 405 nm. The observed trends are perfectly predicted by quantum chemical DFT/TDDFT calculations carried out for these new molecules. PMID:28326140

Characterization of substituted aryl meroterpenoids from red seaweed Hypnea musciformis as potential antioxidants.

PubMed

Chakraborty, Kajal; Joseph, Deepu; Joy, Minju; Raola, Vamshi Krishna

2016-12-01

The ethyl acetate fraction of red seaweed Hypnea musciformis was purified to yield three substituted aryl meroterpenoids, namely, 2-(tetrahydro-5-(4-hydroxyphenyl)-4-pentylfuran-3-yl)-ethyl-4-hydroxybenzoate (1), 2-2-[(4-hydroxybenzoyl)-oxy]-ethyl-4-methoxy-4-2-[(4-methylpentyl)oxy]-3,4-dihydro-2H-6-pyranylbutanoic acid (2) and 3-((5-butyl-3-methyl-5,6-dihydro-2H-pyran-2-yl)-methyl)-4-methoxy-4-oxobutyl benzoate (3). The structures of these compounds, as well as their relative stereochemistries, were confirmed by exhaustive NMR spectroscopic data analyses. Compound 1 exhibited similar 2,2'-diphenylpicrylhydrazyl radical inhibiting and Fe(2+) ion chelating activities (IC50 25.05 and 350.7μM, respectively) as that of commercial antioxidant gallic acid (IC50 32.3 and 646.6μM, respectively), followed by 3 (IC50 231.2 and 667.9μM, respectively), and 2 (IC50 322.4 and 5115.3μM, respectively), in descending order of activities. Structure-activity relationship analysis revealed that the antioxidant activities of these compounds were directly proportional to the steric and hydrophobic parameters. The seaweed derived aryl meroterpenoids might serve as potential lead antioxidative molecules for use in pharmaceutical and food industries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Allylic Amination and N-Arylation-Based Domino Reactions Providing Rapid Three-Component Strategies to Fused Pyrroles with Different Substituted Patterns

PubMed Central

Jiang, Bo; Li, Ying; Tu, Man-Su; Wang, Shu-Liang; Tu, Shu-Jiang; Li, Guigen

2012-01-01

New three-component domino reaction providing divergent approaches to multi-functionalized fused pyrroles with different substituted patterns have been established (40 examples). The direct C(sp3)–N bond formation was achieved through intermolecular allylic amination in a one-pot operation; and N-arylation of amines was realized by varying N-amino acid enaminones. The reaction is easy to perform simply by mixing three common reactants in acetic acid under microwave heating. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good chemical yields. PMID:22852549

Structure–Activity Relationships for a Novel Series of Dopamine D2-like Receptor Ligands Based on N-Substituted 3-Aryl-8-azabicyclo[3.2.1]octan-3-ol

PubMed Central

Paul, Noel M.; Taylor, Michelle; Kumar, Rakesh; Deschamps, Jeffrey R.; Luedtke, Robert R.; Newman, Amy Hauck

2011-01-01

Discovering dopamine D2-like receptor subtype-selective ligands has been a focus of significant investigation. The D2R-selective antagonist 3-[4-(4-chlorophenyl)-4-hydroxypiperidinyl]methylindole (1, L741,626; Ki(D2R/D3R) = 11.2:163 nM) has previously provided a lead template for chemical modification. Herein, analogues have been synthesized where the piperidine was replaced by a tropane ring that reversed the selectivity seen in the parent compound, in human hD2LR- or hD3R-transfected HEK 293 cells (31, Ki(D2R/D3R) = 33.4: 15.5 nM). Further exploration of both N-substituted and aryl ring-substituted analogues resulted in the discovery of several high affinity D2R/D3R ligands with 3-benzofurylmethyl-substituents (e.g., 45, Ki(D2R/D3R) = 1.7:0.34 nM) that induced high affinity not achieved in similarly N-substituted piperidine analogues and significantly (470-fold) improved D3R binding affinity compared to the parent ligand 1. X-ray crystallographic data revealed a distinctive spatial arrangement of pharmacophoric elements in the piperidinol vs tropine analogues, providing clues for the diversity in SAR at the D2 and D3 receptor subtypes. PMID:18774793

Arynes, diaryliodonium salts and azine N-oxides in transition metal-free electrophilic N-arylation

NASA Astrophysics Data System (ADS)

Bugaenko, D. I.; Karchava, A. V.; Yurovskaya, M. A.

2018-03-01

The main approach to the synthesis of aromatic and heteroaromatic amines is based on palladium- and copper-catalyzed N-arylation reactions. Although these methods are highly efficient and provide extensive opportunities for the synthesis of (het)arylamines with various structures and properties, they have some limitations related to the catalysts used and reaction conditions. This review addresses alternative approaches to N-(het)arylation that have been extensively developed in the past decade and are based on the use of arynes, diaryliodonium salts and azine N-oxides as electrophilic (het)arylating agents. Because of mild reaction conditions and no need for catalysts and strong bases, these N-(het)arylation methods are attractive for various synthetic applications and open up new possibilities for the preparation of valuable organic compounds inaccessible via traditional catalytic methods. The attention is focussed on publications of the last decade. The bibliography includes 112 references.

Aryl triolborates: novel reagent for copper-catalyzed N arylation of amines, anilines, and imidazoles.

PubMed

Yu, Xiao-Qiang; Yamamoto, Yasunori; Miyaura, Norio

2008-09-01

The N arylation of primary and secondary aliphatic amines, anilines, and imidazoles with novel potassium aryl triolborates was carried out in the presence of a reoxidant and a catalytic amount of Cu(OAc)(2) (10 mol %). Aryl triolborates were found to be better reagents than aryl boronic acids or potassium aryl trifluoroborates as the former achieved high yields under mild conditions. Coupling of primary and secondary aliphatic amines to give N-aryl amines in excellent yields was performed under oxygen atmosphere. The reactions of anilines and imidazoles to provide N-aryl anilines and N-aryl imidazoles in good yields proceeded smoothly when trimethylamine N-oxide was used as an oxidant.

Synthesis, structure elucidation, DNA-PK and PI3K and anti-cancer activity of 8- and 6-aryl-substituted-1-3-benzoxazines.

PubMed

Morrison, Rick; Al-Rawi, Jasim M A; Jennings, Ian G; Thompson, Philip E; Angove, Michael J

2016-03-03

The synthesis of 6-aryl, 8- aryl, and 8-aryl-6-chloro-2-morpholino-1,3-benzoxazines with potent activity against PI3K and DNA-PK is described. Synthesis of thirty one analogues was facilitated by an improved synthesis of 3-bromo-2-hydroxybenzoic acid 13 by de-sulphonation of 3-bromo-2-hydroxy-5-sulfobenzoic acid 12 en route to 2-methylthio-substituted-benzoxazine intermediates 17-19. From this series, compound 20k (LTURM34) (dibenzo[b,d]thiophen-4-yl) (IC50 = 0.034 μM) was identified as a specific DNA-PK inhibitor, 170 fold more selective for DNA-PK activity compared to PI3K activity. Other compounds of the series show markedly altered selectivity for various PI3K isoforms including compound 20i (8-(naphthalen-1-yl) a potent and quite selective PI3Kδ inhibitor (IC50 = 0.64 μM). Finally, nine compounds were evaluated and showed antiproliferative activity against an NCI panel of cancer cell lines. Compound 20i (8-(naphthalen-1-yl) showed strong anti-proliferative activity against A498 renal cancer cells that warrants further investigation. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Synthesis of substituted isoquinolines utilizing palladium-catalyzed α-arylation of ketones

PubMed Central

Donohoe, Timothy J.; Pilgrim, Ben S.; Jones, Geraint R.; Bassuto, José A.

2012-01-01

The utilization of sequential palladium-catalyzed α-arylation and cyclization reactions provides a general approach to an array of isoquinolines and their corresponding N-oxides. This methodology allows the convergent combination of readily available precursors in a regioselective manner and in excellent overall yields. This powerful route to polysubstituted isoquinolines, which is not limited to electron rich moieties, also allows rapid access to analogues of biologically active compounds. PMID:22753504

The 3,7-diazabicyclo[3.3.1]nonane scaffold for subtype selective nicotinic acetylcholine receptor (nAChR) ligands. Part 1: the influence of different hydrogen bond acceptor systems on alkyl and (hetero)aryl substituents.

PubMed

Eibl, Christoph; Tomassoli, Isabelle; Munoz, Lenka; Stokes, Clare; Papke, Roger L; Gündisch, Daniela

2013-12-01

3,7-Diazabicyclo[3.3.1]nonane is a naturally occurring scaffold interacting with nicotinic acetylcholine receptors (nAChRs). When one nitrogen of the 3,7-diazabicyclo[3.3.1]nonane scaffold was implemented in a carboxamide motif displaying a hydrogen bond acceptor (HBA) functionality, compounds with higher affinities and subtype selectivity for α4β2(∗) were obtained. The nature of the HBA system (carboxamide, sulfonamide, urea) had a strong impact on nAChR interaction. High affinity ligands for α4β2(∗) possessed small alkyl chains, small un-substituted hetero-aryl groups or para-substituted phenyl ring systems along with a carboxamide group. Electrophysiological responses of selected 3,7-diazabicyclo[3.3.1]nonane derivatives to Xenopus oocytes expressing various nAChR subtypes showed diverse activation profiles. Compounds with strongest agonistic profiles were obtained with small alkyl groups whereas a shift to partial agonism/antagonism was observed for aryl substituents. Copyright © 2013 Elsevier Ltd. All rights reserved.

Structural investigation of HIV-1 nonnucleoside reverse transcriptase inhibitors: 2-Aryl-substituted benzimidazoles

NASA Astrophysics Data System (ADS)

Ziółkowska, Natasza E.; Michejda, Christopher J.; Bujacz, Grzegorz D.

2009-11-01

Acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV) is one of the most destructive epidemics in history. Inhibitors of HIV enzymes are the main targets to develop drugs against that disease. Nonnucleoside reverse transcriptase inhibitors of HIV-1 (NNRTIs) are potentially effective and nontoxic. Structural studies provide information necessary to design more active compounds. The crystal structures of four NNRTI derivatives of 2-aryl-substituted N-benzyl-benzimidazole are presented here. Analysis of the geometrical parameters shows that the structures of the investigated inhibitors are rigid. The important geometrical parameter is the dihedral angle between the planes of the π-electron systems of the benzymidazole and benzyl moieties. The values of these dihedral angles are in a narrow range for all investigated inhibitors. There is no significant difference between the structure of the free inhibitor and the inhibitor in the complex with RT HIV-1. X-ray structures of the investigated inhibitors are a good basis for modeling enzyme-inhibitor interactions in rational drug design.

N-Acetylanthranilate Amidase from Arthrobacter nitroguajacolicus Rü61a, an α/β-Hydrolase-Fold Protein Active towards Aryl-Acylamides and -Esters, and Properties of Its Cysteine-Deficient Variant▿ †

PubMed Central

Kolkenbrock, Stephan; Parschat, Katja; Beermann, Bernd; Hinz, Hans-Jürgen; Fetzner, Susanne

2006-01-01

N-acetylanthranilate amidase (Amq), a 32.8-kDa monomeric amide hydrolase, is involved in quinaldine degradation by Arthrobacter nitroguajacolicus Rü61a. Sequence analysis and secondary structure predictions indicated that Amq is related to carboxylesterases and belongs to the α/β-hydrolase-fold superfamily of enzymes; inactivation of (His6-tagged) Amq by phenylmethanesulfonyl fluoride and diethyl pyrocarbonate and replacement of conserved residues suggested a catalytic triad consisting of S155, E235, and H266. Amq is most active towards aryl-acetylamides and aryl-acetylesters. Remarkably, its preference for ring-substituted analogues was different for amides and esters. Among the esters tested, phenylacetate was hydrolyzed with highest catalytic efficiency (kcat/Km = 208 mM−1 s−1), while among the aryl-acetylamides, o-carboxy- or o-nitro-substituted analogues were preferred over p-substituted or unsubstituted compounds. Hydrolysis by His6Amq of primary amides, lactams, N-acetylated amino acids, azocoll, tributyrin, and the acylanilide and urethane pesticides propachlor, propham, carbaryl, and isocarb was not observed; propanil was hydrolyzed with 1% N-acetylanthranilate amidase activity. The catalytic properties of the cysteine-deficient variant His6AmqC22A/C63A markedly differed from those of His6Amq. The replacements effected some changes in Kms of the enzyme and increased kcats for most aryl-acetylesters and some aryl-acetylamides by factors of about three to eight while decreasing kcat for the formyl analogue N-formylanthranilate by several orders of magnitude. Circular dichroism studies indicated that the cysteine-to-alanine replacements resulted in significant change of the overall fold, especially an increase in α-helicity of the cysteine-deficient protein. The conformational changes may also affect the active site and may account for the observed changes in kinetic properties. PMID:17041061

Inhibition of the pore-forming protein perforin by a series of aryl-substituted isobenzofuran-1(3H)-ones.

PubMed

Spicer, Julie A; Huttunen, Kristiina M; Miller, Christian K; Denny, William A; Ciccone, Annette; Browne, Kylie A; Trapani, Joseph A

2012-02-01

An aryl-substituted isobenzofuran-1(3H)-one lead compound was identified from a high throughput screen designed to find inhibitors of the lymphocyte pore-forming protein perforin. A series of analogs were then designed and prepared, exploring structure-activity relationships through variation of 2-thioxoimidazolidin-4-one and furan subunits on an isobenzofuranone core. The ability of the resulting compounds to inhibit the lytic activity of both isolated perforin protein and perforin delivered in situ by intact KHYG-1 natural killer effector cells was determined. Several compounds showed excellent activity at concentrations that were non-toxic to the killer cells. This series represents a significant improvement on previous classes of compounds, being substantially more potent and largely retaining activity in the presence of serum. Copyright © 2011 Elsevier Ltd. All rights reserved.

Copper/amino acid catalyzed cross-couplings of aryl and vinyl halides with nucleophiles.

PubMed

Ma, Dawei; Cai, Qian

2008-11-18

Copper-assisted Ullmann-type coupling reactions are valuable transformations for organic synthesis. Researchers have extensively applied these reactions in both academic and industrial settings. However, two important issues, the high reaction temperatures (normally above 150 degrees C) and the stoichiometric amounts of copper necessary, have greatly limited the reaction scope. To solve these problems, we and other groups have recently explored the use of special ligands to promote these coupling reactions. We first showed that the structure of alpha-amino acids can accelerate Cu-assisted Ullmann reactions, leading to the coupling reactions of aryl halides and alpha-amino acids at 80-90 degrees C. In response to these encouraging results, we also discovered that an l-proline ligand facilitated the following transformations: (1) coupling of aryl halides with primary amines, cyclic secondary amines, and N-containing heterocycles at 40-90 degrees C; (2) coupling of aryl halides with sulfinic acid salts at 80-95 degrees C; (3) azidation of aryl halides and vinyl halides with sodium azide at 40-95 degrees C; (4) coupling of aryl halides with activated methylene compounds at 25-50 degrees C. In addition, we found that N,N-dimethylglycine as a ligand facilitated Cu-catalyzed biaryl ether formation at 90 degrees C. Moreover, Sonogashira reactions worked in the absence of palladium and phosphine ligands, forming enamides from vinyl halides and amides at temperatures ranging from ambient temperature up to 80 degrees C. Furthermore, we discovered that an ortho-amide group can accelerate some Ullmann-type reactions. This functional group in combination with other ligand effects allowed for aryl amination or biaryl ether formation at ambient temperature. The coupling between aryl halides and activated methylene compounds even proceeded at -45 degrees C to enantioselectively form a quaternary carbon center. Taking advantage of these results, we developed several novel approaches

Palladium-catalyzed one-pot three- or four-component coupling of aryl iodides, alkynes, and amines through C-N bond cleavage: efficient synthesis of indole derivatives.

PubMed

Hao, Wei; Geng, Weizhi; Zhang, Wen-Xiong; Xi, Zhenfeng

2014-02-24

An efficient synthesis of N-substituted indole derivatives was realized by combining the Pd-catalyzed one-pot multicomponent coupling approach with cleavage of the C(sp(3))-N bonds. Three or four components of aryl iodides, alkynes, and amines were involved in this coupling process. The cyclopentadiene-phosphine ligand showed high efficiency. A variety of aryl iodides, including cyclic and acyclic tertiary amino aryl iodides, and substituted 1-bromo-2-iodobenzene derivatives could be used. Both symmetric and unsymmetric alkynes substituted with alkyl, aryl, or trimethylsilyl groups could be applied. Cyclic secondary amines such as piperidine, morpholine, 4-methylpiperidine, 1-methylpiperazine, 2-methylpiperidine, and acyclic amines including secondary and primary amines all showed good reactivity. Further application of the resulting indole derivatives was demonstrated by the synthesis of benzosilolo[2,3-b]indole. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design and synthesis of aryl ether and sulfone hydroxamic acids as potent histone deacetylase (HDAC) inhibitors.

PubMed

Pabba, Chittari; Gregg, Brian T; Kitchen, Douglas B; Chen, Zhen Jia; Judkins, Angela

2011-01-01

A series of novel hydroxamic acid based histone deacetylases (HDAC) inhibitors with aryl ether and aryl sulfone residues at the terminus of a substituted, unsaturated 5-carbon spacer moiety have been synthesized for the first time and evaluated. Compounds with meta- and para-substitution on the aryl ring of ether hydroxamic acids 19c, 20c, 19e, 19f and 19g are potent HDAC inhibitors with activities at low nanomolar levels. Copyright © 2010 Elsevier Ltd. All rights reserved.

Palladium-Catalyzed α-Arylation of Aryl Nitromethanes

PubMed Central

2015-01-01

Catalytic conditions for the α-arylation of aryl nitromethanes have been discovered using parallel microscale experimentation, despite two prior reports of the lack of reactivity of these aryl nitromethane precursors. The method efficiently provides a variety of substituted, isolable diaryl nitromethanes. In addition, it is possible to sequentially append two different aryl groups to nitromethane. Mild oxidation conditions were identified to afford the corresponding benzophenones via the Nef reaction, and reduction conditions were optimized to afford several diaryl methylamines. PMID:26584680

Eco-friendly synthesis, in vitro anti-proliferative evaluation, and 3D-QSAR analysis of a novel series of monocationic 2-aryl/heteroaryl-substituted 6-(2-imidazolinyl)benzothiazole mesylates.

PubMed

Racané, Livio; Ptiček, Lucija; Sedić, Mirela; Grbčić, Petra; Kraljević Pavelić, Sandra; Bertoša, Branimir; Sović, Irena; Karminski-Zamola, Grace

2018-04-17

Herein, we describe the synthesis of twenty-one novel water-soluble monocationic 2-aryl/heteroaryl-substituted 6-(2-imidazolinyl)benzothiazole mesylates 3a-3u and present the results of their anti-proliferative assays. Efficient syntheses were achieved by three complementary simple two-step synthetic protocols based on the condensation reaction of aryl/heteroaryl carbaldehydes or carboxylic acid. We developed an eco-friendly synthetic protocol using glycerol as green solvent, particularly appropriate for the condensation of thermally and acid-sensitive heterocycles such as furan, benzofuran, pyrrole, and indole. Screening of anti-proliferative activity was performed on four human tumour cell lines in vitro including pancreatic cancer (CFPAC-1), metastatic colon cancer (SW620), hepatocellular carcinoma (HepG2), and cervical cancer (HeLa), as well as in normal human fibroblast cell lines. All tested compounds showed strong to moderate anti-proliferative activity on tested cell lines depending on the structure containing aryl/heteroaryl moiety coupled to 6-(2-imidazolinyl)benzothiazole moiety. The most potent cytostatic effects on all tested cell lines with [Formula: see text] values ranging from 0.1 to 3.70 [Formula: see text] were observed for benzothiazoles substituted with naphthalene-2-yl 3c, benzofuran-2-yl 3e, indole-3-yl 3j, indole-2-yl 3k, quinoline-2-yl 3s, and quinoline-3-yl 3t and derivatives substituted with phenyl 3a, naphthalene-1-yl 3b, benzothiazole-2-yl 3g, benzothiazole-6-yl 3h, N-methylindole-3-yl 3l, benzimidazole-2-yl 3n, benzimidazole-5(6)-yl 3o, and quinolone-4-yl 3u with [Formula: see text] values ranging from 1.1 to 29.1 [Formula: see text]. Based on obtained anti-proliferative activities, 3D-QSAR models for five cell lines were derived. Molecular volume, molecular surface, the sum of hydrophobic surface areas, molecular mass, and possibility of making dispersion forces were identified by QSAR analyses as molecular properties that are

CuI/L-proline-catalyzed coupling reactions of aryl halides with activated methylene compounds.

PubMed

Xie, Xiaoan; Cai, Guorong; Ma, Dawei

2005-10-13

[reaction: see text] The arylation of ethyl acetoacetate, ethyl benzoyl acetate, and diethyl malonate under the catalysis of CuI/L-proline in DMSO proceeds smoothly at 40-50 degrees C in the presence of Cs2CO3 to provide the 2-aryl-1,3-dicarbonyl compounds in good yields. Both aryl iodides and aryl bromides are compatible with these reaction conditions.

ortho-Substituted (Aryl)(3-nitrobenzo[b]thiophen-2-yl)amines: Study of the Electrochemical Behavior

NASA Astrophysics Data System (ADS)

Cosimelli, Barbara; Lanza, Camilla Zaira; Scavetta, Erika; Severi, Elda; Spinelli, Domenico; Stenta, Marco; Tonelli, Domenica

2009-08-01

The reduction potentials of the title compounds 4 have been measured by cyclic voltammetry. The effect of the substituents has been evaluated by using a linear free energy relationship treatment, thus evidencing that the present ortho-substituents affect the Epc values basically by electronic effects. A comparison with data previously collected on ortho-substituted (aryl)(2-nitrobenzo[b]thiophen-3-yl)amines 3 has provided some interesting information. Different electrochemical behaviors are observed during the reduction (a reversible process and an irreversible process are operating in 3 and 4, respectively): to elucidate the reasons for this different behavior, the "reversible" reduction potentials of 5 and of 6 have been measured. Moreover, higher susceptibility constants have been calculated for compounds of series 4 with respect to those of series 3 (ρ4 = 329 and ρ3 = 182, respectively). A rationale for all of these findings has been offered.

Regioselective Copper-Catalyzed Amination of Chlorobenzoic Acids: Synthesis and Solid-State Structures of N-Aryl Anthranilic Acid Derivatives

PubMed Central

Mei, Xuefeng; August, Adam T.; Wolf, Christian

2008-01-01

A chemo- and regioselective copper-catalyzed cross-coupling reaction for effective amination of 2-chlorobenzoic acids with aniline derivatives has been developed. The method eliminates the need for acid protection and produces a wide range of N-aryl anthranilic acid derivatives in up to 99%. The amination was found to proceed with both electron-rich and electron-deficient aryl chlorides and anilines and also utilizes sterically hindered anilines such as 2,6-dimethylaniline and 2-tert-butylaniline. The conformational isomerism of appropriately substituted N-aryl anthranilic acids has been investigated in the solid state. Crystallographic analysis of seven anthranilic acid derivatives showed formation of two distinct supramolecular architectures exhibiting trans-anti- and unprecedented trans-syn-dimeric structures. PMID:16388629

Stereoselective Vinylation of Aryl N-(2-Pyridylsulfonyl) Aldimines with 1-Alkenyl-1,1-Heterobimetallic Reagents

PubMed Central

Hussain, Nusrah; Hussain, Mahmud M.; Ziauddin, Muhammed; Triyawatanyu, Plengchat; Walsh, Patrick J.

2011-01-01

Vinylation of aryl N-(2-pyridylsulfonyl) aldimines with versatile 1-alkenyl-1,1-borozinc heterobimetallic reagents is disclosed. In situ hydroboration of air-stable B(pin)-alkynes followed by chemoselective transmetallation with dimethylzinc and addition to aldimines provides B(pin)-substituted allylic amines in 60–93% yield in a one-pot procedure. The addition step can be followed by either B–C bond oxidation to provide α-amino ketones (71–98% yield) or Suzuki cross-coupling to furnish trisubstituted 2-arylated (E)-allylic amines (51–73% yield). PMID:22085226

Synthesis of [.sup.13C] and [.sup.2H] substituted methacrylic acid, [.sup.13C] and [.sup.2H] substituted methyl methacrylate and/or related compounds

DOEpatents

Alvarez, Marc A [Santa Fe, NM; Martinez, Rodolfo A [Santa Fe, NM; Unkefer, Clifford J [Los Alamos, NM

2008-01-22

The present invention is directed to labeled compounds of the formulae ##STR00001## wherein Q is selected from the group consisting of --S--, --S(.dbd.O)--, and --S(.dbd.O).sub.2--, Z is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group selected from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each independently selected from the group consisting of a C.sub.1-C.sub.4 lower alkyl, an aryl, and an alkoxy group, and X is selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl group, and a fully-deuterated C.sub.1-C.sub.4 lower alkyl group. The present invention is also directed to a process of preparing labeled compounds, e.g., process of preparing [.sup.13C]methacrylic acid by reacting a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13CH.sub.2)-- aryl sulfone precursor with .sup.13CHI to form a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate, and, reacting the (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate with sodium hydroxide, followed by acid to form [.sup.13C]methacrylic acid. The present invention is further directed to a process of preparing [.sup.2H.sub.8]methyl methacrylate by reacting a (HOOC--C(C.sup.2H.sub.3).sub.2-- aryl sulfinyl intermediate with CD.sub.3I to form a (.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate, and heating the(.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate at temperatures and for time sufficient to form [.sup.2H.sub.8]methyl methacrylate.

Light-Induced C-H Arylation of (Hetero)arenes by In Situ Generated Diazo Anhydrides.

PubMed

Cantillo, David; Mateos, Carlos; Rincon, Juan A; de Frutos, Oscar; Kappe, C Oliver

2015-09-07

Diazo anhydrides (Ar-N=N-O-N=N-Ar) have been known since 1896 but have rarely been used in synthesis. This communication describes the development of a photochemical catalyst-free C-H arylation methodology for the preparation of bi(hetero)aryls by the one-pot reaction of anilines with tert-butyl nitrite and (hetero)arenes under neutral conditions. The key step in this procedure is the in situ formation and subsequent photochemical (>300 nm) homolytic cleavage of a transient diazo anhydride intermediate. The generated aryl radical then efficiently reacts with a (hetero)arene to form the desired bi(hetero)aryls producing only nitrogen, water, and tert-butanol as byproducts. The scope of the reaction for several substituted anilines and (hetero)arenes was investigated. A continuous-flow protocol increasing selectivity and safety has been developed enabling the experimentally straightforward preparation of a variety of substituted bi(hetero)aryls within 45 min of reaction time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design, Synthesis, and Structure--Activity Relationship of New 2-Aryl-3,4-dihydro-β-carbolin-2-ium Salts as Antifungal Agents.

PubMed

Hou, Zhe; Zhu, Li-Fei; Yu, Xin-chi; Sun, Ma-Qiang; Miao, Fang; Zhou, Le

2016-04-13

Twenty-two 2-aryl-9-methyl-3,4-dihydro-β-carbolin-2-ium bromides along with four 9-demethylated derivatives were synthesized and characterized by spectroscopic analysis. By using the mycelium growth rate method, the compounds were evaluated for antifungal activities in vitro against six plant pathogenic fungi, and structure-activity relationships (SAR) were derived. Almost all of the compounds showed obvious inhibition activity on each of the fungi at 150 μM. For all of the fungi, 10 of the compounds showed average inhibition rates of >80% at 150 μM, and most of their EC50 values were in the range of 2.0-30.0 μM. SAR analysis showed that the substitution pattern of the N-aryl ring significantly influences the activity; N9-alkylation improves the activity, whereas aromatization of ring-C reduces the activity. It was concluded that the present research provided a series of new 2-aryl-9-alkyl-3,4-dihydro-β-carbolin-2-iums with excellent antifungal potency and structure optimization design for the development of new carboline antifungal agents.

Synthesis of 2-{(5-phenyl-1,3,4-Oxadiazol-2-yl)sulfanyl}-N-substituted acetamides as potential antimicrobial and hemolytic agents.

PubMed

Rehman, Aziz-ur; Abbasi, Muhammad Athar; Siddiqui, Sabahat Zahra; Ahmad, Irshad; Shahid, Muhammad; Subhani, Zinayyera

2016-05-01

A new series of N-substituted derivatives of 2-{(5-phenyl-1,3,4-Oxadiazol-2-yl)sulfanyl}acetamides was synthesized. The synthesis was carried out by converting benzoic acid (1) into ethyl benzoate (2), benzohydrazide (3) and then 5-pheny-1,3,4-Oxadiazol-2-thiol (4) step by st0ep. The target compounds 6a-p were synthesized by reaction of compound 4 with equimolar ratios of different N-alkyl/aryl substituted 2-bromoacetamide (5a-p) in the presence of DMF and sodium hydride (NaH). The spectral (EI-MS, IR, (1)H-NMR) characterization of all the synthesized compounds reveal their successful synthesis. The compounds were also screened for antimicrobial & hemolytic activity and most of them were found to be active against the selected microbial species at variable extent relative to reference standards. But 6h was the most active against the selected panel of microbes. This series showed less toxicity and may be considered for further biological screening and application trial except 6m, possessing higher cytotoxicity.

Visible-light-driven Photocatalytic N-arylation of Imidazole Derivatives and Arylboronic Acids on Cu/graphene catalyst

NASA Astrophysics Data System (ADS)

Cui, Yan-Li; Guo, Xiao-Ning; Wang, Ying-Yong; Guo, Xiang-Yun

2015-07-01

N-aryl imidazoles play an important role as structural and functional units in many natural products and biologically active compounds. Herein, we report a photocatalytic route for the C-N cross-coupling reactions over a Cu/graphene catalyst, which can effectively catalyze N-arylation of imidazole and phenylboronic acid, and achieve a turnover frequency of 25.4 h-1 at 25 oC and the irradiation of visible light. The enhanced catalytic activity of the Cu/graphene under the light irradiation results from the localized surface plasmon resonance of copper nanoparticles. The Cu/graphene photocatalyst has a general applicability for photocatalytic C-N, C-O and C-S cross-coupling of arylboronic acids with imidazoles, phenols and thiophenols. This study provides a green photocatalytic route for the production of N-aryl imidazoles.

Nucleophilic addition of nitrogen to aryl cations: mimicking Titan chemistry.

PubMed

Li, Anyin; Jjunju, Fred P M; Cooks, R Graham

2013-11-01

The reactivity of aryl cations toward molecular nitrogen is studied systematically in an ion trap mass spectrometer at 10(2) Pascal of nitrogen, the pressure of the Titan main haze layer. Nucleophilic addition of dinitrogen occurs and the nature of aryl group has a significant influence on the reactivity, through inductive effects and by changing the ground state spin multiplicity. The products of nitrogen activation, aryldiazonium ions, react with typical nitriles, aromatic amines, and alkynes (compounds that are relevant as possible Titan atmosphere constituents) to form covalently bonded heterocyclic products. Theoretical calculations at the level [DFT(B3LYP)/6-311++G(d,p)] indicate that the N2 addition reaction is exothermic for the singlet aryl cations but endothermic for their triplet spin isomers. The -OH and -NH2 substituted aryl ions are calculated to have triplet ground states, which is consistent with their decreased nitrogen addition reactivity. The energy needed for the generation of the aryl cations from their protonated precursors (ca. 340 kJ/mol starting with protonated aniline) is far less than that required to directly activate the nitrogen triple bond (the lowest energy excited state of N2 lies ca. 600 kJ/mol above the ground state). The formation of aza-aromatics via arene ionization and subsequent reactions provide a conceivable route to the genesis of nitrogen-containing organic molecules in the interstellar medium and Titan haze layers.

An efficient synthesis of bis-1,3-(3'-aryl-N-heterocycl-1'-yl)arenes as CCC-NHC pincer ligand precursors.

PubMed

Howell, Tyler O; Huckaba, Aron J; Hollis, T Keith

2014-05-02

A report that demonstrated an efficient methodology for the arylation of imidazoles has been extended to bis(N-heterocyclic) compounds. Using bis(aryl) iodonium salts provides high-yielding access to CCC-NHC ligand precursors in a single step. Examples of arylation using various iodonium salts are reported herein with an investigation into the factors governing their relative rate of reactivity. The metalation of one of these compounds using Zr(NMe2)4 and its subsequent treatment with [Pt(COD)Cl2] to yield a transmetalated product are reported.

SYNTHESIS AND BIOLOGICAL EVALUATION OF N-(SUBSTITUTED PHENYL)-2-(5H-[1,2,4]TRIAZINO[5,6-b]INDOL-3-YLSULFANYL)ACETAMIDES AS ANTIMICROBIAL, ANTIDEPRESSANT AND ANTICONVULSANT AGENTS.

PubMed

Shruthi, N; Poojary, Boja; Kumar, Vasantha; Prathibha, A; Hussain, Mumtaz Mohammed; Revanasiddappa, B C; Joshi, Himanshu

2015-01-01

A new series of N-Aryl-2-(5H-[1,2,4]triazino[5,6-b]indol-3-ylsulfanyl)acetamides were synthesized by condensation of tricyclic compound 2,5-dihydro-3H-[1,2,4]triazino[5,6-b]indole-3-thione with chloro N-phenylacetamides. The tricyclic compound was obtained by condensation of Isatin with thiosemicarbazide. Chloro N-phenylacetamides were obtained from different substituted anilines. Their structures were characterized by IR, 1H NMR, LC-MS and elemental analyses. Newly synthesized compounds were screened for antimicrobial, antidepressant and anticonvulsant activities. Preliminary results indicated that most of the compounds showed lesser MIC value than the standard drug used when tested for antimicrobial activity. Some of the compounds were endowed with very good antidepressant and anticonvulsant activity.

Investigation of various N-heterocyclic substituted piperazine versions of 5/ 7-{[2-(4-Aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-2-ol: Effect on affinity and selectivity for dopamine D3 receptor

PubMed Central

Brown, Dennis A.; Mishra, Manoj; Zhang, Suhong; Biswas, Swati; Parrington, Ingrid; Antonio, Tamara; Reith, Maarten E. A.; Dutta, Aloke K.

2009-01-01

Here we report on the design and synthesis of several heterocyclic analogues belonging to the 5/ 7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-2-ol series of molecules. Compounds were subjected to [3H]spiperone binding assays, carried out with HEK-293 cells expressing either D2 or D3 dopamine receptors, in order to evaluate their inhibition constant (Ki) at these receptors. Results indicate that N-substitution on the piperazine ring can accommodate various substituted indole rings. The results also show that in order to maintain high affinity and selectivity for the D3 receptor the heterocyclic ring does not need to be connected directly to the piperazine ring as the majority of compounds included here are linked either via an amide or a methylene linker to the heterocyclic moiety. The enantiomers of the most potent racemic compound 10e exhibited differential activity with (-)-10e (Ki; D2 = 47.5 nM, D3 = 0.57 nM) displaying higher affinity at both D2 and D3 receptors compared to its enantiomer (+)-10e (Ki; D2 = 113 nM, D3 = 3.73 nM). Additionally, compound (-)-10e was more potent and selective for the D3 receptor compared to either 7-OH-DPAT or 5-OH-DPAT. Among the bioisosteric derivatives, the indazole derivative 10g and benzo[b]thiophene derivative 10i exhibited the highest affinity for D2 and D3 receptors. In the functional GTPγS binding study, one of the lead molecules, (-)-15, exhibited potent agonist activity at both D2 and D3 receptors with preferential activity at D3. PMID:19427222

N-substituted methyl maleamates as larvicidal compounds against Aedes aegypti (Diptera: Culicidae).

PubMed

Harburguer, Laura; Gonzalez, Paula V; Gonzalez Audino, Paola; Zerba, Eduardo; Masuh, Héctor

2018-02-01

Severe human arboviral diseases can be transmitted by the mosquito Aedes aegypti (L.), including dengue, chikungunya, zika, and yellow fever. The use of larvicides in containers that can result as potential breeding places and cannot be eliminated is the main alternative in control programs. However, their continuous and widespread use caused an increase in insecticide-resistant populations of this mosquito. The aim of this study was to evaluate the effect of three N-substituted methyl maleamates as larvicides on Ae. aegypti, the N-propyl methyl maleamate (PMM), N-butyl methyl maleamate (BMM), and N-hexyl methyl maleamate (HMM). These compounds could have a different mode of action from those larvicides known so far. We evaluated the larva mortality after 1 and 24 h of exposure and we found that mortality was fast and occurs within the first 60 min. HMM was slightly more effective with LC 50 values of 0.7 and 0.3 ppm for 1 and 24 h of exposure and LC 95 of 11 and 3 ppm. Our results demonstrate that N-substituted methyl maleamates have insecticidal properties for the control of Ae. aegypti larvae. These compounds could become useful alternatives to traditional larvicides after studying their insecticidal mechanism as well as their toxicity towards non target organisms.

Visible-light-driven Photocatalytic N-arylation of Imidazole Derivatives and Arylboronic Acids on Cu/graphene catalyst

PubMed Central

Cui, Yan-Li; Guo, Xiao-Ning; Wang, Ying-Yong; Guo, Xiang-Yun

2015-01-01

N-aryl imidazoles play an important role as structural and functional units in many natural products and biologically active compounds. Herein, we report a photocatalytic route for the C-N cross-coupling reactions over a Cu/graphene catalyst, which can effectively catalyze N-arylation of imidazole and phenylboronic acid, and achieve a turnover frequency of 25.4 h−1 at 25 oC and the irradiation of visible light. The enhanced catalytic activity of the Cu/graphene under the light irradiation results from the localized surface plasmon resonance of copper nanoparticles. The Cu/graphene photocatalyst has a general applicability for photocatalytic C-N, C-O and C-S cross-coupling of arylboronic acids with imidazoles, phenols and thiophenols. This study provides a green photocatalytic route for the production of N-aryl imidazoles. PMID:26189944

Explorations of Substituted Urea Functionality for Discovery of New Activators of the Heme Regulated Inhibitor Kinase

PubMed Central

Chen, Ting; Takrouri, Khuloud; Hee-Hwang, Sung; Rana, Sandeep; Yefidoff-Freedman, Revital; Halperin, Jose; Natarajan, Amarnath; Morisseau, Christophe; Hammock, Bruce; Chorev, Michael; Aktas, Bertal H.

2014-01-01

Heme-regulated inhibitor kinase (HRI), an eukaryotic translation initiation factor 2 alpha (eIF2α) kinase, plays critical roles in cell proliferation, differentiation, and adaptation to cytoplasmic stress. HRI is also a critical modifier of hemoglobin disorders such as β-thalassemia. We previously identified N,N′-diarylureas as potent activators of HRI suitable for studying biology of this important kinase. To expand the repertoire of chemotypes that activate HRI we screened a ~1,900 member N,N′-disubstituted urea library in the surrogate eIF2α phosphorylation assay identifying N-aryl,N′-cyclohexylphenoxyurea as a promising scaffold. We validated hit compounds as a bona-fide HRI activators in secondary assays and explored contributions of substitutions on the N-aryl and N′-cyclohexylphenoxy groups to their activity by studying focused libraries of complementing analogs. We tested these N-aryl,N′-cyclohexylphenoxyureas in the surrogate eIF2α phosphorylation and cell proliferation assays, demonstrating significantly improved bioactivities and specificities. We consider these compounds to represent lead candidates for the development of potent and specific HRI activators. PMID:24261904

Discovery of novel 2-aryl-4-benzoyl-imidazoles targeting the colchicines binding site in tubulin as potential anticancer agents

PubMed Central

Chen, Jianjun; Wang, Zhao; Li, Chien-Ming; Lu, Yan; Vaddady, Pavan K.; Meibohm, Bernd; Dalton, James T.; Miller, Duane D.; Li, Wei

2010-01-01

A series of 2-aryl-4-benzoyl-imidazoles (ABI) was synthesized as a result of structural modifications based on the previous set of 2-aryl-imidazole-4-carboxylic amide (AICA) derivatives and 4-substituted methoxylbenzoyl-aryl-thiazoles (SMART). The average IC50 of the most active compound (5da) was 15.7 nM. ABI analogs have substantially improved aqueous solubility (48.9 μg/mL for 5ga vs. 0.909 μg/mL for SMART-1, 0.137 μg/mL for paclitaxel, and 1.04 μg/mL for Combretastatin A4). Mechanism of action studies indicate that the anticancer activity of ABI analogs is through inhibition of tubulin polymerization by interacting with the colchicine binding site. Unlike paclitaxel and colchicine, the ABI compounds were equally potent against multidrug resistant cancer cells and the sensitive parental melanoma cancer cells. In vivo results indicated that 5cb was more effective than DTIC in inhibiting melanoma xenograph tumor growth. Our results suggest that the novel ABI compounds may be developed to effectively treat drug-resistant tumors. PMID:20919720

Mechanistic Studies on the Copper-Catalyzed N-Arylation of Amides

PubMed Central

Strieter, Eric R.; Bhayana, Brijesh; Buchwald, Stephen L.

2009-01-01

The copper-catalyzed N-arylation of amides, i.e., the Goldberg reaction, is an efficient method for the construction of products relevant to both industry and academic settings. Herein, we present mechanistic details concerning the catalytic and stoichiometric N-arylation of amides. In the context of the catalytic reaction, our findings reveal the importance of chelating diamine ligands in controlling the concentration of the active catalytic species. The consistency between the catalytic and stoichiometric results suggest that the activation of aryl halides occurs through a 1,2-diamine-ligated copper(I) amidate complex. Kinetic studies on the stoichiometric N-arylation of aryl iodides using 1,2-diamine ligated Cu(I) amidates also provide insights into the mechanism of aryl halide activation. PMID:19072233

A one-pot radioiodination of aryl amines via stable diazonium salts: preparation of 125I-imaging agents.

PubMed

Sloan, Nikki L; Luthra, Sajinder K; McRobbie, Graeme; Pimlott, Sally L; Sutherland, Andrew

2017-10-05

An operationally simple, one-pot, two-step tandem procedure that allows the incorporation of radioactive iodine into aryl amines via stable diazonium salts is described. The mild conditions are tolerant of various functional groups and substitution patterns, allowing late-stage, rapid access to a wide range of 125 I-labelled aryl compounds and SPECT radiotracers.

Enantioselective synthesis of substituted piperidines by addition of aryl Grignard reagents to pyridine N-oxides.

PubMed

Hussain, Munawar; Banchelin, Thomas Sainte-Luce; Andersson, Hans; Olsson, Roger; Almqvist, Fredrik

2013-01-04

The synthesis of optically active piperidines by enantioselective addition of aryl Grignard reagents to pyridine N-oxides and lithium binolate followed by reduction is reported for the first time. The reaction results in high yields (51-94%) in combination with good ee (54-80%). Some of these products were subsequently recrystallized, affording enhanced optical purities (>99% ee).

Synthesis and biological evaluation of some novel substituted 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxamides

NASA Astrophysics Data System (ADS)

Jaismy Jacob, P.; Thomas, Anoop; Venkataraman, S.; Hareeshbabu, E.; Manju, S. L.

2017-11-01

A novel class of substituted 4-aryl-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxamide has been synthesized by simple, modified Hantzsch condensation reaction using N-arylacetoacetamides, aryl aldehydes and ammonia. Characterisation of the newly synthesized compounds was carried out by spectral analysis (IR, 1H NMR and Mass Spectroscopy). Antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans and antiulcer activity by aspirin induced and pyloric ligation ulcer model was studied. Results revealed that most of the compounds exhibit significant antimicrobial activity along with antiulcer activity. The compound 6i 4-dimethylamino phenyl group at 4th position of 1,4-dihydropyridine had shown 65% ulcer protection at 10 mg/kg administration in male albino rats.

Design, Synthesis, and Biological Evaluation of Peptidomimetic N-Substituted Cbz-4-Hyp-Hpa-Amides as Novel Inhibitors of Plasmodium falciparum.

PubMed

Bacherikov, Valeriy A; Chittiboyina, Amar G; Avery, Mitchell A

2017-08-01

A new series of peptidomimetic N-substituted Cbz-4-Hyp-Hpa-amides were designed, synthesized, and evaluated for inhibition of the Plasmodium falciparum. Substituents on the N-atom of the amide group were selected alkyl-, allyl-, aryl-, 2-hydroxyethyl-, 2-cyanoethyl-, cyanomethyl-, 2-hydroxyethyl-, 2,2-diethoxyethyl-, or 2-ethoxy-2-oxoethylamino groups, and about of 40 new compounds were synthesized and evaluated for antiplasmodial activity in vitro. Antimalarial activity has been investigated as for the final peptide mimetics, and their immediate predecessors, carrying TBDMS or TBDPS protecting groups on 4-hydroxyproline residue and 18 derivatives exhibited toxicity against P. falciparum. Of these agents, compound 23e was shown to have potent antimalarial activity with IC 50 528 ng/ml. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Optimization of Aryl Amides that Extend Survival in Prion-Infected Mice

PubMed Central

Giles, Kurt; Berry, David B.; Condello, Carlo; Dugger, Brittany N.; Li, Zhe; Oehler, Abby; Bhardwaj, Sumita; Elepano, Manuel; Guan, Shenheng; Silber, B. Michael; Olson, Steven H.

2016-01-01

Developing therapeutics for neurodegenerative diseases (NDs) prevalent in the aging population remains a daunting challenge. With the growing understanding that many NDs progress by conformational self-templating of specific proteins, the prototypical prion diseases offer a platform for ND drug discovery. We evaluated high-throughput screening hits with the aryl amide scaffold and explored the structure–activity relationships around three series differing in their N-aryl core: benzoxazole, benzothiazole, and cyano. Potent anti-prion compounds were advanced to pharmacokinetic studies, and the resulting brain-penetrant leads from each series, together with a related N-aryl piperazine lead, were escalated to long-term dosing and efficacy studies. Compounds from each of the four series doubled the survival of mice infected with a mouse-passaged prion strain. Treatment with aryl amides altered prion strain properties, as evidenced by the distinct patterns of neuropathological deposition of prion protein and associated astrocytic gliosis in the brain; however, none of the aryl amide compounds resulted in drug-resistant prion strains, in contrast to previous studies on compounds with the 2-aminothiazole (2-AMT) scaffold. As seen with 2-AMTs and other effective anti-prion compounds reported to date, the novel aryl amides reported here were ineffective in prolonging the survival of transgenic mice infected with human prions. Most encouraging is our discovery that aryl amides show that the development of drug resistance is not an inevitable consequence of efficacious anti-prion therapeutics. PMID:27317802

Aryl imidazylates and aryl sulfates as electrophiles in metal-free ArS(N)1 reactions.

PubMed

Qrareya, Hisham; Protti, Stefano; Fagnoni, Maurizio

2014-12-05

Some oxygen-bonded substituents were investigated as leaving groups in photoinduced ArS(N)1 reactions. Irradiation of aryl imidazylates and of the corresponding imidazolium salts mainly caused homolysis of the ArO-S bond. However, previously unexplored trifluoroethoxy aryl sulfates were found to undergo efficient metal-free arylation. The sulfates were conveniently generated in situ by dissolving the corresponding imidazolium salts in basic 2,2,2-trifluoroethanol.

Facile N-Arylation of Amines and Sulfonamides and O-Arylation of Phenols and Arenecarboxylic Acids

PubMed Central

Liu, Zhijian; Larock, Richard C.

2008-01-01

An efficient, transition-metal free procedure for the N-arylation of amines, sulfonamides and carbamates and O-arylation of phenols and carboxylic acids has been achieved by allowing these substrates to react with a variety of o-silylaryl triflates in the presence of CsF. Good to excellent yields of arylated products are obtained under very mild reaction conditions. This chemistry readily tolerates a variety of functional groups. PMID:16599619

Synthesis and in vitro anti-proliferative effects of 3-(hetero)aryl substituted 3-[(prop-2-ynyloxy)(thiophen-2-yl)methyl]pyridine derivatives on various cancer cell lines.

PubMed

Reddy Chamakura, Upendar; Sailaja, E; Dulla, Balakrishna; Kalle, Arunasree M; Bhavani, S; Rambabu, D; Kapavarapu, Ravikumar; Rao, M V Basaveswara; Pal, Manojit

2014-03-01

A series of 3-(hetero)aryl substituted 3-[(prop-2-ynyloxy)(thiophen-2-yl)methyl]pyridine derivatives were designed as potential anticancer agents. These compounds were conveniently prepared by using Pd/C-Cu mediated Sonogashira type coupling as a key step. Many of these compounds were found to be promising when tested for their in vitro anti-proliferative properties against six cancer cell lines. All these compounds were found to be selective towards the growth inhibition of cancer cells with IC50 values in the range of 0.9-1.7 μM (against MDA-MB 231 and MCF7 cells), comparable to the known anticancer drug doxorubicin. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimization of Aryl Amides that Extend Survival in Prion-Infected Mice.

PubMed

Giles, Kurt; Berry, David B; Condello, Carlo; Dugger, Brittany N; Li, Zhe; Oehler, Abby; Bhardwaj, Sumita; Elepano, Manuel; Guan, Shenheng; Silber, B Michael; Olson, Steven H; Prusiner, Stanley B

2016-09-01

Developing therapeutics for neurodegenerative diseases (NDs) prevalent in the aging population remains a daunting challenge. With the growing understanding that many NDs progress by conformational self-templating of specific proteins, the prototypical prion diseases offer a platform for ND drug discovery. We evaluated high-throughput screening hits with the aryl amide scaffold and explored the structure-activity relationships around three series differing in their N-aryl core: benzoxazole, benzothiazole, and cyano. Potent anti-prion compounds were advanced to pharmacokinetic studies, and the resulting brain-penetrant leads from each series, together with a related N-aryl piperazine lead, were escalated to long-term dosing and efficacy studies. Compounds from each of the four series doubled the survival of mice infected with a mouse-passaged prion strain. Treatment with aryl amides altered prion strain properties, as evidenced by the distinct patterns of neuropathological deposition of prion protein and associated astrocytic gliosis in the brain; however, none of the aryl amide compounds resulted in drug-resistant prion strains, in contrast to previous studies on compounds with the 2-aminothiazole (2-AMT) scaffold. As seen with 2-AMTs and other effective anti-prion compounds reported to date, the novel aryl amides reported here were ineffective in prolonging the survival of transgenic mice infected with human prions. Most encouraging is our discovery that aryl amides show that the development of drug resistance is not an inevitable consequence of efficacious anti-prion therapeutics. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

Design, synthesis, and characterization of (1-(4-aryl)- 1H-1,2,3-triazol-4-yl)methyl, substituted phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates against Mycobacterium tuberculosis

PubMed Central

Venugopala, Katharigatta N; Dharma Rao, G B; Bhandary, Subhrajyoti; Pillay, Melendhran; Chopra, Deepak; Aldhubiab, Bandar E; Attimarad, Mahesh; Alwassil, Osama Ibrahim; Harsha, Sree; Mlisana, Koleka

2016-01-01

The novel (1-(4-aryl)-1H-1,2,3-triazol-4-yl)methyl, substituted phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives were synthesized by the click reaction of the dihydropyrimidinones, bearing a terminal alkynyl group, with various substituted aryl azides at room temperature using a catalytic amount of Cu(OAc)2 and sodium ascorbate in a 1:2 ratio of acetone and water as a solvent. The newly synthesized compounds were characterized by a number of spectroscopic techniques, such as infrared, liquid chromatography-mass spectrometry, 1H, and 13C nuclear magnetic resonance along with single crystal X-ray diffraction. The current procedure for the synthesis of 1,2,3-triazole hybrids with dihydropyrimidinones is appropriate for the synthesis of a library of analogs 7a-l and the method accessible here is operationally simple and has excellent yields. The title compounds 7a-l were evaluated for their in vitro antitubercular activity against H37RV and multidrug-resistant strains of Mycobacterium tuberculosis by resazurin microplate assay plate method and it was found that compound 7d was promising against H37RV and multidrug-resistant strains of M. tuberculosis at 10 and 15 μg/mL, respectively. PMID:27601885

Design, synthesis, and characterization of (1-(4-aryl)- 1H-1,2,3-triazol-4-yl)methyl, substituted phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates against Mycobacterium tuberculosis.

PubMed

Venugopala, Katharigatta N; Dharma Rao, G B; Bhandary, Subhrajyoti; Pillay, Melendhran; Chopra, Deepak; Aldhubiab, Bandar E; Attimarad, Mahesh; Alwassil, Osama Ibrahim; Harsha, Sree; Mlisana, Koleka

2016-01-01

The novel (1-(4-aryl)-1H-1,2,3-triazol-4-yl)methyl, substituted phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives were synthesized by the click reaction of the dihydropyrimidinones, bearing a terminal alkynyl group, with various substituted aryl azides at room temperature using a catalytic amount of Cu(OAc)2 and sodium ascorbate in a 1:2 ratio of acetone and water as a solvent. The newly synthesized compounds were characterized by a number of spectroscopic techniques, such as infrared, liquid chromatography-mass spectrometry, (1)H, and (13)C nuclear magnetic resonance along with single crystal X-ray diffraction. The current procedure for the synthesis of 1,2,3-triazole hybrids with dihydropyrimidinones is appropriate for the synthesis of a library of analogs 7a-l and the method accessible here is operationally simple and has excellent yields. The title compounds 7a-l were evaluated for their in vitro antitubercular activity against H37RV and multidrug-resistant strains of Mycobacterium tuberculosis by resazurin microplate assay plate method and it was found that compound 7d was promising against H37RV and multidrug-resistant strains of M. tuberculosis at 10 and 15 μg/mL, respectively.

The Ketene-Surrogate Coupling: Catalytic Conversion of Aryl Iodides to Aryl Ketenes via Ynol Ethers**

PubMed Central

Zhang, Wenhan; Ready, Joseph M.

2014-01-01

tert-Butoxyacetylene is shown to undergo Sonogashira coupling with aryl iodides to yield aryl-substituted tert-butyl ynol ethers. These intermediates participate in a [1,5]-hydride shift, which results in the extrusion of isobutylene and the generation of aryl ketenes. The ketenes are trapped in situ with multiple nucleophiles or undergoelectrocyclic ring closure to yield hydroxynaphthalenes and quinolines. PMID:24975840

Organocatalytic asymmetric arylation of indoles enabled by azo groups

NASA Astrophysics Data System (ADS)

Qi, Liang-Wen; Mao, Jian-Hui; Zhang, Jian; Tan, Bin

2018-01-01

Arylation is a fundamental reaction that can be mostly fulfilled by electrophilic aromatic substitution and transition-metal-catalysed aryl functionalization. Although the azo group has been used as a directing group for many transformations via transition-metal-catalysed aryl carbon-hydrogen (C-H) bond activation, there remain significant unmet challenges in organocatalytic arylation. Here, we show that the azo group can effectively act as both a directing and activating group for organocatalytic asymmetric arylation of indoles via formal nucleophilic aromatic substitution of azobenzene derivatives. Thus, a wide range of axially chiral arylindoles have been achieved in good yields with excellent enantioselectivities by utilizing chiral phosphoric acid as catalyst. Furthermore, highly enantioenriched pyrroloindoles bearing two contiguous quaternary chiral centres have also been obtained via a cascade enantioselective formal nucleophilic aromatic substitution-cyclization process. This strategy should be useful in other related research fields and will open new avenues for organocatalytic asymmetric aryl functionalization.

Organocatalytic asymmetric arylation of indoles enabled by azo groups.

PubMed

Qi, Liang-Wen; Mao, Jian-Hui; Zhang, Jian; Tan, Bin

2018-01-01

Arylation is a fundamental reaction that can be mostly fulfilled by electrophilic aromatic substitution and transition-metal-catalysed aryl functionalization. Although the azo group has been used as a directing group for many transformations via transition-metal-catalysed aryl carbon-hydrogen (C-H) bond activation, there remain significant unmet challenges in organocatalytic arylation. Here, we show that the azo group can effectively act as both a directing and activating group for organocatalytic asymmetric arylation of indoles via formal nucleophilic aromatic substitution of azobenzene derivatives. Thus, a wide range of axially chiral arylindoles have been achieved in good yields with excellent enantioselectivities by utilizing chiral phosphoric acid as catalyst. Furthermore, highly enantioenriched pyrroloindoles bearing two contiguous quaternary chiral centres have also been obtained via a cascade enantioselective formal nucleophilic aromatic substitution-cyclization process. This strategy should be useful in other related research fields and will open new avenues for organocatalytic asymmetric aryl functionalization.

Indolyl aryl sulfones as HIV-1 non-nucleoside reverse transcriptase inhibitors: role of two halogen atoms at the indole ring in developing new analogues with improved antiviral activity.

PubMed

Regina, Giuseppe La; Coluccia, Antonio; Piscitelli, Francesco; Bergamini, Alberto; Sinistro, Anna; Cavazza, Antonella; Maga, Giovanni; Samuele, Alberta; Zanoli, Samantha; Novellino, Ettore; Artico, Marino; Silvestri, Romano

2007-10-04

Indolyl aryl sulfones bearing the 4,5-difluoro (10) or 5-chloro-4-fluoro (16) substitution pattern at the indole ring were potent inhibitors of HIV-1 WT and the NNRTI-resistant strains Y181C and K103N-Y181C. These compounds were highly effective against the 112 and the AB1 strains in lymphocytes and inhibited at nanomolar concentration the multiplication of the IIIBBa-L strain in macrophages. Compound 16 was exceptionally potent against RT WT and RTs carrying the K103N, Y181I, and L100I mutations.

Identification and characterization of 4-aryl-3,4-dihydropyrimidin-2(1H)-ones as inhibitors of the fatty acid transporter FATP4.

PubMed

Blackburn, Christopher; Guan, Bing; Brown, James; Cullis, Courtney; Condon, Stephen M; Jenkins, Tracy J; Peluso, Stephane; Ye, Yingchun; Gimeno, Ruth E; Punreddy, Sandhya; Sun, Ying; Wu, Hui; Hubbard, Brian; Kaushik, Virendar; Tummino, Peter; Sanchetti, Praveen; Yu Sun, Dong; Daniels, Tom; Tozzo, Effie; Balani, Suresh K; Raman, Prakash

2006-07-01

Several potent, cell permeable 4-aryl-dihydropyrimidinones have been identified as inhibitors of FATP4. Lipophilic ester substituents at the 5-position and substitution at the para-position (optimal groups being -NO(2) and CF(3)) of the 4-aryl group led to active compounds. In two cases racemates were resolved and the S enantiomers shown to have higher potencies.

No-carrier-added (NCA) aryl (18E) fluorides via the nucleophilic aromatic substitution of electron rich aromatic rings

DOEpatents

Ding, Yu-Shin; Fowler, Joanna S.; Wolf, Alfred P.

1993-01-01

A method for synthesizing no-carrier-added (NCA) aryl [.sup.18 F] fluoride substituted aromatic aldehyde compositions bearing an electron donating group is described. The method of the present invention includes the step of reacting aromatic nitro aldehydes having a suitably protected hydroxyl substitutent on an electron rich ring. The reaction is The U.S. Government has rights in this invention pursuant to Contract Number DE-AC02-76CH00016, between the U.S. Department of Energy and Associated Universities Inc.

Isovanillin derived N-(un)substituted hydroxylamines possessing an ortho-allylic group: valuable precursors to bioactive N-heterocycles.

PubMed

Dulla, Balakrishna; Tangellamudi, Neelima D; Balasubramanian, Sridhar; Yellanki, Swapna; Medishetti, Raghavender; Kumar Banote, Rakesh; Hari Chaudhari, Girish; Kulkarni, Pushkar; Iqbal, Javed; Reiser, Oliver; Pal, Manojit

2014-04-28

The intramolecular 1,3-dipolar cycloaddition of isovanillin derived N-aryl hydroxylamines possessing ortho-allylic dipolarophiles affords novel benzo analogues of tricyclic isoxazolidines that can be readily transformed into functionalized lactams, γ-aminoalcohols and oxazepines. The corresponding N-unsubstituted hydroxylamines give rise to tetrahydroisoquinolines. Anxiogenic properties of these compounds are tested in zebra fish.

Structural studies on bioactive compounds. Part 29: palladium catalysed arylations and alkynylations of sterically hindered immunomodulatory 2-amino-5-halo-4,6-(disubstituted)pyrimidines.

PubMed

Hannah, D R; Sherer, E C; Davies, R V; Titman, R B; Laughton, C A; Stevens, M F

2000-04-01

The immunological agent bropirimine 5 is a tetra-substituted pyrimidine with anticancer and interferon-inducing properties. Synthetic routes to novel 5-aryl analogues of bropirimine have been developed and their potential molecular recognition properties analysed by molecular modelling methods. Sterically challenged 2-amino-5-halo-6-phenylpyrimidin-4-ones (halo = Br or I) are poor substrates for palladium catalysed Suzuki cross-coupling reactions with benzeneboronic acid because the basic conditions of the reaction converts the amphoteric pyrimidinones to their unreactive enolic forms. Palladium-mediated reductive dehalogenation of the pyrimidinone substrates effectively competes with cross-coupling. 2-Amino-5-halo-4-methoxy-6-phenylpyrimidines can be converted to a range of 5-aryl derivatives with the 5-iodopyrimidines being the most efficient substrates. Hydrolysis of the 2-amino-5-aryl-4-methoxy-6-phenylpyrimidines affords the required pyrimidin-4-ones in high yields. Semi-empirical quantum mechanical calculations show how the nature of the 5-substituent influences the equilibrium between the 1H- and 3H-tautomeric forms, and the rotational freedom about the bond connecting the 6-phenyl group and the pyrimidine ring. Both of these factors may influence the biological properties of these compounds.

Picolinoxy group, a new leaving group for anti SN2' selective allylic substitution with aryl anions based on Grignard reagents.

PubMed

Kiyotsuka, Yohei; Acharya, Hukum P; Katayama, Yuji; Hyodo, Tomonori; Kobayashi, Yuichi

2008-05-01

The picolinoxy group was found to be an extremely powerful leaving group for allylic substitution with aryl nucleophiles derived from ArMgBr and CuBr*Me2S. The substitution proceeds with anti SN2' pathway and with high chirality transfer. The electron-withdrawing effect of the pyridyl group and chelation to MgBr2 are likely the origin of success. Results suggesting these effects were obtained.

A Microplate Format Assay for Real-Time Screening for New Aldolases that Accept Aryl-Substituted Acceptor Substrates.

PubMed

Ma, Huan; Enugala, Thilak Reddy; Widersten, Mikael

2015-12-01

Aldolases are potentially important biocatalysts for asymmetric synthesis of polyhydroxylated compounds. Fructose 6-phosphate aldolase (FSA) is of particular interest by virtue of its unusually relaxed dependency on phosphorylated substrates. FSA has been reported to be a promising catalyst of aldol addition involving aryl-substituted acceptors such as phenylacetaldehyde that can react with donor ketones such as hydroxyacetone. Improvement of the low intrinsic activity with bulky acceptor substrates of this type is of great interest but has been hampered by the lack of powerful screening protocols applicable in directed evolution strategies. Here we present a new screen allowing for direct spectrophotometric recording of retro-aldol cleavage. The assay utilizes an aldehyde reductase produced in vitro by directed evolution; it reduces the aldehyde product formed after cleavage of the aldol by FSA. The assay is suitable both for steady-state enzyme kinetics and for real-time activity screening in a 96-well format. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

N,N-Diethylurea-Catalyzed Amidation between Electron-Defficient Aryl Azides and Phenylacetaldehydes

PubMed Central

Xie, Sheng; Ramström, Olof; Yan, Mingdi

2015-01-01

Urea structures, of which N,N-diethylurea (DEU) proved to be the most efficient, were discovered to catalyze amidation reactions between electron-defficient aryl azides and phenylacetaldehydes. Experimental data support 1,3-dipolar cycloaddition between DEU-activated enols and electrophilic phenyl azides, especially perfluoroaryl azides, followed by rearrangement of the triazoline intermediate. The activation of the aldehyde under near-neutral conditions was of special importance in inhibiting dehydration/aromatization of the triazoline intermediate, thus promoting the rearrangement to form aryl amides. PMID:25616121

No-carrier-added (NCA) aryl ([sup 18]F) fluorides via the nucleophilic aromatic substitution of electron rich aromatic rings

DOEpatents

Yushin Ding; Fowler, J.S.; Wolf, A.P.

1993-10-19

A method for synthesizing no-carrier-added (NCA) aryl [.sup.18 F] fluoride substituted aromatic aldehyde compositions bearing an electron donating group is described. The method of the present invention includes the step of reacting aromatic nitro aldehydes having a suitably protected hydroxyl substitutent on an electron rich ring. The reaction is The U.S. Government has rights in this invention pursuant to Contract Number DE-AC02-76CH00016, between the U.S. Department of Energy and Associated Universities Inc.

A comparative study of two novel unsymmetrically substituted triazacyclohexanes

NASA Astrophysics Data System (ADS)

Lamraoui, Hanane; Messai, Amel; Bilge, Duygu; Bilge, Metin; Bouchemma, Ahcen; Parlak, Cemal

2017-06-01

Novel unsymmetrically N-substituted N,N‧-R1N″-R2-1,3,5-triazacyclohexanes (1b and 2b; R1 = p-chlorophenyl or p-methoxyphenyl and R2 = butyl or cyclohexyl) have been synthesized in a good yield from condensation reaction by excess amine. Both triazacyclohexane rings have chair conformation. However, 1b adopts diaxial orientation of aryl groups and an equatorial form of alkyl group whereas 2b prefers an axial orientation of the alkyl group and diequatorial forms of aryl groups. 1b is consolidated by weak C-H⋯π interactions. Intra-molecular C-H⋯O or C-H⋯N hydrogen bonds and C-H⋯π may be effective in the stabilization of 2b. Both compounds have showed moderate antimicrobial activity, but 1b exhibits higher activity than 2b. All experimental results are found in good support to theoretical data. Findings of research may be helpful guide for the medicinal chemists and the field is further open for pharmacokinetics studies.

Synthesis and biological activity of a new class of insecticides: the N-(5-aryl-1,3,4-thiadiazol-2-yl)amides.

PubMed

Eckelbarger, Joseph D; Parker, Marshall H; Yap, Maurice Ch; Buysse, Ann M; Babcock, Jonathan M; Hunter, Ricky; Adelfinskaya, Yelena; Samaritoni, Jack G; Garizi, Negar; Trullinger, Tony K

2017-04-01

Optimization studies on a high-throughput screening (HTS) hit led to the discovery of a series of N-(6-arylpyridazin-3-yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4-thiadiazole ring could lead to more potent biological activity and/or a broader sap-feeding pest spectrum. The resulting N-(5-aryl-1,3,4-thiadiazol-2-yl)amides were explored as a new class of insecticides. Several methods for 2-amino-1,3,4-thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid) and Bemisia tabaci (Gennadius) (sweetpotato whitefly). Structure-activity relationship (SAR) studies on both the amide tail and the aryl A-ring of novel N-(5-aryl-1,3,4-thiadiazol-2-yl)amides led to a new class of insecticidal molecules active against sap-feeding insect pests. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

2-Aryl benzimidazoles: Synthesis, In vitro α-amylase inhibitory activity, and molecular docking study.

PubMed

Adegboye, Akande Akinsola; Khan, Khalid Mohammed; Salar, Uzma; Aboaba, Sherifat Adeyinka; Kanwal; Chigurupati, Sridevi; Fatima, Itrat; Taha, Mohammad; Wadood, Abdul; Mohammad, Jahidul Isalm; Khan, Huma; Perveen, Shahnaz

2018-04-25

Despite of many diverse biological activities exhibited by benzimidazole scaffold, it is rarely explored for the α-amylase inhibitory activity. For that purpose, 2-aryl benzimidazole derivatives 1-45 were synthesized and screened for in vitro α-amylase inhibitory activity. Structures of all synthetic compounds were deduced by various spectroscopic techniques. All compounds revealed inhibition potential with IC 50 values of 1.48 ± 0.38-2.99 ± 0.14 μM, when compared to the standard acarbose (IC 50  = 1.46 ± 0.26 μM). Limited SAR suggested that the variation in the inhibitory activities of the compounds are the result of different substitutions on aryl ring. In order to rationalize the binding interactions of most active compounds with the active site of α-amylase enzyme, in silico study was conducted. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Chemoselective N-arylation of aminobenzamides via copper catalysed Chan-Evans-Lam reactions.

PubMed

Liu, Shuai; Zu, Weisai; Zhang, Jinli; Xu, Liang

2017-11-15

Chemoselective N-arylation of unprotected aminobenzamides was achieved via Cu-catalysed Chan-Evans-Lam cross-coupling with aryl boronic acids for the first time. Simple copper catalysts enable the selective arylation of amino groups in ortho/meta/para-aminobenzamides under open-flask conditions. The reactions were scalable and compatible with a wide range of functional groups.

Toxicity of N-substituted aromatics to acetoclastic methanogenic activity in granular sludge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donlon, B.A.; Razo-Flores, E.; Field, J.A.

1995-11-01

N-substituted aromatics are important priority pollutants entering the environment primarily through anthropogenic activities associated associated with the industrial production of dyes, explosives, pestides, and pharmaceuticals. Anaerobic treatment of wastewaters discharged by these industries could potentially be problematical as a result of the high toxicity of N-substituted aromatics. The objective of this study was to examine the structure-toxicity relationship of N-substituted aromatic compounds to acetoclastic methanogenic bacteria. The toxicity was assayed to serum flasks by measuring methane production in granular sludge. Unacclimated cultures were used to minimize the biotransformation of the toxic organic chemicals during the test. The nature and themore » degree of the aromatic substitution were observed to have a profound effect on the toxicity of the test compound. Nitroaromatic compounds were, on the average, over 500-fold more toxic than their corresponding aromatic amines. Considering the facile reduction of nitro groups by anerobic microorganisms, a dramatic detoxification of nitroaromatics towards methanogens can be expected to occur during anaerobic wastewater treatment. While the toxicity exerted by the N-substituted aromatic compounds was closely correlated with compound apolarity (log P), it was observed that at any given log P, N-substituted phenols had a toxicity that was 2 orders of magnitude higher than that of chlorophenols and alkylphenols. This indicates that toxicity due to the chemical reactivity of nitroaromatics is much more important than partitioning effects in bacterial membranes. 41 refs., 3 figs., 1 tab.« less

Substituted 1,1,1-triaryl-2,2,2-trifluoroethanes and processes for their synthesis

NASA Technical Reports Server (NTRS)

Alston, William B. (Inventor); Gratz, Roy F. (Inventor)

1994-01-01

Synthetic procedures are given for tetraalkyl, tetraacid and dianhydrides substituted 1,1,1-triaryl-2,2,2-trifluoroethanes which comprises: (1) 1,1-bis (dialkylaryl) 1-aryl-2,2,2 trifluoroethane; (2) 1,1-bis (dicarboxyaryl) 1-aryl-2,2,2 trifluoroethane; or (3) cyclic dianhydride or diamine of 1,1-bis (dialkylaryl) 1-aryl-2,2,2 trifluoroethanes. The synthesis of (1) is accomplished by the condensation reaction of an aryltrifluoromethyl ketone with a dialkylaryl compound. The synthesis of (2) is accomplished by oxidation of (1). The synthesis dianhydride of (3) is accomplished by the conversion of (2) to its corresponding cyclic dianhydride. The synthesis of the diamine is accomplished by the similar reaction of an aryltrifluoromethyl ketone with aniline or alkyl substituted or disubstituted anilines. Also, other derivatives of the above are formed by nucleophilic displacement reactions.

Substituted 1,1,1-Triaryl-2,2,2-Trifluoroethanes and Processes for their Synthesis

NASA Technical Reports Server (NTRS)

Alston, William B. (Inventor); Gratz, Roy F. (Inventor)

1999-01-01

Synthetic procedures to tetraalkyls. tetraacids and dianhydrides substituted 1,1,1-triaryl-2,2,2-trifluoroethanes which comprises: (1) 1.1-bis(dialkylaryl)-1-aryl-2,2,2 -trifluoroethane, (2) 1,1-bis(dicarboxyaryl)-1-aryl-2.2,2- trifluoroethane or (3) cyclic dianhydride or diamine of 1,1-bis(dialkylaryl)-1-aryl-2,2,2- trifluoroethanes. The synthesis of (1) is accomplished by the condensation reaction of an aryltrifluoromethyl ketone with a dialkylaryl compound. The synthesis of (2) is accomplished by oxidation of (1). The synthesis dianhydride of (3) is accomplished by the conversion of (2) to its corresponding cyclic dianhydride. The synthesis of the diamine is accomplished by the similar reaction of an aryltrifluoromethyl ketone with aniline or alkyl substituted or disubstituted anihnes. Also, other derivatives of the above are formed by nucleophilic displacement reactions.

Substituted 1,1,1-triaryl-2,2,2-trifluoroethanes and processes for their synthesis

NASA Technical Reports Server (NTRS)

Alston, William B. (Inventor); Gratz, Roy F. (Inventor)

1989-01-01

Synthetic procedures are disclosed for tetraalkyls, tetraacids, and dianhydrides substituted 1,1,1-triaryl 2,2,2-trifluoroethanes which comprises: (1) 1,1-bis (dialkylaryl) 1-aryl 2,2,2-trifluoroethane, (2) 1,1-bis (dicarboxyaryl) 1-aryl 2,2,2-trifluoroethane, or (3) cyclic dianhydride or diamine of 1,1-bis (dialkylaryl) 1-aryl 2,2,2-trifluoroethanes. The synthesis of (1) is accomplished by the condensation reaction of an aryltrifluoromethyl ketone with a dialkylaryl compound. The synthesis of (2) is accomplished by the oxidation of (1). The synthesis dianhydride of (3) is accomplished by the conversion of (2) to its corresponding cyclic dianhydride. The synthesis of the diamine is accomplished by the similar reaction of an aryltrifluoromethyl ketone with aniline or aklyl substituted or disubstituted anilines. Also, other derivatives of the above are formed by nucleophilic displacement reactions.

Substituted 1,1,1-triaryl 2,2,2-trifluoroethanes and processes for their synthesis

NASA Technical Reports Server (NTRS)

Alston, William B. (Inventor); Gratz, Roy F. (Inventor)

1992-01-01

Synthetic procedures to tetraalkyls, tetraacids, and dianhydrides substituted 1,1,1-triaryl 2,2,2-trifluoroethanes which comprises: (1) 1,1-bis(dialkylaryl) 1-aryl-2,2,2-trifluoroethane, (2) 1,1-bis(dicarboxyaryl) 1-aryl-2,2,2-trifluoroethane, or (3) cyclic dianhydride or diamine of 1,1-bis(dialkylaryl) 1-aryl-2,2,2-trifluoroethanes. The synthesis of (1) is accomplished by the condensation reaction of an aryltrifluoromethyl ketone with a dialkylaryl compound. The synthesis of (2) is accomplished by oxidation of (1). The synthesis dianhydride of (3) is accomplished by the conversion of (2) to its corresponding cyclic dianhydride. The synthesis of the diamine is accomplished by the similar reaction of an aryltrifluoromethyl ketone with aniline or alkyl substituted or disubstituted anilines. Also, other derivatives of the above are formed by nucleophilic displacement reactions.

Chemical basis for the phytotoxicity of N-aryl hydroxamic acids and acetanilide analogues.

PubMed

Bravo, Héctor R; Villarroel, Elisa; Copaja, Sylvia V; Argandoña, Victor H

2008-01-01

Germination inhibition activity of N-aryl hydroxamic acids and acetanilide analogues was measured on lettuce seeds (Lactuca sativa). Lipophilicity of the compounds was determined by HPLC. A correlation between lipophilicity values and percentage of germination inhibition was established. A model mechanism of action for auxin was used for analyzing the effect of the substituent at the alpha carbon atom (Ca) on the polarization of hydroxamic and amide functions in relation to the germination inhibition activity observed. Results suggest that the lipophilic and acidic properties play an important role in the phytotoxicity of the compounds. A test with the microalga Chlorella vulgaris was used to evaluate the potential herbicide activity of the hydroxamic acids and acetanilides.

Menthone aryl acid hydrazones: a new class of anticonvulsants.

PubMed

Jain, Jainendra; Kumar, Y; Sinha, Reema; Kumar, Rajeev; Stables, James

2011-01-01

A series of ten compounds (Compounds J(1)-J(10)) of (±) 3-menthone aryl acid hydrazone was synthesized and characterized by thin layer chromatography and spectral analysis. Synthesized compounds were evaluated for anticonvulsant activity after intraperitoneal (i.p) administration to mice by maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure method and minimal clonic seizure test. Minimal motor impairment was also determined for these compounds. Results obtained showed that four compounds out of ten afforded significant protection in the minimal clonic seizure screen at 6 Hz. Compound J(6), 4-Chloro-N-(2-isopropyl-5-methylcyclohexylidene) benzohydrazide was found to be the most active compound with MES ED(50) of 16.1 mg/kg and protective index (pI) of greater than 20, indicating that (±) 3-menthone aryl acid hydrazone possesses better and safer anticonvulsant properties than other reported menthone derivatives viz. menthone Schiff bases, menthone semicarbazides and thiosemicarbazides.

Synthesis, structural, optical and thermal properties of N-methyl-N-aryl benzamide organic single crystals grown by a slow evaporation technique

NASA Astrophysics Data System (ADS)

Prabukanthan, P.; Lakshmi, R.; Harichandran, G.; Kumar, C. Sudarsana

2018-03-01

The organic materials, N-methyl-N-aryl benzamides were synthesized from benzoylation of N-methyl-4-nitrobenzenamine (MNBA) using suitably substituted benzoyl chlorides. The products were purified by recrystallization and their single crystal were grown by a slow evaporation technique. The crystals were characterized by FTIR, UV-Vis-NIR, 1H &13C NMR, and single & powder X-ray diffraction. Thermal stability of the crystals was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Dielectric and NLO properties of MNPB, FMNPB and MMNPB crystals were studied. The second harmonic generation (SHG) has been confirmed by the Kurtz powder test for all these crystals and the SHG efficiency of MMNPB crystal was found to be 2.25 times higher than that of KDP crystal.

Synthesis of substituted pyrazines

DOEpatents

Pagoria, Philip F.; Zhang, Mao Xi

2016-10-04

A method for synthesizing a pyrazine-containing material according to one embodiment includes contacting an iminodiacetonitrile derivative with a base and a reagent selected from a group consisting of hydroxylamine, a hydroxylamine salt, an aliphatic primary amine, a secondary amine, an aryl-substituted alkylamine a heteroaryl-substituted alkyl amine, an alcohol, an alkanolamine and an aryl alcoholamine. Additional methods and several reaction products are presented. ##STR00001##

N-aryl pyrrolo-tetrathiafulvalene based ligands: synthesis and metal coordination.

PubMed

Balandier, Jean-Yves; Chas, Marcos; Dron, Paul I; Goeb, Sébastien; Canevet, David; Belyasmine, Ahmed; Allain, Magali; Sallé, Marc

2010-03-05

A straightforward general synthetic access to N-aryl-1,3-dithiolo[4,5-c]pyrrole-2-thione derivatives 6 from acetylenedicarbaldehyde monoacetal is depicted. In addition to their potentiality as precursors to dithioalkyl-pyrrole derivatives, thiones 6 are key building blocks to N-aryl monopyrrolo-tetrathiafulvalene (MPTTF) derivatives 10. X-ray structures of four of these thiones intermediates, reminiscent of the corresponding MPTTF derivatives, are provided. When the aryl group is a binding pyridyl unit, the MPTTF derivative 10a can coordinate M(II) salts (M = Pt, Pd). The first examples of metal-directed orthogonal MPTTF-based dimers 11-14, obtained through coordination of 10a to cis-blocked square planar Pt or Pd complexes are described. Studies on the parameters influencing the dimer construction are presented, as well as first recognition properties of the resulting electron-rich clip for C(60).

A new route to synthesize aryl acetates from carbonylation of aryl methyl ethers

PubMed Central

Yang, Youdi; Li, Shaopeng; Han, Buxing

2018-01-01

Ether bond activation is very interesting because the synthesis of many valuable compounds involves conversion of ethers. Moreover, C–O bond cleavage is also very important for the transformation of biomass, especially lignin, which abundantly contains ether bonds. Developing efficient methods to activate aromatic ether bonds has attracted much attention. However, this is a challenge because of the inertness of aryl ether bonds. We proposed a new route to activate aryl methyl ether bonds and synthesize aryl acetates by carbonylation of aryl methyl ethers. The reaction could proceed over RhCl3 in the presence of LiI and LiBF4, and moderate to high yields of aryl acetates could be obtained from transformation of various aryl methyl ethers with different substituents. It was found that LiBF4 could assist LiI to cleave aryl methyl ether bonds effectively. The reaction mechanism was proposed by a combination of experimental and theoretical studies. PMID:29795781

Synthesis Of [2h, 13c] And [2h3, 13c]Methyl Aryl Sulfides

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

2004-03-30

The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2,.sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms. The present invention is also directed to the labeled compounds of [.sup.2 H.sub.1, .sup.13 C]methyl iodide and [.sup.2 H.sub.2, .sup.13 C]methyl iodide.

Synthesis of enyne and aryl vinyl sulfoxides: functionalization via Pummerer rearrangement.

PubMed

Souza, Frederico B; Shamim, Anwar; Argomedo, Luiz M Z; Pimenta, Daniel C; Stefani, Hélio A

2015-11-01

An efficient methodology for the synthesis of aryl-substituted vinyl sulfoxides through direct substitution of aryl-substituted alkynyl grignard reagents on menthyl-p-toluenesulfinate followed by Suzuki-Miyaura cross-coupling reaction has been developed. It has also been described that the reaction of alkyl-substituted and cycloalkyl-substituted alkynyl grignard reagents with menthyl-p-toluenesulfinate led to two products, i.e., alkynyl sulfoxide derivatives, as a result of substitution, and enyne sulfoxide derivatives, which resulted from substitution followed by Michael type addition. It was possible to selectively synthesize the enyne sulfoxide derivatives by changing the concentration of the grignard reagent. These alkenyl sulfoxides were transformed into the corresponding [Formula: see text]-thio aldehydes in high yields via additive Pummerer rearrangement.

Reaction of singlet-excited 2,3-diazabicyclo[2.2.2]oct-2-ene and tert-butoxyl radicals with aryl-substituted benzofuranones.

PubMed

Lundgren, Cecilia Vannesjö; Koner, Apurba L; Tinkl, Michael; Pischel, Uwe; Nau, Werner M

2006-03-03

5,7-Di-tert-butyl-3-aryl-3H-benzofuran-2-ones are lactones with potential antioxidant activity, owing to their abstractable benzylic C-H hydrogens. The fluorescence quenching of the azoalkane 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO), an established probe for the hydrogen-donor propensity of chain-breaking antioxidants, was investigated for 16 aryl-substituted benzofuranone derivatives [m,m-(CF3)2, p-CN, m-CN, p-CF3, p-COOCH3, m-CF3, p-Cl, p-F, H, m-CH3, p-CH3, m,p-(CH3)2, p-OCH3, o-CH3, o-CF3, o,m-(CH3)2]. Analysis of the rate data in terms of a linear free energy relationship yielded a reaction constant of rho = +0.35. This implies that n,pi*-excited DBO acts as nucleophilic species. In contrast, hydrogen abstraction of tert-butoxyl radicals from the benzofuranones was accelerated by electron-donating substituents (rho = -0.23), in conformity with the electrophilic character of oxygen-centered alkoxyl radicals. Possible implications for the optimization of the hydrogen-donor propensity of antioxidants through structural variation are discussed.

Identification of 1-Aryl-1H-1,2,3-triazoles as Potential New Antiretroviral Agents.

PubMed

Gonzaga, Daniel T G; Souza, Thiago M L; Andrade, Viviane M M; Ferreira, Vitor F; de C da Silva, Fernando

2018-01-01

Low molecular weight 1-Aryl-1H-1,2,3-triazoles are endowed with various types of biological activities, such as against cancer, HIV and bacteria. Despite the existence of six different classes of antiretroviral drugs in clinical use, HIV/AIDS continue to be an on growing public health problem. In the present study, we synthesized and evaluated thirty 1-Aryl-1H-1,2,3-triazoles against HIV replication. The compounds were prepared by Huisgen 1,3-dipolar cycloaddition protocol catalyzed by Cu(I) between aryl azides and propargylic alcohol followed by further esterification and etherification from a nucleophilic substitution with acid chlorides or alkyl bromides in good yields. The compounds were submitted to the inhibition of HIV replication and evaluation of their cytotoxicity. Initially, the compounds were screened at 10 µM and the most active were further evaluated in order to obtain some pharmacological parameters. Thirty molecules were evaluated, six were selected - because they inhibited more than 80% HIV replication. We further showed that two of these compounds are 8-times more potent, and less cytotoxic, than nevirapine, an antiretroviral drug in clinical use. We identified very simple triazoles with promissing antiretroviral activities that led to the development of new drugs against AIDS. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Synthesis of [.sup.13C] and [.sup.2H] substituted methacrylic acid, [.sup.13C] and [.sup.2H] substituted methyl methacrylate and/or related compounds

DOEpatents

Alvarez, Marc A.; Martinez, Rodolfo A.; Unkefer, Clifford J.

2010-02-16

The present invention is directed to labeled compounds of the formulae ##STR00001## wherein Q is selected from the group consisting of --S(.dbd.O)--, and --S(.dbd.O).sub.2--, Z is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group selected from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each independently selected from the group consisting of a C.sub.1-C.sub.4 lower alkyl, an aryl, and an alkoxy group, and X is selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl group, and a fully-deuterated C.sub.1-C.sub.4 lower alkyl group.

Copper(II)-catalyzed enantioselective hydrosilylation of halo-substituted alkyl aryl and heteroaryl ketones: asymmetric synthesis of (R)-fluoxetine and (S)-duloxetine.

PubMed

Zhou, Ji-Ning; Fang, Qiang; Hu, Yi-Hu; Yang, Li-Yao; Wu, Fei-Fei; Xie, Lin-Jie; Wu, Jing; Li, Shijun

2014-02-14

A set of reaction conditions has been established to facilitate the non-precious copper-catalyzed enantioselective hydrosilylation of a number of structurally diverse β-, γ- or ε-halo-substituted alkyl aryl ketones and α-, β- or γ-halo-substituted alkyl heteroaryl ketones under air to afford a broad spectrum of halo alcohols in high yields and good to excellent enantioselectivities (up to 99% ee). The developed procedure has been successfully applied to the asymmetric synthesis of antidepressant drugs (R)-fluoxetine and (S)-duloxetine, which highlighted its synthetic utility.

Synthesis of novel antimicrobial aryl himachalene derivatives from naturally occurring himachalenes

PubMed Central

Chaudhary, Abha; Sood, Swati; Das, Pralay; Kaur, Pushpinder; Mahajan, Isha; Gulati, Arvind; Singh, Bikram

2014-01-01

Five new 2,9,9-trimethyl-6,7,8,9-tetrahydro-benzocyclohepten-5-ylidene-amine derivatives (16a-16e) were synthesized from α-dehydro-ar-himachalene (11) that was originally prepared from an isomeric mixture of α, β and γ himachalenes (10), the abundant sesquiterpenes of Cedrus deodara essential oil. In addition, different aryl himachalenes derivatives (9, 12, 14 and 15) were also formed from 11. The structures of the synthesized compounds were confirmed on the basis of their NMR, IR and mass spectral data. The prepared compounds were tested against a group of sixteen organisms including gram positive and gram negative bacterial and fungal strains. The introduction of a series of substituted imine groups into aryl himachalenes at 5th position (16a-16e) enhanced antimicrobial activity as compared to the aromatized derivatives (9, 12, 14 and 15) against gram-positive bacteria Bacillus subtilis, Micrococcus luteus and Staphylococcus aureus, and mycotoxigenic fungi Aspergillus parasiticus, A. ochraceous and A. sydowii. graphical Abstract, Figure 1(Fig. 1) PMID:26417335

2-Aryl-2-nitroacetates as Central Precursors to Aryl Nitromethanes, α-Ketoesters, and α-Amino Acids

PubMed Central

Metz, Alison E.

2013-01-01

Nitroarylacetates are useful small molecular building blocks that act as precursors to α-ketoesters and aryl nitromethanes as well as α-amino acids. Methods were developed that produce each of these compound types in good yields. Two different conditions for decarboxylation are discussed for substrates with neutral and electron-poor aryl groups versus electron-rich aryl groups. For formation of the α-ketoesters, new mild conditions for the Nef disproportionation were identified. PMID:23245626

Synthesis Of [2h, 13c]M [2h2m 13c], And [2h3,, 13c] Methyl Aryl Sulfones And Sulfoxides

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.; Schmidt, Jurgen G.

2004-07-20

The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfones and [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfoxides, wherein the .sup.13 C methyl group attached to the sulfur of the sulfone or sulfoxide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing methyl aryl sulfones and methyl aryl sulfoxides.

Crystal structures of five 1-alkyl-4-aryl-1,2,4-triazol-1-ium halide salts.

PubMed

Guino-O, Marites A; Talbot, Meghan O; Slitts, Michael M; Pham, Theresa N; Audi, Maya C; Janzen, Daron E

2015-06-01

The asymmetric units for the salts 4-(4-fluoro-phen-yl)-1-isopropyl-1,2,4-triazol-1-ium iodide, C11H13FN3 (+)·I(-), (1), 1-isopropyl-4-(4-methyl-phen-yl)-1,2,4-triazol-1-ium iodide, C12H16N3 (+)·I(-), (2), 1-isopropyl-4-phenyl-1,2,4-triazol-1-ium iodide, C11H14N3 (+)·I(-), (3), and 1-methyl-4-phenyl-1,2,4-triazol-1-ium iodide, C9H10N3 (+)·I(-), (4), contain one cation and one iodide ion, whereas in 1-benzyl-4-phenyl-1,2,4-triazol-1-ium bromide monohydrate, C15H14N3 (+)·Br(-)·H2O, (5), there is an additional single water mol-ecule. There is a predominant C-H⋯X(halide) inter-action for all salts, resulting in a two-dimensional extended sheet network between the triazolium cation and the halide ions. For salts with para-substitution on the aryl ring, there is an additional π-anion inter-action between a triazolium carbon and iodide displayed by the layers. For salts without the para-substitution on the aryl ring, the π-π inter-actions are between the triazolium and aryl rings. The melting points of these salts agree with the predicted substituent inductive effects.

Room-temperature chromium(II)-catalyzed direct arylation of pyridines, aryl oxazolines, and imines using arylmagnesium reagents.

PubMed

Kuzmina, Olesya M; Knochel, Paul

2014-10-03

We report a CrCl2-catalyzed oxidative arylation of various pyridines, aryl oxazolines, and aryl imines using aromatic Grignard reagents in the presence of 2,3-dichlorobutane (DCB). Most of the reactions proceed rapidly at 25 °C and do not require any additional ligand. Benzo[h]quinoline, 2-arylpyridine, aryl oxazoline, and imines were successfully arylated in good yields under these conditions. A TMS-substituent was used to prevent double arylation. After oxidative cross-coupling the TMS-group was further converted to a second ortho-aryl substituent. Remarkably, inexpensive aryl N-butylimine derivatives are excellent substrates for this oxidative arylation.

Synthesis of oxazolines and oxazines

DOEpatents

Benicewicz, Brian C.; Mitchell, Michael A.

1995-01-01

A process of preparing an oxazoline or oxazine compound of the formula ##STR1## wherein X is an atom selected from the group of oxygen and sulfur, R is selected from the group consisting of C.sub.1-10 alkyl, C.sub.1-10 fluoroalkyl, aryl and substituted-aryl, and n is 2 or 3 comprising ring-closing a compound of the formula ##STR2## wherein X is an atom selected from the group of oxygen and sulfur, R is selected from the group consisting of C.sub.1-10 alkyl, C.sub.1-10 fluoroalkyl, aryl, and substituted aryl, n is 2 or 3, and Y is a bromine or chlorine atom in the presence of a basic reagent consisting essentially of a fluoride salt supported on an inorganic solid substrate is disclosed together with the compounds, 5-bromomethyl-2-phenyl-1,3-oxazoline, 5-methylene-2-phenyl-1,3-oxazine and 4,4-dimethyl-2-vinyl-1,3-oxazoline.

Syntheses, structures and magnetisms of copper(II)–azido coordination compounds with p-substituted benzoates as coligands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Cuiyu; Yu, Nan; Bu, Huaitian

2016-01-15

Employing p-substituted benzoates with electron-withdrawing/electron-donating groups as coligands, four copper–azido compounds, [Cu{sub 1.5}(p-NO{sub 2}-benzoate)(N{sub 3}){sub 2}(H{sub 2}O)]{sub n} (1), [Cu(p-NO{sub 2}-benzoate)(N{sub 3})(H{sub 2}O)]{sub n} (2), [Cu(p-OH-benzoate)(N{sub 3})(H{sub 2}O)]{sub n}·nH{sub 2}O (3) and [Cu(p-CH{sub 3}-benzoate)(N{sub 3})]{sub n} (4), have been hydrothermally synthesized and structurally charactierized by single crystal X-ray diffraction. Structural analysis reveals that all compounds are composed of mixed EO-azido and syn–syn carboxylato-bridged Cu-N{sub 3}/COO chains. Compound 1 features the alternating triple-bridged (μ-EO-N{sub 3})(μ-COO)(μ-H{sub 2}O) and the double-bridged (EO-N{sub 3}){sub 2} modes. Both of 2 and 3 display the triple-bridged fashion (μ-EO-N{sub 3})(μ-COO)(μ-H{sub 2}O). While 4 exhibits the double-bridged modemore » (μ-EO-N{sub 3})(μ-COO). Based on hydrogen-bonding interactions, Cu–N{sub 3}/COO chains in 1–3 are further connected to form 3D supramolecular frameworks. As for compound 4, there are not hydrogen-bonding interactions when the p-CH{sub 3} substituted benzoate is employed as coligand. These compounds show intrachain ferromagnetic performance and different bulk properties. Remarkably, 1 features metamagnetism from antiferromagnetism to ferrimagnetism, while 3 reveals long-range ferromagnetic ordering between Cu(II) ions. Magneto-structural correlation has been also investigated. - Graphical abstract: With p-substituted benzoates as coligands, copper–azido compounds were isolated and structrually, magnetically characterized. Magneto-structural correlation has been investigated in detail.« less

N-heterocycle carbene (NHC)-ligated cyclopalladated N,N-dimethylbenzylamine: a highly active, practical and versatile catalyst for the Heck-Mizoroki reaction.

PubMed

Peh, Guang-Rong; Kantchev, Eric Assen B; Zhang, Chi; Ying, Jackie Y

2009-05-21

The wide dissemination of catalytic protocols in academic and industrial laboratories is facilitated by the development of catalysts that are not only highly active but also user-friendly, stable to moisture, air and long term storage and easy to prepare on a large scale. Herein we describe a protocol for the Heck-Mizoroki reaction mediated by cyclopalladated N,N-dimethylbenzylamine (dmba) ligated with a N-heterocyclic carbene, 1,3-bis(mesityl)imidazol-2-ylidene (IMes), that fulfils these criteria. The precatalyst can be synthesized on approximately 100 g scale by a tri-component, sequential, one-pot reaction of N,N-dimethylbenzylamine, PdCl2 and IMes.HCl in refluxing acetonitrile in air in the presence of K2CO3. This single component catalyst is stable to air, moisture and long term storage and can be conveniently dispensed as a stock solution in NMP. It mediates the Heck-Mizoroki reaction of a range of aryl- and heteroaryl bromides in reagent grade NMP at the 0.1-2 mol% range without the need for rigorous anhydrous techniques or a glovebox, and is active even in air. The catalyst is capable of achieving very high levels of catalytic activity (TON of up to 5.22 x 10(5)) for the coupling of a deactivated arylbromide, p-bromoanisole, with tBu acrylate as a benchmark substrate pair. A wide range of aryl bromides, iodides and, for the first time with a NHC-Pd catalyst, a triflate was coupled with diverse acrylate derivatives (nitrile, tert-butyl ester and amides) and styrene derivatives. The use of excess (>2 equiv.) of the aryl bromide and tert-butyl acrylate leads to mixture of tert-butyl beta,beta-diarylacrylate and tert-butyl cinnamate derivatives depending on the substitution pattern of the aryl bromide. Electron rich m- and p-substituted arylbromides give the diarylated products exclusively, whereas electron-poor aryl bromides give predominantly mono-arylated products. For o-substituted aryl bromides, no doubly arylated products could be obtained under any

The photocatalyzed Meerwein arylation: classic reaction of aryl diazonium salts in a new light.

PubMed

Hari, Durga Prasad; König, Burkhard

2013-04-26

The use of diazonium salts for aryl radical generation and C-H arylation processes has been known since 1896 when Pschorr first used the reaction for intramolecular cyclizations. Meerwein developed it further in the early 1900s into a general arylation method. However, this reaction could not compete with the transition-metal-mediated formation of C(sp(2))-C(sp(2)) bonds. The replacement of the copper catalyst with iron and titanium compounds improved the situation, but the use of photocatalysis to induce the one-electron reduction and activation of the diazonium salts is even more advantageous. The first photocatalyzed Pschorr cyclization was published in 1984, and just last year a series of papers described applications of photocatalytic Meerwein arylations leading to aryl-alkene coupling products. In this Minireview we summarize the origins of this reaction and its scope and applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Anti-cancer agents based on N-acyl-2, 3-dihydro-1H-pyrrolo[2,3-b] quinoline derivatives and a method of making

DOEpatents

Gakh, Andrei; Krasavin, Mikhail; Karapetian, Ruben; Rufanov, Konstantin A; Konstantinov, Igor; Godovykh, Elena; Soldatkina, Olga; Sosnov, Andrey V

2013-04-16

The present disclosure relates to novel compounds that can be used as anti-cancer agents in the prostate cancer therapy. In particular, the invention relates to N-acyl derivatives of 2,3-dihydro-1H-pyrrolo[2,3-b]quinolines having the structural Formula (I), ##STR00001## stereoisomers, tautomers, racemics, prodrugs, metabolites thereof, or pharmaceutically acceptable salt and/or solvate thereof. The meaning of R1 is independently selected from H; C1-C6 Alkyl, cyclo-Alkyl or iso-Alkyl substituents; R2 is selected from C1-C6 Alkyl, cyclo-Alkyl or iso-Alkyl; substituted or non-substituted, fused or non-fused to substituted or non-substituted aromatic ring, aryl or heteroaryl groups. The invention also relates to methods for preparing said compounds, and to pharmaceutical compositions comprising said compounds.

Novel quinazoline ring synthesis by cycloaddition of N-arylketenimines with N,N-disubstituted cyanamides.

PubMed

Shimizu, Masao; Oishi, Akihiro; Taguchi, Yoichi; Gama, Yasuo; Shibuya, Isao

2002-03-01

The reaction of N-aryl-substituted ketenimines with N,N-disubstituted cyanamides or (MeS)2C=N-CN under high pressure afforded 4-(N,N-disubstituted amino) or 4-(MeS)2C=N-substituted quinazoline derivatives, respectively. These products were formed by [4+2] cycloaddition between the aza-diene moieties of the N-arylsubstituted ketenimines and cyano groups. A 4-(unsubstituted amino)quinazoline derivative was synthesized by hydrolysis of the latter product.

Complete inhibition of anisomycin and UV radiation but not cytokine induced JNK and p38 activation by an aryl-substituted dihydropyrrolopyrazole quinoline and mixed lineage kinase 7 small interfering RNA.

PubMed

Wang, Xushan; Mader, Mary M; Toth, John E; Yu, Xiaohong; Jin, Najia; Campbell, Robert M; Smallwood, Jeffrey K; Christe, Michael E; Chatterjee, Arindam; Goodson, Theodore; Vlahos, Chris J; Matter, William F; Bloem, Laura J

2005-05-13

Mixed lineage kinase 7 (MLK7) is a mitogen-activated protein kinase kinase kinase (MAPKKK) that activates the pro-apoptotic signaling pathways p38 and JNK. A library of potential kinase inhibitors was screened, and a series of dihydropyrrolopyrazole quinolines was identified as highly potent inhibitors of MLK7 in vitro catalytic activity. Of this series, an aryl-substituted dihydropyrrolopyrazole quinoline (DHP-2) demonstrated an IC50 of 70 nM for inhibition of pJNK formation in COS-7 cell MLK7/JNK co-transfection assays. In stimulated cells, DHP-2 at 200 nM or MLK7 small interfering RNA completely blocked anisomycin and UV induced but had no effect on interleukin-1beta or tumor necrosis factor-alpha-induced p38 and JNK activation. Additionally, the compound blocked anisomycin and UV-induced apoptosis in COS-7 cells. Heart tissue homogenates from MLK7 transgenic mice treated with DHP-2 at 30 mg/kg had reduced JNK and p38 activation with no apparent effect on ERK activation, demonstrating that this compound can be used to block MLK7-driven MAPK pathway activation in vivo. Taken together, these data demonstrate that MLK7 is the MAPKKK required for modulation of the stress-activated MAPKs downstream of anisomycin and UV stimulation and that DHP-2 can be used to block MLK7 pathway activation in cells as well as in vivo.

Synthesis and evaluation of the NSCLC anti-cancer activity and physical properties of 4-aryl-N-phenylpyrimidin-2-amines.

PubMed

Toviwek, Borvornwat; Suphakun, Praphasri; Choowongkomon, Kiattawee; Hannongbua, Supa; Gleeson, M Paul

2017-10-15

Reported herein are efforts to profile 4-aryl-N-phenylpyrimidin-2-amines in terms of their anti-cancer activity towards non small-cell lung carcinoma (NSCLC) cells. We have synthesized new 4-aryl-N-phenylpyrimidin-2-amines and assessed them in terms of their cytotoxicity (A549, NCI-H187, MCF7, Vero & KB) and physicochemical properties (logD 7.4 and solubility). 13f and 13c demonstrated potent anti-cancer activity in A549 cells (0.2µM), compared to 0.4μM for the NSCLC drug Doxorubicin. 13f also displayed low experimental logD 7.4 (2.9) and the best solubility (∼40μM). Compounds 13b and 13d showed the best balance of A549 anti-cancer activity and selectivity. 13g showed good activity and selectivity comparable with the anti-cancer drug Doxorubicin. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis and antifungal activities of 3-alkyl substituted thieno[2,3-d]pyrimidinones

NASA Astrophysics Data System (ADS)

Wang, H. M.; Deng, S. H.; Zheng, A. H.; Zhang, Q. Y.; Chen, X. B.; Zeng, X. H.; Hu, Y. G.

2016-08-01

The 3-aryl substituted thieno[2,3-d]pyrimidinones 3 by sequential reaction of iminophosphorane 1, aromatic isocyanates and various nucleophiles (HY), found some compounds showed good antitumor and antibacterial activities. Meanwhile, aliphatic isocyanates were applied in the reaction to prepare 3-alkyl substituted thieno[2,3- d]pyrimidinones, but there are no reports of their antifungal activities. As a continuation of our research for new biologically active heterocycles, we herein wish to report a facile synthesis and antifungal activities of 3-alkyl substituted thieno[2,3-d]pyrimidinones 6 via easily accessible iminophosphorane 1. The growth inhibitory effect of one concentration (50mg/L) of compounds 6 against five fungus(Fusarium oxysporium, Rhizoctonia solani, Colletotrichum gossypii, Gibberella zeae and Dothiorella gregaria) in vitro was tested by the method of toxic medium. Compound 6d showed the best inhibition rate against Gibberella zeae with 85.68%.

Crystal structures of five 1-alkyl-4-aryl-1,2,4-triazol-1-ium halide salts

PubMed Central

Guino-o, Marites A.; Talbot, Meghan O.; Slitts, Michael M.; Pham, Theresa N.; Audi, Maya C.; Janzen, Daron E.

2015-01-01

The asymmetric units for the salts 4-(4-fluoro­phen­yl)-1-isopropyl-1,2,4-triazol-1-ium iodide, C11H13FN3 +·I−, (1), 1-isopropyl-4-(4-methyl­phen­yl)-1,2,4-triazol-1-ium iodide, C12H16N3 +·I−, (2), 1-isopropyl-4-phenyl-1,2,4-triazol-1-ium iodide, C11H14N3 +·I−, (3), and 1-methyl-4-phenyl-1,2,4-triazol-1-ium iodide, C9H10N3 +·I−, (4), contain one cation and one iodide ion, whereas in 1-benzyl-4-phenyl-1,2,4-triazol-1-ium bromide monohydrate, C15H14N3 +·Br−·H2O, (5), there is an additional single water mol­ecule. There is a predominant C—H⋯X(halide) inter­action for all salts, resulting in a two-dimensional extended sheet network between the triazolium cation and the halide ions. For salts with para-substitution on the aryl ring, there is an additional π–anion inter­action between a triazolium carbon and iodide displayed by the layers. For salts without the para-substitution on the aryl ring, the π–π inter­actions are between the triazolium and aryl rings. The melting points of these salts agree with the predicted substituent inductive effects. PMID:26090137

Synthesis and electronic structure determination of N-alkyl-substituted bis(imino)pyridine iron imides exhibiting spin crossover behavior.

PubMed

Bowman, Amanda C; Milsmann, Carsten; Bill, Eckhard; Turner, Zoë R; Lobkovsky, Emil; DeBeer, Serena; Wieghardt, Karl; Chirik, Paul J

2011-11-02

Three new N-alkyl substituted bis(imino)pyridine iron imide complexes, ((iPr)PDI)FeNR ((iPr)PDI = 2,6-(2,6-(i)Pr(2)-C(6)H(3)-N═CMe)(2)C(5)H(3)N; R = 1-adamantyl ((1)Ad), cyclooctyl ((Cy)Oct), and 2-adamantyl ((2)Ad)) were synthesized by addition of the appropriate alkyl azide to the iron bis(dinitrogen) complex, ((iPr)PDI)Fe(N(2))(2). SQUID magnetic measurements on the isomeric iron imides, ((iPr)PDI)FeN(1)Ad and ((iPr)PDI)FeN(2)Ad, established spin crossover behavior with the latter example having a more complete spin transition in the experimentally accessible temperature range. X-ray diffraction on all three alkyl-substituted bis(imino)pyridine iron imides established essentially planar compounds with relatively short Fe-N(imide) bond lengths and two-electron reduction of the redox-active bis(imino)pyridine chelate. Zero- and applied-field Mössbauer spectroscopic measurements indicate diamagnetic ground states at cryogenic temperatures and established low isomer shifts consistent with highly covalent molecules. For ((iPr)PDI)FeN(2)Ad, Mössbauer spectroscopy also supports spin crossover behavior and allowed extraction of thermodynamic parameters for the S = 0 to S = 1 transition. X-ray absorption spectroscopy and computational studies were also performed to explore the electronic structure of the bis(imino)pyridine alkyl-substituted imides. An electronic structure description with a low spin ferric center (S = 1/2) antiferromagnetically coupled to an imidyl radical (S(imide) = 1/2) and a closed-shell, dianionic bis(imino)pyridine chelate (S(PDI) = 0) is favored for the S = 0 state. An iron-centered spin transition to an intermediate spin ferric ion (S(Fe) = 3/2) accounts for the S = 1 state observed at higher temperatures. Other possibilities based on the computational and experimental data are also evaluated and compared to the electronic structure of the bis(imino)pyridine iron N-aryl imide counterparts.

Synthesis of new 2-substituted pyrido[2,3-d]pyrimidin-4(1H)-ones and their antibacterial activity.

PubMed

Lakshmi Narayana, B; Ram Rao, A Raghu; Shanthan Rao, P

2009-03-01

2-Substituted-5,7-dimethyl pyrido[2,3-d]pyrimidin-4(1H)-ones (8) were synthesized by oxidation of 2-substituted-5,7-dimethyl dihydropyrido[2,3-d]pyrimidin-4(1H)-ones (7) which were in turn prepared from 2-amino-4,6-dimethyl nicotinamide (5) and substituted aryl aldehydes (6). 2-Amino-4,6-dimethyl nicotinamide (5) was prepared from ethyl cyanoacetate (1) via malonamamidine hydrochloride (3). The compounds were characterized by IR, NMR, MS and elemental analyses. Compounds 7 and 8 were screened for antibacterial activity against gram positive and gram negative bacteria. Dehydrogenated compounds (8) showed less antibacterial activity than the compounds 7. Among all the test compounds screened for antibacterial activity 7c (1.25 microg/ml) showed greater activity. All the synthesized compounds were found inactive when screened for antifungal activity at the concentration of 200 microg/ml.

Tunable Cascade Reaction of Aryl Diazonium Salts and Trialkylamine: Synthesis of Monofluorinated Arylhydrazones and gem-Difluorinated Azo Compounds.

PubMed

Guo, Rui; Zhang, Zhengjuan; Shi, Feng; Tang, Pingping

2016-03-04

The first example of a mild and tunable cascade reaction of aryl diazonium salts and trialkylamine in the presence of Selectfluor to prepare monofluorinated arylhydrazones and gem-difluorinated azo compounds without metal has been explored. In the presence of H2O, the monofluorinated arylhydrazones were observed in moderate to good yield. In the absence of H2O, the gem-difluorinated azo compounds were obtained. The fluorinated arylhydrazones were utilized to synthesize fluorinated pyrazoles and other nitrogen-containing compounds.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chichak, Kelly Scott; Liu, Jie Jerry; Shiang, Joseph John

Optoelectronic devices with enhanced internal outcoupling include a substrate, an anode, a cathode, an electroluminescent layer, and electron transporting layer comprising a fluoro compound of formula I (Ar.sup.2).sub.n--Ar.sup.1--(Ar.sup.2).sub.n I wherein Ar.sup.1 is C.sub.5-C.sub.40 aryl, C.sub.5-C.sub.40 substituted aryl, C.sub.5-C.sub.40 heteroaryl, or C.sub.5-C.sub.40 substituted heteroaryl; Ar.sup.2 is, independently at each occurrence, fluoro- or fluoroalkyl-substituted C.sub.5-40 heteroaryl; and n is 1, 2, or 3.

AN EFFICIENT AQUEOUS N-HETEROCYCLIZATION OF ANILINE DERIVATIVES: MICROWAVE-ASSISTED SYNTHESIS OF N-ARYL AZACYCLOALKANES

EPA Science Inventory

N-aryl azacycloalkanes, an important class of building blocks in natural product and pharmaceuticals, are synthesized via an efficient and simple eco-friendly protocol that involves double N-alkylation of aniline derivatives. The reaction is accelerated by exposure to microwaves ...

Structural optimization of N1-aryl-benzimidazoles for the discovery of new non-nucleoside reverse transcriptase inhibitors active against wild-type and mutant HIV-1 strains.

PubMed

Monforte, Anna Maria; De Luca, Laura; Buemi, Maria Rosa; Agharbaoui, Fatima E; Pannecouque, Christophe; Ferro, Stefania

2018-02-01

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are recommended components of preferred combination antiretroviral therapies used for the treatment of human immunodeficiency virus (HIV) infection. These regimens are extremely effective in suppressing virus replication. Recently, our research group identified some N 1 -aryl-2-arylthioacetamido-benzimidazoles as a novel class of NNRTIs. In this research work we report the design, the synthesis and the structure-activity relationship studies of new compounds (20-34) in which some structural modifications have been introduced in order to investigate their effects on reverse transcriptase (RT) inhibition and to better define the features needed to increase the antiviral activity. Most of the new compounds proved to be highly effective in inhibiting both RT enzyme at nanomolar concentrations and HIV-1 replication in MT4 cells with minimal cytotoxicity. Among them, the most promising N 1 -aryl-2-arylthioacetamido-benzimidazoles and N 1 -aryl-2-aryloxyacetamido-benzimidazoles were also tested toward a panel of single- and double-mutants strain responsible for resistance to NNRTIs, showing in vitro antiviral activity toward single mutants L100I, K103N, Y181C, Y188L and E138K. The best results were observed for derivatives 29 and 33 active also against the double mutants F227L and V106A. Computational approaches were applied in order to rationalize the potency of the new synthesized inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

In vitro function of the aryl hydrocarbon receptor predicts in vivo sensitivity of oviparous vertebrates to dioxin-like compounds

EPA Science Inventory

Differences in sensitivity to dioxin-like compounds (DLCs) among species and taxa presents a major challenge to ecological risk assessments. Activation of the aryl hydrocarbon receptor (AHR) regulates adverse effects associated with exposure to DLCs in vertebrates. Prior investig...

Ruthenium(η⁶,η¹-arene-CH₂-NHC) Catalysts for Direct Arylation of 2-Phenylpyridine with (Hetero)Aryl Chlorides in Water.

PubMed

Kaloğlu, Nazan; Özdemir, İsmail; Gürbüz, Nevin; Arslan, Hakan; Dixneuf, Pierre H

2018-03-13

A series of new benzimidazolium halides were synthesized in good yields as unsymmetrical N -heterocyclic carbene (NHC) precursors containing the N-CH₂-arene group. The benzimidazolium halides were readily converted into ruthenium(II)-NHC complexes with the general formula [RuCl₂(η⁶,η¹-arene-CH₂-NHC)]. The structures of all new compounds were characterized by ¹H NMR (Nuclear Magnetic Resonance), 13 C NMR, FT-IR (Fourier Transform Infrared) spectroscopy and elemental analysis techniques. The single crystal structure of one benzimidazole ruthenium complex, 2b , was determined. The complex is best thought of as containing an octahedrally coordinated Ru center with the arene residue occupying three sites, the remaining sites being occupied by a (carbene)C-Ru bond and two Ru-Cl bonds. The catalytic activity of [RuCl₂(η⁶,η ¹ -arene-CH₂-NHC)] complexes was evaluated in the direct (hetero)arylation of 2-phenylpyridine with (hetero)aryl chlorides in water as the nontoxic reaction medium. These results show that catalysts 2a and 2b were the best for monoarylation with simple phenyl and tolyl chlorides. For functional aryl chlorides, 2d , 2e , and 2c appeared to be the most efficient.

Microwave Assisted Synthesis of 1-[5-(Substituted Aryl)-1H-Pyrazol-3-yl]-3,5-Diphenyl-1H-1,2,4-Triazole as Antinociceptive and Antimicrobial Agents

PubMed Central

Khanage, Shantaram Gajanan; Mohite, Popat Baban; Pandhare, Ramdas Bhanudas; Raju, S. Appala

2014-01-01

Purpose: An efficient technique has been developed for microwave assisted synthesis of 1-[5-(substituted aryl)-1H-pyrazol-3-yl]-3,5-diphenyl-1H-1,2,4-triazole as antinociceptive and antimicrobial agents. Methods: The desired compounds (S1-S10) were synthesized by the microwave irradiation via cyclization of formerly synthesized chalcones of 3,5-diphenyl-1H-1,2,4-triazole and hydrazine hydrate in mild acidic condition. All newly synthesized compounds were subjected to study their antinociceptive and antimicrobial activity. The analgesic potential of compounds was tested by acetic acid induced writhing response and hot plate method. The MIC values for antimicrobial activity were premeditated by liquid broth method. Results: The compounds S1, S2, S4, S6 and S10 were found to be excellent peripherally acting analgesic agents when tested on mice by acetic acid induced writhing method and compounds S3, S6 and S1 at dose level of 100 mg/kg were exhibited superior centrally acting antinociceptive activity when tested by Eddy’s hot plate method. In antimicrobial activity compound S10 found to be broad spectrum antibacterial agent at MIC value of 15.62 µg/ml and compound S6 was exhibited antifungal potential at 15.62 µg/mL on both fungal strains. Conclusion: Some novel pyrazoles clubbed with 1,2,4-triazole derivatives were synthesized and evaluated as possible antimicrobial, centrally and peripherally acting analgesics. PMID:24511473

Synthesis and evaluation of novel N-H and N-substituted indole-2- and 3-carboxamide derivatives as antioxidants agents.

PubMed

Olgen, Süreyya; Kiliç, Zuhal; Ada, Ahmet O; Coban, Tulay

2007-08-01

We have previously reported on the synthesis of novel indole derivatives where some compounds showed significant antioxidant activity. Here, we report the synthesis of novel N-H and N-substituted indole-2- and 3-carboxamide derivatives and investigated their antioxidant role in order to identify structural characteristics responsible for activity. Although all compounds showed a strong inhibitory (95-100%) effect on superoxide anion (SOD) only compounds 4, 5 and 6 showed simliar potency for the inhibition of lipid peroxidation (81-94%) which revealed that compounds 4, 5 and 6 possessed highly potent antioxidant properties. Substitution in the 1-position of the indole ring caused the significant differences between the activity results regarding lipid peroxidation inhibition.

Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds.

PubMed

Best, Daniel; Burns, David J; Lam, Hon Wai

2015-06-15

A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N-H groups are tolerated on the barbituric acid, with no complications arising from N-H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Simple and Efficient Generation of Aryl Radicals from Aryl Triflates: Synthesis of Aryl Boronates and Aryl Iodides at Room Temperature.

PubMed

Liu, Wenbo; Yang, Xiaobo; Gao, Yang; Li, Chao-Jun

2017-06-28

Despite the wide use of aryl radicals in organic synthesis, current methods to prepare them from aryl halides, carboxylic acids, boronic acids, and diazonium salts suffer from limitations. Aryl triflates, easily obtained from phenols, are promising aryl radical progenitors but remain elusive in this regard. Inspired by the single electron transfer process for aryl halides to access aryl radicals, we developed a simple and efficient protocol to convert aryl triflates to aryl radicals. Our success lies in exploiting sodium iodide as the soft electron donor assisted by light. This strategy enables the scalable synthesis of two types of important organic molecules, i.e., aryl boronates and aryl iodides, in good to high yields, with broad functional group compatibility in a transition-metal-free manner at room temperature. This protocol is anticipated to find potential applications in other aryl-radical-involved reactions by using aryl triflates as aryl radical precursors.

Efficient Syntheses of Novel Fluoro-Substituted Pentacenes and Azapentacenes: Molecular and Solid-State Properties.

PubMed

Schwaben, Jonas; Münster, Niels; Klues, Michael; Breuer, Tobias; Hofmann, Philipp; Harms, Klaus; Witte, Gregor; Koert, Ulrich

2015-09-21

Non-symmetrical 6,13-disubstituted pentacenes bearing trifluoromethyl and aryl substituents have been synthesized starting from pentacenequinone. Diazapentacenes with a variety of fluorine substituents were prepared either via a Hartwig-Buchwald aryl amination route or by a SNAr strategy. As a result of a non-symmetric substitution pattern containing electron-donating substituents in combination with electron-accepting fluorine substituents, the synthesized compounds feature distinct molecular dipoles. All compounds are analyzed regarding their optoelectronic properties in solution with special focus on the frontier orbital energies as well as their molecular packing in the crystal structures. The analyses of isolated molecules are complemented by thin-film studies to examine their solid-state properties. A precise comparison between these and the molecular properties gave detailed insights into the exciton binding energies of these compounds, which are explained by means of a simple model considering the molecular packing and polarizabilities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A direct method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels

PubMed Central

Jaganathan, Lakshmanan; Boopathy, Rathanam

2000-01-01

Background In vertebrates, two types of cholinesterases exist, acetylcholinesterase and butyrylcholinesterase. The function of acetylcholinesterase is to hydrolyse acetylcholine, thereby terminating the neurotransmission at cholinergic synapse, while the precise physiological function of butyrylcholinesterase has not been identified. The presence of cholinesterases in tissues that are not cholinergically innervated indicate that cholinesterases may have functions unrelated to neurotransmission. Furthermore, cholinesterases display a genuine aryl acylamidase activity apart from their predominant acylcholine hydrolase activity. The physiological significance of this aryl acylamidase activity is also not known. The study on the aryl acylamidase has been, in part hampered by the lack of a specific method to visualise this activity. We have developed a method to visualise the aryl acylamidase activity on cholinesterase in polyacrylamide gels. Results The o-nitroaniline liberated from o-nitroacetanilide by the action of aryl acylamidase activity on cholinesterases, in the presence of nitrous acid formed a diazonium compound. This compound gave an azo dye complex with N-(1-napthyl)-ethylenediamine, which appeared as purple bands in polyacrylamide gels. Treating the stained gels with trichloroacetic acid followed by Tris-HCl buffer helped in fixation of the stain in the gels. By using specific inhibitors for acetylcholinesterase and butyrylcholinesterase, respectively, differential staining for the aryl acylamidase activities on butyrylcholinesterase and acetylcholinesterase in a sample containing both these enzymes has been demonstrated. A linear relationship between the intensity of colour developed and activity of the enzyme was obtained. Conclusions A novel method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels has been developed. PMID:11231883

A direct method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels.

PubMed

Jaganathan, L; Boopathy, R

2000-01-01

In vertebrates, two types of cholinesterases exist, acetylcholinesterase and butyrylcholinesterase. The function of acetylcholinesterase is to hydrolyse acetylcholine, thereby terminating the neurotransmission at cholinergic synapse, while the precise physiological function of butyrylcholinesterase has not been identified. The presence of cholinesterases in tissues that are not cholinergically innervated indicate that cholinesterases may have functions unrelated to neurotransmission. Furthermore, cholinesterases display a genuine aryl acylamidase activity apart from their predominant acylcholine hydrolase activity. The physiological significance of this aryl acylamidase activity is also not known. The study on the aryl acylamidase has been, in part hampered by the lack of a specific method to visualise this activity. We have developed a method to visualise the aryl acylamidase activity on cholinesterase in polyacrylamide gels. The o-nitroaniline liberated from o-nitroacetanilide by the action of aryl acylamidase activity on cholinesterases, in the presence of nitrous acid formed a diazonium compound. This compound gave an azo dye complex with N-(1-napthyl)-ethylenediamine, which appeared as purple bands in polyacrylamide gels. Treating the stained gels with trichloroacetic acid followed by Tris-HCl buffer helped in fixation of the stain in the gels. By using specific inhibitors for acetylcholinesterase and butyrylcholinesterase, respectively, differential staining for the aryl acylamidase activities on butyrylcholinesterase and acetylcholinesterase in a sample containing both these enzymes has been demonstrated. A linear relationship between the intensity of colour developed and activity of the enzyme was obtained. A novel method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels has been developed.

Mass spectrometry of analytical derivatives. 1. Cyanide cations in the spectra of N-alkyl-N-perfluoroacyl-α-amino acids and their methyl esters

PubMed Central

Todua, Nino G.; Tretyakov, Kirill V.; Mikaia, Anzor I.

2016-01-01

The central mission for the development of the National Institute of Standards and Technology/National Institutes of Health/Environmental Protection Agency Mass Spectral Library is the acquisition of reference gas chromatography–mass spectrometry data for important compounds and their chemical modification products. The addition of reliable reference data of various derivatives of amino acids to The Library, and the study of their behavior under electron ionization conditions may be useful for their identification, structure elucidation, and a better understanding of the data obtained when the same derivatives are subjected to other ionization methods. N-Alkyl-N-perfluoroacyl derivatives of amino acids readily produce previously unreported alkylnitrilium cations of composition [HC≡N-alkyl]+. Homologous [HC≡N-aryl]+ cations are typical for corresponding N-aryl analogs. The formation of other ions characteristic for these derivatives involves oxygen rearrangement giving rise to ions [CnF2n+1–C≡N+–CnH2n+1] and [CnF2n+1–C≡N+-aryl]. The introduction of an N-benzyl substituent in a molecule favors a process producing benzylidene iminium cations. l-Threonine and l-cysteine derivatives exhibit more fragmentation pathways not typical for other α-amino acids; additionally, the Nω-amino group in l-lysine directs the dissociation process and provides structural information on the substitution at the amino functions in the molecule. PMID:26307698

Structure-activity relationship of new antimalarial 1-aryl-3-susbtituted propanol derivatives: Synthesis, preliminary toxicity profiling, parasite life cycle stage studies, target exploration, and targeted delivery.

PubMed

Quiliano, Miguel; Pabón, Adriana; Moles, Ernest; Bonilla-Ramirez, Leonardo; Fabing, Isabelle; Fong, Kim Y; Nieto-Aco, Diego A; Wright, David W; Pizarro, Juan C; Vettorazzi, Ariane; López de Cerain, Adela; Deharo, Eric; Fernández-Busquets, Xavier; Garavito, Giovanny; Aldana, Ignacio; Galiano, Silvia

2018-05-25

Design, synthesis, structure-activity relationship, cytotoxicity studies, in silico drug-likeness, genotoxicity screening, and in vivo studies of new 1-aryl-3-substituted propanol derivatives led to the identification of nine compounds with promising in vitro (55, 56, 61, 64, 66, and 70-73) and in vivo (66 and 72) antimalarial profiles against Plasmodium falciparum and Plasmodium berghei. Compounds 55, 56, 61, 64, 66 and 70-73 exhibited potent antiplasmodial activity against chloroquine-resistant strain FCR-3 (IC 50 s < 0.28 μM), and compounds 55, 56, 64, 70, 71, and 72 showed potent biological activity in chloroquine-sensitive and multidrug-resistant strains (IC 50 s < 0.7 μM for 3D7, D6, FCR-3 and C235). All of these compounds share appropriate drug-likeness profiles and adequate selectivity indexes (77 < SI < 184) as well as lack genotoxicity. In vivo efficacy tests in a mouse model showed compounds 66 and 72 to be promising candidates as they exhibited significant parasitemia reductions of 96.4% and 80.4%, respectively. Additional studies such as liver stage and sporogony inhibition, target exploration of heat shock protein 90 of P. falciparum, targeted delivery by immunoliposomes, and enantiomer characterization were performed and strongly reinforce the hypothesis of 1-aryl-3-substituted propanol derivatives as promising antimalarial compounds. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Toxicity and biodegradability of selected N-substituted phenols under anaerobic conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donlon, B.; Razo-Flores, E.; Hwu, C.S.

1995-12-31

The anaerobic toxicity and biodegradability of N-substituted aromatics were evaluated in order to obtain information on their ultimate biotreatment. The toxicity of selected N-substituted aromatic compounds toward acetoclastic methanogens in granular sludge was measured in batch assays. This toxicity was highly correlated with compound hydrophobicity, indicating that partitioning into the bacterial membranes was an important factor in the toxicity. However, other factors, such as chemical interactions with key cell components, were suggested to be playing an important role. Nitroaromatic compounds were, on the average, over 300-fold more toxic than their amino-substituted counterparts. This finding suggests that the facile reduction ofmore » nitro-groups known to occur in anaerobic environments would result in a high level of detoxification. To test this hypothesis, continuous lab-scale upward-flow anaerobic sludge bed reactors treating 2-nitrophenol and 4-nitrophenol were established. The 4-nitrophenol was readily converted to the corresponding 4-aminophenol, whereas complete mineralization of 2-nitrophenol via intermediate formation of 2-aminophenol was obtained. These conversions led to a dramatic detoxification of the nitrophenols, because it was feasible to treat the highly toxic nitrophenolics at high organic loading rates.« less

NiXantphos: a deprotonatable ligand for room-temperature palladium-catalyzed cross-couplings of aryl chlorides.

PubMed

Zhang, Jiadi; Bellomo, Ana; Trongsiriwat, Nisalak; Jia, Tiezheng; Carroll, Patrick J; Dreher, Spencer D; Tudge, Matthew T; Yin, Haolin; Robinson, Jerome R; Schelter, Eric J; Walsh, Patrick J

2014-04-30

Although the past 15 years have witnessed the development of sterically bulky and electron-rich alkylphosphine ligands for palladium-catalyzed cross-couplings with aryl chlorides, examples of palladium catalysts based on either triarylphosphine or bidentate phosphine ligands for efficient room temperature cross-coupling reactions with unactivated aryl chlorides are rare. Herein we report a palladium catalyst based on NiXantphos, a deprotonatable chelating aryldiphosphine ligand, to oxidatively add unactivated aryl chlorides at room temperature. Surprisingly, comparison of an extensive array of ligands revealed that under the basic reaction conditions the resultant heterobimetallic Pd-NiXantphos catalyst system outperformed all the other mono- and bidentate ligands in a deprotonative cross-coupling process (DCCP) with aryl chlorides. The DCCP with aryl chlorides affords a variety of triarylmethane products, a class of compounds with various applications and interesting biological activity. Additionally, the DCCP exhibits remarkable chemoselectivity in the presence of aryl chloride substrates bearing heteroaryl groups and sensitive functional groups that are known to undergo 1,2-addition, aldol reaction, and O-, N-, enolate-α-, and C(sp(2))-H arylations. The advantages and importance of the Pd-NiXantphos catalyst system outlined herein make it a valuable contribution for applications in Pd-catalyzed arylation reactions with aryl chlorides.

NiXantphos: A Deprotonatable Ligand for Room-Temperature Palladium-Catalyzed Cross-Couplings of Aryl Chlorides

PubMed Central

2015-01-01

Although the past 15 years have witnessed the development of sterically bulky and electron-rich alkylphosphine ligands for palladium-catalyzed cross-couplings with aryl chlorides, examples of palladium catalysts based on either triarylphosphine or bidentate phosphine ligands for efficient room temperature cross-coupling reactions with unactivated aryl chlorides are rare. Herein we report a palladium catalyst based on NiXantphos, a deprotonatable chelating aryldiphosphine ligand, to oxidatively add unactivated aryl chlorides at room temperature. Surprisingly, comparison of an extensive array of ligands revealed that under the basic reaction conditions the resultant heterobimetallic Pd–NiXantphos catalyst system outperformed all the other mono- and bidentate ligands in a deprotonative cross-coupling process (DCCP) with aryl chlorides. The DCCP with aryl chlorides affords a variety of triarylmethane products, a class of compounds with various applications and interesting biological activity. Additionally, the DCCP exhibits remarkable chemoselectivity in the presence of aryl chloride substrates bearing heteroaryl groups and sensitive functional groups that are known to undergo 1,2-addition, aldol reaction, and O-, N-, enolate-α-, and C(sp2)–H arylations. The advantages and importance of the Pd–NiXantphos catalyst system outlined herein make it a valuable contribution for applications in Pd-catalyzed arylation reactions with aryl chlorides. PMID:24745758

Perfluoroalkylation of Aryl-N,N-dimethyl Hydrazones Using Hypervalent Iodine(III) Reagents or Perfluoroalkyl Iodides.

PubMed

Janhsen, Benjamin; Studer, Armido

2017-11-17

Radical trifluoromethylation of aryl N,N-dimethyl hydrazones using TBAI as an initiator and Togni's reagent as a trifluoromethyl radical source is described. Cascades proceed via electron-catalysis; this approach is generally more applicable to hydrazone perfluoroalkylation using perfluoroalkyl iodides as the radical precursors in combination with a base under visible-light initiation.

Highly enantioselective arylation of aldehydes and ketones using AlArEt(2)(THF) as aryl sources.

PubMed

Zhou, Shuangliu; Wu, Kuo-Hui; Chen, Chien-An; Gau, Han-Mou

2009-05-01

A series of AlArEt(2)(THF) (Ar = Ph (1a), 4-MeC(6)H(4) (1b), 4-MeOC(6)H(4) (1c), 4-Me(3)SiC(6)H(4) (1d), 2-naphthyl (1e)) were synthesized from reactions of AlEt(2)Br(THF) with ArMgBr. In CDCl(3) solution, the (1)H NMR spectra showed that AlArEt(2)(THF) compounds exist as a mixture of four species of formulas of AlAr(x)Et(3-x) (THF) (x = 0, 1, 2, or 3). AlArEt(2)(THF) compounds were found to be superior and atom-economic reagents for asymmetric aryl additions to organic carbonyls. Aryl additions of AlArEt(2)(THF) to aldehydes catalyzed by the titanium(IV) complex of (R)-H(8)-BINOL were efficient with a short reaction time of 1 h, affording aryl addition products as exclusive or main products in high yields and excellent enantioselectivities of up to 98% ee. Although ethyl additions to aldehydes occurred in minor extent, this study demonstrates that increasing the amount of AlArEt(2)(THF) from 1.2 to 1.4 or to 1.6 equiv significantly improved the aryl addition products of up to >99%. On the other hand, asymmetric arylations of AlArEt(2)(THF) to ketones employing a titanium(IV) catalyst of (S)-BINOL produced optically active tertiary alcohols exclusively in excellent enantioselectivities of up to 94% ee.

Probing the role of the vancomycin e-ring aryl chloride: selective divergent synthesis and evaluation of alternatively substituted E-ring analogues.

PubMed

Pinchman, Joseph R; Boger, Dale L

2013-05-23

The selective functionalization of vancomycin aglycon derivatives through conversion of the E-ring aryl chloride to a reactive boronic acid and its use in the synthesis of a systematic series of vancomycin E-ring analogues are described. The series was used to examine the E-ring chloride impact in binding d-Ala-d-Ala and on antimicrobial activity. In contrast to the reduced activity of the unsubstituted E-ring derivatives, hydrophobic and relatively nonpolar substituents approach or match the chloro-substituted vancomycin and were insensitive to the electronic character of the substituent (e.g., Cl vs CN/OMe), whereas highly polar substituents fail to provide the enhancements. Moreover, the active permethylated vancomycin aglycon derivatives exhibit VanB VRE antimicrobial activity at levels that approach (typically within 2-fold) their activity against sensitive bacteria. The robust borylation reaction also enabled the functionalization of a minimally protected vancomycin aglycon (N-Boc-vancomycin aglycon) and provides a direct method for the preparation of previously inaccessible analogues.

Increasing human Th17 differentiation through activation of orphan nuclear receptor retinoid acid-related orphan receptor γ (RORγ) by a class of aryl amide compounds.

PubMed

Zhang, Wei; Zhang, Jing; Fang, Leiping; Zhou, Ling; Wang, Shuai; Xiang, Zhijun; Li, Yuan; Wisely, Bruce; Zhang, Guifeng; An, Gang; Wang, Yonghui; Leung, Stewart; Zhong, Zhong

2012-10-01

In a screen for small-molecule inhibitors of retinoid acid-related orphan receptor γ (RORγ), we fortuitously discovered that a class of aryl amide compounds behaved as functional activators of the interleukin 17 (IL-17) reporter in Jurkat cells. Three of these compounds were selected for further analysis and found to activate the IL-17 reporter with potencies of ∼0.1 μM measured by EC₅₀. These compounds were shown to directly bind to RORγ by circular dichroism-based thermal stability experiments. Furthermore, they can enhance an in vitro Th17 differentiation process in human primary T cells. As RORγ remains an orphan nuclear receptor, discovery of these aryl amide compounds as functional agonists will now provide pharmacological tools for us to dissect functions of RORγ and facilitate drug discovery efforts for immune-modulating therapies.

Wholly Aromatic Ether-imides. Potential Materials for n-Type Semiconductors

NASA Technical Reports Server (NTRS)

Dingemans, Theo J.; St.Clair, Terry L.; Samulski, Edward T.; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

We report on the synthesis and characterization of a novel series low-molar-mass ether-imide rod-shaped model compounds. All ether-imides were obtained by terminating the appropriate rigid core dianhydride, i.e. pyromellitic dianhydride (PMDA), 1,4,5,8-naphthalenetetracarboxylic dianhydride (NDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), and 3,3,4,4'-oxydiphthalic dianhydride (ODPA) with three flexible aryl-ether tails of different chain length. The mono-functional aryl-ether amines, i.e. 4-(3-phenoxy-phenoxy)-phenylamine (2) and 4-(3-phenoxy-3-phenoxy-phenoxy)-phenylamine (4), were synthesized using standard fluoro-displacement and Ullmann condensation techniques. The corresponding ether-imide model compounds were obtained in high yields using a one-step solution imidization procedure. Increasing the number of meta-substituted aryl-ether units reduces the melt transition temperatures and at the same time it increases the solubility of the model compounds. Most model compounds are crystalline solids and form isotropic melts upon heating. 2,7-Bis-(-4-phenoxy-phenyl)-benzo[Imn][3,8]phenanthroline1,3,6,8-tetraone (NDA-n0), however, displays a smectic A (SA) when cooled from the isotropic phase, followed by what appears to be either a highly ordered smectic phase or a, columnar phase. This is the first example, known to date, in which a mesophase is detected in a wholly aromatic ether-imide compound. For all compounds we present spectroscopic data and X-ray diffraction data. Cyclic voltammetry was used to determine the redox behavior and pertinent energy levels of the model compounds.

A Convenient, TiCl4/SnCl4-Mediated Synthesis of N-Phenyl or N-Aryl Benzamidines and N-Phenylpicolinamidines

PubMed Central

Patil, Umesh D.; Mahulikar, Pramod P.

2012-01-01

A new, TiCl4-or SnCl4-mediated, solvent-free method was developed for the synthesis of N-Aryl benzamidines and N-phenylpicolinamidines, in moderate-to-good yield, using suitable amines and nitriles as starting materials. PMID:24052858

Design, Synthesis and Biological Evaluation of (E)-N-Aryl-2-arylethene-sulfonamide Analogues as Potent and Orally Bioavailable Microtubule-targeted Anticancer Agents

PubMed Central

Ramana Reddy, M. V.; Mallireddigari, Muralidhar R.; Pallela, Venkat R.; Cosenza, Stephen C.; Billa, Vinay K.; Akula, Balaiah; Venkata Subbaiah, D. R. C.; Bharathi, E. Vijaya; Padgaonkar, Amol; Lv, Hua; Gallo, James M.; Reddy, E. Premkumar

2013-01-01

A series of novel (E)-N-aryl-2-arylethenesulfonamides (6) were synthesized and evaluated for their anticancer activity. Some of the compounds in this series showed potent cytotoxicity against a wide spectrum of cancer cell-lines (IC50 values ranging from 5 to 10 nM) including all drug resistant cell-lines. Nude mice xenograft assays with compound (E)-N-(3-Amino-4-methoxyphenyl)-2-(2′,4′,6′-trimethoxyphenyl)ethenesulfonamide (6t) showed dramatic reduction in tumor size indicating their in vivo potential as anticancer agents. A preliminary drug development study with compound 6t is predicted to have increased blood-brain barrier permeability relative to many clinically used anti-mitotic agents. Mechanistic studies indicate that 6t and some other analogs disrupted microtubule formation, formation of mitotic spindles and arrest of cells in mitotic phase. Compound 6t inhibited purified tubulin polymerization in vitro and in vivo and circumvented drug resistance mediated by P-glycoprotein. Compound 6t specifically competed with colchicine binding to tubulin and with similar avidity as podophylltoxin indicating its binding site on tubulin. PMID:23750455

Synthesis and biological evaluation of novel dioxa-bicycle C-aryl glucosides as SGLT2 inhibitors.

PubMed

Yan, Qi; Ding, Ning; Li, Yingxia

2016-02-08

A series of novel C-aryl glucosides containing dioxa-bicycle were synthesized and evaluated for inhibition activity against hSGLT2. Among the compounds tested, compound 6a showed moderate SGLT2 inhibition activities at 700 nM. The results could benefit the discovery of new SGLT2 inhibitors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

PubMed Central

Mebrahtu, Fanuel M; Manana, Mandlenkosi M; Madumo, Kagiso; Sokamisa, Mokela S

2015-01-01

Summary 1-C and 2-C-branched carbohydrates are present as substructures in a number of biologically important compounds. Although the synthesis of such carbohydrate derivatives is extensively studied, the synthesis of 1,2-cis-2-C-branched C-, S-, and N-glycosides is less explored. In this article a synthetic strategy for the synthesis of 1,2-cis-2-C-branched-aryl-C-glucosides is reported via a hydrogenolytic desulfurization of suitably orientated carbohydrate based hemithioacetals. 1,2-cis-2-Hydroxymethyl and 2-carbaldehyde of aryl-C-glucosides have been synthesized using the current strategy in very good yields. The 2-carbaldehyde-aryl-C-glucosides have been identified as suitable substrates for the stereospecific preparation of 2,3-unsaturated-aryl-C-glycosides (Ferrier products). PMID:26124859

Synthesis of aryl thioethers through the N-chlorosuccinimide-promoted cross-coupling reaction of thiols with Grignard reagents.

PubMed

Cheng, Jun-Hao; Ramesh, Chintakunta; Kao, Hsin-Lun; Wang, Yu-Jen; Chan, Chien-Ching; Lee, Chin-Fa

2012-11-16

A convenient one-pot approach for the synthesis of aryl sulfides through the coupling of thiols with Grignard reagents in the presence of N-chlorosuccinimide is described. The sulfenylchlorides were formed when thiols were treated with N-chlorosuccinimide, and the resulting sulfenylchlorides were then directly reacted with Grignard reagents to provide aryl sulfides in good to excellent yields under mild reaction conditions. Functional groups including ester, fluoro, and chloro are tolerated by the reaction conditions employed. It is important to note that this method has a short reaction time (30 min in total) and represents an alternative approach for the synthesis of aryl sulfides over the existing protocols.

Boron-based dual imaging probes, compositions and methods for rapid aqueous F-18 labeling, and imaging methods using same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zibo; Gabbai, Francois P.; Conti, Peter S.

A composition useful as a PET and/or fluorescence imaging probe a compound a compound of Formula I, including salts, hydrates and solvates thereof: ##STR00001## wherein R.sub.1-R.sub.7 may be independently selected from hydrogen, halogen, hydroxy, alkoxy, nitro, substituted and unsubstituted amino, cycloalkyl, carboxy, carboxylic acids and esters thereof, cyano, haloalkyl, aryl, X is selected from the group consisting of C and N; and A is selected of hydrogen, halogen, hydroxy, alkoxy, nitro, substituted and unsubstituted amino, alkyl, cycloalkyl, carboxy, carboxylic acids and esters thereof, cyano, haloalkyl, aryl, including phenyl and aminophenyl, and heteroaryl.

An Efficient Process for Pd-Catalyzed C–N Cross-Coupling Reactions of Aryl Iodides: Insight Into Controlling Factors

PubMed Central

Fors, Brett P.; Davis, Nicole R.; Buchwald, Stephen L.

2009-01-01

An investigation into Pd-catalyzed C–N cross-coupling reactions of aryl iodides is described. NaI is shown to have a significant inhibitory effect on these processes. By switching to a solvent system in which the iodide byproduct was insoluble, reactions of aryl iodides were accomplished with the same efficiencies as aryl chlorides and bromides. Using catalyst systems based on certain biarylphosphine ligands, aryl iodides were successfully reacted with an array of primary and secondary amines in high yields. Lastly, reactions of heteroarylamines and heteroaryliodides were also conducted in high yields. PMID:19348431

Synthesis of aryl pyrazole via Suzuki coupling reaction, in vitro mushroom tyrosinase enzyme inhibition assay and in silico comparative molecular docking analysis with Kojic acid.

PubMed

Channar, Pervaiz Ali; Saeed, Aamer; Larik, Fayaz Ali; Batool, Bakhtawar; Kalsoom, Saima; Hasan, M M; Erben, Mauricio F; El-Seedi, Hesham R; Ali, Musrat; Ashraf, Zaman

2018-04-30

Aryl pyrazoles are well recognized class of heterocyclic compounds found in several commercially available drugs. Owing to their significance in medicinal chemistry, in this current account we have synthesized a series of suitably substituted aryl pyrazole by employing Suzuki cross-coupling reaction. All compounds were evaluated for inhibition of mushroom tyrosinase enzyme both in vitro and in silico. Compound 3f (IC 50  = 1.568 ± 0.01 µM) showed relatively better potential compared to reference kojic acid (IC 50  = 16.051 ± 1.27 µM). A comparative docking studies showed that compound 3f have maximum binding affinity against mushroom tyrosinase (PDBID: 2Y9X) with binding energy value (-6.90 kcal/mol) as compared to Kojic acid. The 4-methoxy group in compound 3f shows 100% interaction with Cu. Compound 3f displayed hydrogen binding interaction with His61 and His94 at distance of 1.71 and 1.74 Å which might be responsible for higher activity compared to Kojic acid. Copyright © 2018 Elsevier Inc. All rights reserved.

Substitution effect in reversible gel-liquid phase transformation polyoxometalate ionic liquid compounds.

PubMed

Wu, Xuefei; Cai, Huaxue; Wu, Qingyin; Yan, Wenfu

2016-07-28

The substitution effect in a series of POM-type reversible gel-liquid phase transformation ionic liquid compounds, [MIMPS]8P2W16V2O62, [MIMPS]6H2P2W16V2O62 and [MIMPS]4H4P2W16V2O62, has been investigated. Interestingly, there is an obvious substitution effect on the physicochemical properties of these compounds. When protons are substituted in place of ammonium, both the conductivity and the thermo-stability of the compounds can be increased a lot, and more protons can enhance this tendency.

Novel thiophene-based cycloruthenated compounds: synthesis, characterization, and reactivity.

PubMed

Cuesta, Luciano; Maluenda, Irene; Soler, Tatiana; Navarro, Rafael; Urriolabeitia, Esteban P

2011-01-03

The reactions between a series of thiophene-based imines with [(η(6)-C(6)H(6))RuCl(μ-Cl)](2), in a basic medium, and in MeCN give a family of ruthenacycles of stoichiometry [Ru(C^N)(NCMe)(4)]PF(6) (C^N = orthometalated thiopheneimine). In these species, the C-H activation process is produced in most cases at the thiophene ring. When two C-H bonds are competing (thiophene vs aryl), the cyclometalation can be driven regioselectively to the thiophene unit or to the aryl ring as a function of the location of the iminic C=N bond. Cyclometalation can also be oriented to positions 2 or 3 of the thiophene depending on the situation of the imine in the heterocycle (3 or 2, respectively). In all studied cases, the η(6)-C(6)H(6) ligand was substituted by acetonitrile. The X-ray structures of two representative complexes have been determined. These thiophene-based metallacycles react with iodine under very mild conditions affording, after hydrolysis, substituted 3-iodo-2-formyl(benzo)thiophenes or substituted 2-iodo-3-formyl(benzo)thiophenes, as a function of the organometallic precursor.

Improved synthesis of aryltrialkoxysilanes via treatment of aryl Grignard or lithium reagents with tetraalkyl orthosilicates.

PubMed

Manoso, Amy S; Ahn, Chuljin; Soheili, Arash; Handy, Christopher J; Correia, Reuben; Seganish, W Michael; Deshong, Philip

2004-11-26

General reaction conditions for the synthesis of aryl(trialkoxy)silanes from aryl Grignard and lithium reagents and tetraalkyl orthosilicates (Si(OR)(4)) have been developed. Ortho-, meta-, and para-substituted bromoarenes underwent efficient metalation and silylation at low temperature to provide aryl siloxanes. Mixed results were obtained with heteroaromatic substrates: 3-bromothiophene, 3-bromo-4-methoxypyridine, 5-bromoindole, and N-methyl-5-bromoindole underwent silylation in good yield, whereas a low yield of siloxane was obtained from 2-bromofuran, and 2-bromopyridine failed to give silylated product. The synthesis of siloxanes via organolithium and magnesium reagents was limited by the formation of di- and triarylated silanes (Ar(2)Si(OR)(2) and Ar(3)SiOR, respectively) and dehalogenated (Ar-H) byproducts. Silylation at low temperature gave predominantly monoaryl siloxanes, without requiring a large excess of the electrophile. Optimal reaction conditions for the synthesis of siloxanes from aryl Grignard reagents entailed addition of arylmagnesium reagents to 3 equiv of tetraethyl- or tetramethyl orthosilicate at -30 degrees C in THF. Aryllithium species were silylated using 1.5 equiv of tetraethyl- or tetramethyl orthosilicate at -78 degrees C in ether.

Enantioselective epoxidation with chiral MN(III)(salen) catalysts: kinetic resolution of aryl-substituted allylic alcohols.

PubMed

Adam, W; Humpf, H U; Roschmann, K J; Saha-Möller, C R

2001-08-24

A set of aryl-substituted allylic alcohols rac-2 has been epoxidized by chiral Mn(salen*) complexes 1 as the catalyst and iodosyl benzene (PhIO) as the oxygen source. Whereas one enantiomer of the allylic alcohol 2 is preferentially epoxidized to give the threo- or cis-epoxy alcohol 3 (up to 80% ee) as the main product (dr up to >95:5), the other enantiomer of 2 is enriched (up to 53% ee). In the case of 1,1-dimethyl-1,2-dihydronaphthalen-2-ol (2c), the CH oxidation to the enone 4c proceeds enantioselectively and competes with the epoxidation. The absolute configurations of the allylic alcohols 2 and their epoxides 3 have been determined by chemical correlation or CD spectroscopy. The observed diastereo- and enantioselectivities in the epoxidation reactions are rationalized in terms of a beneficial interplay between the hydroxy-directing effect and the attack along the Katsuki trajectory.

Antimycobacterial activity of new N(1)-[1-[1-aryl-3-[4-(1H-imidazol-1-yl)phenyl]-3-oxo]propyl]-pyridine-2-carboxamidrazone derivatives.

PubMed

Zampieri, Daniele; Mamolo, Maria Grazia; Vio, Luciano; Romano, Maurizio; Skoko, Nataša; Baralle, Marco; Pau, Valentina; De Logu, Alessandro

2016-07-15

N(1)-[1-[1-aryl-3-[4-(1H-imidazol-1-yl)phenyl]-3-oxo]propyl]-pyridine-2-carboxamidrazone derivatives were design, synthesized and tested for their in vitro antimycobacterial activity. The new compounds showed a moderate antimycobacterial activity against the tested strain of Mycobacterium tuberculosis H37Ra and a significant antimycobacterial activity against several mycobacteria other than tuberculosis strains. Copyright © 2016 Elsevier Ltd. All rights reserved.

C-H Bond Functionalization via Hydride Transfer: Formation of α-Arylated Piperidines and 1,2,3,4-Tetrahydroisoquinolines via Stereoselective Intramolecular Amination of Benzylic C-H Bonds

PubMed Central

Vadola, Paul A.; Carrera, Ignacio; Sames, Dalibor

2012-01-01

We here report a study of the intramolecular amination of sp3 C-H bonds via the hydride transfer cyclization of N-tosylimines (HT-amination). In this transformation, 5-aryl-aldehydes are subjected to N-toluenesulfonamide in the presence of BF3•OEt2 to effect imine formation and HT-cyclization, leading to 2-aryl-piperidines and 3-aryl-1,2,3,4-tetrahydroisoquinolines in a one-pot procedure. We examined the reactivity of a range of aldehyde substrates as a function of their conformational flexibility. Substrates of higher conformational rigidity were more reactive, giving higher yields of the desired products. However, a single substituent on the alkyl chain linking the N-tosylimine and the benzylic sp3 C-H bonds was sufficient for HT-cyclization to occur. In addition, an examination of various arenes revealed that the electronic character of the hydridic C-H bonds dramatically affects the efficiency of the reaction. We also found that this transformation is highly stereoselective; 2-substituted aldehydes yield cis-2,5-disubstituted piperidines, while 3-substituted aldehydes afford trans-2,4-disubstituted piperidines. The stereoselectivity is a consequence of thermodynamic control. The pseudo-allylic strain between the arene and tosyl group on the piperidine ring is proposed to rationalize the greater stability of the isomer with the aryl ring in the axial position. This preferential placement of the arene is proposed to affect the observed stereoselectivity. PMID:22672002

Pd-Catalyzed N-Arylation of Secondary Acyclic Amides: Catalyst Development, Scope, and Computational Study

PubMed Central

Hicks, Jacqueline D.; Hyde, Alan M.; Cuezva, Alberto Martinez; Buchwald, Stephen L.

2009-01-01

We report the efficient N-arylation of acyclic secondary amides and related nucleophiles with aryl nonaflates, triflates, and chlorides. This method allows for easy variation of the aromatic component in tertiary aryl amides. A new biaryl phosphine with P-bound 3,5-(bis)trifluoromethylphenyl groups was found to be uniquely effective for this amidation. The critical aspects of the ligand were explored through synthetic, mechanistic, and computational studies. Systematic variation of the ligand revealed the importance of (1) a methoxy group on the aromatic carbon of the “top ring” ortho to the phosphorus and (2) two highly electron-withdrawing P-bound 3,5-(bis)trifluoromethylphenyl groups. Computational studies suggest the electron-deficient nature of the ligand is important in facilitating amide binding to the LPd(II)(Ph)(X) intermediate. PMID:19886610

Bis-Aryl Urea Derivatives as Potent and Selective LIM Kinase (Limk) Inhibitors

PubMed Central

Yin, Yan; Zheng, Ke; Eid, Nibal; Howard, Shannon; Jeong, Ji-Hak; Yi, Fei; Guo, Jia; Park, Chul M; Bibian, Mathieu; Wu, Weilin; Hernandez, Pamela; Park, HaJeung; Wu, Yuntao; Luo, Jun-Li; LoGrasso, Philip V.; Feng, Yangbo

2015-01-01

The discovery/optimization of bis-aryl ureas as Limk inhibitors to obtain high potency and selectivity, and appropriate pharmacokinetic properties through systematic SAR studies is reported. Docking studies supported the observed SAR. Optimized Limk inhibitors had high biochemical potency (IC50 < 25 nM), excellent selectivity against ROCK and JNK kinases (> 400-fold), potent inhibition of cofilin phosphorylation in A7r5,PC-3, and CEM-SS T cells (IC50 < 1 μM), and good in vitro and in vivo pharmacokinetic properties. In the profiling against a panel of 61 kinases, compound 18b at 1 μM inhibited only Limk1 and STK16 with ≥ 80% inhibition. Compounds 18b and 18f were highly efficient in inhibiting cell-invasion/migration in PC-3 cells. In addition, compound 18w was demonstrated to be effective on reducing intraocular pressure (IOP) on rat eyes. Taken together, these data demonstrated that we had developed a novel class of bis-aryl urea derived potent and selective Limk inhibitors. PMID:25621531

Synthesis of Quinolines through Three-Component Cascade Annulation of Aryl Diazonium Salts, Nitriles, and Alkynes.

PubMed

Wang, Hao; Xu, Qian; Shen, Sheng; Yu, Shouyun

2017-01-06

An efficient and rapid synthesis of multiply substituted quinolines is described. This method is enabled by a three-component cascade annulation of readily available aryl diazonium salts, nitriles, and alkynes. This reaction is catalyst- and additive-free. Various aryl diazonium salts, nitriles, and alkynes can participate in this transformation, and the yields are up to 83%.

Synthesis and evaluation of ethylnitrosoureas of substituted naphthalimides as anticancer compounds.

PubMed

Pain, Anindita; Samanta, Suva; Dutta, Sushanta; Saxena, Ajit K; Shanmugavel, Mutiah; Sharma, Madhunika; Qazi, Gulam N; Sanyal, Utpal

2007-01-01

Four new ethylnitrosourea derivatives of substituted naphthalimides 3a-d have been synthesized from the respective N-(2-ethylamino) naphthalimides. Their chemical alkylating activity compared with the clinical drug CCNU and an experimental compound Mitonafide indicated that they possess lower alkylating activity than CCNU and comparable activity with the latter. Their anti-tumor efficacies were assessed in vivo in two murine ascites tumors namely Sarcoma-180 (S-180) and Ehrlich ascites carcinoma (EAC) by measuring the increase in median survival times (MST) of drug treated (T) over untreated control (C) mice. CCNU and Mitonafide were used as positive controls for comparison. The representative compound 3a has displayed marginal anti-tumoral activity in these tumors. Three compounds were further screened in vitro in 4 different human tumor cell lines but no significant activity was observed in those lines. These compounds moderately inhibit the synthesis of DNA and RNA in S-180 tumor cells.

Novel Scheme for Biosynthesis of Aryl Metabolites from l-Phenylalanine in the Fungus Bjerkandera adusta

PubMed Central

Lapadatescu, Carmen; Giniès, Christian; Le Quéré, Jean-Luc; Bonnarme, Pascal

2000-01-01

Aryl metabolite biosynthesis was studied in the white rot fungus Bjerkandera adusta cultivated in a liquid medium supplemented with l-phenylalanine. Aromatic compounds were analyzed by gas chromatography-mass spectrometry following addition of labelled precursors (14C- and 13C-labelled l-phenylalanine), which did not interfere with fungal metabolism. The major aromatic compounds identified were benzyl alcohol, benzaldehyde (bitter almond aroma), and benzoic acid. Hydroxy- and methoxybenzylic compounds (alcohols, aldehydes, and acids) were also found in fungal cultures. Intracellular enzymatic activities (phenylalanine ammonia lyase, aryl-alcohol oxidase, aryl-alcohol dehydrogenase, aryl-aldehyde dehydrogenase, lignin peroxidase) and extracellular enzymatic activities (aryl-alcohol oxidase, lignin peroxidase), as well as aromatic compounds, were detected in B. adusta cultures. Metabolite formation required de novo protein biosynthesis. Our results show that l-phenylalanine was deaminated to trans-cinnamic acid by a phenylalanine ammonia lyase and trans-cinnamic acid was in turn converted to aromatic acids (phenylpyruvic, phenylacetic, mandelic, and benzoylformic acids); benzaldehyde was a metabolic intermediate. These acids were transformed into benzaldehyde, benzyl alcohol, and benzoic acid. Our findings support the hypothesis that all of these compounds are intermediates in the biosynthetic pathway from l-phenylalanine to aryl metabolites. Additionally, trans-cinnamic acid can also be transformed via β-oxidation to benzoic acid. This was confirmed by the presence of acetophenone as a β-oxidation degradation intermediate. To our knowledge, this is the first time that a β-oxidation sequence leading to benzoic acid synthesis has been found in a white rot fungus. A novel metabolic scheme for biosynthesis of aryl metabolites from l-phenylalanine is proposed. PMID:10742235

Dimension-controlled assemblies of anion-responsive π-electronic systems bearing aryl substituents with fan-shaped geometries.

PubMed

Lakshmi, Vellanki; Haketa, Yohei; Yamakado, Ryohei; Yasuda, Nobuhiro; Maeda, Hiromitsu

2017-03-30

Pyrrole-4-aryl-substituted dipyrrolyldiketone BF 2 complexes as anion-responsive π-electronic molecules were synthesized via a 3,5-dimethylpyrrole precursor. Mesophases were observed in derivatives that possessed long alkyl chains on the pyrrole-4-aryl groups along with their anion complexes as ion-pairing assemblies in combination with appropriate cations.

Synthesis of 2-Azulenyltetrathiafulvalenes by Palladium-Catalyzed Direct Arylation of 2-Chloroazulenes with Tetrathiafulvalene and Their Optical and Electrochemical Properties.

PubMed

Shoji, Taku; Araki, Takanori; Sugiyama, Shuhei; Ohta, Akira; Sekiguchi, Ryuta; Ito, Shunji; Okujima, Tetsuo; Toyota, Kozo

2017-02-03

Tetrathiafulvalene (TTF) derivatives with 2-azulenyl substituents 5-11 were prepared by the palladium-catalyzed direct arylation reaction of 2-chloroazulenes with TTF in good yield. Photophysical properties of these compounds were investigated by UV-vis spectroscopy and theoretical calculations. Redox behavior of the novel azulene-substituted TTFs was examined by using cyclic voltammetry and differential pulse voltammetry, which revealed their multistep electrochemical oxidation and/or reduction properties. Moreover, these TTF derivatives showed significant spectral change in the visible region under the redox conditions.

Electronic states of aryl radical functionalized graphenes: Density functional theory study

NASA Astrophysics Data System (ADS)

Tachikawa, Hiroto; Kawabata, Hiroshi

2016-06-01

Functionalized graphenes are known as a high-performance molecular device. In the present study, the structures and electronic states of the aryl radical functionalized graphene have been investigated by the density functional theory (DFT) method to elucidate the effects of functionalization on the electronic states of graphene (GR). Also, the mechanism of aryl radical reaction with GR was investigated. The benzene, biphenyl, p-terphenyl, and p-quaterphenyl radicals [denoted by (Bz) n (n = 1-4), where n means numbers of benzene rings in aryl radical] were examined as aryl radicals. The DFT calculation of GR-(Bz) n (n = 1-4) showed that the aryl radical binds to the carbon atom of GR, and a C-C single bond was formed. The binding energies of aryl radicals to GR were calculated to be ca. 6.0 kcal mol-1 at the CAM-B3LYP/6-311G(d,p) level. It was found that the activation barrier exists in the aryl radical addition: the barrier heights were calculated to be 10.0 kcal mol-1. The electronic states of GR-(Bz) n were examined on the basis of theoretical results.

Synthesis and biological screening of 2'-aryl/benzyl-2-aryl-4-methyl-4',5-bithiazolyls as possible anti-tubercular and antimicrobial agents.

PubMed

Abhale, Yogita K; Sasane, Amit V; Chavan, Abhijit P; Deshmukh, Keshav K; Kotapalli, Sudha Sravanti; Ummanni, Ramesh; Sayyad, Sadikali F; Mhaske, Pravin C

2015-04-13

A series of 2'-aryl/benzyl-2-aryl-4-methyl-4',5-bithiazolyl derivatives, 25-64 were synthesized and evaluated for inhibitory activity against Mycobacterium smegmatis MC(2) 155 strain and antimicrobial activities against four pathogenic bacteria Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Proteus vulgaris. Among them, compounds 40, 49, 50, and 54 exhibited moderate to good inhibition on the growth of the bacteria Mycobacterium smegmatis at the concentration of 30 μM. Compounds 26, 40, 44, 54 and 56 exhibited moderate to good antibacterial activity. Compound 5-(2'-(4-fluorobenzyl)thiazol-4'-yl)-2-(4-fluorophenyl)-4-methyl-thiazole (54) exhibited both antitubercular as well as antimicrobial activity against all tested strains. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Synthesis, antiviral evaluation and molecular docking studies of N4-aryl substituted/unsubstituted thiosemicarbazones derived from 1-indanones as potent anti-bovine viral diarrhea virus agents.

PubMed

Soraires Santacruz, María C; Fabiani, Matías; Castro, Eliana F; Cavallaro, Lucía V; Finkielsztein, Liliana M

2017-08-01

A series of N 4 -arylsubstituted thiosemicarbazones derived from 1-indanones and a set of compounds lacking such substitution in the N 4 position of the thiosemicarbazone moiety were synthesized and evaluated for their anti-bovine viral diarrhea virus (BVDV) activity. Among these, derivatives 2 and 15 displayed high activity (EC 50 =2.7±0.4 and 0.7±0.1µM, respectively) as inhibitors of BVDV replication. Novel key structural features related to the anti-BVDV activity were identified by structure-activity relationship (SAR) analysis. In a previous study, the thiosemicarbazone of 5,6-dimethoxy-1-indanone (5,6-TSC) was characterized as a non-nucleoside inhibitor (NNI) of the BVDV RNA-dependent RNA polymerase. In the present work, cross-resistance assays were performed with the most active compounds. Such studies were carried out on 5,6-TSC resistant BVDV (BVDV-TSC r T1) carrying mutations in the viral polymerase. This BVDV mutant was also resistant to compound 15. Molecular docking studies and MM/PBSA calculations were performed to assess the most active derivatives at the 5,6-TSC viral polymerase binding site. The differences in the interaction pattern and the binding affinity of derivative 15 either to the wild type or BVDV-TSC r T1 polymerase were key factors to define the mode of action of this compound. Copyright © 2017 Elsevier Ltd. All rights reserved.

N-Substituted carbazolyloxyacetic acids modulate Alzheimer associated gamma-secretase.

PubMed

Narlawar, Rajeshwar; Pérez Revuelta, Blanca I; Baumann, Karlheinz; Schubenel, Robert; Haass, Christian; Steiner, Harald; Schmidt, Boris

2007-01-01

N-Sulfonylated and N-alkylated carbazolyloxyacetic acids were investigated for the inhibition and modulation of the Alzheimer's disease associated gamma-secretase. The introduction of a lipophilic substituent, which may vary from arylsulfone to alkyl, turned 2-carbazolyloxyacetic acids into potent gamma-secretase modulators. This resulted in the selective reduction of Abeta(42) and an increase of the less aggregatory Abeta(38) fragment by several compounds (e.g., 7d and 8c). Introduction of an electron donating group at position 6 and 8 of N-substituted carbazolyloxyacetic acids either decreased the activity or inversed modulation. The most active compounds displayed activity on amyloid precursor protein (APP) overexpressing cell lines in the low micromolar range and little or no effect on the gamma-secretase cleavage at the epsilon-site.

Redox chromophore compounds and electrodes of metal containing substituted bipyridines

DOEpatents

Elliott, Cecil M.; Redepenning, Jody G.

1986-01-01

Chromophoric compounds, each having a wide range of distinct color changes in response to changes in the oxidation states thereof, are provided in the form of polymerizable monomers, and polymers thereof, of certain metal containing, and electron group substituted, 2,2'-bipyridine compounds.

Copper-catalyzed Green and Expeditious N-Arylation of Sulfoximines using Diaryliodonium Salts

EPA Science Inventory

An ultrasound-accelerated green route for an expeditious N-arylation of NH-sulfoximines is described that involves the use of benign diaryliodonium salts in aqueous polyethylene glycol-400 and copper(I) bromide as catalyst at room temperature. The high yields of the products and...

Distinct molecular structures and hydrogen bond patterns of α,α-diethyl-substituted cyclic imide, lactam, and acetamide derivatives in the crystalline phase

NASA Astrophysics Data System (ADS)

Krivoshein, Arcadius V.; Ordonez, Carlos; Khrustalev, Victor N.; Timofeeva, Tatiana V.

2016-10-01

α,α-Dialkyl- and α-alkyl-α-aryl-substituted cyclic imides, lactams, and acetamides show promising anticonvulsant, anxiolytic, and anesthetic activities. While a number of crystal structures of various α-substituted cyclic imides, lactams, and acetamides were reported, no in-depth comparison of crystal structures and solid-state properties of structurally matched compounds have been carried out so far. In this paper, we report molecular structure and intermolecular interactions of three α,α-diethyl-substituted compounds - 3,3-diethylpyrrolidine-2,5-dione, 3,3-diethylpyrrolidin-2-one, and 2,2-diethylacetamide - in the crystalline phase, as studied using single-crystal X-ray diffraction and IR spectroscopy. We found considerable differences in the patterns of H-bonding and packing of the molecules in crystals. These differences correlate with the compounds' melting points and are of significance to physical pharmacy and formulation development of neuroactive drugs.

C-Aryl glucoside SGLT2 inhibitors containing a biphenyl motif as potential anti-diabetic agents.

PubMed

Ding, Yuyang; Mao, Liufeng; Xu, Dengfeng; Xie, Hui; Yang, Ling; Xu, Hongjiang; Geng, Wenjun; Gao, Yong; Xia, Chunguang; Zhang, Xiquan; Meng, Qingyi; Wu, Donghai; Zhao, Junling; Hu, Wenhui

2015-07-15

A series of highly active C-aryl glucoside SGLT2 inhibitors containing a biphenyl motif were designed and synthesized for biological evaluation. Among the compounds tested, compound 16l demonstrated high inhibitory activity against SGLT2 (IC50=1.9 nM) with an excellent pharmacokinetic profile. Further study indicated that the in vivo efficacy of compound 16l was comparable to that of dapagliflozin, suggesting that further development would be worthwhile. Copyright © 2015 Elsevier Ltd. All rights reserved.

Discovery of N-(4-aryl-5-aryloxy-thiazol-2-yl)-amides as potent RORγt inverse agonists.

PubMed

Wang, Yonghui; Yang, Ting; Liu, Qian; Ma, Yingli; Yang, Liuqing; Zhou, Ling; Xiang, Zhijun; Cheng, Ziqiang; Lu, Sijie; Orband-Miller, Lisa A; Zhang, Wei; Wu, Qianqian; Zhang, Kathleen; Li, Yi; Xiang, Jia-Ning; Elliott, John D; Leung, Stewart; Ren, Feng; Lin, Xichen

2015-09-01

A novel series of N-(4-aryl-5-aryloxy-thiazol-2-yl)-amides as RORγt inverse agonists was discovered. Binding mode analysis of a RORγt partial agonist (2c) revealed by co-crystal structure in RORγt LBD suggests that the inverse agonists do not directly interfere with the interaction between H12 and the RORγt LBD. Detailed SAR exploration led to identification of potent RORγt inverse agonists such as 3m with a pIC50 of 8.0. Selected compounds in the series showed reasonable activity in Th17 cell differentiation assay as well as low intrinsic clearance in mouse liver microsomes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Polymeric media comprising polybenzimidazoles N-substituted with organic-inorganic hybrid moiety

DOEpatents

Klaehn, John R [Idaho Falls, ID; Peterson, Eric S [Idaho Falls, ID; Wertsching, Alan K [Idaho Falls, ID; Orme, Christopher J [Shelley, ID; Luther, Thomas A [Idaho Falls, ID; Jones, Michael G [Pocatello, ID

2009-12-15

A PBI compound includes imidazole nitrogens at least a portion of which are substituted with an organic-inorganic hybrid moiety may be included in a separator medium. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2-- where R is selected from among methyl, phenyl, vinyl, and allyl. The separatory medium may exhibit an H.sub.2, Ar, N.sub.2, O.sub.2, CH.sub.3, or CO.sub.2 gas permeability greater than the gas permeability of a comparable separatory medium comprising the PBI compound without substitution. The separatory medium may further include an electronically conductive medium and/or ionically conductive medium. The separatory medium may be used as a membrane (semi-permeable, permeable, and non-permeable), a barrier, an ion exhcange media, a filter, a gas chromatography coating (such as stationary phase coating in affinity chromatography), etc.

Study of the Air-Tolerant 1,3-Diphosphacyclobutane-2,4-diyl through the Direct Arylation.

PubMed

Ito, Shigekazu

2018-04-01

Installing π-functional substituents on the skeletal phosphorus atoms of the air-tolerant 1,3-diphosphacyclobutane-2,4-diyl unit are promising for tuning the open-shell singlet P-heterocyclic chromophore. The sterically encumbered 1,3-diphosphaCycloButen-4-yl Anion (CBA), generated from the phosphorus-carbon triple bond, was available for the regioselective arylation via nucleophilic aromatic substitution (S N Ar) reaction, addition to arynes, and single-electron transfer (SET) process affording the corresponding P-arylated 1,3-diphosphacyclobutane-2,4-diyls. The photo-absorption and redox properties correlated with the effects of the aryl substituents on the 1,3-diphosphacyclobutane-2,4-diyl unit. The X-ray analyses enabled not only to discuss the metric parameters but also to visualize the radicalic electrons via the electron-density distribution analysis. The electron-donating character of the P-heterocyclic chromophores induced the p-type semiconductor behavior. Detection of hydrogen fluoride via formation of the 1λ 5 ,3λ 5 -diphosphete derivative was also developed. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Functionalized polyfluorenes for use in optoelectronic devices

DOEpatents

Chichak, Kelly Scott [Clifton Park, NY; Lewis, Larry Neil [Scotia, NY; Cella, James Anthony [Clifton Park, NY; Shiang, Joseph John [Niskayuna, NY

2011-11-08

The present invention relates to process comprising reacting a polyfluorenes comprising at least one structural group of formula I ##STR00001## with an iridium (III) compound of formula II ##STR00002## wherein R.sup.1 and R.sup.2 are independently alkyl, substituted alkyl, aryl, substituted aryl or a combination thereof; R.sup.5is H or CHO; R.sup.3 and R.sup.4 are independently hydrogen, alkyl, substituted alkyl, aryl, substituted aryl or a combination thereof; R.sup.11 and R.sup.12 taken together form a substituted or unsubstituted monocyclic or bicyclic heteroaromatic ring; R.sup.13 is independently at each occurrence halo, nitro, hydroxy, amino, alkyl, aryl, arylalkyl, alkoxy, substituted alkoxy, substituted alkyl, substituted aryl, or substituted arylalkyl; Ar is aryl, heteroaryl, substituted aryl, substituted heteroaryl, or a combination thereof; X is selected from a direct bond, alky, substituted alkyl, and combinations thereof; Y is CHO or NH.sub.2; Z is CHO or NH.sub.2 where Z does not equal Y; and p is 0, 1 or 2. The invention also relates to the polyfluorenes, which are products of the reaction, and the use of the polyfluorenes in optoelectronic devices.

Influence of Element Substitution on Corrosion Behavior of Bi2Te3-Based Compounds

NASA Astrophysics Data System (ADS)

Kohri, Hitoshi; Yagasaki, Takayoshi

2018-02-01

Atmospheric water may condense on the surface of Bi2Te3-based compounds constituting the Peltier module, depending on the operating environment used. In the stage of disposal, Bi2Te3-based compounds may come into contact with water in waste disposal sites. There are very few publications about the influence of condensed water on Peltier modules. Bi2Te3-Sb2Te3 or Bi2Te3-Bi2Se3 pseudo binary system compounds are used as p-type material or n-type material, respectively. The lattice distortion will be induced in the crystal of Bi2Te3-based compounds by element substitution due to the reduction in their thermal conductivity. However, the influence of element substitution on the corrosion behavior of Bi2Te3-based compounds remains unclear. In this study, the influence of element substitution on the corrosion behavior of Bi2Te3-based compounds with practical compositions has been investigated. Bi0.5Sb1.5Te3 or Bi2Te2.85Se0.15 was prepared by the vertical Bridgman method. The electrochemical properties at room temperature were evaluated by cyclic voltammetry in a standard three-electrode cell. The working electrolyte was a naturally aerated 0.6 or 3.0 mass% NaCl solution. From the tendency for corrosion potential for all the samples, the corrosion sensitivity of ternary compounds was slightly higher than that of binary compounds. From the trend of current density, it was found that Bi0.5Sb1.5Te3 had a corrosion resistance intermediate between Bi2Te3 and Sb2Te3. On the other hand, corrosion resistance was affected despite a small amount of Se substitution, and the corrosion resistance of Bi2Te2.85Se0.15 was close to or lower than that of Bi2Se3. From the observation results of the corrosion products, the trends of morphology and composition of corrosion products for Bi0.5Sb1.5Te3 or Bi2Te2.85Se0.15 were consistent with those of Sb2Te3 or Bi2Se3, respectively. From the results of x-ray photoelectron spectroscopy for the electrolyte after testing, the possibility that a

Influence of Element Substitution on Corrosion Behavior of Bi2Te3-Based Compounds

NASA Astrophysics Data System (ADS)

Kohri, Hitoshi; Yagasaki, Takayoshi

2018-06-01

Atmospheric water may condense on the surface of Bi2Te3-based compounds constituting the Peltier module, depending on the operating environment used. In the stage of disposal, Bi2Te3-based compounds may come into contact with water in waste disposal sites. There are very few publications about the influence of condensed water on Peltier modules. Bi2Te3-Sb2Te3 or Bi2Te3-Bi2Se3 pseudo binary system compounds are used as p-type material or n-type material, respectively. The lattice distortion will be induced in the crystal of Bi2Te3-based compounds by element substitution due to the reduction in their thermal conductivity. However, the influence of element substitution on the corrosion behavior of Bi2Te3-based compounds remains unclear. In this study, the influence of element substitution on the corrosion behavior of Bi2Te3-based compounds with practical compositions has been investigated. Bi0.5Sb1.5Te3 or Bi2Te2.85Se0.15 was prepared by the vertical Bridgman method. The electrochemical properties at room temperature were evaluated by cyclic voltammetry in a standard three-electrode cell. The working electrolyte was a naturally aerated 0.6 or 3.0 mass% NaCl solution. From the tendency for corrosion potential for all the samples, the corrosion sensitivity of ternary compounds was slightly higher than that of binary compounds. From the trend of current density, it was found that Bi0.5Sb1.5Te3 had a corrosion resistance intermediate between Bi2Te3 and Sb2Te3. On the other hand, corrosion resistance was affected despite a small amount of Se substitution, and the corrosion resistance of Bi2Te2.85Se0.15 was close to or lower than that of Bi2Se3. From the observation results of the corrosion products, the trends of morphology and composition of corrosion products for Bi0.5Sb1.5Te3 or Bi2Te2.85Se0.15 were consistent with those of Sb2Te3 or Bi2Se3, respectively. From the results of x-ray photoelectron spectroscopy for the electrolyte after testing, the possibility that a

Pseudoephedrine-Directed Asymmetric α-Arylation of α-Amino Acid Derivatives.

PubMed

Atkinson, Rachel C; Fernández-Nieto, Fernando; Mas Roselló, Josep; Clayden, Jonathan

2015-07-27

Available α-amino acids undergo arylation at their α position in an enantioselective manner on treatment with base of N'-aryl urea derivatives ligated to pseudoephedrine as a chiral auxiliary. In situ silylation and enolization induces diastereoselective migration of the N'-aryl group to the α position of the amino acid, followed by ring closure to a hydantoin with concomitant explulsion of the recyclable auxiliary. The hydrolysis of the hydantoin products provides derivatives of quaternary amino acids. The arylation avoids the use of heavy-metal additives, and is successful with a range of amino acids and with aryl rings of varying electronic character. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Substituted 2-benzothiazolamines as sodium flux inhibitors: quantitative structure-activity relationships and anticonvulsant activity.

PubMed

Hays, S J; Rice, M J; Ortwine, D F; Johnson, G; Schwarz, R D; Boyd, D K; Copeland, L F; Vartanian, M G; Boxer, P A

1994-10-01

Thirty-two aryl-substituted 2-benzothiazolamines have been tested for their ability to modulate sodium flux in rat cortical slices. A QSAR analysis, applied to these derivatives, showed a trend toward increasing potency as sodium flux inhibitors with increasing lipophilicity, decreasing size, and increasing electron withdrawal of the benzo ring substituents. Additionally, 4- or 5-substitution of the benzo ring was found to decrease potency. The combination of increased lipophilicity, small size, and electron withdrawal severely limited which groups were tolerated on the benzo ring, thus suggesting that the optimal substitution patterns have been prepared within this series. Nine of these compounds were potent inhibitors of veratridine-induced sodium flux (NaFl). These nine compounds also proved to be anticonvulsant in the maximal electroshock (MES) assay. Fourteen additional 2-benzothiazolamines demonstrated activity in the MES screen, yet exhibited no activity in the NaFl assay. These derivatives may be interacting at the sodium channel in a manner not discernible by the flux paradigm, or they may be acting by an alternative mechanism in vivo.

Reaction of the antitumor antibiotic olivomycin I with aryl diazonium salts. Synthesis, cytotoxic and antiretroviral potency of 5-aryldiazenyl-6-O-deglycosyl derivatives of olivomycin I.

PubMed

Tevyashova, Anna N; Olsufyeva, Eugenia N; Turchin, Konstantin F; Balzarini, Jan; Bykov, Eugenyi E; Dezhenkova, Lyubov G; Shtil, Alexander A; Preobrazhenskaya, Maria N

2009-07-15

The azo coupling of the antibiotic olivomycin I (1) with aryl diazonium tetrafluoroborates produced 5-aryldiazenyl-6-O-deglycosyl derivatives of 1. The structures of new compounds were confirmed by (1)H NMR and mass spectrometry analysis. A quantum-chemical study was performed to analyze the possible directions of electrophilic substitution of 1 and the easiness of 6-O-disaccharide hydrolysis in the course of azo coupling. The antiproliferative and anti-retroviral activities of novel derivatives were studied.

Comparison of aryl hydrocarbon hydroxylase and acetanilide 4-hydroxylase induction by polycyclic aromatic compounds in human and mouse cell lines.

PubMed

Jaiswal, A K; Nebert, D W; Eisen, H W

1985-08-01

The human MCF-7 and the mouse Hepa-1 cell culture lines were compared for aryl hydrocarbon hydroxylase and acetanilide 4-hydroxylase inducibility by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and benzo[a]anthracene (BA) and TCDD- and BA-specific binding in the cytosol and nucleus. The effective concentration of BA in the growth medium required to induce either enzyme to 50% of its maximally inducible activity (EC50) was the same (5-11 microM) in both MCF-7 and Hepa-1 cells. On the other hand, the EC50 for TCDD in MCF-7 cells (5-25 nM) was more than 40-fold greater than that in Hepa-1 cells (0.4 to 0.6 nM). P1-450- and P3-450-specific mouse cDNA probes were used to quantitate mRNA induction in the Hepa-1 cell line. P1-450 mRNA was induced markedly by TCDD and benzo[a] anthracene, whereas P3-450 mRNA was induced negligibly. A P1-450-specific human cDNA probe was used to quantitate P1-450 mRNA induction in the MCF-7 cell line. Aryl hydrocarbon hydroxylase inducibility by TCDD or BA always paralleled P1-450 mRNA inducibility in either the mouse or human line. Although the cytosolic Ah receptor in Hepa-1 cells was easily detected by sucrose density gradient centrifugation, gel permeation chromatography, and anion-exchange high-performance liquid chromatography, the cytosolic receptor cannot be detected in MCF-7 cells. Following in vivo exposure of cultures to radiolabeled TCDD, the intranuclear concentration of inducer-receptor complex was at least fifty times greater in Hepa-1 than MCF-7 cultures. The complete lack of measurable cytosolic receptor and almost totally absent inducer-receptor complex in the nucleus of MCF-7 cells was, therefore, out of proportion to its capacity for aryl hydrocarbon hydroxylase and acetanilide 4-hydroxylase inducibility. This MCF-7 line should provide an interesting model for a better understanding of the mechanisms of drug-metabolizing enzyme induction by polycyclic aromatic compounds, including the Ah receptor-mediated mechanism.

Palladium- and Copper-Catalyzed Arylation of Carbon-Hydrogen Bonds

PubMed Central

Daugulis, Olafs; Do, Hien-Quang; Shabashov, Dmitry

2010-01-01

The transition-metal-catalyzed functionalization of C-H bonds is a powerful method for generating carbon-carbon bonds. Although significant advances to this field have been reported during the last decade, many challenges remain. First, most of the methods are substrate-specific and thus cannot be generalized. Second, conversions of unactivated (i.e. not benzylic or alpha to heteroatom) sp3 C–H bonds to C–C bonds are rare, with most examples limited to t-butyl groups—a conversion that is inherently simple because there are no β-hydrogens that can be eliminated. Finally, the palladium, rhodium, and ruthenium catalysts routinely used for the conversion of C–H bonds to C–C bonds are expensive. Catalytically active metals that are cheaper and less exotic (e.g. copper, iron, and manganese) are rarely used. This Account describes our attempts to provide solutions to these three problems. We have developed a general method for directing-group-containing arene arylation by aryl iodides. Using palladium acetate as the catalyst, we arylated anilides, benzamides, benzoic acids, benzylamines, and 2-substituted pyridine derivatives under nearly identical conditions. We have also developed a method for the palladium-catalyzed auxiliary-assisted arylation of unactivated sp3 C–H bonds. This procedure allows for the β-arylation of carboxylic acid derivatives and the γ-arylation of amine derivatives. Furthermore, copper catalysis can be used to mediate the arylation of acidic arene C–H bonds (i.e. those with pKa values <35 in DMSO). Using a copper iodide catalyst in combination with a base and a phenanthroline ligand, we successfully arylated electron-rich and electron-deficient heterocycles and electron-poor arenes possessing at least two electron-withdrawing groups. The reaction exhibits unusual regioselectivity: arylation occurs at the most hindered position. This copper-catalyzed method supplements the well-known C–H activation/borylation methodology, in which

Palladium- and copper-catalyzed arylation of carbon-hydrogen bonds.

PubMed

Daugulis, Olafs; Do, Hien-Quang; Shabashov, Dmitry

2009-08-18

The transition-metal-catalyzed functionalization of C-H bonds is a powerful method for generating carbon-carbon bonds. Although significant advances to this field have been reported during the past decade, many challenges remain. First, most of the methods are substrate-specific and thus cannot be generalized. Second, conversions of unactivated (i.e., not benzylic or alpha to heteroatom) sp(3) C-H bonds to C-C bonds are rare, with most examples limited to t-butyl groups, a conversion that is inherently simple because there are no beta-hydrogens that can be eliminated. Finally, the palladium, rhodium, and ruthenium catalysts routinely used for the conversion of C-H bonds to C-C bonds are expensive. Catalytically active metals that are cheaper and less exotic (e.g., copper, iron, and manganese) are rarely used. This Account describes our attempts to provide solutions to these three problems. We have developed a general method for directing-group-containing arene arylation by aryl iodides. Using palladium acetate as the catalyst, we arylated anilides, benzamides, benzoic acids, benzylamines, and 2-substituted pyridine derivatives under nearly identical conditions. We have also developed a method for the palladium-catalyzed auxiliary-assisted arylation of unactivated sp(3) C-H bonds. This procedure allows for the beta-arylation of carboxylic acid derivatives and the gamma-arylation of amine derivatives. Furthermore, copper catalysis can be used to mediate the arylation of acidic arene C-H bonds (i.e., those with pK(a) values <35 in DMSO). Using a copper iodide catalyst in combination with a base and a phenanthroline ligand, we successfully arylated electron-rich and electron-deficient heterocycles and electron-poor arenes possessing at least two electron-withdrawing groups. The reaction exhibits unusual regioselectivity: arylation occurs at the most hindered position. This copper-catalyzed method supplements the well-known C-H activation/borylation methodology, in

Diaryl-substituted norbornadienes with red-shifted absorption for molecular solar thermal energy storage.

PubMed

Gray, Victor; Lennartson, Anders; Ratanalert, Phasin; Börjesson, Karl; Moth-Poulsen, Kasper

2014-05-25

Red-shifting the absorption of norbornadienes (NBDs), into the visible region, enables the photo-isomerization of NBDs to quadricyclanes (QCs) to be driven by sunlight. This is necessary in order to utilize the NBD-QC system for molecular solar thermal (MOST) energy storage. Reported here is a study on five diaryl-substituted norbornadienes. The introduced aryl-groups induce a significant red-shift of the UV/vis absorption spectrum of the norbornadienes, and device experiments using a solar-simulator set-up demonstrate the potential use of these compounds for MOST energy storage.

Volatilization of benzene and eight alkyl-substituted benzene compounds from water

USGS Publications Warehouse

Rathbun, R.E.; Tai, D.Y.

1988-01-01

Predicting the fate of organic compounds in streams and rivers often requires knowledge of the volatilization characteristics of the compounds. The reference-substance concept, involving laboratory-determined ratios of the liquid-film coefficients for volatilization of the organic compounds to the liquid-film coefficient for oxygen absorption, is used to predict liquid-film coefficients for streams and rivers. In the absence of experimental data, two procedures have been used for estimating these liquid-film coefficient ratios. These procedures, based on the molecular-diffusion coefficient and on the molecular weight, have been widely used but never extensively evaluated. Liquid-film coefficients for the volatilization of benzene and eight alkyl-substituted benzene compounds (toluene through n-octylbenzene) from water were measured in a constant-temperature, stirred water bath. Liquid-film coefficients for oxygen absorption were measured simultaneously. A range of water mixing conditions was used with a water temperature of 298.2 K. The ratios of the liquid-film coefficients for volatilization to the liquid-film coefficient for oxygen absorption for all of the organic compounds were independent of mixing conditions in the water. Experimental ratios ranged from 0.606 for benzene to 0.357 for n-octylbenzene. The molecular-diffusion-coefficient procedure accurately predicted the ratios for ethylbenzene through n-pentylbenzene with a power dependence of 0.566 on the molecular-diffusion coefficient, in agreement with published values. Predicted ratios for benzene and toluene were slightly larger than the experimental ratios. These differences were attributed to possible interactions between the molecules of these compounds and the water molecules and to benzene-benzene interactions that form dimers. Because these interactions also are likely to occur in natural waters, it was concluded that the experimental ratios are more correct than the predicted ratios for

Electronic regioselectivity of diarylalkynes in cobalt-mediated Pauson-Khand reaction: an experimental and computational study with para- and meta-substituted diarylalkynes and norbornene.

PubMed

Fager-Jokela, Erika; Muuronen, Mikko; Patzschke, Michael; Helaja, Juho

2012-10-19

Both steric and electronic factors of substituted alkynes are known to guide α/β-cyclopentenone regioselectivity in the cobalt-mediated Pauson-Khand reaction (PKR). In synthetic applications of the PKR, the steric factors can often override or render possible electronic effects. This study examined alkyne-dependent electronic regioselectivity of cyclopentenone formation in PKR with norbornene and sterically equivalent, but electronically unsymmetrical, meta- and para-substituted diarylethynyls to unveil the role of electronic effects alone. In agreement with the literature reports, EDG para-substituted aryls, to some extent, favored the cyclopentenone α-regioisomer, while the EWG-substituted aryls correspondingly preferred the β-regioisomer. The cooperation of EGW and EDG in diaryl-substituted alkynes did not lead to any increased regioselectivities that could be expected by a "push-pull" effect. Both EWG and EDG meta-substituted aryls preferred the β-regioisomer, which was demonstrated by 3,5-dimethoxy- and 3,5-bis(trifluoromethyl)-1-phenylethynyls that yielded 1/1.6 and 1/2.0 α/β-regioselectivities, respectively. Theoretically, inspection of Hammett values of α-alkyne carbons gave qualitatively satisfactory prediction for para-substituted aryls but correlated only weakly with meta-substituted effects. Computational investigations at the DFT level revealed a correlation between NBO charges and the regioselectivity. Overall, the results suggest that the polarity of an alkyne, also designated by the relative polarization of aryl α-carbons, dictates the regioselectivity in the absence of steric effects.

2-(Hetero(aryl)methylene)hydrazine-1-carbothioamides as potent urease inhibitors.

PubMed

Saeed, Aamer; Imran, Aqeel; Channar, Pervaiz A; Shahid, Mohammad; Mahmood, Wajahat; Iqbal, Jamshed

2015-02-01

A small series of 2-(hetero(aryl)methylene) hydrazine-1-carbothioamides including two aryl derivatives was synthesized and tested for their inhibitory activity against urease. Compound (E)-2-(Furan-2-ylmethylene) hydrazine-1-carbothioamide (3f), having a furan ring, was the most potent inhibitor of urease with an IC50 value of 0.58 μM. Molecular modeling was carried out through docking the designed compounds into the urease binding site to predict whether these derivatives have analogous binding mode to the urease inhibitors. The study revealed that all of the tested compounds bind with both metal atoms at the active site of the enzyme. The aromatic ring of the compounds forms ionic interactions with the residues, Ala(440), Asp(494), Ala(636), and Met(637). © 2014 John Wiley & Sons A/S.

Atropisomerism about Aryl-C(sp(3)) Bonds: Conformational Behavior of Substituted Phenylcyclohexanes in Solution.

PubMed

Flos, Manon; Lameiras, Pedro; Denhez, Clément; Mirand, Catherine; Berber, Hatice

2016-03-18

A catalytic hydrogenation of cannabidiol derivatives known as phenylcyclohexenes was used to prepare epimeric (1R,1S) and/or rotameric (M,P) phenylcyclohexanes. The reaction is diastereoselective, in favor of the 1S epimer, when large groups are attached to the phenyl ring. For each epimer, variable-temperature NMR experiments, including EXSY spectroscopy and DFT calculations, were used to determine the activation energies of the conformational exchange arising from the restricted rotation about the aryl-C(sp(3)) bond that led to two unequally populated rotamers. The conformational preference arises essentially from steric interactions between substituents vicinal to the pivot bond. The conformers of epimers (1S)-2e,f show high rotational barriers of up to 92 kJ mol(-1), unlike those of (1R)-2e,f and with much lower barriers of ∼72 kJ mol(-1). The height of the barriers not only depends on the substituents at the axis of chirality but also is influenced by the position of a methyl group on the monoterpene ring. The feature most favorable to high rotational barriers is when the methyl at C1 lies equatorially. This additional substituent effect, highlighted for the first time, seems fundamental to allowing atropisomerism in hindered ortho-substituted phenylcyclohexanes.

Palladium-Catalyzed, N-(2-Aminophenyl)acetamide-Assisted Ortho-Arylation of Substituted Benzamides: Application to the Synthesis of Urolithins B, M6, and M7.

PubMed

Reddy, M Damoder; Blanton, Alexandra N; Watkins, E Blake

2017-05-19

Pd-catalyzed, selective, monoarylation of ortho-C-H bonds of various benzamides with aryl/heteroaryl iodides has been realized using N-(2-aminophenyl)acetamide (APA) as a new bidentate directing group for the first time. The reaction was tolerant of a wide range of functional groups, and a variety of biaryl amide derivatives were successfully prepared in good to moderate yield. The utilization of N-(2-aminophenyl)acetamide as a novel directing group, Mn(OAc) 2 as a co-oxidant (silver free reaction conditions), and absolute ortho-monoaryl selectivity are notable features of this reaction. In addition, the obtained monoarylated products could be further transformed into the bioactive natural products and human microflora metabolites of dietary ellagic acid derivatives, urolithin B, urolithin M6, and urolithin M7.

A multidisciplinary study of 3-(β-d-glucopyranosyl)-5-substituted-1,2,4-triazole derivatives as glycogen phosphorylase inhibitors: Computation, synthesis, crystallography and kinetics reveal new potent inhibitors.

PubMed

Kun, Sándor; Begum, Jaida; Kyriakis, Efthimios; Stamati, Evgenia C V; Barkas, Thomas A; Szennyes, Eszter; Bokor, Éva; Szabó, Katalin E; Stravodimos, George A; Sipos, Ádám; Docsa, Tibor; Gergely, Pál; Moffatt, Colin; Patraskaki, Myrto S; Kokolaki, Maria C; Gkerdi, Alkistis; Skamnaki, Vassiliki T; Leonidas, Demetres D; Somsák, László; Hayes, Joseph M

2018-03-10

3-(β-d-Glucopyranosyl)-5-substituted-1,2,4-triazoles have been revealed as an effective scaffold for the development of potent glycogen phosphorylase (GP) inhibitors but with the potency very sensitive to the nature of the alkyl/aryl 5-substituent (Kun et al., Eur. J. Med. Chem. 2014, 76, 567). For a training set of these ligands, quantum mechanics-polarized ligand docking (QM-PLD) demonstrated good potential to identify larger differences in potencies (predictive index PI = 0.82) and potent inhibitors with K i 's < 10 μM (AU-ROC = 0.86). Accordingly, in silico screening of 2335 new analogues exploiting the ZINC docking database was performed and nine predicted candidates selected for synthesis. The compounds were prepared in O-perbenzoylated forms by either ring transformation of 5-β-d-glucopyranosyl tetrazole by N-benzyl-arenecarboximidoyl chlorides, ring closure of C-(β-d-glucopyranosyl)formamidrazone with aroyl chlorides, or that of N-(β-d-glucopyranosylcarbonyl)arenethiocarboxamides by hydrazine, followed by deprotections. Kinetics experiments against rabbit muscle GPb (rmGPb) and human liver GPa (hlGPa) revealed five compounds as potent low μM inhibitors with three of these on the submicromolar range for rmGPa. X-ray crystallographic analysis sourced the potency to a combination of favorable interactions from the 1,2,4-triazole and suitable aryl substituents in the GP catalytic site. The compounds also revealed promising calculated pharmacokinetic profiles. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Understanding and Exploitation of Neighboring Heteroatom Effect for the Mild N-Arylation of Heterocycles with Diaryliodonium Salts under Aqueous Conditions: A Theoretical and Experimental Mechanistic Study.

PubMed

Bihari, Tamás; Babinszki, Bence; Gonda, Zsombor; Kovács, Szabolcs; Novák, Zoltán; Stirling, András

2016-07-01

The mechanism of arylation of N-heterocycles with unsymmetric diaryliodonium salts is elucidated. The fast and efficient N-arylation reaction is interpreted in terms of the bifunctionality of the substrate: The consecutive actions of properly oriented Lewis base and Brønsted acid centers in sufficient proximity result in the fast and efficient N-arylation. The mechanistic picture points to a promising synthetic strategy where suitably positioned nucleophilic and acidic centers enable functionalization, and it is tested experimentally.

Iron-catalyzed, directed oxidative arylation of olefins with organozinc and Grignard reagents.

PubMed

Ilies, Laurean; Okabe, Jun; Yoshikai, Naohiko; Nakamura, Eiichi

2010-06-18

Chelation-controlled arylation of olefins with organozinc or Grignard reagents proceeds in the presence of an iron catalyst, under mild conditions and typically without the need of external ligands, to afford substituted olefins in high yield and with complete regio- and stereocontrol.

Copper-catalyzed aerobic oxidative C-H functionalization of substituted pyridines: synthesis of imidazopyridine derivatives.

PubMed

Yu, Jipan; Jin, Yunhe; Zhang, Hao; Yang, Xiaobo; Fu, Hua

2013-12-02

A novel, efficient, and practical method for the synthesis of imidazopyridine derivatives has been developed through the copper-catalyzed aerobic oxidative C-H functionalization of substituted pyridines with N-(alkylidene)-4H-1,2,4-triazol-4-amines. The procedure occurs by cleavage of the N-N bond in the N-(alkylidene)-4H-1,2,4-triazol-4-amines and activation of an aryl C-H bond in the substituted pyridines. This is the first example of the preparation of imidazopyridine derivatives by using pyridines as the substrates by transition-metal-catalyzed C-H functionalization. This method should provide a novel and efficient strategy for the synthesis of other nitrogen heterocycles. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of 2-aryl and 3-aryl benzo[b]furan thioethers using aryl sulfonyl hydrazides as sulfenylation reagents.

PubMed

Zhao, Xia; Zhang, Lipeng; Lu, Xiaoyu; Li, Tianjiao; Lu, Kui

2015-03-06

An efficient, metal-free protocol used to synthesize aryl benzo[b]furan thioethers based on the I2-catalyzed cross-coupling of benzo[b]furans as well as the electrophilic cyclization of 2-alkynylphenol derivatives with aryl sulfonyl hydrazides was developed. Various 2-aryl and 3-aryl benzo[b]furan thioethers were obtained in moderate to good yields.

Acute toxicity induced by 2-aryl-N-methylsuccinimides.

PubMed

Rankin, G O; Shih, H C; Teets, V J; Nicoll, D W; Brown, P I

1990-04-01

Phensuximide (PSX) is a 2-arylsuccinimide useful in the treatment of absence seizures. PSX is a mild urotoxicant and is structurally related to N-phenylsuccinimide (NPS) and its antifungal derivatives. Since substitution of the phenyl ring of NPS with chloro or tert-butyl groups can produce compounds with enhanced nephrotoxic potential, it was felt that similar substitutions on the phenyl ring of PSX also might produce derivatives with enhanced nephrotoxic potential. Three derivatives of PSX were prepared and tested: 2-(3-chlorophenyl)-N-methylsuccinimide (CPMS); 2-(4-tert-butylphenyl)-N-methylsuccinimide (BPMS) and 2-(3,5-dichlorophenyl)-N-methylsuccinimide (DPMS). In one set of experiments, male Fischer 344 rats were administered a single intraperitoneal (i.p.) injection of a succinimide (0.4 or 1.0 mmol kg-1) or vehicle (sesame oil, 2.5 ml kg-1) and renal function monitored at 24 and 48 h. Only minor changes in renal function were noted with the PSX derivatives. BPMS and DPMS (1.0 mmol kg-1) treatment induced mild renal tubular necrosis and thickening of the glomerular membranes. However, no significant morphological changes were noted in ureters, bladder or liver in any treatment group. In a second set of experiments, rats were pretreated with phenobarbital (75 mg kg-1 day-1, i.p., 3 days) followed by a single i.p. injection of DPMS (0.4 or 1.0 mmol kg-1) or DPMS vehicle. Renal function was monitored as before. Phenobarbital pretreatment did not markedly enhance the functional nephrotoxicity induced by DPMS (0.4 mmol), but tubular necrosis was greater than observed in non-phenobarbital-pretreated rats receiving DPMS (1.0 mmol kg-1). In addition, hepatotoxicity was observed as the appearance of numerous non-staining vacuoles in hypertrophied hepatocytes. In the phenobarbital plus DPMS (1.0 mmol kg-1) treatment group, all rats died by 48 h. Prior to death, rats exhibited increased proteinuria (+3), hematuria (+3) and blood urea nitrogen concentration. At 24 h

Design and Synthesis of Candidate Prophylactic and Therapeutic Compounds for Use in the Management of Organophosphorus Poisoning.

DTIC Science & Technology

1985-01-01

resynthesis. The Grignard reagent , prepared from 4- chlorobromobenzene and magnesium metal, was treated with NN-diethyl-P- methylphosphonamidic chloride and the...ref. 26-28). Thus, diethylaminodichlorophosphine was treated with two equivalents of butyl Grignard reagent to give phosphinous amide 1 in 63% yield...compound following a general method developed by Ash Stevens Inc. for the synthesis of substituted aryl methylphosphinates. Thus, the Grignard reagent

Structural modifications of N-(1,2,3,4-tetrahydronaphthalen-1-yl)-4-aryl-1-piperazinehexanamides: influence on lipophilicity and 5-HT7 receptor activity. Part III.

PubMed

Leopoldo, Marcello; Lacivita, Enza; De Giorgio, Paola; Fracasso, Claudia; Guzzetti, Sara; Caccia, Silvio; Contino, Marialessandra; Colabufo, Nicola A; Berardi, Francesco; Perrone, Roberto

2008-09-25

Starting from the previously reported 5-HT 7 receptor agents 4-7 with N-(1,2,3,4-tetrahydronaphthalen-1-yl)-4-aryl-1-piperazinehexanamide structure, the 1-(2-methylthiophenyl)-, 1-(2-diphenyl)-, 1-(2-isopropylphenyl)-, and 1-(2-methoxyphenyl)piperazine derivatives 8-31 were designed with the primary aim to obtain new compounds endowed with suitable physicochemical properties for rapid and extensive penetration into the brain. The affinities for 5-HT 7, 5-HT 1A, and D 2 receptors of compounds 8-31 were assessed, and several compounds displayed 5-HT 7 receptor affinities in the nanomolar range. Among these, N-(4-cyanophenylmethyl)-4-(2-diphenyl)-1-piperazinehexanamide (25) showed high 5-HT 7 receptor affinity (Ki = 0.58 nM), high selectivity over 5-HT 1A and D 2 receptors (324- and 245-fold, respectively), and agonist properties (maximal effect = 82%, EC 50 = 0.60 microM). After intraperitoneal injection in mice, 25 rapidly reached the systemic circulation and entered the brain. Its brain concentration-time profile paralleled that in plasma, indicating that 25 rapidly and freely distributes across the blood-brain barrier. Compound 25 underwent N-dealkylation to the corresponding 1-arylpiperazine metabolite.

Palladium-Catalyzed Arylation of Fluoroalkylamines

PubMed Central

Brusoe, Andrew T.; Hartwig, John F.

2015-01-01

We report the synthesis of fluorinated anilines by palladium-catalyzed coupling of fluoroalkylamines with aryl bromides and aryl chlorides. The products of these reactions are valuable because anilines typically require the presence of an electron-withdrawing substituent on nitrogen to suppress aerobic or metabolic oxidation, and the fluoroalkyl groups have steric properties and polarity distinct from those of more common electron-withdrawing amide and sulfonamide units. The fluoroalkylaniline products are unstable under typical conditions for C–N coupling reactions (heat and strong base). However, the reactions conducted with the weaker base KOPh, which has rarely been used in cross-coupling to form C–N bonds, occurred in high yield in the presence of a catalyst derived from commercially available AdBippyPhos and [Pd(allyl)Cl]2. Under these conditions, the reactions occur with low catalyst loadings (<0.50 mol % for most substrates) and tolerate the presence of various functional groups that react with the strong bases that are typically used in Pd-catalyzed C–N cross-coupling reactions of aryl halides. The resting state of the catalyst is the phenoxide complex, (BippyPhosPd(Ar)OPh); due to the electron-withdrawing property of the fluoroalkyl substituent, the turnover-limiting step of the reaction is reductive elimination to form the C–N bond. PMID:26065341

Palladium-Catalyzed Indole, Pyrrole, and Furan Arylation by Aryl Chlorides

PubMed Central

Nadres, Enrico T.; Lazareva, Anna; Daugulis, Olafs

2011-01-01

The palladium-catalyzed direct arylation of indoles, pyrroles, and furans by aryl chlorides has been demonstrated. The method employs a palladium acetate catalyst, 2-(dicyclohexylphosphino)-biphenyl ligand, and an inorganic base. Electron-rich and electron-poor aryl chlorides as well as chloropyridine coupling partners can be used and arylated heterocycles are obtained in moderate to good yields. Optimization of base, ligand, and solvent is required for achieving best results. PMID:21192652

Design, synthesis, and anti-HIV-1 activity of 1-aromatic methyl-substituted 3-(3,5-dimethylbenzyl)uracil and N-3,5-dimethylbenzyl-substituted urea derivatives

PubMed Central

Sakakibara, Norikazu; Baba, Masanori; Okamoto, Mika; Toyama, Masaaki; Demizu, Yosuke; Misawa, Takashi; Kurihara, Masaaki; Irie, Kohji; Kato, Yoshihisa; Maruyama, Tokumi

2015-01-01

Background A new series of 1-aromatic methyl-substituted 3-(3,5-dimethylbenzyl)uracil and N-3,5-dimethylbenzyl-substituted urea derivatives were synthesized and evaluated as non-nucleoside HIV-1 reverse transcriptase inhibitors. Methods A series of new 6-azido and 6-amino derivatives of 1-substituted-3-(3,5-dimethylbenzyl)uracils were synthesized using our previously reported method, and three acyclic derivatives were synthesized from urea. The anti-HIV-1 activities of these compounds were determined based on the inhibition of virus-induced cytopathogenicity in MT-4 cells. The cytotoxicities of the compounds were evaluated using the viability of mock-infected cells. Results Some of these compounds showed good-to-moderate activities against HIV-1 with half maximal effective concentration (EC50) values in the submicromolar or subnanomolar range. Compared with emivirine, compound 6-amino-3-(3,5-dimethylbenzyl)-1-(4-aminobenzyl)uracil showed significant anti-HIV-1 activity with an EC50 value of 10 nM and a high selectivity index of 1923. Preliminary structure–activity relationship studies and molecular modeling analyses were carried out to explore the major interactions between HIV-1 reverse transcriptase and the potent inhibitor 6-amino-3-(3,5-dimethylbenzyl)-1-(4-aminobenzyl)uracil; these results may be important for further development of this class of compounds as anti-HIV-1 agents. Conclusion The excellent activity of 6-amino-3-(3,5-dimethylbenzyl)-1-(4-aminobenzyl)uracil (EC50: 0.010 ± 0.006 µM, SI: >1923) may serve as the basis for conducting further investigations on the behavior of this class of compounds against drug-resistant mutants. PMID:26149262

C-H bond functionalization via hydride transfer: formation of α-arylated piperidines and 1,2,3,4-tetrahydroisoquinolines via stereoselective intramolecular amination of benzylic C-H bonds.

PubMed

Vadola, Paul A; Carrera, Ignacio; Sames, Dalibor

2012-08-17

We here report a study of the intramolecular amination of sp(3) C-H bonds via the hydride transfer cyclization of N-tosylimines (HT-amination). In this transformation, 5-aryl aldehydes are subjected to N-toluenesulfonamide in the presence of BF(3)·OEt(2) to effect imine formation and HT-cyclization, leading to 2-arylpiperidines and 3-aryl-1,2,3,4-tetrahydroisoquinolines in a one-pot procedure. We examined the reactivity of a range of aldehyde substrates as a function of their conformational flexibility. Substrates of higher conformational rigidity were more reactive, giving higher yields of the desired products. However, a single substituent on the alkyl chain linking the N-tosylimine and the benzylic sp(3) C-H bonds was sufficient for HT-cyclization to occur. In addition, an examination of various arenes revealed that the electronic character of the hydridic C-H bonds dramatically affects the efficiency of the reaction. We also found that this transformation is highly stereoselective; 2-substituted aldehydes yield cis-2,5-disubstituted piperidines, while 3-substituted aldehydes afford trans-2,4-disubstituted piperidines. The stereoselectivity is a consequence of thermodynamic control. The pseudoallylic strain between the arene and tosyl group on the piperidine ring is proposed to rationalize the greater stability of the isomer with the aryl ring in the axial position. This preferential placement of the arene is proposed to affect the observed stereoselectivity.

Rational enhancement of second-order nonlinearity: bis-(4-methoxyphenyl)hetero-aryl-amino donor-based chromophores: design, synthesis, and electrooptic activity.

PubMed

Davies, Joshua A; Elangovan, Arumugasamy; Sullivan, Philip A; Olbricht, Benjamin C; Bale, Denise H; Ewy, Todd R; Isborn, Christine M; Eichinger, Bruce E; Robinson, Bruce H; Reid, Philip J; Li, Xiaosong; Dalton, Larry R

2008-08-13

Two new highly hyperpolarizable chromophores, based on N,N- bis-(4-methoxyphenyl) aryl-amino donors and phenyl-trifluoromethyl-tricyanofuran (CF3-Ph-TCF) acceptor linked together via pi-conjugation through 2,5-divinylenethienyl moieties as the bridge, have been designed and synthesized successfully for the first time. The aryl moieties on the donor side of the chromophore molecules were varied as to be thiophene and 1-n-hexylpyrrole. The linear and nonlinear optical (NLO) properties of all compounds were evaluated in addition to recording relevant thermal and electrochemical data. The properties of the two new molecules were comparatively studied. These results are critically analyzed along with two other compounds, reported earlier from our laboratories and our collaborator's, that contain (i) aliphatic chain-bearing aniline and (ii) dianisylaniline as donors, keeping the bridge (2,5-divinylenethienyl-), and the acceptor (CF3-Ph-TCF), constant. Trends in theoretically (density functional theory, DFT) predicted, zero-frequency gas-phase hyperpolarizability [beta(0;0,0)] values are shown to be consistent with the trends in beta HRS(-2omega;omega,omega), as measured by Hyper-Rayleigh Scattering (HRS), when corrected to zero-frequency using the two-level model (TLM) approximation. Similarly, trends in poling efficiency data (r33/E(p)) and wavelength dispersion measured by reflection ellipsometry (using a Teng-Man apparatus) and attenuated total reflection (ATR) are found to fit the TLM and DFT predictions. A 3-fold enhancement in bulk nonlinearity (r33) is realized as the donor subunits are changed from alkylaniline to dianisylaminopyrrole donors. The results of these studies provide insight into the complicated effects on molecular hyperpolarizability of substituting heteroaromatic subunits into the donor group structures. These studies also demonstrate that, when frequency dependence and electric-field-induced ordering behavior are correctly accounted for, ab initio

Synthesis and Utilization of Trialkylammonium-Substituted Cyclodextrins as Water-Soluble Chiral NMR Solvating Agents for Anionic Compounds.

PubMed

Dowey, Alison E; Puentes, Cira Mollings; Carey-Hatch, Mira; Sandridge, Keyana L; Krishna, Nikhil B; Wenzel, Thomas J

2016-04-01

Cationic trialkylammonium-substituted α-, β-, and γ-cyclodextrins containing trimethyl-, triethyl-, and tri-n-propylammonium substituent groups were synthesized and analyzed for utility as water-soluble chiral nuclear magnetic resonance (NMR) solvating agents. Racemic and enantiomerically pure (3-chloro-2-hydroxypropyl)trimethyl-, triethyl-, and tri-n-propyl ammonium chloride were synthesized from the corresponding trialkyl amine hydrochloride and either racemic or enantiomerically pure epichlorohydrin. The ammonium salts were then reacted with α-, β-, and γ-cyclodextrins at basic pH to provide the corresponding randomly substituted cationic cyclodextrins. The (1) H NMR spectra of a range of anionic, aromatic compounds was recorded with the cationic cyclodextrins. Cyclodextrins with a single stereochemistry at the hydroxy group on the (2-hydroxypropyl)trialkylammonium chloride substituent were often but not always more effective than the corresponding cyclodextrin in which the C-2 position was racemic. In several cases, the larger triethyl or tri-n-propyl derivatives were more effective than the corresponding trimethyl derivative at causing enantiomeric differentiation. None of the cyclodextrin derivatives were consistently the most effective for all of the anionic compounds studied. © 2016 Wiley Periodicals, Inc.

Amphoteric Be in GaN: Experimental Evidence for Switching between Substitutional and Interstitial Lattice Sites

NASA Astrophysics Data System (ADS)

Tuomisto, Filip; Prozheeva, Vera; Makkonen, Ilja; Myers, Thomas H.; Bockowski, Michal; Teisseyre, Henryk

2017-11-01

We show that Be exhibits amphoteric behavior in GaN, involving switching between substitutional and interstitial positions in the lattice. This behavior is observed through the dominance of BeGa in the positron annihilation signals in Be-doped GaN, while the emergence of VGa at high temperatures is a consequence of the Be impurities being driven to interstitial positions. The similarity of this behavior to that found for Na and Li in ZnO suggests that this could be a universal property of light dopants substituting for heavy cations in compound semiconductors.

Amphoteric Be in GaN: Experimental Evidence for Switching between Substitutional and Interstitial Lattice Sites.

PubMed

Tuomisto, Filip; Prozheeva, Vera; Makkonen, Ilja; Myers, Thomas H; Bockowski, Michal; Teisseyre, Henryk

2017-11-10

We show that Be exhibits amphoteric behavior in GaN, involving switching between substitutional and interstitial positions in the lattice. This behavior is observed through the dominance of Be_{Ga} in the positron annihilation signals in Be-doped GaN, while the emergence of V_{Ga} at high temperatures is a consequence of the Be impurities being driven to interstitial positions. The similarity of this behavior to that found for Na and Li in ZnO suggests that this could be a universal property of light dopants substituting for heavy cations in compound semiconductors.

Structure of aryl O -demethylase offers molecular insight into a catalytic tyrosine-dependent mechanism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohler, Amanda C.; Mills, Matthew J. L.; Adams, Paul D.

Some strains of soil and marine bacteria have evolved intricate metabolic pathways for using environmentally derived aromatics as a carbon source. Many of these metabolic pathways go through intermediates such as vanillate, 3-O-methylgallate, and syringate. Demethylation of these compounds is essential for downstream aryl modification, ring opening, and subsequent assimilation of these compounds into the tricarboxylic acid (TCA) cycle, and, correspondingly, there are a variety of associated aryl demethylase systems that vary in complexity. Intriguingly, only a basic understanding of the least complex system, the tetrahydrofolate-dependent aryl demethylase LigM from Sphingomonas paucimobilis, a bacterial strain that metabolizes lignin-derived aromatics, wasmore » previously available. LigM-catalyzed demethylation enables further modification and rin g opening of the single-ring aromatics vanillate and 3-Omethylgallate, which are common byproducts of biofuel production. We characterize aryl O-demethylation by LigM and report its 1.81-Å crystal structure, revealing a unique demethylase fold and a canonical folate-binding domain. Structural homology and geometry optimization calculations enabled the identification of LigM's tetrahydrofolate-binding site and protein-folate interactions. Computationally guided mutagenesis and kinetic analyses allowed the identification of the enzyme's aryl-binding site location and determination of its unique, catalytic tyrosine-dependent reaction mechanism. This work defines LigM as a distinct demethylase, both structurally and functionally, and provides insight into demethylation and its reaction requirements. Our results afford the mechanistic details required for efficient utilization of LigM as a tool for aryl O-demethylation and as a component of synthetic biology efforts to valorize previously underused aromatic compounds.« less

Structure of aryl O -demethylase offers molecular insight into a catalytic tyrosine-dependent mechanism

DOE PAGES

Kohler, Amanda C.; Mills, Matthew J. L.; Adams, Paul D.; ...

2017-04-03

Some strains of soil and marine bacteria have evolved intricate metabolic pathways for using environmentally derived aromatics as a carbon source. Many of these metabolic pathways go through intermediates such as vanillate, 3-O-methylgallate, and syringate. Demethylation of these compounds is essential for downstream aryl modification, ring opening, and subsequent assimilation of these compounds into the tricarboxylic acid (TCA) cycle, and, correspondingly, there are a variety of associated aryl demethylase systems that vary in complexity. Intriguingly, only a basic understanding of the least complex system, the tetrahydrofolate-dependent aryl demethylase LigM from Sphingomonas paucimobilis, a bacterial strain that metabolizes lignin-derived aromatics, wasmore » previously available. LigM-catalyzed demethylation enables further modification and rin g opening of the single-ring aromatics vanillate and 3-Omethylgallate, which are common byproducts of biofuel production. We characterize aryl O-demethylation by LigM and report its 1.81-Å crystal structure, revealing a unique demethylase fold and a canonical folate-binding domain. Structural homology and geometry optimization calculations enabled the identification of LigM's tetrahydrofolate-binding site and protein-folate interactions. Computationally guided mutagenesis and kinetic analyses allowed the identification of the enzyme's aryl-binding site location and determination of its unique, catalytic tyrosine-dependent reaction mechanism. This work defines LigM as a distinct demethylase, both structurally and functionally, and provides insight into demethylation and its reaction requirements. Our results afford the mechanistic details required for efficient utilization of LigM as a tool for aryl O-demethylation and as a component of synthetic biology efforts to valorize previously underused aromatic compounds.« less

Cloning and heterologous expression of two aryl-aldehyde dehydrogenases from the white-rot basidiomycete Phanerochaete chrysosporium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, Tomofumi; Fukuoka Institute of Health and Environmental Sciences, 39 Mukaizano, Dazaifu-shi, Fukuoka 818-0135; Ichinose, Hirofumi

2010-04-09

We identified two aryl-aldehyde dehydrogenase proteins (PcALDH1 and PcALDH2) from the white-rot basidiomycete Phanerochaete chrysosporium. Both PcALDHs were translationally up-regulated in response to exogenous addition of vanillin, one of the key aromatic compounds in the pathway of lignin degradation by basidiomycetes. To clarify the catalytic functions of PcALDHs, we isolated full-length cDNAs encoding these proteins and heterologously expressed the recombinant enzymes using a pET/Escherichia coli system. The open reading frames of both PcALDH1 and PcALDH2 consisted of 1503 nucleotides. The deduced amino acid sequences of both proteins showed high homologies with aryl-aldehyde dehydrogenases from other organisms and contained ten conservedmore » domains of ALDHs. Moreover, a novel glycine-rich motif 'GxGxxxG' was located at the NAD{sup +}-binding site. The recombinant PcALDHs catalyzed dehydrogenation reactions of several aryl-aldehyde compounds, including vanillin, to their corresponding aromatic acids. These results strongly suggested that PcALDHs metabolize aryl-aldehyde compounds generated during fungal degradation of lignin and various aromatic xenobiotics.« less

Nitrosation of aryl and heteroaryltrifluoroborates with nitrosonium tetrafluoroborate.

PubMed

Molander, Gary A; Cavalcanti, Livia N

2012-05-04

Organotrifluoroborates have emerged as an alternative to toxic and air- and moisture-sensitive organometallic species for the synthesis of functionalized aryl and heteroaryl compounds. It has been shown that the trifluoroborate moiety can be easily converted into a variety of different substituents in a late synthetic stage. In this paper, we disclose a mild, selective, and convenient method for the ipso-nitrosation of organotrifluoroborates using nitrosonium tetrafluoroborate (NOBF(4)). Aryl- and heteroaryltrifluoroborates were converted into the corresponding nitroso products in good to excellent yields. This method proved to be tolerant of a broad range of functional groups.

NITROSATION OF ARYL AND HETEROARYLTRIFLUOROBORATES WITH NITROSONIUM TETRAFLUOROBORATE

PubMed Central

Cavalcanti, Livia N.

2012-01-01

Organotrifluoroborates have emerged as an alternative to toxic and air- and moisture sensitive organometallic species for the synthesis of functionalized aryl and heteroaryl compounds. It has been shown that the trifluoroborate moiety can be easily converted into a variety of different substituents in a late synthetic stage. In this paper we disclose a mild, selective, and convenient method for the ipso-nitrosation of organotrifluoroborates using nitrosonium tetrafluoroborate (NOBF4). Aryl- and heteroaryltrifluoroborates were converted into the corresponding nitroso products in good to excellent yields. This method proved to be tolerant of a broad range of functional groups. PMID:22524190

General and mild Ni(0)-catalyzed α-arylation of ketones using aryl chlorides.

PubMed

Fernández-Salas, José A; Marelli, Enrico; Cordes, David B; Slawin, Alexandra M Z; Nolan, Steven P

2015-03-02

A general methodology for the α-arylation of ketones using a nickel catalyst has been developed. The new well-defined [Ni(IPr*)(cin)Cl] (1 c) pre-catalyst showed great efficiency for this transformation, allowing the coupling of a wide range of ketones, including acetophenone derivatives, with various functionalised aryl chlorides. This cinnamyl-based Ni-N-heterocyclic carbene (NHC) complex has demonstrated a different behaviour to previously reported NHC-Ni catalysts. Preliminary mechanistic studies suggest a Ni(0)/Ni(II) catalytic cycle to be at play. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, crystal structures, computational studies and antimicrobial activity of new designed bis((5-aryl-1,3,4-oxadiazol-2-yl)thio)alkanes

NASA Astrophysics Data System (ADS)

Ahmed, Muhammad Naeem; Sadiq, Beenish; Al-Masoudi, Najim A.; Yasin, Khawaja Ansar; Hameed, Shahid; Mahmood, Tariq; Ayub, Khurshid; Tahir, Muhammad Nawaz

2018-03-01

A new series of bis((5-aryl-1,3,4-oxadiazol-2-yl)thio)alkanes 4-14 have been synthesized via nucleophilic substitution reaction of dihaloalkanes with respective 1,3,4-oxadiazole-2-thiols 3a-f, and characterized by spectroscopic techniques. The structures of 4 and 12 were unambiguously confirmed by single-crystal X-ray diffraction analysis. Density functional theory calculations at B3LYP/6-31 + G(d) level of theory were performed for comparison of X-ray geometric parameters, molecular electrostatic potential (MEP) and frontier molecular orbital analyses of synthesized compounds. MEP analysis revealed that these compounds are nucleophilic in nature. Frontier molecular orbitals (FMOs) analysis of 4-14 was performed for evaluation of kinetic stability. All synthesized compounds were screened in vitro for antimicrobial activity against three bacterial and three fungal strains and showed promising results.

Practical Iron- and Cobalt-Catalyzed Cross-Coupling Reactions between N-Heterocyclic Halides and Aryl or Heteroaryl Magnesium Reagents.

PubMed

Kuzmina, Olesya M; Steib, Andreas K; Fernandez, Sarah; Boudot, Willy; Markiewicz, John T; Knochel, Paul

2015-05-26

The reaction scope of iron- and cobalt-catalyzed cross-coupling reactions in the presence of isoquinoline (quinoline) in the solvent mixture tBuOMe/THF has been further investigated. Various 2-halogenated pyridine, pyrimidine, and triazine derivatives were arylated under these mild conditions in excellent yields. The presence of isoquinoline allows us to perform Fe-catalyzed cross-coupling reactions between 6-chloroquinoline and aryl magnesium reagents. Furthermore, it was found that the use of 10% N,N-dimethylquinoline-8-amine increases the yields of some Co-catalyzed cross-coupling reactions with chloropyridines bearing electron-withdrawing substituents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Substituted N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamides: potent anticonvulsants that affect frequency (use) dependence and slow inactivation of sodium channels.

PubMed

Lee, Hyosung; Park, Ki Duk; Torregrosa, Robert; Yang, Xiao-Fang; Dustrude, Erik T; Wang, Yuying; Wilson, Sarah M; Barbosa, Cindy; Xiao, Yucheng; Cummins, Theodore R; Khanna, Rajesh; Kohn, Harold

2014-07-24

We prepared 13 derivatives of N-(biphenyl-4'-yl)methyl (R)-2-acetamido-3-methoxypropionamide that differed in type and placement of a R-substituent in the terminal aryl unit. We demonstrated that the R-substituent impacted the compound's whole animal and cellular pharmacological activities. In rodents, select compounds exhibited excellent anticonvulsant activities and protective indices (PI=TD50/ED50) that compared favorably with clinical antiseizure drugs. Compounds with a polar, aprotic R-substituent potently promoted Na+ channel slow inactivation and displayed frequency (use) inhibition of Na+ currents at low micromolar concentrations. The possible advantage of affecting these two pathways to decrease neurological hyperexcitability is discussed.

Metal-Mediated Halogen Exchange in Aryl and Vinyl Halides: A Review

PubMed Central

Evano, Gwilherm; Nitelet, Antoine; Thilmany, Pierre; Dewez, Damien F.

2018-01-01

Halogenated arenes and alkenes are of prime importance in many areas of science, especially in the pharmaceutical, agrochemical, and chemical industries. While the simplest ones are commercially available, some of them are still hardly accessible depending on their substitution patterns and the nature of the halogen atom. Reactions enabling the selective and efficient replacement of the halogen atom of an aryl or alkenyl halide by another one, lighter, or heavier, are therefore of major importance since they can be used for example to turn a less reactive aryl/alkenyl chloride into the more reactive iodinated derivatives or, in a reversed sense, to block an undesired reactivity, for late-stage modifications or for the introduction of a radionuclide. If some halogen exchange reactions are possible with activated substrates, they usually require catalysis with metal complexes. Remarkably efficient processes have been developed for metal-mediated halogen exchange in aryl and vinyl halides: they are overviewed, in a comprehensive manner, in this review article. PMID:29755967

Metal-Mediated Halogen Exchange in Aryl and Vinyl Halides: a Review

NASA Astrophysics Data System (ADS)

Evano, Gwilherm; Nitelet, Antoine; Thilmany, Pierre; Dewez, Damien F.

2018-04-01

Halogenated arenes and alkenes are of prime importance in many areas of science, especially in the pharmaceutical, agrochemical and chemical industries. While the simplest ones are commercially available, some of them are still hardly accessible depending on their substitution patterns and the nature of the halogen atom. Reactions enabling the selective and efficient replacement of the halogen atom of an aryl or alkenyl halide by another one, lighter or heavier, are therefore of major importance since they can be used for example to turn a less reactive aryl/alkenyl chloride into the more reactive iodinated derivatives or, in a reversed sense, to block an undesired reactivity, for late-stage modifications or for the introduction of a radionuclide. If some halogen exchange reactions are possible with activated substrates, they usually require catalysis with metal complexes. Remarkably efficient processes have been developed for metal-mediated halogen exchange in aryl and vinyl halides: they are overviewed, in a comprehensive manner, in this review article.

Design, synthesis, and anti-HIV-1 activity of 1-aromatic methyl-substituted 3-(3,5-dimethylbenzyl)uracil and N-3,5-dimethylbenzyl-substituted urea derivatives.

PubMed

Sakakibara, Norikazu; Baba, Masanori; Okamoto, Mika; Toyama, Masaaki; Demizu, Yosuke; Misawa, Takashi; Kurihara, Masaaki; Irie, Kohji; Kato, Yoshihisa; Maruyama, Tokumi

2015-02-01

A new series of 1-aromatic methyl-substituted 3-(3,5-dimethylbenzyl)uracil and N-3,5-dimethylbenzyl-substituted urea derivatives were synthesized and evaluated as non-nucleoside HIV-1 reverse transcriptase inhibitors. A series of new 6-azido and 6-amino derivatives of 1-substituted-3-(3,5-dimethylbenzyl)uracils were synthesized using our previously reported method, and three acyclic derivatives were synthesized from urea. The anti-HIV-1 activities of these compounds were determined based on the inhibition of virus-induced cytopathogenicity in MT-4 cells. The cytotoxicities of the compounds were evaluated using the viability of mock-infected cells. Some of these compounds showed good-to-moderate activities against HIV-1 with half maximal effective concentration (EC50) values in the submicromolar or subnanomolar range. Compared with emivirine, compound 6-amino-3-(3,5-dimethylbenzyl)-1-(4-aminobenzyl)uracil showed significant anti-HIV-1 activity with an EC50 value of 10 nM and a high selectivity index of 1923. Preliminary structure-activity relationship studies and molecular modeling analyses were carried out to explore the major interactions between HIV-1 reverse transcriptase and the potent inhibitor 6-amino-3-(3,5-dimethylbenzyl)-1-(4-aminobenzyl)uracil; these results may be important for further development of this class of compounds as anti-HIV-1 agents. The excellent activity of 6-amino-3-(3,5-dimethylbenzyl)-1-(4-aminobenzyl)uracil (EC50: 0.010 ± 0.006 µM, SI: >1923) may serve as the basis for conducting further investigations on the behavior of this class of compounds against drug-resistant mutants. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Alternative mechanistic explanation for ligand-dependent selectivities in copper-catalyzed N- and O-arylation reactions.

PubMed

Yu, Hai-Zhu; Jiang, Yuan-Ye; Fu, Yao; Liu, Lei

2010-12-29

The ligand-dependent selectivities in Ullmann-type reactions of amino alcohols with iodobenzene by β-diketone- and 1,10-phenanthroline-ligated Cu(I) complexes were recently explained by the single-electron transfer and iodine atom transfer mechanisms (Jones, G. O., Liu, P., Houk, K. N., and Buchwald, S. L. J. Am. Chem. Soc. 2010, 132, 6205.). The present study shows that an alternative, oxidative addition/reductive elimination mechanism may also explain the selectivities. Calculations indicate that a Cu(I) complex with a negatively charged β-diketone ligand is electronically neutral, so that oxidative addition of ArI to a β-diketone-ligated Cu(I) prefers to occur (and occur readily) in the absence of the amino alcohol. Thus, coordination of the amino alcohol in its neutral form can only occur at the Cu(III) stage where N-coordination is favored over O-coordination. The coordination step is the rate-limiting step and the outcome is that N-arylation is favored with the β-diketone ligand. On the other hand, a Cu(I) complex with a neutral 1,10-phenanthroline ligand is positively charged, so that oxidative addition of ArI to a 1,10-phenanthroline-ligated Cu(I) has to get assistance from a deprotonated amino alcohol substrate. This causes oxidative addition to become the rate-limiting step in the 1,10-phenanthroline-mediated reaction. The immediate product of the oxidative addition step is found to undergo facile reductive elimination to provide the arylation product. Because O-coordination of a deprotonated amino alcohol is favored over N-coordination in the oxidative addition transition state, O-arylation is favored with the 1,10-phenanthroline ligand.

Synthesis of some N-substituted indole derivatives and their biological activities.

PubMed

el-Diwani, H; Nakkady, S S; Hishmat, O H; el-Shabrawy, O A; Mahmoud, S S

1992-03-01

Acylation of 2,3-diphenyl-5-methoxy-indole using ethyl chloroformate or chloroacetyl chloride in dimethylformamide and sodium hydride yielded the N-substituted derivatives 1 and 2, respectively. While Friedel-Crafts acylation using chloroacetyl chloride afforded di-4,6-chloroacetyl derivative 3, the reaction of the N-chloroacetyl derivative 2 with amines, hydrazines, urea, semicarbazide hydrochloride, thiophenol, benzimidazole-2-thiol, thiosemicarbazide, 2-mercaptoethanol and thioglycolic acid was studied. Several of the compounds were tested for their effect on arterial blood pressure, antiinflammatory and ulcerogenic activities.

Structural and magnetic behavior of (Ni, Cu) substituted Nd0.67Sr0.33MnO3 perovskite compounds

NASA Astrophysics Data System (ADS)

Arun, B.; Sudakshina, B.; Akshay, V. R.; Chandrasekhar, K. Devi; Yang, H. D.; Vasundhara, M.

2018-05-01

Structural and magnetic phase transition of Ni and Cu substituted Nd0.67Sr0.33MnO3 perovskite compounds have been investigated. The Rietveld refinement of X-ray powder diffraction patterns confirms that both compounds have crystallized into an orthorhombic structure with Pbnm space group same as that of Nd0.67Sr0.33MnO3 compound. X-ray absorption spectra studies completely ruled out the possibility of existence of any impurities. Both compounds do not obey the Curie-Weiss law indicates the presence of some ferromagnetic clusters within the paramagnetic matrix. Ni substituted compound shows a lower value of TC and Cu substituted compound shows a higher value of TC than that of the parent. Non-saturating tendency of magnetization is more prominently seen in the case of Cu substituted compound, indicating an increase in the AFM component.

Design and synthesis of N₁-aryl-benzimidazoles 2-substituted as novel HIV-1 non-nucleoside reverse transcriptase inhibitors.

PubMed

Monforte, Anna-Maria; Ferro, Stefania; De Luca, Laura; Lo Surdo, Giuseppa; Morreale, Francesca; Pannecouque, Christophe; Balzarini, Jan; Chimirri, Alba

2014-02-15

A series of novel N1-aryl-2-arylthioacetamido-benzimidazoles were synthesized and evaluated as inhibitors of human immunodeficiency virus type-1 (HIV-1). Some of them proved to be effective in inhibiting HIV-1 replication at submicromolar and nanomolar concentration acting as HIV-1 non-nucleoside RT inhibitors (NNRTIs), with low cytotoxicity. The preliminary structure-activity relationship (SAR) of these new derivatives was discussed and rationalized by docking studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Iron-Catalyzed Intramolecular C(sp(2))-N Cyclization of 1-(N-Arylpyrrol-2-yl)ethanone O-Acetyl Oximes toward Pyrrolo[1,2-a]quinoxaline Derivatives.

PubMed

Zhang, Zhiguo; Li, Junlong; Zhang, Guisheng; Ma, Nana; Liu, Qingfeng; Liu, Tongxin

2015-07-02

An efficient and convenient iron-catalyzed protocol has been developed for the synthesis of substituted pyrrolo[1,2-a]quinoxalines from 1-(N-arylpyrrol-2-yl)ethanone O-acetyl oximes through N-O bond cleavage and intramolecular directed C-H arylation reactions in acetic acid.

Synthesis and in vitro cytotoxicity of 5-substituted 2-cyanoimino-4-imidazodinone and 2-cyanoimino-4-pyrimidinone derivatives.

PubMed

Chern, Jyh-Haur; Shia, Kak-Shan; Chang, Chung-Ming; Lee, Chung-Chi; Lee, Yen-Chun; Tai, Chia-Liang; Lin, Ying-Ting; Chang, Chih-Shiang; Tseng, Huan-Yi

2004-03-08

A series of 5-substituted 2-cyanoimino-4-imidazodinone and 2-cyanoimino-4-pyrimidinone derivatives were synthesized and their anticancer cytotoxicity were evaluated in in vitro assay. It was found that the bulky aryl functionality in the 5-position of the 2-cyanoimino-4-imidazolidinone compounds was essential for the cytotoxicity of these heterocyclic compounds. Some of the derivatives exhibited modest cytotoxicity against a variety of cancer cell lines. One of the derivatives, [1-[6-(4-chlorophenoxy)hexyl]-5-oxo-4-phenyl-3-(4-pyridyl)tetrahydro-1H-2-imidazolyliden]aminomethanenitrile (Compound 11), exhibited the most potent cytotoxic activity with IC(50) in the nanomolar range. The cytotoxicity of these derivatives was selection with no apparent toxic effect toward normal fibroblasts.

Palladium-Catalyzed Direct C–H Arylation of Cyclic Enaminones with Aryl Iodides

PubMed Central

Yu, Yi-Yun; Bi, Lei

2013-01-01

A ligand-free method for the Pd-catalyzed direct arylation of cyclic enaminones using aryl iodides was developed. This method can be applied to a wide range of cyclic enaminones and aryl iodides with excellent C5-regioselectivity. Using widely available aryl iodides, the generality of this transformation provides easy access to a variety of 3-arylpiperidine structural motifs. PMID:23750615

Comparative Ab-Initio Study of Substituted Norbornadiene-Quadricyclane Compounds for Solar Thermal Storage.

PubMed

Kuisma, Mikael J; Lundin, Angelica M; Moth-Poulsen, Kasper; Hyldgaard, Per; Erhart, Paul

2016-02-25

Molecular photoswitches that are capable of storing solar energy, so-called molecular solar thermal storage systems, are interesting candidates for future renewable energy applications. In this context, substituted norbornadiene-quadricyclane systems have received renewed interest due to recent advances in their synthesis. The optical, thermodynamic, and kinetic properties of these systems can vary dramatically depending on the chosen substituents. The molecular design of optimal compounds therefore requires a detailed understanding of the effect of individual substituents as well as their interplay. Here, we model absorption spectra, potential energy storage, and thermal barriers for back-conversion of several substituted systems using both single-reference (density functional theory using PBE, B3LYP, CAM-B3LYP, M06, M06-2x, and M06-L functionals as well as MP2 calculations) and multireference methods (complete active space techniques). Already the diaryl substituted compound displays a strong red-shift compared to the unsubstituted system, which is shown to result from the extension of the conjugated π-system upon substitution. Using specific donor/acceptor groups gives rise to a further albeit relatively smaller red-shift. The calculated storage energy is found to be rather insensitive to the specific substituents, although solvent effects are likely to be important and require further study. The barrier for thermal back-conversion exhibits strong multireference character and as a result is noticeably correlated with the red-shift. Two possible reaction paths for the thermal back-conversion of diaryl substituted quadricyclane are identified and it is shown that among the compounds considered the path via the acceptor side is systematically favored. Finally, the present study establishes the basis for high-throughput screening of norbornadiene-quadricyclane compounds as it provides guidelines for the level of accuracy that can be expected for key properties from

Anticancer activity and anti-inflammatory studies of 5-aryl-1,4-benzodiazepine derivatives.

PubMed

Sandra, Cortez-Maya; Eduardo, Cortes Cortes; Simon, Hernandez-Ortega; Teresa, Ramirez Apan; Antonio, Nieto Camacho; Lijanova, Irina V; Marcos, Martinez-Garcia

2012-07-01

A series of 5-aryl-1,4-benzodiazepines with chloro- or fluoro-substituents in the second ring have been synthesized and their anti-inflammatory, myeloperoxidase and anticancer properties studied. The synthesized compounds showed potential anti-inflammatory and anticancer activities, which were enhanced in the presence of a chloro-substituent in the second ring of the 5-aryl-1,4- benzodiazepine.

Synthesis of N4-(Substituted phenyl)-N4-alkyl/desalkyl-9H-pyrimido[4,5-b]indole-2,4-diamines and Identification of New Microtubule Disrupting Compounds that are Effective against Multidrug Resistant Cells1

PubMed Central

Gangjee, Aleem; Zaware, Nilesh; Devambatla, Ravi Kumar Vyas; Raghavan, Sudhir; Westbrook, Cara D.; Dybdal-Hargreaves, Nicholas F.; Hamel, Ernest; Mooberry, Susan L.

2013-01-01

A series of fourteen N4-(substituted phenyl)-N4-methyl/desmethyl-9H-pyrimido[4,5-b]indole-2,4-diamines was synthesized as potential microtubule targeting agents. The synthesis involved a Fisher indole cyclization of 2-amino-6-hydrazinylpyrimidin-4(3H)-one with cyclohexanone, followed by oxidation, chlorination and displacement with appropriate anilines. Compounds 6, 14 and 15 had low nanomolar potency against MDA-MB-435 tumor cells and depolymerized microtubules. Compound 6 additionally had nanomolar GI50 values against 57 of the NCI 60-tumor panel cell lines. Mechanistic studies showed that 6 inhibited tubulin polymerization and [3H]colchicine binding to tubulin. The most potent compounds were all effective in cells expressing P-glycoprotein or the βIII isotype of tubulin, which have been associated with clinical drug reisistence. Modeling studies provided the potential interactions of 6, 14 and 15 within the colchicine site. PMID:23332369

Arylation of Rhodium(II) Azavinyl Carbenes with Boronic Acids

PubMed Central

Selander, Nicklas; Worrell, Brady T.; Chuprakov, Stepan; Velaparthi, Subash; Fokin, Valery V.

2013-01-01

A highly efficient and stereoselective arylation of in situ generated azavinyl carbenes affording 2,2-diaryl enamines at ambient temperatures has been developed. These transition metal carbenes are directly produced from readily available and stable 1-sulfonyl-1,2,3-triazoles in the presence of a rhodium carboxylate catalyst. In several cases, the enamines generated in this reaction can be cyclized into substituted indoles employing copper catalysts. PMID:22913576

Arylation, alkenylation, and alkylation of 2-halopyridine N-oxides with grignard reagents: a solution to the problem of C2/C6 regioselective functionalization of pyridine derivatives.

PubMed

Zhang, Song; Liao, Lian-Yan; Zhang, Fang; Duan, Xin-Fang

2013-03-15

A facile arylation, alkenylation, and alkylation of functionalized 2-halopyridine N-oxides with various Grignard reagents was developed. It represented a highly efficient and selective C-H bond functionalization of pyridine derivatives in the presence of reactive C-Cl or C-Br bonds. Using Cl or Br as a blocking group, C2/C6 site-controllable functionalization of pyridine derivatives has been achieved. Various pyridine compounds can be prepared as illustrated in the total syntheses of Onychine, dielsine, and PARP-1 inhibitor GPI 16539.

Oxidative tandem nitrosation/cyclization of N-aryl enamines with nitromethane toward 3-(trifluoromethyl)quinoxalines.

PubMed

Yang, Zhi-Jun; Liu, Chuan-Zhuo; Hu, Bo-Lun; Deng, Chen-Liang; Zhang, Xing-Guo

2014-12-04

A novel one-pot strategy for the synthesis of 3-trifluoromethylquinoxalines from N-aryl enamines and nitromethane was developed. The tandem reaction is achieved through nitrosation of alkenes, tautomerization and cyclization, which can be applicable to a wide range of enamines with excellent functional group tolerance and afford quinoxalines in moderate to good yields.

Synthesis of Quaternary Carbon Stereogenic Centers through Enantioselective Cu-Catalyzed Allylic Substitutions with Vinylaluminum Reagents

PubMed Central

Gao, Fang; McGrath, Kevin P.; Lee, Yunmi; Hoveyda, Amir H.

2010-01-01

Catalytic enantioselective allylic substitution (EAS) reactions, which involve the use of alkyl- or aryl-substituted vinylaluminum reagents and afford 1,4-dienes containing a quaternary carbon stereogenic center at their C-3 site, are disclosed. The C–C bond forming transformations are promoted by 0.5–2.5 mol % of sulfonate bearing chiral bidentate N-heterocyclic carbene (NHC) complexes, furnishing the desired products efficiently (66–97% yield of isolated products) and in high site- (>98% SN2′) and enantioselectivity [up to 99:1 enantiomer ratio (er)]. To the best of our knowledge, the present report puts forward the first cases of allylic substitution reactions that result in the generation of all-carbon quaternary stereogenic centers through the addition of a vinyl unit. The aryl- and vinyl-substituted vinylaluminum reagents, which cannot be prepared in high efficiency through direct reaction with diisobutylaluminum hydride, are accessed through a recently introduced Ni-catalyzed reaction of the corresponding terminal alkynes with the same inexpensive metal-hydride agent. Sequential Ni-catalyzed hydrometallations and Cu-catalyzed C–C bond forming reactions allow for efficient and selective synthesis of a range of enantiomerically enriched EAS products, which cannot cannot be accessed by previously disclosed strategies (due to inefficient vinylmetal synthesis or low reactivity and/or selectivity with Si-substituted derivatives). The utility of the protocols developed is demonstrated through a concise enantioselective synthesis of natural product bakuchiol. PMID:20860365

Synthesis of Donor/Acceptor-Substituted Diazo Compounds in Flow and Their Application in Enantioselective Dirhodium-Catalyzed Cyclopropanation and C-H Functionalization.

PubMed

Rackl, Daniel; Yoo, Chun-Jae; Jones, Christopher W; Davies, Huw M L

2017-06-16

A tandem reaction system has been developed for the preparation of donor/acceptor-substituted diazo compounds in continuous flow coupled to dirhodium-catalyzed C-H functionalization or cyclopropanation. Hydrazones were oxidized in flow by solid-supported N-iodo-p-toluenesulfonamide potassium salt (PS-SO 2 NIK) to generate the diazo compounds, which were then purified by passing through a column of molecular sieves/sodium thiosulfate.

Discovery of 5-substituted tetrahydronaphthalen-2yl-methyl with N-phenyl-N-(piperidin-4-yl)propionamide derivatives as potent opioid receptor ligands.

PubMed

Deekonda, Srinivas; Wugalter, Lauren; Kulkarni, Vinod; Rankin, David; Largent-Milnes, Tally M; Davis, Peg; Bassirirad, Neemah M; Lai, Josephine; Vanderah, Todd W; Porreca, Frank; Hruby, Victor J

2015-09-15

A new series of novel opioid ligands have been designed and synthesized based on the 4-anilidopiperidine scaffold containing a 5-substituted tetrahydronaphthalen-2yl)methyl group with different N-phenyl-N-(piperidin-4-yl)propionamide derivatives to study the biological effects of these substituents on μ and δ opioid receptor interactions. Recently our group reported novel 4-anilidopiperidine analogues, in which several aromatic ring-contained amino acids were conjugated with N-phenyl-N-(piperidin-4-yl)propionamide and examined their biological activities at the μ and δ opioid receptors. In continuation of our efforts in these novel 4-anilidopiperidine analogues, we took a peptidomimetic approach in the present design, in which we substituted aromatic amino acids with tetrahydronaphthalen-2yl methyl moiety with amino, amide and hydroxyl substitutions at the 5th position. In in vitro assays these ligands, showed very good binding affinity and highly selective toward the μ opioid receptor. Among these, the lead ligand 20 showed excellent binding affinity (2 nM) and 5000 fold selectivity toward the μ opioid receptor, as well as functional selectivity in GPI assays (55.20 ± 4.30 nM) and weak or no agonist activities in MVD assays. Based on the in vitro bioassay results the lead compound 20 was chosen for in vivo assessment for efficacy in naïve rats after intrathecal administration. Compound 20 was not significantly effective in alleviating acute pain. This discrepancy between high in vitro binding affinity, moderate in vitro activity, and low in vivo activity may reflect differences in pharmacodynamics (i.e., engaging signaling pathways) or pharmacokinetics (i.e., metabolic stability). In sum, our data suggest that further optimization of this compound 20 is required to enhance in vivo activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Aryl sulfonates as neutral photoacid generators (PAGs) for EUV lithography

NASA Astrophysics Data System (ADS)

Sulc, Robert; Blackwell, James M.; Younkin, Todd R.; Putna, E. Steve; Esswein, Katherine; DiPasquale, Antonio G.; Callahan, Ryan; Tsubaki, Hideaki; Tsuchihashi, Tooru

2009-03-01

EUV lithography (EUVL) is a leading candidate for printing sub-32 nm hp patterns. In order for EUVL to be commercially viable at these dimensions, a continuous evolution of the photoresist material set is required to simultaneously meet the aggressive specifications for resolution, resist sensitivity, LWR, and outgassing rate. Alternative PAG designs, especially if tailored for EUVL, may aid in the formation of a material set that helps achieve these aggressive targets. We describe the preparation, characterization, and lithographic evaluation of aryl sulfonates as non-ionic or neutral photoacid generators (PAGs) for EUVL. Full lithographic characterization is reported for our first generation resist formulation using compound H, MAP-1H-2.5. It is benchmarked against MAP-1P-5.0, which contains the well-known sulfonium PAG, triphenylsulfonium triflate (compound P). Z-factor analysis indicates nZ32 = 81.4 and 16.8 respectively, indicating that our first generation aryl sulfonate formulations require about 4.8x improvement to match the results achieved with a model onium PAG. Improving the acid generation efficiency and use of the generated byproducts is key to the continued optimization of this class of PAGs. To that end, we believe EI-MS fragmentation patterns and molecular simulations can be used to understand and optimize the nature and efficiency of electron-induced PAG fragmentation.

Asymmetric synthesis of N-allylic indoles via regio- and enantioselective allylation of aryl hydrazines

PubMed Central

Xu, Kun; Gilles, Thomas; Breit, Bernhard

2015-01-01

The asymmetric synthesis of N-allylic indoles is important for natural product synthesis and pharmaceutical research. The regio- and enantioselective N-allylation of indoles is a true challenge due to the favourable C3-allylation. We develop here a new strategy to the asymmetric synthesis of N-allylic indoles via rhodium-catalysed N-selective coupling of aryl hydrazines with allenes followed by Fischer indolization. The exclusive N-selectivities and good to excellent enantioselectivities are achieved applying a rhodium(I)/DTBM-Segphos or rhodium(I)/DTBM-Binap catalyst. This method permits the practical synthesis of valuable chiral N-allylated indoles, and avoids the N- or C-selectivity issue. PMID:26137886

Structure-activity relationships of amide-phosphonate derivatives as inhibitors of the human soluble epoxide hydrolase.

PubMed

Kim, In-Hae; Park, Yong-Kyu; Nishiwaki, Hisashi; Hammock, Bruce D; Nishi, Kosuke

2015-11-15

Structure-activity relationships of amide-phosphonate derivatives as inhibitors of the human soluble epoxide hydrolase (sEH) were investigated. First, a series of alkyl or aryl groups were substituted on the carbon alpha to the phosphonate function in amide compounds to see whether substituted phosphonates can act as a secondary pharmacophore. A tert-butyl group (16) on the alpha carbon was found to yield most potent inhibition on the target enzyme. A 4-50-fold drop in inhibition was induced by other substituents such as aryls, substituted aryls, cycloalkyls, and alkyls. Then, the modification of the O-substituents on the phosphonate function revealed that diethyl groups (16 and 23) were preferable for inhibition to other longer alkyls or substituted alkyls. In amide compounds with the optimized diethylphosphonate moiety and an alkyl substitution such as adamantane (16), tetrahydronaphthalene (31), or adamantanemethane (36), highly potent inhibitions were gained. In addition, the resulting potent amide-phosphonate compounds had reasonable water solubility, suggesting that substituted phosphonates in amide inhibitors are effective for both inhibition potency on the human sEH and water solubility as a secondary pharmacophore. Copyright © 2015 Elsevier Ltd. All rights reserved.

40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Halogenated-N-(2-propenyl)-N... New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl... identified generically as halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide (P-83-1085) is subject...

40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated-N-(2-propenyl)-N... New Uses for Specific Chemical Substances § 721.275 Halogenated-N-(2-propenyl)-N-(substituted phenyl... identified generically as halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide (P-83-1085) is subject...

Amination of electrophilic aromatic compounds by vicarious nucleophilic substitution

DOEpatents

Mitchell, Alexander R.; Pagoria, Philip F.; Schmidt, Robert D.

2000-01-01

The present invention relates to a process to aminate electrophilic aromatic compounds by vicarious nucleophilic substitution of hydrogen using quaternary hydrazinium salts. The use of trialkylhydrazinium halide, e.g., trimethylhydrazinium iodide, as well as hydroxylamine, alkoxylamines, and 4-amino-1,2,4-triazole to produce aminated aromatic structures, such as 1,3-diamino-2,4,6-trinitrobenzene (DATB), 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and 3,5-diamino-2,4,6-trinitrotoluene (DATNT), is described. DATB and TATB are useful insensitive high explosives. TATB is also used for the preparation of benzenehexamine, a starting material for the synthesis of novel materials (optical imaging devices, liquid crystals, ferromagnetic compounds).

Proline/pipecolinic acid-promoted copper-catalyzed P-arylation.

PubMed

Huang, Cheng; Tang, Xu; Fu, Hua; Jiang, Yuyang; Zhao, Yufen

2006-06-23

We have developed a convenient and efficient approach for P-arylation of organophosphorus compounds containing P-H. Using commercially available and inexpensive proline and pipecolinic acid as the ligands greatly improved the efficiency of the coupling reactions, so the method can provide an entry to arylphosphonates, arylphosphinates and arylphosphine oxides.

Combination of Aryl Diselenides/Hydrogen Peroxide and Carbon Nanotube-Rhodium Nanohybrid for Naphthols Oxidation: An Efficient Route towards Trypanocidal Quinones.

PubMed

de Carvalho, Renato L; Jardim, Guilherme A M; Santos, Augusto; Araujo, Maria H; Oliveira, Willian X C; Bombaça, Ana Cristina; Menna-Barreto, Rubem F S; Gopi, Elumalai; Gravel, Edmond; Doris, Eric; da Silva Júnior, Eufrânio Nunes

2018-06-14

We report a combination of aryl diselenides/hydrogen peroxide and carbon nanotube-rhodium nanohybrid for naphthols oxidation towards synthesis of 1,4-naphthoquinones and evaluation of their relevant trypanocidal activity. Under a combination of (PhSe)2/H2O2 in the presence of O2 in i-PrOH/Hexane, several benzenoid (A-ring) substituted quinones were prepared in moderate to high yields. We also studied the contribution of RhCNT as co-catalyst in this process and, in some cases, yields were improved. This method provides an efficient and versatile alternative for preparing A-ring modified naphthoquinonoid compounds with relevant biological profile. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Novel Access to Arylated and Heteroarylated Beta-Carboline Based PDE5 Inhibitors

PubMed Central

Ahmed, Nermin S.; Gary, Bernard D.; Piazza, Gary A.; Tinsley, Heather N.; Laufer, Stefan; Abadi, Ashraf H.

2016-01-01

Starting from a previously reported lead compound GR30040X (a hydantoin tetrahydro-β-carboline derivative with a 4- pyridinyl ring at C- 5), a series of structurally related tetrahydro-β-carboline derivatives were prepared. The tet-rahydro-β-carboline skeleton was fused either to a hydantoin or to a piperazindione ring, the pendant aryl group attached to C-5 or C-6 was changed to a 3, 4-dimethoxyphenyl or a 3-pyridinyl ring; different N-substituents on the terminal ring were introduced, a straight chain ethyl group, a branched tert. butyl and P-chlorophenyl group rather than n-butyl group of the lead compound. All four possible diastereomers of target tetrahydro-β-carboline derivatives were prepared, separated by column chromatography and the significance of these stereochemical manipulations was studied. Synthesized compounds were evaluated for their inhibitory effect versus PDE5. Seven hits were obtained with appreciable inhibitory activity versus PDE5 with IC50s 0.14 - 4.99 μM. PMID:21054274

Synthesis of alkyl- and aryl-amino-substituted anthraquinone derivatives by microwave-assisted copper(0)-catalyzed Ullmann coupling reactions.

PubMed

Baqi, Younis; Müller, Christa E

2010-05-01

This protocol describes the efficient, generally applicable Ullmann coupling reaction of bromaminic acid with alkyl- or aryl-amines in phosphate buffer under microwave irradiation using elemental copper as a catalyst. The reaction leads to a number of biologically active compounds. As a prototypical example, the synthesis of a new, potent antagonist of human platelet P2Y(12) receptors, which has potential as an antithrombotic drug, is described in detail. The optimized protocol includes a description of an appropriate reaction setup, thin layer chromatography for monitoring the reaction and a procedure for the isolation, purification and characterization of the anticipated product. The reaction is performed without the use of a glove box and there is no requirement for an inert atmosphere. The reaction typically proceeds within 2-30 min, the protocol, including workup, generally takes 1-3 h to complete.

Pd-Catalyzed Cross-Coupling Reactions of Amides and Aryl Mesylates

PubMed Central

Dooleweerdt, Karin; Fors, Brett P.; Buchwald, Stephen L.

2010-01-01

A catalyst, based on a biarylphosphine ligand, for the Pd-catalyzed cross-coupling reactions of amides and aryl mesylates is described. This system allows an array of aryl and heteroaryl mesylates to be transformed into the corresponding N-arylamides in moderate to excellent yields. PMID:20420379

Sulfonamidation of Aryl and Heteroaryl Halides through Photosensitized Nickel Catalysis.

PubMed

Kim, Taehoon; McCarver, Stefan J; Lee, Chulbom; MacMillan, David W C

2018-03-19

Herein we report a highly efficient method for nickel-catalyzed C-N bond formation between sulfonamides and aryl electrophiles. This technology provides generic access to a broad range of N-aryl and N-heteroaryl sulfonamide motifs, which are widely represented in drug discovery. Initial mechanistic studies suggest an energy-transfer mechanism wherein C-N bond reductive elimination occurs from a triplet excited Ni II complex. Late-stage sulfonamidation in the synthesis of a pharmacologically relevant structure is also demonstrated. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and pharmacological evaluation of N-substituted 2-(2-oxo-2H-chromen-4-yloxy)propanamide as cyclooxygenase inhibitors.

PubMed

Rambabu, D; Mulakayala, Naveen; Ismail; Kumar, K Ravi; Kumar, G Pavan; Mulakayala, Chaitanya; Kumar, Chitta Suresh; Kalle, Arunasree M; Rao, M V Basaveswara; Oruganti, Srinivas; Pal, Manojit

2012-11-01

A series of novel N-substituted 2-(2-oxo-2H-chromen-4-yloxy)propanamide derivatives were synthesized via converting the readily available 4-hydroxy coumarin to the corresponding ethyl 2-(2-oxo-2H-chromen-4-yloxy)propanoate followed by hydrolysis and then reacting with different substituted amines. The molecular structures of two representative compounds, that is, 3 and 5l were confirmed by single crystal X-ray diffraction study. All the compounds synthesized were evaluated for their cyclooxygenase (COX) inhibiting properties in vitro. The compound 5i showed balanced selectivity towards COX-2 over COX-1 inhibition and good docking scores when docked into the COX-2 protein. Copyright © 2012 Elsevier Ltd. All rights reserved.

Applications of Palladium-Catalyzed C-N Cross-Coupling Reactions.

PubMed

Ruiz-Castillo, Paula; Buchwald, Stephen L

2016-10-12

Pd-catalyzed cross-coupling reactions that form C-N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C-N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.

Applications of Palladium-Catalyzed C–N Cross-Coupling Reactions

PubMed Central

2016-01-01

Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts. PMID:27689804

Emissive polymeric materials for optoelectronic devices

DOEpatents

Shiang, Joseph John [Niskayuna, NY; Chichak, Kelly Scott [Clifton Park, NY; Cella, James Anthony [Clifton Park, NY; Lewis, Larry Neil [Scotia, NY; Janora, Kevin Henry [Schenectady, NY

2011-07-05

Polymers including at least one structural unit derived from a compound of formula I or including at least one pendant group of formula II may be used in optoelectronic devices ##STR00001## wherein R.sup.1, R.sup.3, R.sup.4 and R.sup.6 are independently hydrogen, alkyl, alkoxy, oxaalkyl, alkylaryl, aryl, arylalkyl, heteroaryl, substituted alkyl; substituted alkoxy, substituted oxaalkyl, substituted alkylaryl, substituted aryl, substituted arylalkyl, or substituted heteroaryl; R.sup.1a is hydrogen or alkyl; R.sup.2 is alkylene, substituted alkylene, oxaalkylene, CO, or CO.sub.2; R.sup.2a is alkylene; R.sup.5 is independently at each occurrence hydrogen, alkyl, alkylaryl, aryl, arylalkyl, alkoxy, carboxy, substituted alkyl; substituted alkylaryl, substituted aryl, substituted arylalkyl, or substituted alkoxy, X is halo, triflate, --B(OR.sup.1a).sub.2, or ##STR00002## located at the 2, 5- or 2, 7-positions; and L is derived from phenylpyridine, tolylpyridine, benzothienylpyridine, phenylisoquinoline, dibenzoquinozaline, fluorenylpyridine, ketopyrrole, 2-(1-naphthyl)benzoxazole)), 2-phenylbenzoxazole, 2-phenylbenzothiazole, coumarin, thienylpyridine, phenylpyridine, benzothienylpyridine, 3-methoxy-2-phenylpyridine, thienylpyridine, phenylimine, vinylpyridine, pyridylnaphthalene, pyridylpyrrole, pyridylimidazole, phenylindole, derivatives thereof or combinations thereof.

Spectroscopic Identification of the Au-C Bond Formation upon Electroreduction of an Aryl Diazonium Salt on Gold.

PubMed

Guo, Limin; Ma, Lipo; Zhang, Yelong; Cheng, Xun; Xu, Ye; Wang, Jin; Wang, Erkang; Peng, Zhangquan

2016-11-08

Electroreduction of aryl diazonium salts on gold can produce organic films that are more robust than their analogous self-assembled monolayers formed from chemical adsorption of organic thiols on gold. However, whether the enhanced stability is due to the Au-C bond formation remains debated. In this work, we report the electroreduction of an aryl diazonium salt of 4,4'-disulfanediyldibenzenediazonium on gold forming a multilayer of Au-(Ar-S-S-Ar) n , which can be further degraded to a monolayer of Au-Ar-S - by electrochemical cleavage of the S-S moieties within the multilayer. By conducting an in situ surface-enhanced Raman spectroscopic study of both the multilayer formation/degradation and the monolayer reduction/oxidation processes, coupled to density functional theory calculations, we provide compelling evidence that an Au-C bond does form upon electroreduction of aryl diazonium salts on gold and that the enhanced stability of the electrografted organic films is due to the Au-C bond being intrinsically stronger than the Au-S bond for a given phenylthiolate compound by ca. 0.4 eV.

Novel N-substituted aminobenzamide scaffold derivatives targeting the dipeptidyl peptidase-IV enzyme.

PubMed

Al-Balas, Qosay A; Sowaileh, Munia F; Hassan, Mohammad A; Qandil, Amjad M; Alzoubi, Karem H; Mhaidat, Nizar M; Almaaytah, Ammar M; Khabour, Omar F

2014-01-01

The dipeptidyl peptidase-IV (DPP-IV) enzyme is considered a pivotal target for controlling normal blood sugar levels in the body. Incretins secreted in response to ingestion of meals enhance insulin release to the blood, and DPP-IV inactivates these incretins within a short period and stops their action. Inhibition of this enzyme escalates the action of incretins and induces more insulin to achieve better glucose control in diabetic patients. Thus, inhibition of this enzyme will lead to better control of blood sugar levels. In this study, computer-aided drug design was used to help establish a novel N-substituted aminobenzamide scaffold as a potential inhibitor of DPP-IV. CDOCKER software available from Discovery Studio 3.5 was used to evaluate a series of designed compounds and assess their mode of binding to the active site of the DPP-IV enzyme. The designed compounds were synthesized and tested against a DPP-IV enzyme kit provided by Enzo Life Sciences. The synthesized compounds were characterized using proton and carbon nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, and determination of melting point. Sixty-nine novel compounds having an N-aminobenzamide scaffold were prepared, with full characterization. Ten of these compounds showed more in vitro activity against DPP-IV than the reference compounds, with the most active compounds scoring 38% activity at 100 μM concentration. The N-aminobenzamide scaffold was shown in this study to be a valid scaffold for inhibiting the DPP-IV enzyme. Continuing work could unravel more active compounds possessing the same scaffold.

6-shogaol, a major compound in ginger, induces aryl hydrocarbon receptor-mediated transcriptional activity and gene expression.

PubMed

Yoshida, Kazutaka; Satsu, Hideo; Mikubo, Ayano; Ogiwara, Haru; Yakabe, Takafumi; Inakuma, Takahiro; Shimizu, Makoto

2014-06-18

Xenobiotics are usually detoxified by drug-metabolizing enzymes and excreted from the body. The expression of many of drug-metabolizing enzymes is regulated by the aryl hydrocarbon receptor (AHR). Some substances in vegetables have the potential to be AHR ligands. To search for vegetable components that exhibit AHR-mediated transcriptional activity, we assessed the activity of vegetable extracts and identified the active compounds using the previously established stable AHR-responsive HepG2 cell line. Among the hot water extracts of vegetables, the highest activity was found in ginger. The ethyl acetate fraction of the ginger hot water extract remarkably induced AHR-mediated transcriptional activity, and the major active compound was found to be 6-shogaol. Subsequently, the mRNA levels of AHR-targeting drug-metabolizing enzymes (CYP1A1, UGT1A1, and ABCG 2) and the protein level of CYP1A1 in HepG2 cells were shown to be increased by 6-shogaol. This is the first report that 6-shogaol can regulate the expression of detoxification enzymes by AHR activation.

Discovery of 4-aryl-N-arylcarbonyl-2-aminothiazoles as Hec1/Nek2 inhibitors. Part I: optimization of in vitro potencies and pharmacokinetic properties.

PubMed

Lee, Ying-Shuan E; Chuang, Shih-Hsien; Huang, Lynn Y L; Lai, Chun-Liang; Lin, Yu-Hsiang; Yang, Ju-Ying; Liu, Chia-Wei; Yang, Sheng-chuan; Lin, Her-Sheng; Chang, Chia-chi; Lai, Jun-Yu; Jian, Pei-Shiou; Lam, King; Chang, Jia-Ming; Lau, Johnson Y N; Huang, Jiann-Jyh

2014-05-22

A series of 4-aryl-N-arylcarbonyl-2-aminothiazoles of scaffold 4 was designed and synthesized as Hec1/Nek2 inhibitors. Structural optimization of 4 led to compound 32 bearing C-4' 4-methoxyphenoxy and 4-(o-fluoropyridyl)carbonyl groups that showed low nanomolar in vitro antiproliferative activity (IC50: 16.3-42.7 nM), high intravenous AUC (64.9 μM·h, 2.0 mg/kg) in SD rats, and significant in vivo antitumor activity (T/C = 32%, 20 mg/kg, IV) in mice bearing human MDA-MB-231 xenografts. Cell responses resulting from Hec1/Nek2 inhibition were observed in cells treated with 32, including a reduced level of Hec1 coimmunoprecipitated with Nek2, degradation of Nek2, mitotic abnormalities, and apoptosis. Compound 32 showed selectivity toward cancer cells over normal phenotype cells and was inactive in a [(3)H]astemizole competitive binding assay for hERG liability screening. Therefore, 32 is as a good lead toward the discovery of a preclinical candidate targeting Hec1/Nek2 interaction.

Copper Mediated Fluorination of Aryl Iodides

PubMed Central

Fier, Patrick S.; Hartwig, John F.

2012-01-01

The synthesis of aryl fluorides has been a topic of considerable interest because of the importance of aryl fluorides in pharmaceuticals, agrochemicals and materials. The stability, reactivity and biological properties of aryl fluorides can be distinct from those of the corresponding arenes. Methods for the synthesis of aryl fluorides, however, are limited. We report the conversion of a diverse set of aryl iodides to the corresponding aryl fluorides. This reaction occurs with a cationic copper reagent and silver fluoride. Preliminary results suggest this reaction is enabled by a facile reductive elimination from a cationic aryl copper(III) fluoride. PMID:22709145

Copper-Catalyzed C(sp2)-S Coupling Reactions for the Synthesis of Aryl Dithiocarbamates with Thiuram Disulfide Reagents.

PubMed

Dong, Zhi-Bing; Liu, Xing; Bolm, Carsten

2017-11-03

An efficient protocol for the copper-catalyzed preparation of aryl dithiocarbamates from aryl iodides and inexpensive, environmentally benign tetraalkylthiuram disulfides was developed. The features of mild reaction conditions, high yields, and broad substrate scope render this new approach synthetically attractive for the preparation of potentially biologically active compounds.

Metal-free, visible-light-mediated direct C-H arylation of heteroarenes with aryl diazonium salts.

PubMed

Hari, Durga Prasad; Schroll, Peter; König, Burkhard

2012-02-15

Visible light along with 1 mol % eosin Y catalyzes the direct C-H bond arylation of heteroarenes with aryl diazonium salts by a photoredox process. We have investigated the scope of the reaction for several aryl diazonium salts and heteroarenes. The general and easy procedure provides a transition-metal-free alternative for the formation of aryl-heteroaryl bonds.

Substituted N-(Biphenyl-4′-yl)methyl (R)-2-Acetamido-3-methoxypropionamides: Potent Anticonvulsants That Affect Frequency (Use) Dependence and Slow Inactivation of Sodium Channels

PubMed Central

2015-01-01

We prepared 13 derivatives of N-(biphenyl-4′-yl)methyl (R)-2-acetamido-3-methoxypropionamide that differed in type and placement of a R-substituent in the terminal aryl unit. We demonstrated that the R-substituent impacted the compound’s whole animal and cellular pharmacological activities. In rodents, select compounds exhibited excellent anticonvulsant activities and protective indices (PI = TD50/ED50) that compared favorably with clinical antiseizure drugs. Compounds with a polar, aprotic R-substituent potently promoted Na+ channel slow inactivation and displayed frequency (use) inhibition of Na+ currents at low micromolar concentrations. The possible advantage of affecting these two pathways to decrease neurological hyperexcitability is discussed. PMID:25004277

Stable trifluorostyrene containing compounds grafted to base polymers, and their use as polymer electrolyte membranes

DOEpatents

Yang, Zhen-Yu; Roelofs, Mark Gerrit

2010-11-09

A fluorinated ion exchange polymer prepared by grafting at least one grafting monomer on to at least one base polymer, wherein the grafting monomer comprises structure 1a or 1b: wherein Z comprises S, SO.sub.2, or POR wherein R comprises a linear or branched perfluoroalkyl group of 1 to 14 carbon atoms optionally containing oxygen or chlorine, an alkyl group of 1 to 8 carbon atoms, an aryl group of 6 to 12 carbon atoms or a substituted aryl group of 6 to 12 carbon atoms; RF comprises a linear or branched perfluoroalkene group of 1 to 20 carbon atoms, optionally containing oxygen or chlorine; Q is chosen from F, --OM, NH.sub.2, --N(M)SO.sub.2R.sup.2.sub.F, and C(M)(SO.sub.2R.sup.2.sub.F).sub.2, wherein M comprises H, an alkali cation, or ammonium; R.sup.2.sub.F groups comprises alkyl of 1 to 14 carbon atoms which may optionally include ether oxygens or aryl of 6 to 12 carbon atoms where the alkyl or aryl groups may be perfluorinated or partially fluorinated; and n is 1 or 2 for 1a, and n is 1, 2, or 3 for 1b. These ion exchange polymers are useful in preparing catalyst coated membranes and membrane electrode assemblies used in fuel cells.

40 CFR 721.225 - 2-Chloro-N-methyl-N-substituted acetamide (generic name).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 2-Chloro-N-methyl-N-substituted... Specific Chemical Substances § 721.225 2-Chloro-N-methyl-N-substituted acetamide (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance 2-chloro-N...

40 CFR 721.225 - 2-Chloro-N-methyl-N-substituted acetamide (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 2-Chloro-N-methyl-N-substituted... Specific Chemical Substances § 721.225 2-Chloro-N-methyl-N-substituted acetamide (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance 2-chloro-N...

Synthesis and conformation analysis of 3-substituted derivatives of 1H,3H-pyrido[2,3-d] pyrimidin-4-one of expected depressive nervous system. Part III.

PubMed

Chodkowski, Andrzej; Herold, Franciszek; Kleps, Jerzy

2004-01-01

Four series of new 1-aryl (heteroaryl) piperazinylacetyl derivatives of 1H,3H-pyrido[2,3-d] pyrimidin-4-one VIIa-o were synthesised. Substrates for the synthesis of VIa-d were obtained from the respective 3H-pyrido[2.3-d]pyrimidines IVa-d in the reaction with NaBH4. Compounds VIa-d were prepared by chloroacetylation. The obtained 1-chloroacetyl derivatives in the reaction with respective aryl (heteroaryl) piperazine formed 1-aminoacetyl derivatives of 2-phenyl-1 H.3H-pyrido[2.3-d]pyrimidin-4-one compounds VII1a-n. The structure ol compounds was analysed by 1H, 13C NMR spectroscopy.

Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds**

PubMed Central

Best, Daniel; Burns, David J; Lam, Hon Wai

2015-01-01

A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N—H groups are tolerated on the barbituric acid, with no complications arising from N—H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. PMID:25959544

Design, microwave-mediated synthesis and biological evaluation of novel 4-aryl(alkyl)amino-3-nitroquinoline and 2,4-diaryl(dialkyl)amino-3-nitroquinolines as anticancer agents.

PubMed

Chauhan, Monika; Rana, Anil; Alex, Jimi Marin; Negi, Arvind; Singh, Sandeep; Kumar, Raj

2015-02-01

Design, microwave-assisted synthesis of novel 4-aryl (alkyl)amino-3-nitroquinoline (1a-1l) and 2,4-diaryl (dialkyl)amino-3-nitroquinolines (2a-2k and 3a) via regioselective and complete nucleophilic substitution of 2,4-dichloro-3-nitroquinoline, respectively in water are presented. The newly synthesized compounds were evaluated for the first time for antiproliferative activity against EGFR overexpressing human lung (A-549 and H-460) and colon (HCT-116-wild type and HCT-116-p53 null) cancer cell lines. Some notions about structure-activity relationships (SAR) are presented. Compounds 2e, 2f, 2j and 3a overall exhibited excellent anticancer activity comparable to erlotinib which was used as a positive control. Molecular modeling studies disclosed the recognition pattern of the compounds and also supported the observed SAR. Copyright © 2014 Elsevier Inc. All rights reserved.

Design and Synthesis of Potent in Vitro and in Vivo Anticancer Agents Based on 1-(3′,4′,5′-Trimethoxyphenyl)-2-Aryl-1H-Imidazole

PubMed Central

Romagnoli, Romeo; Baraldi, Pier Giovanni; Prencipe, Filippo; Oliva, Paola; Baraldi, Stefania; Tabrizi, Mojgan Aghazadeh; Lopez-Cara, Luisa Carlota; Ferla, Salvatore; Brancale, Andrea; Hamel, Ernest; Ronca, Roberto; Bortolozzi, Roberta; Mariotto, Elena; Basso, Giuseppe; Viola, Giampietro

2016-01-01

A novel series of tubulin polymerization inhibitors, based on the 1-(3′,4′,5′-trimethoxyphenyl)-2-aryl-1H-imidazole scaffold and designed as cis-restricted combretastatin A-4 analogues, was synthesized with the goal of evaluating the effects of various patterns of substitution on the phenyl at the 2-position of the imidazole ring on biological activity. A chloro and ethoxy group at the meta- and para-positions, respectively, produced the most active compound in the series (4o), with IC50 values of 0.4-3.8 nM against a panel of seven cancer cell lines. Except in HL-60 cells, 4o had greater antiproliferative than CA-4, indicating that the 3′-chloro-4′-ethoxyphenyl moiety was a good surrogate for the CA-4 B-ring. Experiments carried out in a mouse syngenic model demonstrated high antitumor activity of 4o, which significantly reduced the tumor mass at a dose thirty times lower than that required for CA-4P, which was used as a reference compound. Altogether, our findings suggest that 4o is a promising anticancer drug candidate that warrants further preclinical evaluation. PMID:27216165

Highly selective biaryl cross-coupling reactions between aryl halides and aryl Grignard reagents: a new catalyst combination of N-heterocyclic carbenes and iron, cobalt, and nickel fluorides.

PubMed

Hatakeyama, Takuji; Hashimoto, Sigma; Ishizuka, Kentaro; Nakamura, Masaharu

2009-08-26

Combinations of N-heterocyclic carbenes (NHCs) and fluoride salts of the iron-group metals (Fe, Co, and Ni) have been shown to be excellent catalysts for the cross-coupling reactions of aryl Grignard reagents (Ar(1)MgBr) with aryl and heteroaryl halides (Ar(2)X) to give unsymmetrical biaryls (Ar(1)-Ar(2)). Iron fluorides in combination with SIPr, a saturated NHC ligand, catalyze the biaryl cross-coupling between various aryl chlorides and aryl Grignard reagents in high yield and high selectivity. On the other hand, cobalt and nickel fluorides in combination with IPr, an unsaturated NHC ligand, exhibit interesting complementary reactivity in the coupling of aryl bromides or iodides; in contrast, with these substrates the iron catalysts show a lower selectivity. The formation of homocoupling byproducts is suppressed markedly to less than 5% in most cases by choosing the appropriate metal fluoride/NHC combination. The present catalyst combinations offer several synthetic advantages over existing methods: practical synthesis of a broad range of unsymmetrical biaryls without the use of palladium catalysts and phosphine ligands. On the basis of stoichiometric control experiments and theoretical studies, the origin of the unique catalytic effect of the fluoride counterion can be ascribed to the formation of a higher-valent heteroleptic metalate [Ar(1)MF(2)]MgBr as the key intermediate in our proposed catalytic cycle. First, stoichiometric control experiments revealed the stark differences in chemical reactivity between the metal fluorides and metal chlorides. Second, DFT calculations indicate that the initial reduction of di- or trivalent metal fluoride in the wake of transmetalation with PhMgCl is energetically unfavorable and that formation of a divalent heteroleptic metalate complex, [PhMF(2)]MgCl (M = Fe, Co, Ni), is dominant in the metal fluoride system. The heteroleptic ate-complex serves as a key reactive intermediate, which undergoes oxidative addition with Ph

5-(1-Aryl-3-(thiophen-2-yl)-1H-pyrazol-4-yl)-1H-tetrazoles: Synthesis, structural characterization, Hirshfeld analysis, anti-inflammatory and anti-bacterial studies

NASA Astrophysics Data System (ADS)

Kumbar, Mahadev N.; Kamble, Ravindra R.; Dasappa, Jagadeesh Prasad; Bayannavar, Praveen K.; Khamees, Hussien Ahmed; Mahendra, M.; Joshi, Shrinivas D.; Dodamani, Suneel; Rasal, V. P.; Jalalpure, Sunil

2018-05-01

A series of novel 5-(1-aryl-3-(thiophen-2-yl)-1H-pyrazol-4-yl)-1H-tetrazoles 7(h-s) were designed and synthesized. Structural characterization was done by spectral and single crystal X-ray studies. The intermolecular interactions of compound 7n were quantified and visualized using Hirshfeld surface analysis. Structures of newly synthesized compounds were docked into active site of COX-2 enzyme PDB:

Photoredox activation for the direct β-arylation of ketones and aldehydes.

PubMed

Pirnot, Michael T; Rankic, Danica A; Martin, David B C; MacMillan, David W C

2013-03-29

The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a broad range of carbonyl β-functionalization reactions and is amenable to enantioselective catalysis.

Cannabinoid receptor type 2 (CB2)-selective N-aryl-oxadiazolyl-propionamides: synthesis, radiolabelling, molecular modelling and biological evaluation

PubMed Central

2012-01-01

Background The endocannabinoid system is involved in many physiological and pathological processes. Two receptors (cannabinoid receptor type 1 (CB1) and type 2 (CB2)) are known so far. Many unwanted psychotic side effects of inhibitors of this system can be addressed to the interaction with CB1. While CB1 is one of the most abundant neuroreceptors, CB2 is expressed in the brain only at very low levels. Thus, highly potent and selective compounds for CB2 are desired. N-aryl-((hetero)aromatic)-oxadiazolyl-propionamides represent a promising class of such selective ligands for the human CB2. Here, a library of various derivatives is studied for suitable routes for labelling with 18F. Such 18F-labelled compounds can then be employed as CB2-selective radiotracers for molecular imaging studies employing positron emission tomography (PET). Results By varying the N-arylamide substructure, we explored the binding pocket of the human CB2 receptor and identified 9-ethyl-9H-carbazole amide as the group with optimal size. Radioligand replacement experiments revealed that the modification of the (hetero)aromatic moiety in 3-position of the 1,2,4-oxadiazoles shows only moderate impact on affinity to CB2 but high impact on selectivity towards CB2 with respect to CB1. Further, we could show by autoradiography studies that the most promising compounds bind selectively on CB2 receptors in mouse spleen tissue. Molecular docking studies based on a novel three-dimensional structural model of the human CB2 receptor in its activated form indicate that the compounds bind with the N-arylamide substructure in the binding pocket. 18F labelling at the (hetero)aromatic moiety at the opposite site of the compounds via radiochemistry was carried out. Conclusions The synthesized CB2-selective compounds have high affinity towards CB2 and good selectivity against CB1. The introduction of labelling groups at the (hetero)aromatic moiety shows only moderate impact on CB2 affinity, indicating the

N-substituted imidazolines and ethylenediamines and their action on alpha- and beta-adrenergic receptors.

PubMed

Hamada, A; Yaden, E L; Horng, J S; Ruffolo, R R; Patil, P N; Miller, D D

1985-09-01

A series of N-substituted imidazolines and ethylenediamines were synthesized and examined for their activity in alpha- and beta-adrenergic systems. The length of the intermediate side chain between the catechol and imidazoline ring or the amine of the ethylenediamine segment was shown to affect the adrenergic activity. N-[2-(3,4-Dihydroxyphenyl)ethyl]imidazoline hydrochloride (2) and N-[2-(3,4-dihydroxyphenyl)ethyl]ethylenediamine dihydrochloride (4), both with two methylene groups between the catechol and amine segment, were found to be somewhat selective for alpha 2-adrenergic receptors while 1-(3,4-dihydroxybenzyl)imidazoline hydrochloride (1) and N-2-(3,4-dihydroxybenzyl)ethylenediamine dihydrochloride (3), both with one methylene group between the catechol and amine segment, were more selective for alpha1-adrenergic receptors in a pithed rat model. Of the four compounds examined, only compound 2 showed significant direct activity on beta1- and beta2-adrenergic receptors.

Synthetic, Infrared, 1Hand 13CNMR Spectral Studies on N-(p-Substituted Phenyl)-p-Substituted Benzenesulphonamides, p-X'C6H4SO2NH- (p-XC6H4), where X' or X = H, CH3, C2H5, F, Cl or Br

NASA Astrophysics Data System (ADS)

Gowda, B. Thimme; Jayalakshmi, K. L.; Shetty, Mahesha

2004-05-01

Thirty N-(p-substituted phenyl)-p-substituted benzenesulphonamides of the general formula, p-X'C6H4SO2NH(p-XC6H4), where X' or X = H, CH3, C2H5, F, Cl or Br, are synthesised and their infrared spectra in the solid state and 1H and 13C NMR spectra in solution are measured. The N-H stretching vibrational frequencies, νN-H vary in the range 3334 - 3219 cm-1, while the asymmetric and symmetric SO2 vibrations appear in the ranges 1377 - 1311 cm-1 and 1182 - 1151 cm-1, respectively. The compounds exhibit S-N and C-N stretching vibrational absorptions in the ranges 937 - 898 cm-1 and 1310 - 1180 cm-1, respectively. There are no particular trends in the variation of these frequencies on substitution with either electron withdrawing or electron donating groups. The 1H and 13C chemical shifts of N-(p-substituted phenyl)-p-substituted benzenesulphonamides, are assigned to various protons and carbons of the two benzene rings. Further, incremental shifts of the ring protons and carbons due to -SO2NH(p-XC6H4) groups in the compounds of the formula, C6H5SO2NH(p-XC6H4), and p-X'C6H4SO2- and p-X'C6H4SO2NH- groups in the compounds of the formula, p-X'C6H4SO2NH(C6H5) are computed and used to calculate the 1H and 13C chemical shifts of the parallely substituted compounds of the general formula p-X'C6H4SO2NH(p-XC6H4). The computed values agree well with the observed chemical shifts. The above incremental shifts are found to correlate with the Hammett substituent parameters.

Cytotoxic Activity and Structure-Activity Relationship of Triazole-Containing Bis(Aryl Ether) Macrocycles.

PubMed

Hernández-Vázquez, Eduardo; Chávez-Riveros, Alejandra; Romo-Pérez, Adriana; Ramírez-Apán, María Teresa; Chávez-Blanco, Alma D; Morales-Bárcenas, Rocío; Dueñas-González, Alfonso; Miranda, Luis D

2018-05-17

Cancer continues to be a worldwide health problem. Certain macrocyclic molecules have become attractive therapeutic alternatives for this disease because of their efficacy and, frequently, their novel mechanisms of action. Herein, we report the synthesis of a series of 20-, 21-, and 22-membered macrocycles containing triazole and bis(aryl ether) moieties. The compounds were prepared by a multicomponent approach from readily available commercial substrates. Notably, some of the compounds displayed interesting cytotoxicity against cancer (PC-3) and breast (MCF-7) cell lines, especially those bearing an aliphatic or a trifluoromethyl substituent on the N-phenyl moiety (IC 50 <13 μm). Additionally, some of the compounds were able to induce apoptosis relative to the solvent control; in particular, (Z)-N-cyclohexyl-7-oxo-6-[4-(trifluoromethyl)phenyl]-1 1 H-3,10-dioxa-6-aza-1(4,1)-triazola-4(1,3),9(1,4)-dibenzenacyclotridecaphane-5-carboxamide (12 f) was the most potent in this regard (22.7 % of apoptosis). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electronic properties of thiolate compounds of oxomolybdenum(V) and their tungsten and selenium analogues. Effects of /sup 17/O, /sup 98/Mo, and /sup 95/Mo isotope substitution upon ESR spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, G.R.; Brunette, A.A.; McDonell, A.C.

1981-04-22

The series of crystalline, mononuclear B/sup +/(MO(XR)/sub 4/)/sup -/ and triply bridged binuclear B/sup +/(M/sub 2/O/sub 2/(XR)/sub 6/(OMe))/sup -/(M = Mo, W; X = S, Se; R = aryl; B = quaternary cation) salts have been isolated and the anions (MoO(SR)/sub 4/)/sup -/ (R = Et, CH/sub 2/Ph) stabilized in solution at -60/sup 0/C. The mononuclear anions are intensely colored due to a ligand-to-metal charge-transfer transition which is absent in the binuclear species. The magnetic susceptibilities of (Et/sub 4/N)(MO(SPh)/sub 4/) show a Curie dependence in the range 300 to 4.2 K with minor deviations in the tungsten compound. The behaviormore » is essentially that of magnetically dilute 4d/sup 1/ and 5d/sup 1/ systems exhibiting a tetragonal ligand field and greatly reduced spin-orbit coupling on the metal. The presence of strong spin-spin coupling in the binuclear compounds leads to magnetic moments close to 0. ESR spectra (at X- and Q-band frequencies) of the mononuclear anions exhibit axial symmetry, and /sup 98/Mo and /sup 95/Mo isotope substitution and computer simulation permit accurate extraction of the g and hyperfine tensor anisotropies. Exceptionally arrow line widths permit observation of /sup 17/O-superhyperfine coupling in /sup 17/O-enriched (/sup 98/MoO(SPh)/sub 4/)/sup -/(a = 2.2 x 10/sup -4/cm/sup -1/).« less

Α-aryl-N-alkyl nitrones, as potential agents for stroke treatment: synthesis, theoretical calculations, antioxidant, anti-inflammatory, neuroprotective, and brain-blood barrier permeability properties.

PubMed

Chioua, Mourad; Sucunza, David; Soriano, Elena; Hadjipavlou-Litina, Dimitra; Alcázar, Alberto; Ayuso, Irene; Oset-Gasque, María Jesús; González, María Pilar; Monjas, Leticia; Rodríguez-Franco, María Isabel; Marco-Contelles, José; Samadi, Abdelouahid

2012-01-12

We report the synthesis, theoretical calculations, the antioxidant, anti-inflammatory, and neuroprotective properties, and the ability to cross the blood-brain barrier (BBB) of (Z)-α-aryl and heteroaryl-N-alkyl nitrones as potential agents for stroke treatment. The majority of nitrones compete with DMSO for hydroxyl radicals, and most of them are potent lipoxygenase inhibitors. Cell viability-related (MTT assay) studies clearly showed that nitrones 1-3 and 10 give rise to significant neuroprotection. When compounds 1-11 were tested for necrotic cell death (LDH release test) nitrones 1-3, 6, 7, and 9 proved to be neuroprotective agents. In vitro evaluation of the BBB penetration of selected nitrones 1, 2, 10, and 11 using the PAMPA-BBB assay showed that all of them cross the BBB. Permeable quinoline nitrones 2 and 3 show potent combined antioxidant and neuroprotective properties and, therefore, can be considered as new lead compounds for further development in specific tests for potential stroke treatment.

Synthesis, Biological Evaluation, and Autophagy Mechanism of 12N-Substituted Sophoridinamines as Novel Anticancer Agents.

PubMed

Bi, Chongwen; Zhang, Na; Yang, Peng; Ye, Cheng; Wang, Yanxiang; Fan, Tianyun; Shao, Rongguang; Deng, Hongbin; Song, Danqing

2017-02-09

A series of 12 N -substituted sophoridinamine derivatives were synthesized and evaluated for their cytotoxic activities in human HepG2 hepatoma cells. Structure-activity relationship revealed that introduction of a suitable arylidene or arylethyl at the N '-end could greatly enhance antiproliferation potency. Among them, compound 6b possessing a N '-trimethoxyphenyl methylene exhibited potent antiproliferation effect against three human tumor cell lines including HepG2, leukemia (K562), and breast cancer (HMLE), with IC 50 between 0.55 and 1.7 μM. The underlying mechanism of 6b against tumor cells is to block autophagic flux, mainly through neutralizing lysosomal acidity. Our results indicated that compound 6b is a potent lysosomal deacidification agent and is accordingly able to block autophagic flux and inhibit tumor cell growth.

Rh(III)-Catalyzed C-H Activation of Benzoylacetonitriles and Tandem Cyclization with Diazo Compounds to Substituted Benzo[ de]chromenes.

PubMed

Fang, Feifei; Zhang, Chunmei; Zhou, Chaofan; Li, Yazhou; Zhou, Yu; Liu, Hong

2018-04-06

Rh (III)-catalyzed C-H activation of benzoylacetonitriles in coupling with diazo compounds was developed to synthesize diversified substituted benzo[ de]chromenes via a formal (4 + 2) cycloaddition with a diazo compound and subsequent tandem (4 + 2) cycloaddition with another diazo compound. Intriguingly, synthesis of substituted benzo[ de]chromenes and their decarboxylation products could be realized by controlling the reaction conditions. These reactions have a broad range of substrates, moderate to good yields, and high regioselectivity.

Photoredox Activation for the Direct β-Arylation of Ketones and Aldehydes

PubMed Central

Pirnot, Michael T.; Rankic, Danica A.; Martin, David B. C.; MacMillan, David W. C.

2013-01-01

The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a broad range of carbonyl β-functionalization reactions and is amenable to enantioselective catalysis. PMID:23539600

Solvent-free synthesis, spectral correlations and antimicrobial activities of some aryl E 2-propen-1-ones

NASA Astrophysics Data System (ADS)

Sathiyamoorthi, K.; Mala, V.; Sakthinathan, S. P.; Kamalakkannan, D.; Suresh, R.; Vanangamudi, G.; Thirunarayanan, G.

2013-08-01

Totally 38 aryl E 2-propen-1-ones including nine substituted styryl 4-iodophenyl ketones have been synthesised using solvent-free SiO2-H3PO4 catalyzed Aldol condensation between respective methyl ketones and substituted benzaldehydes under microwave irradiation. The yields of the ketones are more than 80%. The synthesised chalcones were characterized by their analytical, physical and spectroscopic data. The spectral frequencies of synthesised substituted styryl 4-iodophenyl ketones have been correlated with Hammett substituent constants, F and R parameters using single and multi-linear regression analysis. The antimicrobial activities of 4-iodophenyl chalcones have been studied using Bauer-Kirby method.

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

Synthesis of new substituted azetidinoyl and thiazolidinoyl-1,3,4-thiadiazino (6,5-b) indoles as promising anti-inflammatory agents.

PubMed

Bhati, Sudhir Kumar; Kumar, Ashok

2008-11-01

Various N-({5-[(arylmethylene)amino]-1,3,4-thiadiazol-2-yl}methyl) [1,3,4] thiadiazino[6,5-b]indol-3-amine (6a-6h), 2-aryl-3-{5-[([1,3,4] thiadiazino[6,5-b]indol-3-ylamino)methyl]-1,3,4-thiadiazol-2-yl}-1,3-thiazolidin-4-one (7a-7h), and 3-chloro-4-aryl-1-{5-[{[1,3,4]thiadiazino[6,5-b]indol-3-ylamino]methyl]-1,3,4-thiadiazol-2-yl}azetidin-2-one (8a-8h) have been synthesized in the present study. The structure of these newly synthesized compounds were confirmed by their analytical and spectral data. These compounds were also evaluated for their anti-inflammatory, ulcerogenic and analgesic activities. Compound 8g has shown most active anti-inflammatory and analgesic activities with better ulcerogenic activity than phenylbutazone, while this compound was found to be associated with lesser degree of anti-inflammatory and analgesic activities as compared to indomethacin.

Chalcones as Promising Lead Compounds on Cancer Therapy.

PubMed

León-González, Antonio J; Acero, Nuria; Muñoz-Mingarro, Dolores; Navarro, Inmaculada; Martín-Cordero, Carmen

2015-01-01

Chalcones constitute a group of phenolic compounds that command an increasing interest on cancer research. Natural chalcones are widespread through the plant kingdom. The most abundant and investigated chalcones are isoliquiritigenin, flavokawain and xanthohumol, which are present in the Fabaceae, Piperaceae, Cannabaceae, and Moraceae families. These chalcones have been shown to be promising lead antitumor-chemopreventive drugs by three different activities: antioxidants, cytotoxic and apoptosis inducers. In the recent years, SAR (structure-activity relationship) has contributed towards the improvement of anticancer properties of chalcones by substituting aryl rings and introducing heterocyclic moieties. This review summarizes the anticancer activities shown by natural chalcones and the SAR and describes how different chemical moiety modifications could lead them to be therapeutically useful in the treatment of cancer.

Persistent Epithelial Defects and Corneal Opacity After Collagen Cross-Linking With Substitution of Dextran (T-500) With Dextran Sulfate in Compounded Topical Riboflavin.

PubMed

Höllhumer, Roland; Watson, Stephanie; Beckingsale, Peter

2017-03-01

Collagen cross-linking (CXL) is a commonly performed procedure to prevent the progression of keratoconus. Riboflavin is an essential part of the procedure, which facilitates both the cross-linking process and protection of intraocular structures. Dextran can be added to riboflavin to create an isotonic solution. This case report highlights the importance of compounding riboflavin with the correct dextran solution. A retrospective case series. Six eyes of 4 male patients with keratoconus aged from 20 to 38 years underwent CXL with substitution of 20% dextran (T-500) with 20% dextran sulfate in a compounded riboflavin 0.1% solution. Postoperatively, persistent corneal epithelial defects, stromal haze, and then scarring occurred. Corneal transplantation was performed for visual rehabilitation but was complicated by graft rejection followed by failure (n = 1 eye), dehiscence (n = 4), cataract (n = 2), post-laser ablation haze (n = 1), and steroid-induced glaucoma (n = 2). The visual outcome was <6/18 in all 6 cases because of irregular astigmatism and stromal haze. Thinning, vascularization, and scarring of the residual host tissue were noted. Substitution of dextran (T-500) with dextran sulfate in riboflavin solutions during CXL results in loss of vision from permanent corneal opacity. Residual host changes may compromise the results of corneal transplantation.

Stable trifluorostyrene containing compounds grafted to base polymers, and their use as polymer electrolyte membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zhen-Yu; Roelofs, Mark Gerrit

2010-11-09

A fluorinated ion exchange polymer prepared by grafting at least one grafting monomer on to at least one base polymer, wherein the grafting monomer comprises structure 1a or 1b: wherein Z comprises S, SO.sub.2, or POR wherein R comprises a linear or branched perfluoroalkyl group of 1 to 14 carbon atoms optionally containing oxygen or chlorine, an alkyl group of 1 to 8 carbon atoms, an aryl group of 6 to 12 carbon atoms or a substituted aryl group of 6 to 12 carbon atoms; RF comprises a linear or branched perfluoroalkene group of 1 to 20 carbon atoms, optionallymore » containing oxygen or chlorine; Q is chosen from F, --OM, NH.sub.2, --N(M)SO.sub.2R.sup.2.sub.F, and C(M)(SO.sub.2R.sup.2.sub.F).sub.2, wherein M comprises H, an alkali cation, or ammonium; R.sup.2.sub.F groups comprises alkyl of 1 to 14 carbon atoms which may optionally include ether oxygens or aryl of 6 to 12 carbon atoms where the alkyl or aryl groups may be perfluorinated or partially fluorinated; and n is 1 or 2 for 1a, and n is 1, 2, or 3 for 1b. These ion exchange polymers are useful in preparing catalyst coated membranes and membrane electrode assemblies used in fuel cells.« less

Synthesis and evaluation of dual antiplatelet activity of bispidine derivatives of N-substituted pyroglutamic acids.

PubMed

Misra, Ankita; Anil Kumar, K S; Jain, Manish; Bajaj, Kirti; Shandilya, Shyamali; Srivastava, Smriti; Shukla, Pankaj; Barthwal, Manoj K; Dikshit, Madhu; Dikshit, Dinesh K

2016-03-03

N-aralkylpyroglutamides of substituted bispidine were prepared and evaluated for their ability to inhibit collagen induced platelet aggregation, both in vivo and in vitro. Some compounds showed high anti-platelet efficacy (in vitro) of which six inhibited both collagen as well as U46619 induced platelet aggregation with concentration dependent anti-platelet efficacy through dual mechanism. In particular, the compound 4j offered significant protection against collagen epinephrine induced pulmonary thromboembolism as well as ferric chloride induced arterial thrombosis, without affecting bleeding tendency in mice. Therefore, the present study suggests that the compound 4j displays a remarkable antithrombotic efficacy much better than aspirin and clopidogrel. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

PASS-predicted design, synthesis and biological evaluation of cyclic nitrones as nootropics.

PubMed

Marwaha, Alka; Goel, R K; Mahajan, Mohinder P

2007-09-15

Out of 400 virtually designed imidazoline N-oxides, five cyclic nitrones were selected on the basis of PASS prediction as potent nootropics and were evaluated for their biological activities in albino mice. The selected N-alkyl and aryl-substituted nitrones were found to be excellent nootropics. A series of lead compounds acting as cognition enhancers have been provided, which can be further exploited in search of such New Chemical Entities (NCEs).

Palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate: A practical synthesis of unsymmetrical ureas

PubMed Central

Vinogradova, Ekaterina V.; Fors, Brett P.; Buchwald, Stephen L.

2012-01-01

An efficient method for palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate is reported. The protocol allows for the synthesis of unsymmetrical N,N'-di- and N,N,N'-trisubstituted ureas in one pot, and is tolerant of a wide range of functional groups. Insight into the mechanism of aryl isocyanate formation is gleaned through studies of the transmetallation and reductive elimination steps of the reaction, including the first demonstration of reductive elimination from an arylpalladium isocyanate complex to produce an aryl isocyanate. PMID:22716197

Synthesis and antitumoral activity of novel 3-(2-substituted-1,3,4-oxadiazol-5-yl) and 3-(5-substituted-1,2,4-triazol-3-yl) beta-carboline derivatives.

PubMed

Formagio, Anelise S Nazari; Tonin, Lilian T Düsman; Foglio, Mary Ann; Madjarof, Christiana; de Carvalho, João Ernesto; da Costa, Willian Ferreira; Cardoso, Flávia P; Sarragiotto, Maria Helena

2008-11-15

Several novel 1-substituted-phenyl beta-carbolines bearing the 2-substituted-1,3,4-oxadiazol-5-yl and 5-substituted-1,2,4-triazol-3-yl groups at C-3 were synthesized and evaluated for their in vitro anticancer activity. The assay results pointed thirteen compounds with growth inhibition effect (GI(50)<100 microM) for all eight different types of human cancer cell lines tested. The beta-carbolines 7a and 7h, bearing the 3-(2-metylthio-1,3,4-oxadiazol-5-yl) group, displayed high selectivity and potent anticancer activity against ovarian cell line with GI(50) values lying in the nanomolar concentration range (GI(50)=10 nM for both compounds). The 1-(N,N-dimethylaminophenyl)-3-(5-thioxo-1,2,4-triazol-3-yl) beta-carboline (8g) was the most active compound, showing particular effectiveness on lung (GI(50)=0.06 microM), ovarian and renal cell lines. The potent anticancer activity presented for synthesized compounds 7a, 7h, and 8g, together with their easiness of synthesis, makes these compounds promising anticancer agents.

Aryl sulfonate based anticancer alkylating agents.

PubMed

Sheikh, Hamdullah Khadim; Arshad, Tanzila; Kanwal, Ghazala

2018-05-01

This research work revolves around synthesis of antineoplastic alkylating sulfonate esters with dual alkylating sites for crosslinking of the DNA strands. These molecules were evaluated as potential antineoplastic cross linking alkylating agents by reaction with the nucleoside of Guanine DNA nucleobase at both ends of the synthesized molecule. Synthesis of the alkylating molecules and the crosslinking with the guanosine nucleoside was monitored by MALDITOF mass spectroscopy. The synthesized molecule's crosslinking or adduct forming rate with the nucleoside was compared with that of 1,4 butane disulfonate (busulfan), in form of time taken for the appearance of [M+H] + . It was found that aryl sulfonate leaving group was causing higher rate of nucleophilic attack by the Lewis basic site of the nucleobase. Furthermore, the rate was also found to be a function of electron withdrawing or donating nature of the substituent on the aryl ring. Compound with strong electron withdrawing substituent on the para position of the ring reacted fastest. Hence, new alkylating agents were synthesized with optimized or desired reactivity.

Ligand-Enabled meta-Selective C-H Arylation of Nosyl-Protected Phenethylamines, Benzylamines, and 2-Aryl Anilines.

PubMed

Ding, Qiuping; Ye, Shengqing; Cheng, Guolin; Wang, Peng; Farmer, Marcus E; Yu, Jin-Quan

2017-01-11

A Pd-catalyzed, meta-selective C-H arylation of nosyl-protected phenethylamines and benzylamines is disclosed using a combination of norbornene and pyridine-based ligands. Subjecting nosyl protected 2-aryl anilines to this protocol led to meta-C-H arylation at the remote aryl ring. A diverse range of aryl iodides are tolerated in this reaction, along with select heteroaryl iodides. Select aryl bromides bearing ortho-coordinating groups can also be utilized as effective coupling partners in this reaction. The use of pyridine ligands has allowed the palladium loading to be reduced to 2.5 mol %. Furthermore, a catalytic amount of 2-norbornene (20 mol %) to mediate this meta-C-H activation process is demonstrated for the first time. Utilization of a common protecting group as the directing group for meta-C-H activation of amines is an important feature of this reaction in terms of practical applications.

Dual C-H functionalization of N-aryl amines: synthesis of polycyclic amines via an oxidative Povarov approach.

PubMed

Min, Chang; Sanchawala, Abbas; Seidel, Daniel

2014-05-16

Iminium ions generated in situ via copper(I) bromide catalyzed oxidation of N-aryl amines readily undergo [4 + 2] cycloadditions with a range of dienophiles. This method involves the functionalization of both a C(sp(3))-H and a C(sp(2))-H bond and enables the rapid construction of polycyclic amines under relatively mild conditions.

Atropisomerization in N-aryl-2(1H)-pyrimidin-(thi)ones: a ring-opening/rotation/ring-closure process in place of a classical rotation around the pivot bond.

PubMed

Najahi, Ennaji; Vanthuyne, Nicolas; Nepveu, Françoise; Jean, Marion; Alkorta, Ibon; Elguero, José; Roussel, Christian

2013-12-20

Uncatalyzed racemization processes in atropisomeric diphenyl-like frameworks are classically described as the result of the rotation around the pivotal single bond linking two planar frameworks. Severe constraints leading to more or less distorted transition states account for the experimental barrier to atropenantiomerization. In 1988, one of us hypothesized that, in N-aryl-2(1H)-pyrimidin-(thi)ones, a ring-opening/ring-closure process was contributing to the observed racemization process accounting for the lower barriers in the sulfur analogues than in oxygen analogues. Now, a series of six novel 6-amino-5-cyano-1,4-disubstituted-2(1H)-pyrimidinones 5a-5f and two 6-amino-5-cyano-4-p-tolyl-1-substituted-2(1H)-pyrimidinethiones 6a and 6b were synthesized and characterized through spectroscopic and X-ray diffraction studies. Semipreparative HPLC chiral separation was achieved, and enantiomerization barriers were obtained by thermal racemization. The rotational barriers of 6-amino-5-cyano-1-o-tolyl-4-p-tolyl-2(1H)-pyrimidinone (5b) and 6-amino-5-cyano-1-(naphthalen-1-yl)-4-p-tolyl-2(1H)-pyrimidinone (5e) were found to be 120.4 and 125.1 kJ·mol(-1) (n-BuOH, 117 °C), respectively, and those of the corresponding thiones were 116.8 and 109.6 kJ·mol(-1) (EtOH, 78 °C), respectively. DFT calculations of the rotational barriers clearly ruled out the classical rotation around the pivotal bond with distorted transition states in the case of the sulfur derivatives. Instead, the ranking of the experimental barriers (sulfur versus oxygen, and o-tolyl versus 1-naphthyl in both series) was nicely reproduced by calculations when the rotation occurred via a ring-opened form in N-aryl-2(1H)-pyrimidinethiones.

Synthesis of 3,3-disubstituted oxindoles by visible-light-mediated radical reactions of aryl diazonium salts with N-arylacrylamides.

PubMed

Fu, Weijun; Xu, Fengjuan; Fu, Yuqin; Zhu, Mei; Yu, Jiaqi; Xu, Chen; Zou, Dapeng

2013-12-06

A mild and efficient visible-light-mediated diarylation of N-arylacrylamides with aryl diazonium salts under mild conditions has been developed. This method provides convenient access to a variety of useful 3,3-disubstituted oxindoles by constructing two C-C bonds in one step.

Influence of Zr substitution on the stabilization of ThMn{sub 12}-type (Nd{sub 1−α}Zr{sub α})(Fe{sub 0.75}Co{sub 0.25}){sub 11.25}Ti{sub 0.75}N{sub 1.2−1.4} (α = 0–0.3) compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakuma, N.; Yano, M.; Kato, A.

2016-05-15

The influence of Zr substitution in ThMn{sub 12} compounds was investigated using strip casting alloys. It was found that Zr substitution stabilized (Nd{sub 1−α}Zr{sub α})(Fe{sub 0.75}Co{sub 0.25}){sub 11.25}Ti{sub 0.75}N{sub 1.2−1.4} (α = 0–0.3) compounds. Specifically, a reduction in the lattice constant along the a-axis was observed. Energy-dispersive X-ray spectroscopy mapping combined with Cs-corrected scanning transmission electron microscopy indicated that Zr atoms preferentially occupied Nd 2a sites. Both the magnetic anisotropy field and saturation polarization were maximum at Zr substitution ratio α = 0.1. The (Nd{sub 1−α}Zr{sub α})(Fe{sub 0.75}Co{sub 0.25}){sub 11.25}Ti{sub 0.75}N{sub 1.2−1.4} (α = 0–0.3) compounds displayed higher saturation polarizationmore » than Nd{sub 2}Fe{sub 14}B at high temperatures.« less

Synthesis of Secondary Aromatic Amides via Pd-Catalyzed Aminocarbonylation of Aryl Halides Using Carbamoylsilane as an Amide Source.

PubMed

Tong, Wenting; Cao, Pei; Liu, Yanhong; Chen, Jianxin

2017-11-03

Using N-methoxymethyl-N-organylcarbamoyl(trimethyl)silanes as secondary amides source, the direct transformation of aryl halides into the corresponding secondary aromatic amides via palladium-catalyzed aminocarbonylation is described. The reactions tolerated a broad range of functional groups on the aryl ring except big steric hindrance of substituent. The types and the relative position of substituents on the aryl ring impact the coupling efficiency.

Suzuki–Miyaura Cross-Coupling of Aryl Carbamates and Sulfamates: Experimental and Computational Studies

PubMed Central

Quasdorf, Kyle W.; Antoft-Finch, Aurora; Liu, Peng; Silberstein, Amanda L.; Komaromi, Anna; Blackburn, Tom; Ramgren, Stephen D.; Houk, K. N.; Snieckus, Victor; Garg, Neil K.

2011-01-01

The first Suzuki–Miyaura cross-coupling reactions of the synthetically versatile O-aryl carbamate and O-sulfamate groups is described. The transformations utilize the inexpensive, bench-stable catalyst NiCl2(PCy3)2 to furnish biaryls in good to excellent yields. A broad scope for this methodology has been demonstrated. Substrates with electron-donating and electron-withdrawing groups (EDGs, EWGs) are tolerated, in addition to those that possess ortho substitutents. Furthermore, heteroaryl substrates may be employed as coupling partners. A computational study providing the full catalytic cycles for these cross-coupling reactions is described. The oxidative additions with carbamates and sulfamates occur via a five-centered transition state, resulting in the exclusive cleavage of the Ar–O bond. Water is found to stabilize the Ni–carbamate catalyst resting state, and thus provides rationalization of the relative decreased rate of coupling of carbamates. Several synthetic applications are presented to showcase the utility of the methodology in the synthesis of polysubstituted aromatic compounds of natural product and bioactive molecule interest. PMID:21456551

Direct sp(3)C-H acroleination of N-aryl-tetrahydroisoquinolines by merging photoredox catalysis with nucleophilic catalysis.

PubMed

Feng, Zhu-Jia; Xuan, Jun; Xia, Xu-Dong; Ding, Wei; Guo, Wei; Chen, Jia-Rong; Zou, You-Quan; Lu, Liang-Qiu; Xiao, Wen-Jing

2014-04-07

Sequence catalysis merging photoredox catalysis (PC) and nucleophilic catalysis (NC) has been realized for the direct sp(3) C-H acroleination of N-aryl-tetrahydroisoquinoline (THIQ). The reaction was performed under very mild conditions and afforded products in 50-91% yields. A catalytic asymmetric variant was proved to be successful with moderate enantioselectivities (up to 83 : 17 er).

Development of 1-aryl-3-furanyl/thienyl-imidazopyridine templates for inhibitors against hypoxia inducible factor (HIF)-1 transcriptional activity.

PubMed

Fuse, Shinichiro; Ohuchi, Toshiaki; Asawa, Yasunobu; Sato, Shinichi; Nakamura, Hiroyuki

2016-12-15

1,3-Disubstituted-imidazopyridines were designed for developing inhibitors against HIF-1 transcriptional activity. Designed compounds were rapidly synthesized from a key aromatic scaffold via microwave-assisted Suzuki-Miyaura coupling/CH direct arylation sequence. Evaluation of ability to inhibit the hypoxia induced transcriptional activity of HIF-1 revealed that the compound 2i and 3a retained the same level of the inhibitory activity comparing with that of known inhibitor, YC-1 (1). Identified, readily accessible 1-aryl-3-furanyl/thienyl-imidazopyridine templates should be useful for future drug development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Direct asymmetric aldol reaction of aryl ketones with aryl aldehydes catalyzed by chiral BINOL-derived zincate catalyst.

PubMed

Li, Hong; Da, Chao-Shan; Xiao, Yu-Hua; Li, Xiao; Su, Ya-Ning

2008-09-19

Direct asymmetric aldol reaction of aryl ketones with aryl aldehydes catalyzed by chiral metal complex is reported for the first time herein. Two novel semicrown chiral ligands 1a and 1b were synthesized from (S)- and (R)-BINOL, respectively, and then employed to catalyze the direct asymmetric aldol addition of aryl ketones to aryl aldehydes. Introduced with 2.0 equiv of diethylzinc, 1b had higher enantioselectivity than 1a. Up to 97% yield and up to 80% enantioselectivity were achieved.

Synthesis, antimalarial activity, heme binding and docking studies of N-substituted 4-aminoquinoline-pyrimidine molecular hybrids.

PubMed

Maurya, Shiv Shyam; Khan, Shabana I; Bahuguna, Aparna; Kumar, Deepak; Rawat, Diwan S

2017-03-31

A series of novel N-substituted 4-aminoquinoline-pyrimidine hybrids have been synthesized via simple and economic route and evaluated for their antimalarial activity. Most compounds showed potent antimalarial activity against both CQ-sensitive and CQ-resistant strains with high selectivity index. All the compounds were found to be non-toxic to the mammalian cell lines. The most active compound 7b was analysed for heme binding activity using UV-spectrophotometer. Compound was found to interact with heme and a complex formation between compound and heme in a 1:1 stoichiometry ratio was determined using job plots. The interaction of these hybrids was also investigated by the molecular docking studies in the binding site of wild type Pf-DHFR-TS and quadruple mutant Pf-DHFR-TS. The pharmacokinetic property analysis of best active compounds was also studied by ADMET prediction. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The sonochemical arylation of malonic esters mediated by manganese triacetate.

PubMed

Meciarova, M; Toma, S; Luche, J L

2001-04-01

The intermolecular arylation of malonate esters in acetic acid solution in the presence of manganese(III) triacetate is known to proceed via an Electron Transfer mechanism. Under sonication, this reaction undergoes only minor changes. In contrast, the intramolecular reaction of dimethyl alpha-(3-phenylpropyl)malonate provides a new case of sonochemical switching, with the formation of compounds 7-9, while conventional thermal conditions generate only the bicyclic compound 6. Reactions using the more powerful oxidant, cerium ammonium nitrate are governed by the formation of the nitrate ester 11. Compounds 7-9 are isolated in yields lower than with MnTA, and in proportions depending on the conditions, thermal or sonochemical.

Anti-Helicobacter pylori activities of selected N-substituted cinnamamide derivatives evaluated on reference and clinical bacterial strains.

PubMed

Klesiewicz, Karolina; Karczewska, Elżbieta; Nowak, Paweł; Skiba-Kurek, Iwona; Sito, Edward; Pańczyk, Katarzyna; Koczurkiewicz, Paulina; Żelaszczyk, Dorota; Pękala, Elżbieta; Waszkielewicz, Anna M; Budak, Alicja; Marona, Henryk; Gunia-Krzyżak, Agnieszka

2018-05-01

In this study, thirty-five N-substituted derivatives of cinnamic acid amide (cinnamamide) were evaluated for anti-Helicobacter pylori activity using an agar disc-diffusion method. Qualitative screening was performed on a reference H. pylori strain (ATCC 43504), resulting in the identification of the three most active compounds, 8 (R,S-(2E)-3-(4-chlorophenyl)-N-(2-hydroxypropyl)prop-2-enamide, minimal inhibitory concentration, MIC = 7.5 µg/mL), 23 ((2E)-3-(4-chlorophenyl)-N-(2-hydroxycyclohexyl)prop-2-enamide, MIC = 10 µg/mL), and 28 ((2E)-3-(4-chlorophenyl)-N-(4-oxocyclohexyl)prop-2-enamide, MIC = 10 µg/mL). These compounds were further tested on twelve well-characterized clinical strains, yielding MIC values that ranged from 10 to 1000 µg/mL. Preliminary safety assessments of the compounds were made using the MTT viability test for cytotoxicity and Ames test for mutagenicity, which showed them to be generally safe, although compounds 8 and 28 showed mutagenic activity at some of the tested concentrations. The results of this study showed the anti-H. pylori potential of cinnamamide derivatives.

Effect of conformational mobility and hydrogen-bonding interactions on the selectivity of some guanidinoaryl-substituted mechanism-based inhibitors of trypsin-like serine proteases.

PubMed

Rai, R; Katzenellenbogen, J A

1992-11-13

Previously, we have reported that some guanidino-substituted alpha- and beta-aryl enol lactones I and II behaved as selective, mechanism-based inhibitors of some trypsin-like proteases (Rai, R.; Katzenellenbogen, J.A. J. Med. Chem., submitted). In this study, we describe the synthesis and kinetic evaluation of some related, guanidino-substituted enol lactones having greater conformational mobility and affording additional hydrogen-bonding sites at the active site. The alpha-aryl-substituted lactones 1 and 2, which have greater conformational mobility in the guanidinoaryl linkage than I, selectively inhibited the trypsin-like enzymes, and they were relatively poor inactivators of alpha-chymotrypsin and human neutrophil elastase (HNE). The iodo enol lactone 2 permanently inactivated trypsin, urokinase, tissue plasminogen activator, and plasmin, showing exceptionally high specificity in its interaction with trypsin and urokinase. The selectivity pattern exhibited by the closely related, conformationally less mobile alpha-aryl-substituted iodo lactone Ib, which was previously shown to be a selective suicide substrate of urokinase and plasmin, provides an interesting comparison. The alpha-benzamido-substituted lactones 3 and 4, which afford an additional site for active-site hydrogen bonding, were found to be very potent alternate substrate inhibitors of trypsin and urokinase. In addition, the iodo lactone 4 permanently inactivated alpha-chymotrypsin. The importance of secondary interactions in increasing the specificities in the case of alpha-chymotrypsin is discussed.

OBO-Protected Pyruvates as Reagents for the Synthesis of Functionalized Heteroaromatic Compounds.

PubMed

Alves Esteves, C Henrique; Koyioni, Maria; Christensen, Kirsten E; Smith, Peter D; Donohoe, Timothy J

2018-06-15

Pd-catalyzed α-arylation of methyl-OBO-ketone (OBO = 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl) gives rise to arylated OBO-protected pyruvates. By appropriate prefunctionalization of the aryl ring or by subsequent functionalization at the α-carbonyl position of the arylated OBO-ketones, useful diketo OBO-protected carboxylates can be generated. Cyclization, aromatization, and OBO deprotection of these intermediates, using two distinct routes, gives access to valuable α-acyl heteroaromatic compounds.

On the molecular and supramolecular properties of N,N‧-disubstituted iminoisoindolines: Synthesis, spectroscopy, X-ray structure and Hirshfeld surface analyses, and DFT calculations of two (E)-N,N‧-bis(aryl)iminoisoindolines (aryl = 2-tert-butylphenyl or perfluorophenyl)

NASA Astrophysics Data System (ADS)

Bitzer, Rodrigo S.; Visentin, Lorenzo C.; Hörner, Manfredo; Nascimento, Marco A. C.; Filgueiras, Carlos A. L.

2017-02-01

Supramolecular studies of iminoisoindoline-derived compounds have been prompted by their biological and photophysical properties. In this article, we report the synthesis, spectroscopy, X-ray structural characterization, and DFT study of two N,N‧-(aryl)-disubstituted 1-iminoisoindolines, namely (E)-N,N‧-bis(2-tert-butylphenyl)iminoisoindoline (2-t-BuPhimiso) and (E)-N,N‧-bis(perfluorophenyl)iminoisoindoline (F5Phimiso). Our X-ray structural analyses have shown that the isoindoline N2 atom of 2-t-BuPhimiso is slightly pyramidalized whereas the respective atom of F5Phimiso displays the expected trigonal planar geometry. The supramolecular arrangement of 2-t-BuPhimiso comprises one-dimensional chains along the [101] direction formed by Csbnd H···πarene interactions, in which the isoindoline ring behaves as a hydrogen-bond donor. For 2-t-BuPhimiso, DFT calculations at the B97-D3/6-311G** level have shown that the dimer formed by this Csbnd H···πarene contact displays a binding energy of -12.83 kcal mol-1. Product F5Phimiso assembles in the crystal state through type-I F3 synthons in addition to Csbnd H⋯F, C-Fδ-···πF+, and πarene/F-πarene/F stacking interactions. Accordingly, our DFT-D3 calculations have confirmed that these interactions synergistically play a dominating role in the crystal packing of F5Phimiso. Finally, the relative stability of the (Z) and (E) isomers of each product has been evaluated at the DFT level of theory. Our calculations have shown that the (E) forms are the most stable ones.

2-Aryl-8-aza-3-deazaadenosine Analogues of 5’-O-[N-(Salicyl)sulfamoyl]adenosine: Nucleoside Antibiotics that Block Siderophore Biosynthesis in Mycobacterium tuberculosis

PubMed Central

Krajczyk, Anna; Zeidler, Joanna; Januszczyk, Piotr; Dawadi, Surendra; Boshoff, Helena I.; Barry, Clifton E.; Ostrowski, Tomasz; Aldrich, Courtney C.

2016-01-01

A series of 5’-O-[N-(salicyl)sulfamoyl]-2-aryl-8-aza-3-deazaadenosines were designed to block mycobactin biosynthesis in Mycobacterium tuberculosis (Mtb) through inhibition of the essential adenylating enzyme MbtA. The synthesis of the 2-aryl-8-aza-3-deazaadenosine nucleosides featured sequential copper-free palladium-catalyzed Sonogashira coupling of a precursor 4-cyano-5-iodo-1,2,3-triazolonucleoside with terminal alkynes and Minakawa-Matsuda annulation reaction. These modified nucleosides were shown to inhibit MbtA with apparent Ki values ranging from 6.1 to 25 nM and to inhibit Mtb growth under iron-deficient conditions with minimum inhibitory concentrations ranging from 12.5 to >50 μM. PMID:27265685

Improve the biodegradability of post-hydrothermal liquefaction wastewater with ozone: conversion of phenols and N-heterocyclic compounds.

PubMed

Yang, Libin; Si, Buchun; Martins, Marcio Arêdes; Watson, Jamison; Chu, Huaqiang; Zhang, Yuanhui; Tan, Xiaobo; Zhou, Xuefei; Zhang, Yalei

2017-04-01

Hydrothermal liquefaction is a promising technology to convert wet biomass into bio-oil. However, post-hydrothermal liquefaction wastewater (PHWW) is also produced during the process. This wastewater contains a high concentration of organic compounds, including phenols and N-heterocyclic compounds which are two main inhibitors for biological treatment. Thus, proper treatment is required. In this work, ozone was used to convert phenols and N-heterocyclic compounds with a dosage range of 0-4.64 mg O 3 /mL PHWW. After ozone treatment, the phenols were fully converted, and acids were produced. However, N-heterocyclic compounds were found to have a low conversion rate (21.7%). The kinetic analysis for the degradation of phenols and N-heterocyclic compounds showed that the substitute played an important role in determining the priority of ozone reactions. The OH moiety in the ring compounds (phenols and pyridinol) may form hydroxyl radical, which lead to an efficient reaction. A substantial improved biodegradability of PHWW was observed after ozone treatment. The ratio of BOD 5 /COD was increased by about 32.36%, and reached a maximum of 0.41. The improved biodegradability of PHWW was justified by the conversion of phenols and N-heterocyclic compounds.

Fire and heat resistant laminating resins based on malemeido and citraconimido substituted 1 -2,4- and -2,6- diaminobenzenes

NASA Technical Reports Server (NTRS)

Mikroyannidis, John A.; Kourtides, Demetrius A. (Inventor)

1987-01-01

A novel class of fire and heat resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-(dialkox phosphonyl) methyl-2-4 and -2,6-diamino benzenes was presented. The polymer precursors are prepared by reacting 1-(diorgano oxyphosphonyl) methyl-2-4- and -2,6-diamino benzenes with maliec anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivaties of 1 (diorgano oxyphosphonyl) methyl -2,4- and -2,6-diamino benzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarboxylic dianhydride, or aryl diisocyanates, such as methylene bis(4-phenyl isocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by diferential scanning calorimetry and the thermal stability of the polymers is ascertained by thermogravimetric analysis.

Gold-Catalyzed Formal C-C Bond Insertion Reaction of 2-Aryl-2-diazoesters with 1,3-Diketones.

PubMed

Ren, Yuan-Yuan; Chen, Mo; Li, Ke; Zhu, Shou-Fei

2018-06-29

The transition-metal-catalyzed formal C-C bond insertion reaction of diazo compounds with monocarbonyl compounds is well established, but the related reaction of 1,3-diketones instead gives C-H bond insertion products. Herein, we report a protocol for a gold-catalyzed formal C-C bond insertion reaction of 2-aryl-2-diazoesters with 1,3-diketones, which provides efficient access to polycarbonyl compounds with an all-carbon quaternary center. The aryl ester moiety plays a crucial role in the unusual chemoselectivity, and the addition of a Brønsted acid to the reaction mixture improves the yield of the C-C bond insertion product. A reaction mechanism involving cyclopropanation of a gold carbenoid with an enolate and ring-opening of the resulting donor-acceptor-type cyclopropane intermediate is proposed. This mechanism differs from that of the traditional Lewis-acid-catalyzed C-C bond insertion reaction of diazo compounds with monocarbonyl compounds, which involves a rearrangement of a zwitterion intermediate as a key step. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antitumor activity of JS-K [O2-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate] and related O2-aryl diazeniumdiolates in vitro and in vivo.

PubMed

Shami, Paul J; Saavedra, Joseph E; Bonifant, Challice L; Chu, Jingxi; Udupi, Vidya; Malaviya, Swati; Carr, Brian I; Kar, Siddhartha; Wang, Meifeng; Jia, Lee; Ji, Xinhua; Keefer, Larry K

2006-07-13

The literature provides evidence that metabolic nitric oxide (NO) release mediates the cytotoxic activities (against human leukemia and prostate cancer xenografts in mice) of JS-K, a compound of structure R(2)N-N(O)=NO-Ar for which R(2)N is 4-(ethoxycarbonyl)piperazin-1-yl and Ar is 2,4-dinitrophenyl. Here we present comparative data on the potencies of JS-K and 41 other O(2)-arylated diazeniumdiolates as inhibitors of HL-60 human leukemia cell proliferation, as well as in the NCI 51-cell-line screen for six of them. The data show JS-K to be the most potent of the 42 in both screens and suggest that other features of its structure and metabolism besides NO release may contribute importantly to its activity. Results with control compounds implicate JS-K's arylating ability, and the surprisingly low IC(50) value of the N-(ethoxycarbonyl)piperazine byproduct of NO release suggests a role for the R(2)N moiety. In addition to the above-mentioned in vivo activities, JS-K is shown here to be carcinostatic in a rat liver cancer model.

Dopamine D(3) receptor antagonists. 1. Synthesis and structure-activity relationships of 5,6-dimethoxy-N-alkyl- and N-alkylaryl-substituted 2-aminoindans.

PubMed

Haadsma-Svensson, S R; Cleek, K A; Dinh, D M; Duncan, J N; Haber, C L; Huff, R M; Lajiness, M E; Nichols, N F; Smith, M W; Svensson, K A; Zaya, M J; Carlsson, A; Lin, C H

2001-12-20

5,6-Dimethoxy-2-(N-dipropyl)-aminoindan (3, PNU-99194A) was found to be a selective dopamine D(3) receptor antagonist with potential antipsychotic properties in animal models. To investigate the effects of nitrogen substitution on structure-activity relationships, a series of 5,6-dimethoxy-N-alkyl- and N-alkylaryl-substituted 2-aminoindans were synthesized and evaluated in vitro for binding affinity and metabolic stability. The results indicate that substitution at the amine nitrogen of the 2-aminoindans is fairly limited to the di-N-propyl group in order to achieve selective D(3) antagonists. Thus, combinations of various alkyl groups were generally inactive at the D(3) receptor. Although substitution with an N-alkylaryl or N-alkylheteroaryl group yields compounds with potent D(3) binding affinity, the D(2) affinity is also enhanced, resulting in a less than 4-fold preference for the D(3) receptor site, and no improvements in metabolic stability were noted. A large-scale synthesis of the D(3) antagonist 3 has been developed that has proven to be reproducible with few purification steps. The improvements include the use of 3,4-dimethoxybenzaldehyde as a low-cost starting material to provide the desired 5,6-dimethoxy-1-indanone 5c in good overall yield (65%) and the formation of a soluble silyl oxime 17 that was reduced efficiently with BH(3).Me(2)S. The resulting amino alcohol was alkylated and then deoxygenated using a Lewis acid and Et(3)SiH to give the desired product 3 in good overall yield of ( approximately 65%) from the indanone 5c.

Design and synthesis of highly potent benzodiazepine gamma-secretase inhibitors: preparation of (2S,3R)-3-(3,4-difluorophenyl)-2-(4-fluorophenyl)-4- hydroxy-N-((3S)-1-methyl-2-oxo-5- phenyl-2,3-dihydro-1H-benzo[e][1,4]-diazepin-3-yl)butyramide by use of an asymmetric Ireland-Claisen rearrangement.

PubMed

Churcher, Ian; Williams, Susie; Kerrad, Sonia; Harrison, Timothy; Castro, José L; Shearman, Mark S; Lewis, Huw D; Clarke, Earl E; Wrigley, Jonathan D J; Beher, Dirk; Tang, Yui S; Liu, Wensheng

2003-06-05

Novel benzodiazepine-containing gamma-secretase inhibitors for potential use in Alzheimer's disease have been designed that incorporate a substituted hydrocinnamide C-3 side chain. A syn combination of alpha-alkyl or aryl and beta-hydroxy or hydroxymethyl substituents was shown to give highly potent compounds. In particular, (2S,3R)-3-(3,4-difluorophenyl)-2-(4-fluorophenyl)-4-hydroxy-N-((3S)-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)butyramide (34) demonstrated excellent in vitro potency (IC(50) = 0.06 nM). 34 could also be selectively methylated to give [(3)H]-28, which is of use in radioligand binding assays.

Propargylic activation across a heterobimetallic ir-sn catalyst: nucleophilic substitution and indene formation with propargylic alcohols.

PubMed

Chatterjee, Paresh Nath; Roy, Sujit

2010-07-02

A nucleophilic substitution of propargylic alcohols with carbon (arene, heteroarene, and allyltrimethylsilane), sulfur (thiol), oxygen (alcohol), and nitrogen (sulfonamide) nucleophiles has been demonstrated using a high-valent [Ir(COD)(SnCl(3))Cl(mu-Cl)](2) catalyst in 1,2-dichloroethane to afford the corresponding propargylic products in moderate to excellent yields. Alkyl or aryl substituted tertiary propargylic alcohols produce substituted indenes with bulky arenes via allenylic intermediate. An electrophilic mechanism is proposed from Hammett correlation.

Use of Aryl Chlorides as Electrophiles in Pd-Catalyzed Alkene Difunctionalization Reactions

PubMed Central

Rosen, Brandon R.; Ney, Joshua E.; Wolfe, John P.

2010-01-01

The development of conditions that allow use of inexpensive aryl chlorides as electrophiles in Pd-catalyzed alkene carboamination and carboetherification reactions is described. A catalyst composed of Pd(OAc)2 and S-Phos minimizes N-arylation of the substrate and prevents formation of mixtures of regioisomeric products. A number of heterocycles, including pyrrolidines, isoxazolidines, tetrahydrofurans, and pyrazolidines, are efficiently generated with this method. PMID:20297834

40 CFR 721.267 - N-[2-[(substituted dinitrophenyl)azo]diallylamino-4- substituted phenyl] acetamide (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.267 N-[2-[(substituted dinitrophenyl)azo]diallylamino-4- substituted phenyl] acetamide (generic name). (a) Chemical substance and...

Fire and heat resistant laminating resins based on maleimido and citraconimido substituted 1-(diorgano oxyphosphonyl) methyl -2,4- and -2,6- diaminobenzenes

NASA Technical Reports Server (NTRS)

Mikroyannidis, John A. (Inventor); Kourtides, Demetrius A. (Inventor)

1987-01-01

A class of fire and heat resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-((dialkoxyphosphonyl) methyl)-2-4 and -2,6-diaminobenzenes are described. The polymer precursors are prepared by reacting 1-((diorganooxyphosphonyl) methyl)-2-4 and -2,6-diaminobenzenes with maleic anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivatives of 1-((diorganooxyphosphonyl) methyl)-2,4 and -2,6-diaminobenzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarbocylic dianhydride, or aryl diisocyanates, such as methylenebis (4-phenylisocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by differential scanning calorimetry (DSC) and the thermal stability of the polymers is ascertained by thermogravimetric analysis (TGA).

Transition Metal Free C-N Bond Forming Dearomatizations and Aryl C-H Aminations by in Situ Release of a Hydroxylamine-Based Aminating Agent.

PubMed

Farndon, Joshua J; Ma, Xiaofeng; Bower, John F

2017-10-11

We outline a simple protocol that accesses directly unprotected secondary amines by intramolecular C-N bond forming dearomatization or aryl C-H amination. The method is dependent on the generation of a potent electrophilic aminating agent released by in situ deprotection of O-Ts activated N-Boc hydroxylamines.

Polybenzimidazole compounds

DOEpatents

Klaehn, John R [Idaho Falls, ID; Peterson, Eric S [Idaho Falls, ID; Orme, Christopher J [Shelley, ID; Jones, Michael G [Chubbuck, ID; Wertsching, Alan K [Idaho Falls, ID; Luther, Thomas A [Idaho Falls, ID; Trowbridge, Tammy L [Idaho Falls, ID

2011-11-22

A PBI compound includes imidazole nitrogens at least a portion of which are substituted with a moiety containing a carbonyl group, the substituted imidazole nitrogens being bonded to carbon of the carbonyl group. At least 85% of the nitrogens may be substituted. The carbonyl-containing moiety may include RCO--, where R is alkoxy or haloalkyl. The PBI compound may exhibit a first temperature marking an onset of weight loss corresponding to reversion of the substituted PBI that is less than a second temperature marking an onset of decomposition of an otherwise identical PBI compound without the substituted moiety. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may use more than 5 equivalents in relation to the imidazole nitrogens to be substituted.

Anaerobic Aryl Reductive Dehalogenation of Halobenzoates by Cell Extracts of “Desulfomonile tiedjei”

PubMed Central

DeWeerd, Kim A.; Suflita, Joseph M.

1990-01-01

We studied the transformation of halogenated benzoates by cell extracts of a dehalogenating anaerobe, “Desulfomonile tiedjei.” We found that cell extracts possessed aryl reductive dehalogenation activity. The activity was heat labile and dependent on the addition of reduced methyl viologen, but not on that of reduced NAD, NADP, flavin mononucleotide, flavin adenine dinucleotide, desulfoviridin, cytochrome c3, or benzyl viologen. Dehalogenation activity in extracts was stimulated by formate, CO, or H2, but not by pyruvate plus coenzyme A or by dithionite. The pH and temperature optima for aryl dehalogenation were 8.2 and 35°C, respectively. The rate of dehalogenation was proportional to the amount of protein in the assay mixture. The substrate specificity of aryl dehalogenation activity for various aromatic compounds in “D. tiedjei” cell extracts was identical to that of whole cells, except differences were observed in the relative rates of halobenzoate transformation. Dehalogenation was 10-fold greater in “D. tiedjei” extracts prepared from cells cultured in the presence of 3-chlorobenzoate, suggesting that the activity was inducible. Aryl reductive dehalogenation in extracts was inhibited by sulfite, sulfide, and thiosulfate, but not sulfate. Experiments with combinations of substrates suggested that cell extracts dehalogenated 3-iodobenzoate more readily than either 3,5-dichlorobenzoate or 3-chlorobenzoate. Dehalogenation activity was found to be membrane associated. This is the first report characterizing aryl dehalogenation activity in cell extracts of an obligate anaerobe. PMID:16348308

Photoinduced Electron Transfer-based Halogen-free Photosensitizers: Covalent meso-Aryl (Phenyl, Naphthyl, Anthryl, and Pyrenyl) as Electron Donors to Effectively Induce the Formation of the Excited Triplet State and Singlet Oxygen for BODIPY Compounds.

PubMed

Zhang, Xian-Fu; Feng, Nan

2017-09-19

Pristine BODIPY compounds have negligible efficiency to generate the excited triplet state and singlet oxygen. In this report, we show that attaching a good electron donor to the BODIPY core can lead to singlet oxygen formation with up to 58 % quantum efficiency. For this purpose, BODIPYs with meso-aryl groups (phenyl, naphthyl, anthryl, and pyrenyl) were synthesized and characterized. The fluorescence, excited triplet state, and singlet oxygen formation properties for these compounds were measured in various solvents by UV/Vis absorption, steady-state and time-resolved fluorescence methods, as well as laser flash photolysis technique. In particular, the presence of anthryl and pyrenyl showed substantial enhancement on the singlet oxygen formation ability of BODIPY with up to 58 % and 34 % quantum efficiency, respectively, owing to their stronger electron-donating ability. Upon the increase in singlet oxygen formation, the fluorescence quantum yield and lifetime values of the aryl-BODIPY showed a concomitant decrease. The increase in solvent polarity enhances the singlet oxygen generation but decreases the fluorescence quantum yield. The results are explained by the presence of intramolecular photoinduced electron transfer from the aryl moiety to BODIPY core. This method of promoting T 1 formation is very different from the traditional heavy atom effect by I, Br, or transition metal atoms. This type of novel photosensitizers may find important applications in organic oxygenation reactions and photodynamic therapy of tumors. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A modified approach to 2-(N-aryl)-1,3-oxazoles: application to the synthesis of the IMPDH inhibitor BMS-337197 and analogues.

PubMed

Dhar, T G Murali; Guo, Junqing; Shen, Zhongqi; Pitts, William J; Gu, Henry H; Chen, Bang-Chi; Zhao, Rulin; Bednarz, Mark S; Iwanowicz, Edwin J

2002-06-13

[structure: see text] A modified approach to the synthesis of 2-(N-aryl)-1,3-oxazoles, employing an optimized iminophosphorane/heterocumulene-mediated methodology, and its application to the synthesis of BMS-337197, a potent inhibitor of IMPDH, are described.

Crystal structure of 5-{4'-[(2-{2-[2-(2-ammonio-eth-oxy)eth-oxy]eth-oxy}eth-yl)carbamo-yl]-4-meth-oxy-[1,1'-biphen-yl]-3-yl}-3-oxo-1,2,5-thia-diazo-lidin-2-ide 1,1-dioxide: a potential inhibitor of the enzyme protein tyrosine phosphatase 1B (PTP1B).

PubMed

Ruddraraju, Kasi Viswanatharaju; Hillebrand, Roman; Barnes, Charles L; Gates, Kent S

2015-04-01

The title compound, C24H32N4O8S, (I), crystallizes as a zwitterion. The terminal amine N atom of the [(2-{2-[2-(2-ammonio-eth-oxy)eth-oxy]eth-oxy}eth-yl)carbamo-yl] side chain is protonated, while the 1,2,5-thia-diazo-lidin-3-one 1,1-dioxide N atom is deprotonated. The side chain is turned over on itself with an intra-molecular N-H⋯O hydrogen bond. The 1,2,5-thia-diazo-lidin-3-one 1,1-dioxide ring has an envelope conformation with the aryl-substituted N atom as the flap. Its mean plane is inclined by 62.87 (8)° to the aryl ring to which it is attached, while the aryl rings of the biphenyl unit are inclined to one another by 20.81 (8)°. In the crystal, mol-ecules are linked by N-H⋯O and N-H⋯N hydrogen bonds, forming slabs lying parallel to (010). Within the slabs there are C-H⋯O and C-H⋯N hydrogen bonds and C-H⋯π inter-actions present.

Substitutional and interstitial oxygen in wurtzite GaN

NASA Astrophysics Data System (ADS)

Wright, A. F.

2005-11-01

Density-functional theory was used to compute energy-minimum configurations and formation energies of substitutional and interstitial oxygen (O) in wurtzite GaN. The results indicate that O substituted at a N site (ON) acts as a single donor with the ionized state (ON+1) being the most stable O state in p-type GaN. In n-type GaN, interstitial O (OI) is predicted to be a double acceptor and O substituted at a Ga site (OGa) is predicted to be a triple acceptor. The formation energies of these two species are comparable to that of ON in n-type GaN and, as such, they should form and compensate the ON donors. The extent of compensation was estimated for both Ga-rich and N-rich conditions with a total O concentration of 1017cm-3. Ga-rich conditions yielded negligible compensation and an ON concentration in excess of 9.9×1016cm-3. N-rich conditions yielded a 25% lower ON concentration, due to the increased stability of OI and OGa relative to ON, and moderate compensation. These findings are consistent with experimental results indicating that O acts as a donor in GaN(O). Complexes of ON with the Mg acceptor and OI with the Si donor were examined. Binding energies for charge-conserving reactions were ⩾0.5eV, indicating that these complexes can exist in equilibrium at room temperature. Complexes of ON with the Ga vacancy in n-type GaN were also examined and their binding energies were 1.2 and 1.4eV, indicating that appreciable concentrations can exist in equilibrium even at elevated temperatures.

Aryl hydrocarbon receptor

PubMed Central

Kiss, Elina A.; Vonarbourg, Cedric

2012-01-01

Intestinal homeostasis results from a complex mutualism between gut microbiota and host cells. Defining the molecular network regulating such mutualism is currently of increasing interest, as its deregulation is reported to lead to increased susceptibility to infections, chronic inflammatory bowel diseases and cancer. Until now, the focus has been on the mechanism, by which the composition of indigenous microbiota shapes the immune system. In a recent study, we have shown that dietary compounds have also the ability to affect innate immune system. This regulation involves aryl hydrocarbon receptor (AhR), a sensor of plant-derived phytochemicals, which mediates the maintenance of Retinoic acid related orphan receptor γ t-expressing innate lymphoid cells (RORγt+ ILC) in the gut and consequently formation of postnatal lymphoid follicles. Thus, AhR represents the first evidence of a molecular link between diet and immunity at intestinal mucosal surfaces. PMID:22909905

Synthesis and Photoluminescent Properties of Arylethynyl substituted 9,10-Anthraquinones

NASA Technical Reports Server (NTRS)

Yang, Jin-Hua; Dass, Amala; Sotiriou-Leventis, Chariklia; Leventis, Nicholas

2003-01-01

A series of arylethynyl substituted anthraquinones were synthesized via Sonogashira coupling reactions of 2,7- dibromo-, 2,6-dibromo- and 2-bromoanthraquinone with para-substituted phenylacetylenes. While the redox properties of those compounds are almost insensitive to substitution, their absorption maxima are linearly related to the Hammett constants for electron donating and electron withdrawing groups separately. All compounds are photoluminescent both in solution (quantum yield of emission approximately 2%) and as solids. X-ray crystallographic characterization of 2,7-bisphenylethynyl anthraquinone indicates a monoclinic p2(l/n) space group and no indication for pi-overlap that would promote self-quenching. The emission maxima are red- shifted by both electron donating and electron withdrawing groups alike. The Stokes shifts of all compounds are significant and are correlated to the electronic properties of the substituents. The reduced forms of these compounds are also photoluminescent and the emission originates from the dihydroanthraquinone core.

Antiplasmodial Activity of [(Aryl)arylsulfanylmethyl]Pyridine▿ †‡

PubMed Central

Kumar, Sanjay; Das, Sajal Kumar; Dey, Sumanta; Maity, Pallab; Guha, Mithu; Choubey, Vinay; Panda, Gautam; Bandyopadhyay, Uday

2008-01-01

A series of [(aryl)arylsufanylmethyl]pyridines (AASMP) have been synthesized. These compounds inhibited hemozoin formation, formed complexes (KD = 12 to 20 μM) with free heme (ferriprotoporphyrin IX) at a pH close to the pH of the parasite food vacuole, and exhibited antimalarial activity in vitro. The inhibition of hemozoin formation may develop oxidative stress in Plasmodium falciparum due to the accumulation of free heme. Interestingly, AASMP developed oxidative stress in the parasite, as evident from the decreased level of glutathione and increased formation of lipid peroxide, H2O2, and hydroxyl radical (·OH) in P. falciparum. AASMP also caused mitochondrial dysfunction by decreasing mitochondrial potential (ΔΨm) in malaria parasite, as measured by both flow cytometry and fluorescence microscopy. Furthermore, the generation of ·OH may be mainly responsible for the antimalarial effect of AASMP since ·OH scavengers such as mannitol, as well as spin trap α-phenyl-n-tertbutylnitrone, significantly protected P. falciparum from AASMP-mediated growth inhibition. Cytotoxicity testing of the active compounds showed selective activity against malaria parasite with selectivity indices greater than 100. AASMP also exhibited profound antimalarial activity in vivo against chloroquine resistant P. yoelii. Thus, AASMP represents a novel class of antimalarial. PMID:18025110

Synthetic versatility of 2-substituted-6-methyl 2,3-dihydropyridinones in the synthesis of polyfunctional piperidine-based compounds and related β amino acid derivatives.

PubMed

Yang, Yang; Hardman, Clayton

2017-10-18

Chiral 2-substituted-6-methyl 2,3-dihydropyidinones 9, which can be facilely obtained from an asymmetric vinylogous Mannich reaction (VMR) with 1,3-bis-trimethysily enol ether, were used as versatile intermediates in constructing chiral polyfunctional piperidine-based compounds. The 6-methyl group of such compounds can be conveniently functionalized via alkylation and acylation reactions to provide efficient entries to the synthesis of a variety of chiral multi-substituted piperidine-based compounds. Further elaboration of the corresponding intermediates also provided access to polyfunctional indolizidine-based compounds. These methods were showcased in an asymmetric synthesis of 2,6-di-substituted piperidine compound 13, reported as the key intermediate in the synthesis of (+)-calvine and a natural alkaloid (-)-indolizidine 209D. Furthermore, selective C5 iodination of compound 9 enabled the installation of additional functional groups at this position. Finally, we demonstrated that the oxidative cleavage of 2-substituted-6-methyl-2,3-dihydropyidinones is a practical and efficient method for the enantioselective synthesis of β-amino acids, which can undergo further intra-molecular cyclization to give the corresponding chiral four-membered β-lactam derivatives.

γ-Alumina Nanoparticle Catalyzed Efficient Synthesis of Highly Substituted Imidazoles.

PubMed

Reddy, Bandapalli Palakshi; Vijayakumar, Vijayaparthasarathi; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah

2015-10-21

γ-Alumina nano particle catalyzed multi component reaction of benzil, arylaldehyde and aryl amines afforded the highly substituted 1,2,4,5-tetraaryl imidazoles with good to excellent yield in less reaction time under the sonication as well as the conventional methods. Convenient operational simplicity, mild conditions and the reusability of catalyst were the other advantages of this developed protocol.

Photo- and radiation chemical induced degradation of lignin model compounds.

PubMed

Lanzalunga; Bietti, M

2000-07-01

The basic mechanistic aspects of the photo- and radiation chemistry of lignin model compounds (LMCs) are discussed with respect to important processes related to lignin degradation. Several reactions occur after direct irradiation, photosensitized or radiation chemically induced oxidation of LMCs. Direct irradiation studies on LMCs have provided supportive evidence for the involvement of hydrogen abstraction reactions from phenols, beta-cleavage of substituted alpha-aryloxyacetophenones and cleavage of ketyl radicals (formed by photoreduction of aromatic ketones or hydrogen abstraction from arylglycerol beta-aryl ethers) in the photoyellowing of lignin rich pulps. Photosensitized and radiation chemically induced generation of reactive oxygen species and their reaction with LMCs are reviewed. The side-chain reactivity of LMC radical cations, generated by radiation chemical means, is also discussed in relation with the enzymatic degradation of lignin.

Spectrophotometric, voltammetric and cytotoxicity studies of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its N(4)-substituted derivatives: A combined experimental-computational study

NASA Astrophysics Data System (ADS)

Akgemci, Emine Guler; Saf, Ahmet Ozgur; Tasdemir, Halil Ugur; Türkkan, Ercan; Bingol, Haluk; Turan, Suna Ozbas; Akkiprik, Mustafa

2015-02-01

In this study, 2-hydroxy-5-methoxyacetophenone thiosemicarbazone (HMAT) and its novel N(4) substituted derivatives were synthesized and characterized by different techniques. The optical band gap of the compounds and the energy of HOMO were experimentally examined by UV-vis spectra and cyclic voltammetry measurements, respectively. Furthermore, the conformational spaces of the compounds were scanned with molecular mechanics method. The geometry optimization, HOMO and LUMO energies, the energy gap of the HOMO-LUMO, dipole moment of the compounds were theoretically calculated by the density functional theory B3LYP/6-311++G(d,p) level. The minimal electronic excitation energy and maximum wavelength calculations of the compounds were also performed by TD-DFT//B3LYP/6-311++G(d,p) level of theory. Theoretically calculated values were compared with the related experimental values. The combined results exhibit that all compounds have good electron-donor properties which affect anti-proliferative activity. The cytotoxic effects of the compounds were also evaluated against HeLa (cervical carcinoma), MCF-7 (breast carcinoma) and PC-3 (prostatic carcinoma) cell lines using the standard MTT assay. All tested compounds showed antiproliferative effect having IC50 values in different range. In comparison with that of HMAT, it was obtained that while ethyl group on 4(N)-substituted position decreased in potent anti-proliferative effect, the phenyl group on the position increased in anti-proliferative effect for the tested cancer cell line. Considering the molecular energy parameters, the cytotoxicity activities of the compounds were discussed.

Straightforward Entry toward Highly Substituted 2,3-Dihydrobenz[ b]oxepines by Ring Expansion of Benzopyryliums with Donor-Acceptor Diazo Compounds.

PubMed

Courant, Thibaut; Pasco, Morgane; Lecourt, Thomas

2018-05-04

Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[ b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This cationic reaction cascade first involves addition of a donor-acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C-C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially.

Amino acid-substituted gemini surfactant-based nanoparticles as safe and versatile gene delivery agents.

PubMed

Singh, Jagbir; Yang, Peng; Michel, Deborah; Verrall, Ronald E; Foldvari, Marianna; Badea, Ildiko

2011-05-01

Gene based therapy represents an important advance in the treatment of diseases that heretofore have had either no treatment or cure. To capitalize on the true potential of gene therapy, there is a need to develop better delivery systems that can protect these therapeutic biomolecules and deliver them safely to the target sites. Recently, we have designed and developed a series of novel amino acid-substituted gemini surfactants with the general chemical formula C(12)H(25) (CH(3))(2)N(+)-(CH(2))(3)-N(AA)-(CH(2))(3)-N(+) (CH(3))(2)-C(12)H(25) (AA= glycine, lysine, glycyl-lysine and, lysyl-lysine). These compounds were synthesized and tested in rabbit epithelial cells using a model plasmid and a helper lipid. Plasmid/gemini/lipid (P/G/L) nanoparticles formulated using these novel compounds achieved higher gene expression than the nanoparticles containing the parent unsubstituted compound. In this study, we evaluated the cytotoxicity of P/G/L nanoparticles and explored the relationship between transfection efficiency/toxicity and their physicochemical characteristics (such as size, binding properties, etc.). An overall low toxicity is observed for all complexes with no significant difference among substituted and unsubstituted compounds. An interesting result revealed by the dye exclusion assay suggests a more balanced protection of the DNA by the glycine and glycyl-lysine substituted compounds. Thus, the higher transfection efficiency is attributed to the greater biocompatibility and flexibility of the amino acid/peptide-substituted gemini surfactants and demonstrates the feasibility of using amino acid-substituted gemini surfactants as gene carriers for the treatment of diseases affecting epithelial tissue.

Anti-cancer agents based on 4-(hetero)Ary1-1,2,5-oxadiazol-3-yl Amino derivatives and a method of making

DOEpatents

Gakh, Andrei A.; Krasavin, Mikhail; Karapetian, Ruben; Rufanov, Konstantin A.; Konstantinov, Igor; Godovykh, Elena; Soldatkina, Olga; Sosnov, Andrey V.

2013-01-29

The present disclosure relates to novel compounds that can be used as anti-cancer agents in the prostate cancer therapy. ##STR00001## In particular, the invention relates N-substituted derivatives of 4-(hetero)aryl-1,2,5-oxadiazol-3-yl amines having the structural Formula (I) and (II), stereoisomers, tautomers, racemics, prodrugs, metabolites thereof, or pharmaceutically acceptable salt and/or solvate thereof. Meaning of R1 and R2 in the Formula (I) and (II) are defined in claim 1. The invention also relates to methods for preparing said compounds, and to pharmaceutical compositions comprising said compounds.

anticonvulsant and toxicity evaluation of newer 4H-benzo[1,4]oxazin-3-ones: The effect of two hydrogen bonding domains.

PubMed

Siddiqui, Nadeem; Ali, Ruhi; Arshad, M Faiz; Ahsan, Waquar; Ahmed, Sharique; Alam, M Shamsher

2010-11-01

A series of (Z)-2-(substituted aryl)-N-(3-oxo-4-(substituted carbamothioyl)-3,4-dihydro-2H-benzo[b][1,4]oxazin-7-yl) hydrazine carboxamides (6a-r) was synthesized using 2-amino-5-nitrophenol as a starting material. All the synthesized compounds possessed two hydrogen-bonding domains and their effect on the activity was studied thereof. The anticonvulsant activity was assessed by the maximal electroshock test (MES), subcutaneous pentylenetetrazole test (scPTZ) and intraperitoneal thiosemicarbazide test (ipTSC). Compounds (6b, 6h, 6i, and 6p) were found to be the most potent of the series as they showed 83-100% protection in the MES test. They also displayed considerable activity in the chemically induced seizure tests. Most of the tested compounds were devoid of the neurotoxic and hepatotoxic effects.

Methoxy-Directed Aryl-to-Aryl 1,3-Rhodium Migration

PubMed Central

Zhang, Jing; Liu, Jun-Feng; Ugrinov, Angel; Pillai, Anthony F. X.; Sun, Zhong-Ming; Zhao, Pinjing

2015-01-01

Through-space metal/hydrogen shift is an important strategy for transition metal-catalyzed C-H bond activation. Here we describe the synthesis and characterization of a Rh(I) 2,6-dimethoxybenzoate complex that underwent stoichiometric rearrangement via a highly unusual 1,3- rhodium migration. This aryl-to-aryl 1,3-Rh/H shift was also demonstrated in a Rh(I)-catalyzed decarboxylative conjugate addition to form a C-C bond at a meta position instead of the ipso-carboxyl position. A deuterium-labeling study under the conditions of Rh(I)-catalyzed protodecarboxylation revealed the involvement of an ortho-methoxy group in a multi-step pathway of consecutive sp3 and sp2 C-H bond activations. PMID:24171626

Synthesis and Biological Evaluation of Substituted N-[3-(1H-Pyrrol-1-yl)methyl]-1,2,5,6-tetrahydropyridin-1-yl]benzamide/ benzene Sulfonamides as Anti-Inflammatory Agents

PubMed Central

Gangapuram, Madhavi; Mazzio, Elizabeth; Eyunni, Suresh; Soliman, Karam F. A.; Redda, Kinfe K.

2014-01-01

The pharmacological activities of tetrahydropyridine (THP) derivatives are dependent on the substituent ring moiety. In this study, we investigate the anti-inflammatory activities of 12 newly synthesized substituted N-[3-(1H-pyrrol-1-yl)methyl]-1,2,5,6-tetrahydrobenzamide/benzene sulfonamides (9a–l) in murine BV-2 microglial cells. All compounds were initially screened for attenuation of nitric oxide (NO) production in lipopolysaccharide (LPS) (1 μg/mL)-activated microglial cells. The data show that only SO2-substituted THPs were effective at sub-lethal concentrations (IC50 values of 12.92 μM (9i), 14.64 μM (9j), 19.63 μM (9k)) relative to L-N6-(1-iminoethyl)lysine positive control (IC50 = 3.1 μM). The most potent SO2-substituted compound (9i) also blocked the LPS-inducible nitric oxide synthase (iNOS) and attenuated the release of several cytokines including IL-1α, IL-10, and IL-6. These findings establish the moderate immunomodulating effects of SO2-substituted THP derivatives. PMID:24585402

Transamination at the Crossroad of the One-Pot Synthesis of N-Substituted Quinonediimines and C-Substituted Benzobisimidazoles.

PubMed

Andeme Edzang, Judicaelle; Chen, Zhongrui; Audi, Hassib; Canard, Gabriel; Siri, Olivier

2016-10-10

A green and very efficient synthesis of N-substituted benzoquinonediimines or C-substituted benzo-bis(imidazole) derivatives is described under similar conditions. The different reaction pathway is only controlled by the nature of the primary amines, which tunes the reactivity of the intermediates.

Polymerization of tellurophene derivatives via microwave-assisted palladium-catalyzed ipso-arylative polymerization**

PubMed Central

Park, Young S.; Wu, Qin; Nam, Chang-Yong; Grubbs, Robert B.

2014-01-01

We report the synthesis of a tellurophene-containing low bandgap polymer, PDPPTe2T, via microwave-assisted palladium-catalyzed ipso-arylative polymerization of 2,5-bis[(α-hydroxy-α,α-diphenyl)methyl]tellurophene with a diketopyrrolopyrrole (DPP) monomer. Compared with the corresponding thiophene analog, PDPPTe2T absorbs light of longer wavelengths and has a smaller bandgap. Bulk heterojunction solar cells prepared from PDPPTe2T and PC71BM show PCE values of up to 4.4%. External quantum efficiency measurements show that PDPPTe2T produces photocurrent at wavelengths up to 1 μm. DFT calculations suggest that the atomic substitution from sulfur to tellurium increases electronic coupling to decrease the length of the carbon-carbon bonds between the tellurophene and thiophene rings, which results in the red-shift in absorption upon substitution of tellurium for sulfur. PMID:25145499

Superconductivity and role of pnictogen and Fe substitution in 112-LaPdxP n2 (P n =Sb ,Bi )

NASA Astrophysics Data System (ADS)

Retzlaff, Reiner; Buckow, Alexander; Komissinskiy, Philipp; Ray, Soumya; Schmidt, Stefan; Mühlig, Holger; Schmidl, Frank; Seidel, Paul; Kurian, Jose; Alff, Lambert

2015-03-01

We report on the epitaxial growth of As-free and phase-pure thin films of the 112-pnictide compounds LaPdxP n2 (P n =Sb ,Bi ) grown on (100) MgO substrates by molecular beam epitaxy. X-ray diffraction, reflection high-energy electron diffraction, and x-ray photoelectron spectroscopy confirm the HfCuSi2 structure of the material with a peculiar pnictogen square net layer. The superconducting transition temperature Tc varies little with Pd concentration. LaPdxSb2 has a higher Tc (3.2 K) by about 20% compared with LaPdxBi2 (2.7 K). Fe substitution of Pd leads to a rapid decay of superconductivity, suggesting that these superconductors are conventional type II.

Docking of oxalyl aryl amino benzoic acid derivatives into PTP1B

PubMed Central

Verma, Neelam; Mittal, Minakshi; Verma, Raman kumar

2008-01-01

Protein Tyrosine Phosphatases (PTPs) that function as negative regulators of the insulin signaling cascade have been identified as novel targets for the therapeutic enhancement of insulin action in insulin resistant disease states. Reducing Protein Tyrosine Phosphatase1B (PTP1B) abundance not only enhances insulin sensitivity and improves glucose metabolism but also protects against obesity induced by high fat feeding. PTP1B inhibitors such as Formylchromone derivatives, 1, 2-Naphthoquinone derivatives and Oxalyl aryl amino benzoic derivatives may eventually find an important clinical role as insulin sensitizers in the management of Type-II Diabetes and metabolic syndrome. We have carried out docking of modified oxalyl aryl amino benzoic acid derivatives into three dimensional structure of PTP1B using BioMed CAChe 6.1. These compounds exhibit good selectivity for PTP1B over most of phosphatases in selectivity panel such as SHP-2, LAR, CD45 and TCPTP found in literature. This series of compounds identified the amino acid residues such as Gly220 and Arg221 are important for achieving specificity via H-bonding interactions. Lipophilic side chain of methionine in modified oxalyl aryl amino benzoic acid derivative [1b (a2, b2, c1, d)] lies in closer vicinity of hydrophobic region of protein consisted of Meth258 and Phe52 in comparison to active ligand. Docking Score in [1b (a2, b2, c1, d)] is -131.740Kcal/mol much better than active ligand score -98.584Kcal/mol. This information can be exploited to design PTP1B specific inhibitors. PMID:19238234

Antimicrobial and hypoglycemic activities of novel N-Mannich bases derived from 5-(1-adamantyl)-4-substituted-1,2,4-triazoline-3-thiones.

PubMed

Al-Abdullah, Ebtehal S; Al-Tuwaijri, Hanaa M; Hassan, Hanan M; Haiba, Mogedda E; Habib, Elsayed E; El-Emam, Ali A

2014-12-11

The reaction of 5-(1-adamantyl)-4-ethyl or allyl-1,2,4-triazoline-3-thione with formaldehyde solution and various 1-substituted piperazines yielded the corresponding N-Mannich bases. The newly synthesized N-Mannich bases were tested for in vitro inhibitory activities against a panel of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Six compounds showed potent antibacterial activity against one or more of the tested microorganisms, while two compounds exhibited moderate activity against the tested Gram-positive bacteria. None of the newly synthesized compounds were proved to possess marked activity against Candida albicans. The oral hypoglycemic activity of six compounds was determined in streptozotocin (STZ)-induced diabetic rats. Four compounds produced significant strong dose-dependent reduction of serum glucose levels, compared to gliclazide at 10 mg/kg dose level (potency ratio > 75%).

Co-evaluation of plant extracts as petrochemical substitutes and for biologically active compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

McChesney, J.D.; Adams, R.P.

Recent efforts to discover phytochemicals that could substitute for petroleum-derived fuels and industrial feedstocks have not given much attention to the potential of these same phytochemicals to provide sources of biologically active compounds. The suitability of extraction products made to assess specific plants as potential botanochemical sources has been evaluated for use in screening procedures for evidence of biologically active compounds. Screening procedures for antibacterial, antifungal and toxic properties are discussed. Screening results are presented for extracts of nearly 80 species of plants from the southeastern United States and southern Great Plains that had previously been evaluated as sources ofmore » botanochemicals.« less

9-Substituted acridine derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors possessing antioxidant activity for Alzheimer's disease treatment.

PubMed

Makhaeva, Galina F; Lushchekina, Sofya V; Boltneva, Natalia P; Serebryakova, Olga G; Rudakova, Elena V; Ustyugov, Alexey A; Bachurin, Sergey O; Shchepochkin, Alexander V; Chupakhin, Oleg N; Charushin, Valery N; Richardson, Rudy J

2017-11-01

We investigated the inhibitory activity of 4 groups of novel acridine derivatives against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and carboxylesterase (CaE) using the methods of enzyme kinetics and molecular docking. Antioxidant activity of the compounds was determined using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS + ) radical decolorization assay as their ability to scavenge free radicals. Analysis of the esterase profiles and antiradical activities of the acridine derivatives showed that 9-aryl(heteroaryl)-N-methyl-9,10-dihydroacridines have a high radical-scavenging activity but low potency as AChE and BChE inhibitors, whereas 9-aryl(heteroaryl)-N-methyl-acridinium tetrafluoroborates effectively inhibit cholinesterases but do not exhibit antiradical activity. In contrast, a group of derivatives of 9-heterocyclic amino-N-methyl-9,10-dihydroacridine has been found that combine effective inhibition of AChE and BChE with rather high radical-scavenging activity. The results of molecular docking well explain the observed features in the efficacy, selectivity, and mechanism of cholinesterase inhibition by the acridine derivatives. Thus, in a series of acridine derivatives we have found compounds possessing dual properties of effective and selective cholinesterase inhibition together with free radical scavenging, which makes promising the use of the acridine scaffold to create multifunctional drugs for the therapy of neurodegenerative diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multimetallic Catalysis Enabled Cross-Coupling of Aryl Bromides with Aryl Triflates

PubMed Central

Ackerman, Laura K.G.; Lovell, Matthew M.

2015-01-01

Transition metal-catalyzed strategies for the formation of new C-C bonds have revolutionized the field of organic chemistry, enabling the efficient synthesis of ligands, materials, and biologically active molecules.1–3 In cases where a single metal fails to promote a selective or efficient transformation, the synergistic cooperation4 of two distinct catalysts – multimetallic catalysis – can be employed instead. Many important reactions rely on multimetallic catalysis,5 including the Wacker oxidation of olefins6–8 and the Sonogashira coupling of alkynes with aryl halides.9–10 However, the application of this strategy, even in recently developed methods11, has largely been limited to the use of metals with distinct reactivities, with only one metal catalyst undergoing an oxidative addition.12 In this manuscript, we demonstrate that cooperativity between two d10 metal catalysts, (bipyridine)nickel and (1,3-bis(diphenylphosphino)propane)palladium, enables a general cross-Ullman reaction.13–15 Our method couples aryl bromides with aryl triflates directly, eliminating the use of arylmetal reagents and avoiding the challenge of differentiating between multiple C–H bonds that is required for many C–H activation methods.16–17 The selectivity does not require an excess of either substrate and originates from the orthogonal activity of the two catalysts and the relative stability of the two arylmetal intermediates. While (dppp)Pd reacts preferentially with aryl triflates to afford a persistent intermediate, (bpy)Ni reacts preferentially with aryl bromides to form a transient, reactive intermediate. Although each catalyst forms less than 5% cross product in isolation, together they are able to achieve up to 94% yield. Our results reveal a new, general method for the synthesis of biaryls, heteroaryls, and dienes, as well as a new mechanism for selective transmetalation between two catalysts. We anticipate that this reaction will simplify the synthesis of

Synthesis and biological evaluation of novel quinazoline-sulfonamides as anti-cancer agents.

PubMed

Poudapally, Suresh; Battu, Shankar; Velatooru, Loka Reddy; Bethu, Murali Satyanarayana; Janapala, Venkateswara Rao; Sharma, Somesh; Sen, Subhabrata; Pottabathini, Narender; Iska, Vijaya Bhaskara Reddy; Katangoor, Vidya

2017-05-01

A robust economic approach to N-(quinazoline-4-yl)sulfonamides was developed and synthesized different aryl, hetero aryl, alkyl and cyclopropyl sulfonamides in excellent yields. All the compounds were evaluated for cytotoxic affinity to SKOV3, DU145, THP1, U937, and COLO205 cell lines. Interesting to find that the bulkiness of substituent at C-2 position of quinazoline forces the molecule to flip around in order to bind in the active site, when compared to the binding preference of previously known quinazoline compounds. Among the 21 compounds synthesized 2b, 2d, 2e, 2h, 2i, 3c, 3d, 3f, 3g and 3h found to be active on all the cell lines tested with IC 50 values <10µg/mL. Performed docking simulations to understand the binding preference of various C-2 substituted quinazoline sulfonamides. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of Substituted Pyrimido[5,4-b]indoles as Selective Toll-Like Receptor 4 Ligands

PubMed Central

2013-01-01

A cell-based high-throughput screen to identify small molecular weight stimulators of the innate immune system revealed substituted pyrimido[5,4-b]indoles as potent NFκB activators. The most potent hit compound selectively stimulated Toll-like receptor 4 (TLR4) in human and mouse cells. Synthetic modifications of the pyrimido[5,4-b]indole scaffold at the carboxamide, N-3, and N-5 positions revealed differential TLR4 dependent production of NFκB and type I interferon associated cytokines, IL-6 and interferon γ-induced protein 10 (IP-10) respectively. Specifically, a subset of compounds bearing phenyl and substituted phenyl carboxamides induced lower IL-6 release while maintaining higher IP-10 production, skewing toward the type I interferon pathway. Substitution at N-5 with short alkyl substituents reduced the cytotoxicity of the leading hit compound. Computational studies supported that active compounds appeared to bind primarily to MD-2 in the TLR4/MD-2 complex. These small molecules, which stimulate innate immune cells with minimal toxicity, could potentially be used as adjuvants or immune modulators. PMID:23656327

Camphyl-based α-diimine palladium complexes: highly efficient precatalysts for direct arylation of thiazoles in open-air.

PubMed

Chen, Fu-Min; Lu, Dong-Dong; Hu, Li-Qun; Huang, Ju; Liu, Feng-Shou

2017-07-21

Based on the strategy of the development of phosphine-free palladium-catalyzed direct C-H arylation, a series of camphyl-based α-diimine palladium complexes bearing sterically bulky substituents were synthesized and characterized. The palladium complexes were applied for the cross-coupling of thiazole derivatives with aryl bromides. The effect of the sterically bulky substituent on the N-aryl moiety as well as the reaction conditions was screened. Under the optimal protocols, a wide range of aryl bromides can be smoothly coupled with thiazoles in good to excellent yields in the presence of a low palladium loading of 0.2 mol% under open-air conditions.

Halogen Substitution Effects on N2 O Schiff Base Ligands in Unprecedented Abrupt FeII Spin Crossover Complexes.

PubMed

Phonsri, Wasinee; Macedo, David S; Vignesh, Kuduva R; Rajaraman, Gopalan; Davies, Casey G; Jameson, Guy N L; Moubaraki, Boujemaa; Ward, Jas S; Kruger, Paul E; Chastanet, Guillaume; Murray, Keith S

2017-05-23

A family of halogen-substituted Schiff base iron(II) complexes, [Fe II (qsal-X) 2 ], (qsal-X=5-X-N-(8-quinolyl)salicylaldimines)) in which X=F (1), Cl (2), Br (3) or I (4) has been investigated in detail. Compound 1 shows a temperature invariant high spin state, whereas the others all show abrupt spin transitions, at or above room temperature, namely, 295 K (X=I) up to 342 K (X=Br), these being some of the highest T 1/2 values obtained, to date, for Fe II N/O species. We have recently reported subtle symmetry breaking in [Fe II (qsal-Cl) 2 ] 2 with two spin transition steps occurring at 308 and 316 K. A photomagnetic study reveals almost full HS conversion of [Fe II (qsal-I) 2 ] 4 at low temperature (T(LIESST)=54 °K). The halogen substitution effects on the magnetic properties, as well as the crystal packing of the [Fe II (qsal-X) 2 ] compounds and theoretical calculations, are discussed in depth, giving important knowledge for the design of new spin crossover materials. In comparison to the well known iron(III) analogues, [Fe III (qsal-X) 2 ] + , the two extra π-π and P4AE interactions found in [Fe II (qsal-X) 2 ] compounds, are believed to be accountable for the spin transitions occurring at ambient temperatures. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, characterization, and anticancer activity of a series of ketone-N(4)-substituted thiosemicarbazones and their ruthenium(II) arene complexes.

PubMed

Su, Wei; Qian, Quanquan; Li, Peiyuan; Lei, Xiaolin; Xiao, Qi; Huang, Shan; Huang, Chusheng; Cui, Jianguo

2013-11-04

A series of ketone-N(4)-substituted thiosemicarbazone (TSC) compounds (L1-L9) and their corresponding [(η(6)-p-cymene)Ru(II)(TSC)Cl](+/0) complexes (1-9) were synthesized and characterized by NMR, IR, elemental analysis, and HR-ESI-mass spectrometry. The molecular structures of L4, L9, 1-6, and 9 were determined by single-crystal X-ray diffraction analysis. The compounds were further evaluated for their in vitro antiproliferative activities against the SGC-7901 human gastric cancer, BEL-7404 human liver cancer, and HEK-293T noncancerous cell lines. Furthermore, the interactions of the compounds with DNA were followed by electrophoretic mobility spectrometry studies.

Aryl diazonium salts: a new class of coupling agents for bonding polymers, biomacromolecules and nanoparticles to surfaces.

PubMed

Mahouche-Chergui, Samia; Gam-Derouich, Sarra; Mangeney, Claire; Chehimi, Mohamed M

2011-07-01

This critical review summarizes existing knowledge on the use of diazonium salts as a new generation of surface modifiers and coupling agents for binding synthetic polymers, biomacromolecules, and nanoparticles to surfaces. Polymer grafts can be directly grown at surfaces through the so-called grafting from approaches based on several polymerization methods but can also be pre-formed in solution and then grafted to surfaces through grafting onto strategies including "click" reactions. Several routes are also described for binding biomacromolecules through aryl layers in view of developing biosensors and protein arrays, while the use of aryl diazonium coupling agents is extended to the attachment of nanoparticles. Patents and industrial applications of the surface chemistry of diazonium compounds are covered. This review stresses the paramount role of aryl diazonium coupling agents in adhesion, surface and materials sciences (114 references).

C2 Arylated Benzo[b]thiophene Derivatives as Staphylococcus aureus NorA Efflux Pump Inhibitors.

PubMed

Liger, François; Bouhours, Pascale; Ganem-Elbaz, Carine; Jolivalt, Claude; Pellet-Rostaing, Stéphane; Popowycz, Florence; Paris, Jean-Marc; Lemaire, Marc

2016-02-04

An innovative and straightforward synthesis of second-generation 2-arylbenzo[b]thiophenes as structural analogues of INF55 and the first generation of our laboratory-made molecules was developed. The synthesis of C2-arylated benzo[b]thiophene derivatives was achieved through a method involving direct arylation, followed by simple structural modifications. Among the 34 compounds tested, two of them were potent NorA pump inhibitors, which led to a 16-fold decrease in the ciprofloxacin minimum inhibitory concentration (MIC) against the SA-1199B strain at concentrations of 0.25 and 0.5 μg mL(-1) (1 and 1.5 μm, respectively). This is a promising result relative to that obtained for reserpine (MIC=20 μg mL(-1)), a reference compound amongst NorA pump inhibitors. These molecules thus represent promising candidates to be used in combination with ciprofloxacin against fluoroquinolone-resistant strains. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cyclopropylamines from N,N-dialkylcarboxamides and Grignard reagents in the presence of titanium tetraisopropoxide or methyltitanium triisopropoxide.

PubMed

de Meijere, Armin; Chaplinski, Vladimir; Winsel, Harald; Kordes, Markus; Stecker, Björn; Gazizova, Vesta; Savchenko, Andrei I; Boese, Roland; Schill, Farina

2010-12-10

Thirty-three different N,N-dialkyl- and N-alkyl-N-phosphorylalkyl-substituted carboxamides 9-17 were treated with unsubstituted as well as with 2-alkyl-, 2,2-dialkyl-, and 3-alkenyl-substituted ethylmagnesium bromides 6 in the presence of stoichiometric amounts of titanium tetraisopropoxide or methyltitanium triisopropoxide to furnish substituted cyclopropylamines 20-25 in 20-98% yield, depending on the substituents with no (1:1) to excellent (>25:1) diastereoselectivities. Generally higher yields (up to 98%) of the cyclopropylamines 20-28 without loss of the diastereoselectivity were obtained with methyltitanium triisopropoxide as the titanium mediator. Under these conditions, even dioxolane-protected ketones and halogen-substituted and chiral as well as achiral alkyloxyalkyl-substituted carboxamides could be converted to the correspondingly substituted cyclopropylamines with unsubstituted as well as phenyl- and a variety of alkyl-substituted ethylmagnesium bromides in addition to numerous heteroatom-containing (e.g., halogen-, trityloxy-, tetrahydropyranyloxy-substituted) Grignard reagents (62 examples altogether). The transformation of N,N-diformylalkylamines 54 with ethylmagnesium bromide in the presence of methyltitanium triisopropoxide to N,N-dicyclopropyl-N-alkylamines 55 can be brought about in up to 82% yield (6 examples). An asymmetric variant of the titanium-mediated cyclopropanation of N,N-dialkylcarboxamides has been developed by applying chiral titanium mediators generated from stoichiometric amounts of titanium tetraisopropoxide and chiral diamino or diol ligands, respectively. The most efficient chiral mediators turned out to be titanium bistaddolates that provided the corresponding cyclopropylamines with enantiomeric excesses (ee) of up to 84%. Evaluation of several silyl-based additives revealed that the reaction can also efficiently be carried out with substoichiometric amounts (down to 25 mol%) of the titanium reagent, as long as 2-aryl- or 2

Synthesis and antileishmanial activity of 6-mono-substituted and 3,6-di-substituted acridines obtained by acylation of proflavine.

PubMed

Di Giorgio, Carole; Shimi, Kamal; Boyer, Gérard; Delmas, Florence; Galy, Jean-Pierre

2007-10-01

Two new series of diaminoacridinic derivatives obtained from proflavine and N-(6-amino-3-acridinyl)acetamide were synthesised and assessed for their cytotoxic and antileishmanial activities. Two compounds, N-[6-(acetylamino)-3-acridinyl]acetamide and N-[6-(benzoylamino)-3-acridinyl]benzamide demonstrated highly specific antileishmanial properties against the intracellular amastigote form of the parasite. Structure-activity relationships established that the antiproliferative activity against human cells was greatly enhanced by the presence of a benzoylamino group in 6-mono-substituted acridines, while the presence of two acetylamino or benzoylamino groups in 3,6-di-substituted acridines strongly increased the specificity of the molecules for Leishmania parasite, suggesting that symmetric conformations could preferentially interfere with Leishmania metabolism.

Analytical characterization of bioactive N-benzyl-substituted phenethylamines and 5-methoxytryptamines.

PubMed

Brandt, Simon D; Elliott, Simon P; Kavanagh, Pierce V; Dempster, Nicola M; Meyer, Markus R; Maurer, Hans H; Nichols, David E

2015-04-15

Substances based on the N-(2-methoxybenzyl)phenethylamine template ('NBOMe' derivatives) play an important role in medicinal research but some of these derivatives have also appeared as 'research chemicals' for recreational use which has attracted attention worldwide. A major challenge associated with newly emerging substances includes the lack of analytical data and the ability to correctly identify positional isomers. Six N-benzylphenethylamines based on the 2,5-dimethoxy-4-iodophenethylamine structure ('25I') and twelve substituted N-benzyl-5-methoxytryptamines ('5MT') have been prepared and extensively characterized. Techniques used for characterization were gas chromatography/ion trap mass spectrometry in electron and chemical ionization mode, liquid chromatography/diode array detection (DAD), infrared spectroscopy, electrospray high mass accuracy quadrupole time-of-flight tandem mass spectrometry, and triple quadrupole tandem mass spectrometry. The characterization of 18 'NBOMe' compounds provided a comprehensive collection of chromatographic and spectral data. Four groups of three positional isomers, i.e. 25I-NB2OMe, 25I-NB3OMe, 25I-NB4OMe, 25I-NB2B, 25I-NB3B, 25I-NB4B and their 5-methoxytryptamine counterparts, were included and assessed for ability to obtain differentiation. Six meta-substituted N-benzyl derivatives of 5-methoxytryptamine (CF3, F, CH3, Cl, I, SCH3) were also studied. The implementation of mass spectral techniques was helpful for the differentiation between isomers, for example, when considering the difference in a number of ion ratios. This was considered beneficial in cases where chromatographic separation was only partially achieved under liquid chromatography (LC) conditions. The use of LC/DAD analysis was also found to be valuable for this particular purpose, which confirmed the integrative value of complementary techniques used in areas related to forensic toxicology. Copyright © 2015 John Wiley & Sons, Ltd.

Reusable copper-catalyzed cross-coupling reactions of aryl halides with organotins in inexpensive ionic liquids.

PubMed

Li, Jin-Heng; Tang, Bo-Xiao; Tao, Li-Ming; Xie, Ye-Xiang; Liang, Yun; Zhang, Man-Bo

2006-09-15

A combination of Cu2O nanoparticles with P(o-tol)3 shows highly catalytic activity for the Stille cross-coupling reaction. A series of copper catalysts and ligands were evaluated, and Cu2O nanoparticles combined with P(o-tol)3 provided the best results. In the presence of Cu2O nanoparticles and P(o-tol)3, a variety of aryl halides including aryl chlorides underwent the Stille reaction with organotins smoothly in moderate to excellent yields using inexpensive TBAB (n-Bu4NBr) as the medium. It is noteworthy that the Cu2O/P(o-tol)3/TBAB system can be recovered and reused at least three times without any loss of catalytic activity among the reactions of aryl iodides and activated aryl bromides.

Processable Electronically Conducting Polymers

DTIC Science & Technology

1991-01-01

polyheterocycles and will be discussed in detail later. The Grignard coupling reaction of alkyl substituted 1,4- dibromobenzenes was initially employed, as...R 2 ,R 3 ) along with alkyl , aryl, benzyl, and -CH 2 CN substituents on the nitrogen (R I ). Since aniline preferentially oxidatively polymerizes at...but, in the case of N-aryl substituted anilines , an alternative mecha- nism has been proposed [171], which is outlined in Scheme 9. Both poly(N

Rhodium-catalysed asymmetric allylic arylation of racemic halides with arylboronic acids

NASA Astrophysics Data System (ADS)

Sidera, Mireia; Fletcher, Stephen P.

2015-11-01

Csp2-Csp2 cross-coupling reactions between arylboronic acid and aryl halides are widely used in both academia and industry and are strategically important in the development of new agrochemicals and pharmaceuticals. Csp2-Csp3 cross-coupling reactions have been developed, but enantioselective variations are rare and simply retaining the stereochemistry is a problem. Here we report a highly enantioselective Csp2-Csp3 bond-forming method that couples arylboronic acids to racemic allyl chlorides. Both enantiomers of a cyclic chloride are converted into a single enantiomer of product via a dynamic kinetic asymmetric transformation. This Rh-catalysed method uses readily available and inexpensive building blocks and is mild and broadly applicable. For electron-deficient, electron-rich or ortho-substituted boronic acids better results are obtained with racemic allyl bromides. Oxygen substitution in the allyl halide is tolerated and the products can be functionalized to provide diverse building blocks. The approach fills a significant gap in the methods for catalytic asymmetric synthesis.

Electrochemical Grafting of Graphene Nano Platelets with Aryl Diazonium Salts.

PubMed

Qiu, Zhipeng; Yu, Jun; Yan, Peng; Wang, Zhijie; Wan, Qijin; Yang, Nianjun

2016-10-26

To vary interfacial properties, electrochemical grafting of graphene nano platelets (GNP) with 3,5-dichlorophenyl diazonium tetrafluoroborate (aryl-Cl) and 4-nitrobenzene diazonium tetrafluoroborate (aryl-NO 2 ) was realized in a potentiodynamic mode. The covalently bonded aryl layers on GNP were characterized using atomic force microscopy and X-ray photoelectron spectroscopy. Electrochemical conversion of aryl-NO 2 into aryl-NH 2 was conducted. The voltammetric and impedance behavior of negatively and positively charged redox probes (Fe(CN) 6 3-/4- and Ru(NH 3 ) 6 2+/3+ ) on three kinds of aryl layers grafted on GNP reveal that their interfacial properties are determined by the charge states of redox probes and reactive terminal groups (-Cl, -NO 2 , -NH 2 ) in aryl layers. On aryl-Cl and aryl-NH 2 garted GNP, selective and sensitive monitoring of positively charged lead ions as well as negatively charged nitrite and sulfite ions was achieved, respectively. Such a grafting procedure is thus a perfect way to design and control interfacial properties of graphene.

Palladium-Catalyzed α-Arylation of 2-Chloroacetates and 2-Chloroacetamides

PubMed Central

Traister, Kaitlin M.; Barcellos, Thiago

2013-01-01

A method has been developed for the Pd-catalyzed synthesis of α-(hetero)aryl esters and amides through a Suzuki–Miyaura cross-coupling reaction. This method avoids the use of strong base, does not necessitate inert or low temperature formation of reagents, and does not require the use of a large excess of organometallic reagent. Utilization of organotrifluoroborate salts as nucleophilic partners allows a variety of functional groups and heterocyclic compounds to be tolerated. PMID:23570264

Polybenzimidazole compounds

DOEpatents

Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

2010-08-10

A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

Catalytic Arylation and Vinylation Reactions Directed by Anionic Oxygen Functions via Cleavage of C - H and C - C Bonds

NASA Astrophysics Data System (ADS)

Satoh, Tetsuya; Miura, Masahiro

Aromatic compounds having oxygen-containing substituents such as phenols, phenyl ketones, benzyl alcohols, and benzoic acids undergo regioselective arylation and vinylation via C-H bond cleavage in the presence of transition-metal catalysts. The latter two substrates are also arylated and vinylated via C-C bond cleavage accompanied by liberation of ketones and CO2, respectively. Coordination of their anionic oxygen to the metal center is the key to activate the inert bonds effectively and regioselectively. The recent progress of these oxygen-directed reactions is summarized herein.

C–H arylation of unsubstituted furan and thiophene with acceptor bromides: access to donor–acceptor–donor-type building blocks for organic electronics.

PubMed

Matsidik, Rukiya; Martin, Johannes; Schmidt, Simon; Obermayer, Johannes; Lombeck, Florian; Nübling, Fritz; Komber, Hartmut; Fazzi, Daniele; Sommer, Michael

2015-01-16

Pd-catalyzed direct arylation (DA) reaction conditions have been established for unsubstituted furan (Fu) and thiophene (Th) with three popular acceptor building blocks to be used in materials for organic electronics, namely 4,7-dibromo-2,1,3-benzothiadiazole (BTBr2), N,N′-dialkylated 2,6-dibromonaphthalene-1,4,5,8-bis(dicarboximide) (NDIBr2), and 1,4-dibromotetrafluorobenzene (F4Br2). Reactions with BTBr2, F4Br2, and NDIBr2 require different solvents to obtain high yields. The use of dimethylacetamide (DMAc) is essential for the successful coupling of BTBr2 and F4Br2, but detrimental for NDIBr2, as the electron-deficient NDI core is prone to nucleophilic core substitution in DMAc as solvent but not in toluene. NDIFu2 is much more planar compared to NDITh2, resulting in an enhanced charge-transfer character, which makes it an interesting building block for conjugated systems designed for organic electronics. This study highlights direct arylation as a simple and inexpensive method to construct a series of important donor–acceptor–donor building blocks to be further used for the preparation of a variety of conjugated materials.

Screening a mouse liver gene expression Compendium Identifies Effectors of the Aryl Hydrocarbon receptor (AhR)

EPA Science Inventory

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates the biological and toxic effects of 2,3, 7 ,8-tetrachlorodibenzo-p-dioxin {TCDD), dioxin-like compounds (DLC) as well as some drugs and endogenous tryptophan metabolites. Short-term act...

Aryl-Aryl Interactions in Designed Peptide Folds: Spectroscopic Characteristics and Placement Issues for Optimal Structure Stabilization

PubMed Central

Anderson, Jordan M.; Kier, Brandon; Jurban, Brice; Byrne, Aimee; Shu, Irene; Eidenschink, Lisa A.; Shcherbakov, Alexander A.; Hudson, Mike; Fesinmeyer, R. M.; Andersen, Niels H.

2017-01-01

We have extended our studies of Trp/Trp to other Aryl/Aryl through-space interactions that stabilize hairpins and other small polypeptide folds. Herein we detail the NMR and CD spectroscopic features of these types of interactions. NMR data remains the best diagnostic for characterizing the common T-shape orientation. Designated as an edge-to-face (EtF or FtE) interaction, large ring current shifts are produced at the edge aryl ring hydrogens and, in most cases, large exciton couplets appear in the far UV circular dichroic (CD) spectrum. The preference for the face aryl in FtE clusters is W≫Y≥F (there are some exceptions in the Y/F order); this sequence corresponds to the order of fold stability enhancement and always predicts the amplitude of the lower energy feature of the exciton couplet in the CD spectrum. The CD spectra for FtE W/W, W/Y, Y/W, and Y/Y pairs all include an intense feature at 225–232 nm. An additional couplet feature seen for W/Y, W/F, Y/Y and F/Y clusters, is a negative feature at 197–200 nm. Tyr/Tyr (as well as F/Y and F/F) interactions produce much smaller exciton couplet amplitudes. The Trp-cage fold was employed to search for the CD effects of other Trp/Trp and Trp/Tyr cluster geometries: several were identified. In this account, we provide additional examples of the application of cross-strand aryl/aryl clusters for the design of stable β-sheet models and a scale of fold stability increments associated with all possible FtE Ar/Ar clusters in several structural contexts. PMID:26850220

Anticonvulsants Based on the α-Substituted Amide Group Pharmacophore Bind to and Inhibit Function of Neuronal Nicotinic Acetylcholine Receptors.

PubMed

Krivoshein, Arcadius V

2016-03-16

Although the antiepileptic properties of α-substituted lactams, acetamides, and cyclic imides have been known for over 60 years, the mechanism by which they act remains unclear. I report here that these compounds bind to the nicotinic acetylcholine receptor (nAChR) and inhibit its function. Using transient kinetic measurements with functionally active, nondesensitized receptors, I have discovered that (i) α-substituted lactams and cyclic imides are noncompetitive inhibitors of heteromeric subtypes (such as α4β2 and α3β4) of neuronal nAChRs and (ii) the binding affinity of these compounds toward the nAChR correlates with their potency in preventing maximal electroshock (MES)-induced convulsions in mice. Based on the hypothesis that α-substituted amide group is the essential pharmacophore of these drugs, I found and tested a simple compound, 2-phenylbutyramide. This compound indeed inhibits nAChR and shows good anticonvulsant activity in mice. Molecular docking simulations suggest that α-substituted lactams, acetamides, and cyclic imides bind to the same sites on the extracellular domain of the receptor. These new findings indicate that inhibition of brain nAChRs may play an important role in the action of these antiepileptic drugs, a role that has not been previously recognized.

A novel series of N-acyl substituted indole-linked benzimidazoles and naphthoimidazoles as potential anti inflammatory, anti biofilm and anti microbial agents.

PubMed

Abraham, Rajan; Prakash, Periakaruppan; Mahendran, Karthikeyan; Ramanathan, Murugappan

2018-01-01

A novel N-acyl substituted indole-linked benzimidazoles and naphthoimidazoles were synthesized. Their chemical structures were confirmed using spectroscopic tools including 1 H NMR, 13 C NMR and CHN-elemental analyses. Anti inflammatory activity for all target compounds was evaluated in-vitro. The synthesized compounds hinder the biofilm formation and control the growth of the pathogen, Staphylococcus epidermis. Anti microbial activity of the compounds was evaluated against both Gram negative and Gram positive bacteria such as Staphylococcus aureus (MTCC 2940), Pseudomonas aeruginosa (MTCC424), Escherchia coli (MTCC 443) and Enterococcus fecalis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis and biological evaluation of substituted N-[3-(1H-pyrrol-1-yl)methyl]-1,2,5,6-tetrahydropyridin-1-yl]benzamide/benzene sulfonamides as anti-inflammatory agents.

PubMed

Gangapuram, Madhavi; Mazzio, Elizabeth; Eyunni, Suresh; Soliman, Karam F A; Redda, Kinfe K

2014-05-01

The pharmacological activities of tetrahydropyridine (THP) derivatives are dependent on the substituent ring moiety. In this study, we investigate the anti-inflammatory activities of 12 newly synthesized substituted N-[3-(1H-pyrrol-1-yl)methyl]-1,2,5,6-tetrahydrobenzamide/benzene sulfonamides (9a-l) in murine BV-2 microglial cells. All compounds were initially screened for attenuation of nitric oxide (NO) production in lipopolysaccharide (LPS) (1 µg/mL)-activated microglial cells. The data show that only SO2 -substituted THPs were effective at sub-lethal concentrations (IC50 values of 12.92 µM (9i), 14.64 µM (9j), 19.63 µM (9k)) relative to L-N6-(1-iminoethyl)lysine positive control (IC50  = 3.1 µM). The most potent SO2 -substituted compound (9i) also blocked the LPS-inducible nitric oxide synthase (iNOS) and attenuated the release of several cytokines including IL-1α, IL-10, and IL-6. These findings establish the moderate immuno-modulating effects of SO2 -substituted THP derivatives. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Potency of Indolyl Aryl Sulfone Nonnucleoside Inhibitors towards Drug-Resistant Human Immunodeficiency Virus Type 1 Reverse Transcriptase Mutants Is Due to Selective Targeting of Different Mechanistic Forms of the Enzyme

PubMed Central

Cancio, Reynel; Silvestri, Romano; Ragno, Rino; Artico, Marino; De Martino, Gabriella; La Regina, Giuseppe; Crespan, Emmanuele; Zanoli, Samantha; Hübscher, Ulrich; Spadari, Silvio; Maga, Giovanni

2005-01-01

Indolyl aryl sulfone (IAS) nonnucleoside inhibitors have been shown to potently inhibit the growth of wild-type and drug-resistant human immunodeficiency virus type 1 (HIV-1), but their exact mechanism of action has not been elucidated yet. Here, we describe the mechanism of inhibition of HIV-1 reverse transcriptase (RT) by selected IAS derivatives. Our results showed that, depending on the substitutions introduced in the IAS common pharmacophore, these compounds can be made selective for different enzyme-substrate complexes. Moreover, we showed that the molecular basis for this selectivity was a different association rate of the drug to a particular enzymatic form along the reaction pathway. By comparing the activities of the different compounds against wild-type RT and the nonnucleoside reverse transcriptase inhibitor-resistant mutant Lys103Asn, it was possible to hypothesize, on the basis of their mechanism of action, a rationale for the design of drugs which could overcome the steric barrier imposed by the Lys103Asn mutation. PMID:16251294

Comparative theoretical studies of differently bridged nitramino-substituted ditetrazole 2-N-oxides with high detonation performance and an oxygen balance of around zero.

PubMed

Wu, Qiong; Kou, Bo; Hang, Zusheng; Zhu, Weihua

2017-06-01

In this work, six (A-F) nitramino (-NHNO 2 )-substituted ditetrazole 2-N-oxides with different bridging groups (-CH 2 -, -CH 2 -CH 2 -, -NH-, -N=N-, and -NH-NH-) were designed. The six compounds were based on the parent compound tetrazole 2-N-oxide, which possesses a high oxygen balance and high density. The structure, heat of formation, density, detonation properties (detonation velocity D and detonation pressure P), and the sensitivity of each compound was investigated systematically via density functional theory, by studying the electrostatic potential, and using molecular mechanics. The results showed that compounds A-F all have outstanding energetic properties (D: 9.1-10.0 km/s; P: 38.0-46.7 GPa) and acceptable sensitivities (h 50 : 28-37 cm). The bridging group present was found to greatly affect the detonation performance of each ditetrazole 2-N-oxide, and the compound with the -NH-NH- bridging group yielded the best results. Indeed, this compound (F) was calculated to have comparable sensitivity to the famous and widely used high explosive 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX), but with values of D and P that were about 8.7% and 19.4% higher than those for HMX, respectively. The present study shows that tetrazole 2-N-oxide is a useful parent compound which could potentially be used in the design of new and improved high-energy compounds to replace existing energetic compounds such as HMX.

Efficient one-step Suzuki arylation of unprotected halonucleosides, using water-soluble palladium catalysts.

PubMed

Western, Elizabeth C; Daft, Jonathan R; Johnson, Edward M; Gannett, Peter M; Shaughnessy, Kevin H

2003-08-22

Modification of nucleosides to give pharmaceutically active compounds, mutagenesis models, and oligonucleotide structural probes continues to be of great interest. The aqueous-phase modification of unprotected halonucleosides is reported herein. Using a catalyst derived from tris(3-sulfonatophenyl)phosphine (TPPTS) and palladium acetate, 8-bromo-2'-deoxyguanosine (8-BrdG) is coupled with arylboronic acids to give 8-aryl-2'-deoxyguanosine adducts (8-ArdG) in excellent yield in a 2:1 water:acetonitrile solvent mixture. The TPPTS ligand was found to be superior to water-soluble alkylphosphines for this coupling reaction. The coupling chemistry has been extended to 8-bromo-2'-deoxyadenosine (8-BrdA) and 5-iodo-2'-deoxyuridine (5-IdU), as well as the ribonucleosides 8-bromoguanosine and 8-bromoadenosine. Good to excellent yields of arylated adducts are obtained in all cases. With use of tri(4,6-dimethyl-3-sulfonatophenyl)phosphine (TXPTS), the Suzuki coupling of 8-BrdA and 5-IdU can be accomplished in less than 1 h at room temperature. This methodology represents an efficient and general method for halonucleoside arylation that does not require prior protection of the nucleoside.

Synthesis of 3-iodoindoles by the Pd/Cu-catalyzed coupling of N,N-dialkyl-2-iodoanilines and terminal acetylenes, followed by electrophilic cyclization.

PubMed

Yue, Dawei; Yao, Tuanli; Larock, Richard C

2006-01-06

[reaction: see text] 3-Iodoindoles have been prepared in excellent yields by coupling terminal acetylenes with N,N-dialkyl-o-iodoanilines in the presence of a Pd/Cu catalyst, followed by an electrophilic cyclization of the resulting N,N-dialkyl-o-(1-alkynyl)anilines using I2 in CH2Cl2. Aryl-, vinylic-, alkyl-, and silyl-substituted terminal acetylenes undergo this process to produce excellent yields of 3-iodoindoles. The reactivity of the carbon-nitrogen bond cleavage during cyclization follows the following order: Me > n-Bu, Me > Ph, and cyclohexyl > Me. Subsequent palladium-catalyzed Sonogashira, Suzuki, and Heck reactions of the resulting 3-iodoindoles proceed smoothly in good yields.

Synthesis and antihyperlipaemic activity of some 2-aminomethyl-3-aryl-5,6,7,8-tetrahydrobenzo(b)/5,6-dimethylthieno++ +(2,3- d) -pyrimidin-4-ones.

PubMed

Gadad, A K; Kapsi, S G; Anegundi, R I; Pattan, S R; Mahajanshetti, C S; Shishoo, C J

1996-10-01

A series of 2-aminomethyl-3-aryl-5,6,7,8-tetrahydrobenzo(b)/5,6-dimethylthieno (2,3-d) pyrimidin-4-ones (IX) were prepared by the displacement reaction between various amines and 2-chloromethyl-3-aryl-5,6, 7,8-tetrahydrobenzo(b)/5, 6-dimethylthieno(2, 3-d) pyrimidin-4-ones (VIII), which are obtained by the cyclization of corresponding chloroacetylamino derivatives (VII) under acidic condition. Compounds VII were obtained by the interaction of VI and chloroacetylchloride in glacial acetic acid. Compounds VIII were converted to corresponding 2-acetoxymethyl derivatives (X) with potassium acetate in glacial acetic acid. Selected compounds were screened for antihyperlipaemic activity in albino rats, whereby most of these compounds were found to be active. The serum cholesterol and triglyceride lowering activities exhibited by compounds 1 and 3 were found to be comparable to that of gemfibrozil. Compounds 1 and 3 were also found to be safe as indicated by their acute toxicity study.

Selective Se-for-S substitution in Cs-bearing uranyl compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gurzhiy, Vladislav V., E-mail: vladgeo17@mail.ru; Tyumentseva, Olga S.; Krivovichev, Sergey V.

Phase formation in the mixed sulfate-selenate aqueous system of uranyl nitrate and cesium nitrate has been investigated. Two types of crystalline compounds have been obtained and characterized using a number of experimental (single crystal XRD, FTIR, SEM) and theoretical (information-based complexity calculations, topological analysis) techniques. No miscibility gaps have been observed for Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se), which crystallizes in tetragonal system, P-42{sub 1}m, a =9.616(1)–9.856(2), c =8.105(1)–8.159(1) Å, V =749.6(2)–792.5(3) Å{sup 3}. Nine phases with variable amount of S and Se have been structurally characterized. The structures of the Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}]more » (T= S, Se) compounds are based upon the [(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}]{sup 2-} layers of corner-sharing uranyl pentagonal bipyramids and TO{sub 4} tetrahedra. The layers contain two types of tetrahedral sites: T1 (3-connected, i.e. having three O atoms shared by adjacent uranyl polyhedra) and T2 (4-connected). The Se-for-S substitution in tetrahedral sites is highly selective with smaller S{sup 6+} cation showing a strong preference for the more tightly bonded T2 site. Crystallization in the pure Se system starts with the formation of Cs{sub 2}[(UO{sub 2})(SeO{sub 4}){sub 2}(H{sub 2}O)](H{sub 2}O) crystals, its subsequent dissolution and formation of Cs{sub 2}[(UO{sub 2}){sub 2}(SeO{sub 4}){sub 3}]. The information-based structural complexity calculations for these two phases support the rule that more topologically complex structures form at the latest stages of crystallization. - Graphical abstract: Nine phases representing the Cs{sub 2}[(UO{sub 2}){sub 2}(TO{sub 4}){sub 3}] (T= S, Se) solid solution series with variable amount of S and Se have been prepared by isothermal evaporation from aqueous solutions and characterized using a number of experimental and theoretical techniques. No immiscibility is observed

Pd-Catalyzed regioselective intramolecular dehydrogenative C-5 cross coupling in an N-substituted pyrrole-azole system.

PubMed

Tripathi, Krishna N; Ray, Devalina; Singh, Ravi P

2017-12-06

Functionalized polycyclic pyrrole-azole structures possessing fused six membered and seven membered rings were directly synthesized via ligand-enabled, Pd-catalyzed, site selective, intramolecular cross couplings of N-substituted pyrrole-azoles. C5-H activation in the presence of a reactive C2-H remains a challenge that needs to be addressed and this was targeted to be resolved through the present approach by specifically generating the cyclized products with 83-100% selectivity. The featured methodology provides a novel disconnection for the synthesis of pyrrole containing alkaloids and medicinal compounds.

Replacing Conventional Carbon Nucleophiles with Electrophiles: Nickel-Catalyzed Reductive Alkylation of Aryl Bromides and Chlorides

PubMed Central

2012-01-01

A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (−OH, −NHTs, −OAc, −OTs, −OTf, −COMe, −NHBoc, −NHCbz, −CN, −SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki–Miyaura, Stille, and Hiyama–Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R–X) and no reaction at the nucleophilic carbon (R–[M]) for organoboron (−Bpin), organotin (−SnMe3), and organosilicon (−SiMe2OH) containing organic halides (X–R–[M]). A Hammett study showed a linear correlation of σ and σ(−) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2–1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents. PMID:22463689

The Pd-Catalyzed Conversion of Aryl Chlorides, Triflates, and Nonaflates to Nitroaromatics

PubMed Central

Fors, Brett P.; Buchwald, Stephen L.

2009-01-01

An efficient Pd-catalyst for the transformation of aryl chlorides, triflates and nonaflates to nitroaromatics has been developed. This reaction proceeds under weekly basic conditions and displays a broad scope and excellent functional group compatibility. Moreover, this method allows for the synthesis of aromatic nitro compounds that cannot be accessed efficiently via other nitration protocols. Mechanistic insight into the trasmetallation step of the catalytic process is also reported. PMID:19737014

Synthesis of substituted tetrahydroisoquinolines by lithiation then electrophilic quench.

PubMed

Talk, Ruaa A; Duperray, Alexia; Li, Xiabing; Coldham, Iain

2016-06-07

Substituted N-tert-butoxycarbonyl (Boc)-1,2,3,4-tetrahydroisoquinolines were prepared and treated with n-butyllithium in THF at -50 °C to test the scope of the metallation and electrophilic quench. The lithiation was optimised by using in situ ReactIR spectroscopy and the rate of rotation of the carbamate was determined. The 1-lithiated intermediates could be trapped with a variety of electrophiles to give good yields of 1-substituted tetrahydroisoquinoline products. Treatment with acid or reduction with LiAlH4 allows conversion to the N-H or N-Me compound. The chemistry was applied to the efficient total syntheses of the alkaloids (±)-crispine A and (±)-dysoxyline.

Aryl sulfate formation in sea urchins (Strongylocentrotus droebachiensis) ingesting marine algae (Fucus distichus) containing 2,6-dimethylnapthalene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malins, D.C.; Roubal, W.T.

1982-04-01

The metabolism of tritiated 2,6-dimethylnapthalene (2,6-DMN) was studied in sea urchins (Strongylocentrotus droebachiensis) feeding on marine algae (Fucus distichus). The Fucus accumulated this hydrocarbon from sea water without converting it to metabolites. Most of the tritium accumulated by the sea urchins (e.g., 70.8% after 3 days) from feeding on 2,6-DMN-exposed Fucus was present in the exoskeleton (shell and spines). Moreover, after 3 days feeding, about 90% of the tritium in the total metabolite fraction of the gonads and digestive tract of the sea urchin was present as sulfate derivatives. These metabolites were identified through hydrolysis with aryl sulfatase, followed bymore » thin-layer chromatography of the products. After 14 days of feeding, the tritium associated with the sulfate derivatives decreased in the gonads and digestive tract to 61 and 65%, respectively, of the total metabolite fraction. Hydroxy compounds from sulfatase hydrolysis were chromatographed using multiple elutions with toluene. The hydroxy isomers were separated and the R/sub f/ values were compared to those of pure reference compounds. The data indicated that 80% of the 2,6-dimethylnaphtyl sulfate contained the sulfate on the 1 and/or 3 position of the aromatic ring. Moreover, 6-methyl-2-naphthalenemethanol was not detected, which implies that sea urchins, unlike fish, metabolize alkyl-substituted aromatic hydrocarbons primarily through aromatic ring oxidations.« less

Lipase-Catalyzed Kinetic Resolution of Novel Antifungal N-Substituted Benzimidazole Derivatives.

PubMed

Łukowska-Chojnacka, Edyta; Staniszewska, Monika; Bondaryk, Małgorzata; Maurin, Jan K; Bretner, Maria

2016-04-01

A series of new N-substituted benzimidazole derivatives was synthesized and their antifungal activity against Candida albicans was evaluated. The chemical step included synthesis of appropriate ketones containing benzimidazole ring, reduction of ketones to the racemic alcohols, and acetylation of alcohols to the esters. All benzimidazole derivatives were obtained with satisfactory yields and in relatively short times. All synthesized compounds exhibit significant antifungal activity against Candida albicans 900028 ATCC (% cell inhibition at 0.25 μg concentration > 98%). Additionally, racemic mixtures of alcohols were separated by lipase-catalyzed kinetic resolution. In the enzymatic step a transesterification reaction was applied and the influence of a lipase type and solvent on the enantioselectivity of the reaction was studied. The most selective enzymes were Novozyme SP 435 and lipase Amano AK from Pseudomonas fluorescens (E > 100). © 2016 Wiley Periodicals, Inc.

Facile synthesis of highly substituted 3-aminofurans from thiazolium salts, aldehydes, and dimethyl acetylenedicarboxylate.

PubMed

Ma, Cheng; Ding, Hanfeng; Wu, Guangming; Yang, Yewei

2005-10-28

[reaction: see text] A facile preparation of 3-aminofuran derivatives via multicomponent reactions of thiazole carbenes, aldehydes, and dimethyl acetylenedicarboxylate (DMAD) is reported. In this process, the thiazole carbenes, generated in situ from thiazolium salts, reacted with aldehydes and DMAD at -78 to 0 degree C in CH(2)Cl(2) to afford the substituted furans in moderate to good yields. Eight substituted thiazolium salts were employed as carbene precursors in the reaction. Besides aryl aldehydes, alpha,beta-unsaturated aldehydes, aliphatic aldehydes, and arenedial were also investigated and found to be applicable to this reaction.

Palladium-catalysed carbonylative α-arylation of nitromethane.

PubMed

Lian, Zhong; Friis, Stig D; Skrydstrup, Troels

2015-02-28

A simple and mild Pd-catalysed carbonylative α-arylation of nitromethane has been realised providing access to α-nitro aryl ketones from an array of aryl and heteroaryl iodides. The methodology requires only a mild base and uses the convenient solid CO releasing molecule, COgen in a two-chamber system. Changing to the isotopically labelled (13)COgen, [(13)C]-acyl labelling can be effected through the generation of a near stoichiometric amount of (13)CO. Lastly, the significance of the generated products as synthetic intermediates is demonstrated.

Selective cyclopalladation of R3P=NCH2Aryl iminophosphoranes. Experimental and computational study.

PubMed

Bielsa, Raquel; Navarro, Rafael; Urriolabeitia, Esteban P; Lledós, Agustí

2007-11-26

The orientation of the orthopalladation of iminophosphoranes R3P=NCH2Aryl (R=Ph, Aryl=Ph (1a), C6H(4)-2-Br (1b), C6H4-Me-2 (1e), C6H3-(Me)(2)-2,5 (1f); R=p-tolyl, Aryl=Ph (1c); R=m-tolyl, Aryl=Ph (1d); R3P=MePh2P, and Aryl=Ph (1g)) has been studied. 1a reacts with Pd(OAc)2 (OAc=acetate) giving endo-[Pd(micro-Cl){C,N-C6H4(PPh2=NCH2Ph)-2}]2 (3a), while exo-[Pd(micro-Br){C,N-C6H4(CH2N=PPh3)-2}]2 (3b) could only be obtained by the oxidative addition of 1b to Pd2(dba)3. The endo form of the metalated ligand is favored kinetically and thermodynamically, as shown by the conversion of exo-[Pd(micro-OAc){C,N-C6H4(CH2N=PPh3)-2}]2 (2b) into endo-[Pd(micro-OAc){C,N-C6H4(PPh2=NCH2Ph)-2}]2 (2a) in refluxing toluene. The orientation of the reaction is not affected by the introduction of electron-releasing substituents at the Ph rings of the PR3 (1c and 1d) or the benzyl units (1e and 1f), and endo complexes (3c-3f) were obtained in all cases. The palladation of MePh2P=NCH2Ph (1g) can be regioselectively oriented as a function of the solvent. The exo isomer [Pd(micro-Cl){C6H4(CH2N=PPh2Me)-2}]2 (exo-3g) is obtained in refluxing CH2Cl2, while endo-[Pd(micro-Cl){C,N-C6H4(PPh(Me)=NCH2Ph)-2}]2 (endo-3g) can be isolated as a single isomer in refluxing toluene. In this case, the exo metalation is kinetically favored while an endo process occurs under thermodynamic control, as shown through the rearrangement of [Pd(micro-OAc){C6H4(CH2N=PPh2Me)-2}]2 (exo-2g) into [Pd(micro-OAc){C,N-C6H4(P(Ph)Me=NCH2Ph)-2}]2 (endo-2g) in refluxing toluene. The preference for the endo palladation of 1a and the kinetic versus thermodynamic control in 1g has been explained through DFT studies of the reaction mechanism.

Mechanism-based inactivation of benzo(a)pyrene hydroxylase by aryl acetylenes and aryl olefins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gan, L.S.; Lu, J.Y.L.; Alworth, W.L.

A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxgenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, 3-ethynylperylene, 2-ethynylfluorene, methyl 1-pyrenyl acetylene, cis- and trans-1-(2-bromovinyl)pyrene, and 1-allylpyrene serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo(a)pyrene hydroxylase, while 1-vinylpyrene and phenyl 1-pyrenyl acetylene do not cause a detectable suicide inhibition of benzo(a)pyrene hydroxylase. The mechanism-based loss of benzo(a)pyrene hydroxylase caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes (suicide destruction). The suicide inhibition by these aryl acetylenesmore » therefore does not involve covalent binding to the heme moiety of the monooxygenase. Nevertheless, in the presence of NADPH, /sup 3/H-labeled 1-ethynylpyrene becomes covalently attached to the cytochrome P-450 protein; the measured stoichiometry of binding is one 1-ethynylpyrene per P-450 heme unit. The authors conclude that the inhibition of benzo(a)pyrene hydroxylase produced by 1-ethynylpyrene may be related to the mechanism of suicide inhibition of P-450 activity by chloramphenicol rather than the mechanism of suicide destruction of P-450 previously described for acetylene and propyne.« less

A new class of anticonvulsants possessing 6 Hz psychomotor seizure test activity: 2-(1H-benzotriazol-1-yl)-N'-[substituted] acetohydrazides.

PubMed

Kumar, Praveen; Tripathi, Laxmi

2012-05-01

A series of 2-(1H-Benzotriazol-1-yl)-N'-[substituted]acetohydrazides were designed & synthesized keeping in view the structural requirement of pharmacophore and evaluated for anticonvulsant activity and neurotoxicity. The new compounds were characterized using FT-IR, 1H NMR, mass spectral data and elemental analysis. The anticonvulsant activity of the titled compounds was assessed using the 6 Hz psychomotor seizure test. The neurotoxicity was assessed using the rotorod method. The most active compound of the series was N'-[4-(1,3-Benzodioxol-5-yloxy)benzylidene]-2-(1H-benzotriazol-1-yl)acetohydrazide (BTA 9), which showed good activity with 75 % protection (3/4, 0.5 h) at a dose of 100 mg/kg in mice. All the compounds exhibited no neurotoxicity. A computational study was carried out for calculation of pharmacophore pattern and prediction of pharmacokinetic properties. Titled compounds have also exhibited good binding properties with epilepsy molecular targets such as glutamate, GABA (A) delta, GABA (A) alpha-1 receptors and Na/H exchanger, in Lamarckian genetic algorithm based flexible docking studies.

Pharmacological and structure-activity relationship evaluation of 4-aryl-1-diphenylacetyl(thio)semicarbazides.

PubMed

Wujec, Monika; Kędzierska, Ewa; Kuśmierz, Edyta; Plech, Tomasz; Wróbel, Andrzej; Paneth, Agata; Orzelska, Jolanta; Fidecka, Sylwia; Paneth, Piotr

2014-04-16

This article describes the synthesis of six 4-aryl-(thio)semicarbazides (series a and b) linked with diphenylacetyl moiety along with their pharmacological evaluation on the central nervous system in mice and computational studies, including conformational analysis and electrostatic properties. All thiosemicarbazides (series b) were found to exhibit strong antinociceptive activity in the behavioural model. Among them, compound 1-diphenylacetyl-4-(4-methylphenyl)thiosemicarbazide 1b was found to be the most potent analgesic agent, whose activity is connected with the opioid system. For compounds from series a significant anti-serotonergic effect, especially for compound 1-diphenylacetyl-4-(4-methoxyphenyl)semicarbazide 2b was observed. The computational studies strongly support the obtained results.

Synthesis, crystal structure determination, biological screening and docking studies of N1-substituted derivatives of 2,3-dihydroquinazolin-4(1H)-one as inhibitors of cholinesterases.

PubMed

Sultana, Nargis; Sarfraz, Muhammad; Tanoli, Saba Tahir; Akram, Muhammad Safwan; Sadiq, Abdul; Rashid, Umer; Tariq, Muhammad Ilyas

2017-06-01

Pursuing the strategy of developing potent AChE inhibitors, we attempted to carry out the N 1 -substitution of 2,3-dihydroquinazolin-4(1H)-one core. A set of 32 N-alkylated/benzylated quinazoline derivatives were synthesized, characterized and evaluated for their inhibition against cholinesterases. N-alkylation of the series of the compounds reported previously (N-unsubstituted) resulted in improved activity. All the compounds showed inhibition of both enzymes in the micromolar to submicromolar range. Structure activity relationship (SAR) of the 32 derivatives showed that N-benzylated compounds possess good activity than N-alkylated compounds. N-benzylated compounds 2ad and 2af were found very active with their IC 50 values toward AChE in submicromolar range (0.8µM and 0.6µM respectively). Binding modes of the synthesized compounds were explored by using GOLD (Genetic Optimization for Ligand Docking) suit v5.4.1. Computational predictions of ADMET studies reveal that all the compounds have good pharmacokinetic properties with no AMES toxicity and carcinogenicity. Moreover, all the compounds are predicted to be absorbed in human intestine and also have the ability to cross blood brain barrier. Overall, the synthesized compounds have established a structural foundation for the design of new inhibitors of cholinesterase. Copyright © 2017 Elsevier Inc. All rights reserved.

Synthesis and Anticancer Activity of 2-(Alkyl-, Alkaryl-, Aryl-, Hetaryl-)-[1,2,4]triazolo[1,5-c]quinazolines

PubMed Central

Kovalenko, Sergiy I.; Antypenko, Lyudmyla M.; Bilyi, Andriy K.; Kholodnyak, Sergiy V.; Karpenko, Olexandr V.; Antypenko, Olexii M.; Mykhaylova, Natalya S.; Los, Tetyana I.; Kolomoets, Olexandra S.

2013-01-01

The combinatorial library of novel potential anticancer agents, namely, 2-(alkyl-, alkaryl-, aryl-, hetaryl-)[1,2,4]triazolo[1,5-c]quinazolines, was synthesized by the heterocyclization of the alkyl-, alkaryl-, aryl-, hetarylcarboxylic acid (3H-quinazoline-4-ylidene)hydrazides by oxidative heterocyclization of the 4-(arylidenehydrazino)quinazolines using bromine, and by the heterocyclization of N-(2-cyanophenyl)formimidic acid ethyl ester. The optimal method for synthesis of the s-triazolo[1,5-c]quinazolines appeared to be cyclocondensation of the corresponding carboxylic acid (3H-quinazoline-4-ylidene)hydrazides. The compounds’ structures were established by 1H, 13C NMR, LC- and EI-MS analysis. The in vitro screening of anticancer activity determined the most active compound to be 3,4,5-trimethoxy-N′-[quinazolin-4(3H)-ylidene]benzohydrazide (3.20) in micromolar concentrations with the GI50 level (MG_MID, GI50 is 2.29). Thus, the cancer cell lines whose growth is greatly inhibited by compound 3.20 are: non-small cell lung cancer (NCI-H522, GI50=0.34), CNS (SF-295, GI50=0.95), ovarian (OVCAR-3, GI50=0.33), prostate (PC-3, GI50=0.56), and breast cancer (MCF7, GI50=0.52), leukemia (K-562, GI50=0.41; SR, GI50=0.29), and melanoma (MDA-MB-435, GI50=0.31; SK-MEL-5, GI50=0.74; UACC-62, GI50=0.32). SAR-analysis is also discussed. PMID:23833709

2-(Alkylamino)-3-aryl-6,7-dihydrobenzofuran-4(5H)-ones: Improved Synthesis and their Photophysical Properties

PubMed Central

Kumar, Manoj; Kumawat, Lokesh Kumar; Gupta, Vinod Kumar; Sharma, Anuj

2015-01-01

Furans are an important class of compounds and exhibit a diverse range of activities and properties. As such, improved synthetic access to furans is an important research goal. In the present report, a solvent- and catalyst-free reaction between 5,5-dimethyl-1,3-cyclohexanedione (dimedone), an aryl aldehyde and an isocyanide under microwave irradiation is presented. This method is significantly improved from previously described protocols in terms of applicability of wide ranging aryl aldehydes, better yields, shorter reaction times, facile work up and essentially no need of column chromatography. The photophysical properties of this series of compounds were studied for their possible applicability in the field of metal ion sensors. In solution, two compounds, 2-(cyclohexylamino)-3-(1H-indol-3-yl)-6,6-dimethyl-6,7-dihydrobenzofuran-4(5H)-one (1 i) and 2-(tert-butylamino)-3-(1H-indol-3-yl)-6,6-dimethyl-6,7-dihydrobenzofuran-4(5H)-one (1 j), underwent an observable color change from yellow to colorless in the presence of aluminum(III) ions. Further studies to investigate the UV absorption and luminescence behavior of these compounds revealed their utility as “naked-eye sensors” for aluminum detection. PMID:26491643

Synthesis and conformational analysis of new arylated-diphenylurea derivatives related to sorafenib drug via Suzuki-Miyaura cross-coupling reaction

NASA Astrophysics Data System (ADS)

Al-Masoudi, Najim A.; Essa, Ali Hashem; Alwaaly, Ahmed A. S.; Saeed, Bahjat A.; Langer, Peter

2017-10-01

Sorafenib, is a relatively new cytostatic drug approved for the treatment of renal cell and hepatocellular carcinoma. The development of new sorafenib analogues offers the possibility of generating structures of increased potency. To this end, a series of arylated-diphenylurea analogues 17-31 were synthesized via Suzuki-Miyaura coupling reaction, related to sorafenib by treatment of three diarylureas 2-4 having 3-bromo, 4-chloro and 2-iodo groups with various arylboronic acids. Conformational analysis of the new arylated urea analogues has been investigated using MOPAC 2016 of semi empirical PM7 Hamiltonian computational method. Our results showed that all compounds preferred the trans-trans conformations. Compound 17 has been selected to calculate the torsional energy profiles for rotation around the urea bonds and found to be existed predominantly in the trans-trans conformation with only very minimal fluctuation in conformation.

Phytomonitoring and phytoremediation of agrochemicals and related compounds based on recombinant cytochrome P450s and aryl hydrocarbon receptors (AhRs).

PubMed

Shimazu, Sayuri; Inui, Hideyuki; Ohkawa, Hideo

2011-04-13

Molecular mechanisms of metabolism and modes of actions of agrochemicals and related compounds are important for understanding selective toxicity, biodegradability, and monitoring of biological effects on nontarget organisms. It is well-known that in mammals, cytochrome P450 (P450 or CYP) monooxygenases metabolize lipophilic foreign compounds. These P450 species are inducible, and both CYP1A1 and CYP1A2 are induced by aryl hydrocarbon receptor (AhR) combined with a ligand. Gene engineering of P450 and NADPH cytochrome P450 oxidoreductase (P450 reductase) was established for bioconversion. Also, gene modification of AhRs was developed for recombinant AhR-mediated β-glucronidase (GUS) reporter assay of AhR ligands. Recombinant P450 genes were transformed into plants for phytoremediation, and recombinant AhR-mediated GUS reporter gene expression systems were each transformed into plants for phytomonitoring. Transgenic rice plants carrying CYP2B6 metabolized the herbicide metolachlor and remarkably reduced the residues in the plants and soils under paddy field conditions. Transgenic Arabidopsis plants carrying recombinant guinea pig (g) AhR-mediated GUS reporter genes detected PCB126 at the level of 10 ng/g soils in the presence of biosurfactants MEL-B. Both phytomonitoring and phytoremediation plants were each evaluated from the standpoint of practical uses.

Synthesis of sulfadiazinyl acyl/aryl thiourea derivatives as calf intestinal alkaline phosphatase inhibitors, pharmacokinetic properties, lead optimization, Lineweaver-Burk plot evaluation and binding analysis.

PubMed

Sajid-Ur-Rehman; Saeed, Aamer; Saddique, Gufran; Ali Channar, Pervaiz; Ali Larik, Fayaz; Abbas, Qamar; Hassan, Mubashir; Raza, Hussain; Fattah, Tanzeela Abdul; Seo, Sung-Yum

2018-06-02

To seek the new medicinal potential of sulfadiazine drug, the free amino group of sulfadiazine was exploited to obtain acyl/aryl thioureas using simple and straightforward protocol. Acyl/aryl thioureas are well recognized bioactive pharmacophore containing moieties. A new series (4a-4j) of sulfadiazine derived acyl/aryl thioureas was synthesized and characterized through spectroscopic and elemental analysis. The synthesized derivatives 4a-4j were subjected to calf intestinal alkaline phosphatase (CIAP) activity. The derivative 4a-4j showed better inhibition potential compared to standard monopotassium phosphate (MKP). The compound 4c exhibited higher potential in the series with IC 50 0.251 ± 0.012 µM (standard KH 2 PO 4 4.317 ± 0.201 µM). Lineweaver-Burk plots revealed that most potent derivative 4c inhibition CIAP via mixed type pathway. Pharmacological investigations showed that synthesized compounds 4a-4j obey Lipinsk's rule. ADMET parameters evaluation predicted that these molecule show significant lead like properties with minimum possible toxicity and can serve as templates in drug designing. The synthetic compounds show none mutagenic and irritant behavior. Molecular docking analysis showed that compound 4c interacts with Asp273, His317 and Arg166 amino acid residues. Copyright © 2018. Published by Elsevier Ltd.

Reaction of bromine and chlorine with phenolic compounds and natural organic matter extracts--Electrophilic aromatic substitution and oxidation.

PubMed

Criquet, Justine; Rodriguez, Eva M; Allard, Sebastien; Wellauer, Sven; Salhi, Elisabeth; Joll, Cynthia A; von Gunten, Urs

2015-11-15

Phenolic compounds are known structural moieties of natural organic matter (NOM), and their reactivity is a key parameter for understanding the reactivity of NOM and the disinfection by-product formation during oxidative water treatment. In this study, species-specific and/or apparent second order rate constants and mechanisms for the reactions of bromine and chlorine have been determined for various phenolic compounds (phenol, resorcinol, catechol, hydroquinone, phloroglucinol, bisphenol A, p-hydroxybenzoic acid, gallic acid, hesperetin and tannic acid) and flavone. The reactivity of bromine with phenolic compounds is very high, with apparent second order rate constants at pH 7 in the range of 10(4) to 10(7) M(-1) s(-1). The highest value was recorded for the reaction between HOBr and the fully deprotonated resorcinol (k = 2.1 × 10(9) M(-1) s(-1)). The reactivity of phenolic compounds is enhanced by the activating character of the phenolic substituents, e.g. further hydroxyl groups. With the data set from this study, the ratio between the species-specific rate constants for the reactions of chlorine versus bromine with phenolic compounds was confirmed to be about 3000. Phenolic compounds react with bromine or chlorine either by oxidation (electron transfer, ET) or electrophilic aromatic substitution (EAS) processes. The dominant process mainly depends on the relative position of the hydroxyl substituents and the possibility of quinone formation. While phenol, p-hydroxybenzoic acid and bisphenol A undergo EAS, hydroquinone, catechol, gallic acid and tannic acid, with hydroxyl substituents in ortho or para positions, react with bromine by ET leading to quantitative formation of the corresponding quinones. Some compounds (e.g. phloroglucinol) show both partial oxidation and partial electrophilic aromatic substitution and the ratio observed for the pathways depends on the pH. For the reaction of six NOM extracts with bromine, electrophilic aromatic substitution

Doubly 15N-substituted diazenylium: THz laboratory spectra and fractionation models

NASA Astrophysics Data System (ADS)

Dore, L.; Bizzocchi, L.; Wirström, E. S.; Degli Esposti, C.; Tamassia, F.; Charnley, S. B.

2017-07-01

Context. Isotopic fractionation in dense molecular cores has been suggested as a possible origin of large 14N/15N ratio variations in solar system materials. While chemical models can explain some observed variations with different fractionation patterns for molecules with -NH or -CN functional groups, they fail to reproduce the observed ratios in diazenylium (N2H+). Aims: Observations of doubly 15N-substituted species could provide important constraints and insights for theoretical chemical models of isotopic fractionation. However, spectroscopic data are very scarce. Methods: The rotational spectra of the fully 15N-substituted isopologues of the diazenylium ion, 15N2H+ and 15N2D+, have been investigated in the laboratory well into the THz region by using a source-modulation microwave spectrometer equipped with a negative glow discharge cell. An extended chemical reaction network has been used to estimate what ranges of 15N fractionation in doubly 15N-substituted species could be expected in the interstellar medium (ISM). Results: For each isotopologue of the H- and D-containing pair, nine rotational transitions were accurately measured in the frequency region 88 GHz-1.2 THz. The analysis of the spectrum provided very precise rest frequencies at millimeter and sub-millimeter wavelengths, useful for the radioastronomical identification of the rotational lines of 15N2H+ and 15N2D+ in the ISM.

Tuning the Magnetic Properties and Structural Stabilities of the 2-17-3 Magnets Sm2Fe17X3 (X =C , N) by Substituting La or Ce for Sm

NASA Astrophysics Data System (ADS)

Pandey, Tribhuwan; Du, Mao-Hua; Parker, David S.

2018-03-01

Designing a permanent magnet with reduced critical rare-earth content is of paramount importance in the development of cost-effective modern technologies. By performing comprehensive first-principles calculations, we investigate the potential avenues for reducing the critical rare-earth content in Sm2Fe17N3 and Sm2Fe17C3 by making a La or Ce substitution for Sm. The calculated magnetic properties of base compounds are in good agreement with the previous low-temperature (4.2-K) experimental measurements, and they show a large axial anisotropy. Although La or Ce substitution results in a slight reduction of magnetic anisotropy, the magnetic moments of Fe atoms mostly remain unchanged. Specifically, large axial anisotropies of 7.2 and 4.1 MJ /m3 are obtained for SmCeFe17 N3 and SmLaFe17 N3 , respectively. These values of anisotropies are comparable to the state-of-the-art permanent magnet Nd2 Fe14 B . The foremost limitation of Sm2 Fe17X3 magnets for practical application is the formation nitrogen or carbon vacancies at high temperatures. By calculating the N- (C)- vacancy formation energy, we show that La or Ce substitution enhances the vacancy formation energy. This enhanced vacancy formation energy will likely improve the thermodynamic stability of these alloys at high temperatures. Therefore, La- or Ce-substituted Sm2Fe17C3 and Sm2Fe17N3 compounds are promising candidates for high-performance permanent magnets with substantially reduced rare-earth content.

Tuning the Magnetic Properties and Structural Stabilities of the 2-17-3 Magnets Sm 2Fe 17X 3 (X=C, N) by Substituting La or Ce for Sm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandey, Tribhuwan; Du, Mao-Hua; Parker, David S.

Designing a permanent magnet with reduced critical rare-earth content is of paramount importance in the development of cost-effective modern technologies. By performing comprehensive first-principles calculations, we investigate the potential avenues for reducing the critical rare-earth content in Sm 2Fe 17N 3 and Sm 2Fe 17C 3 by making a La or Ce substitution for Sm. The calculated magnetic properties of base compounds are in good agreement with the previous low-temperature (4.2-K) experimental measurements, and they show a large axial anisotropy. Although La or Ce substitution results in a slight reduction of magnetic anisotropy, the magnetic moments of Fe atoms mostlymore » remain unchanged. Specifically, large axial anisotropies of 7.2 and 4.1 MJ/m 3 are obtained for SmCeFe 17N 3 and SmLaFe 17N 3, respectively. These values of anisotropies are comparable to the state-of-the-art permanent magnet Nd 2Fe 14B. The foremost limitation of Sm 2Fe 17X 3 magnets for practical application is the formation nitrogen or carbon vacancies at high temperatures. By calculating the N- (C)- vacancy formation energy, we show that La or Ce substitution enhances the vacancy formation energy. Here, this enhanced vacancy formation energy will likely improve the thermodynamic stability of these alloys at high temperatures. Therefore, La- or Ce-substituted Sm 2Fe 17C 3 and Sm 2Fe 17N 3 compounds are promising candidates for high-performance permanent magnets with substantially reduced rare-earth content.« less

Tuning the Magnetic Properties and Structural Stabilities of the 2-17-3 Magnets Sm 2Fe 17X 3 (X=C, N) by Substituting La or Ce for Sm

DOE PAGES

Pandey, Tribhuwan; Du, Mao-Hua; Parker, David S.

2018-03-05

Designing a permanent magnet with reduced critical rare-earth content is of paramount importance in the development of cost-effective modern technologies. By performing comprehensive first-principles calculations, we investigate the potential avenues for reducing the critical rare-earth content in Sm 2Fe 17N 3 and Sm 2Fe 17C 3 by making a La or Ce substitution for Sm. The calculated magnetic properties of base compounds are in good agreement with the previous low-temperature (4.2-K) experimental measurements, and they show a large axial anisotropy. Although La or Ce substitution results in a slight reduction of magnetic anisotropy, the magnetic moments of Fe atoms mostlymore » remain unchanged. Specifically, large axial anisotropies of 7.2 and 4.1 MJ/m 3 are obtained for SmCeFe 17N 3 and SmLaFe 17N 3, respectively. These values of anisotropies are comparable to the state-of-the-art permanent magnet Nd 2Fe 14B. The foremost limitation of Sm 2Fe 17X 3 magnets for practical application is the formation nitrogen or carbon vacancies at high temperatures. By calculating the N- (C)- vacancy formation energy, we show that La or Ce substitution enhances the vacancy formation energy. Here, this enhanced vacancy formation energy will likely improve the thermodynamic stability of these alloys at high temperatures. Therefore, La- or Ce-substituted Sm 2Fe 17C 3 and Sm 2Fe 17N 3 compounds are promising candidates for high-performance permanent magnets with substantially reduced rare-earth content.« less

Synthesis of a Bicyclic Azetidine with In Vivo Antimalarial Activity Enabled by Stereospecific, Directed C(sp3)-H Arylation.

PubMed

Maetani, Micah; Zoller, Jochen; Melillo, Bruno; Verho, Oscar; Kato, Nobutaka; Pu, Jun; Comer, Eamon; Schreiber, Stuart L

2017-08-16

The development of new antimalarial therapeutics is necessary to address the increasing resistance to current drugs. Bicyclic azetidines targeting Plasmodium falciparum phenylalanyl-tRNA synthetase comprise one promising new class of antimalarials, especially due to their activities against three stages of the parasite's life cycle, but a lengthy synthetic route to these compounds may affect the feasibility of delivering new therapeutic agents within the cost constraints of antimalarial drugs. Here, we report an efficient synthesis of antimalarial compound BRD3914 (EC 50 = 15 nM) that hinges on a Pd-catalyzed, directed C(sp 3 )-H arylation of azetidines at the C3 position. This newly developed protocol exhibits a broad substrate scope and provides access to valuable, stereochemically defined building blocks. BRD3914 was evaluated in P. falciparum-infected mice, providing a cure after four oral doses.

Direct synthesis of anti-1,3-diols through nonclassical reaction of aryl Grignard reagents with isopropenyl acetate.

PubMed

Jiao, Yinchun; Cao, Chenzhong; Zhou, Zaichun

2011-01-21

A series of symmetrical aromatic 1,3-diols were efficiently synthesized from substituted aryl Grignard reagents and isopropenyl acetate in a one-step reaction that formed anti products as the major species. Both experimental and theoretical studies suggested that the reaction involves the formation of a relatively stable intermediate E containing a six-membered ring from intermediate A. The stereoselectivity of the reactions and the molecular structure of the products were confirmed by NMR spectroscopy, X-ray diffraction, and gas chromatography.

17O NMR spectroscopy of substituted methyleneindanones: relationship between chemical shift and oxygen atom electron density

NASA Astrophysics Data System (ADS)

Kumar, Arvind; Boykin, David W.

1993-07-01

17O NMR spectroscopic data for eigth β-substituted methyleneindanones obtained at natural abundance in acetonitrile at 75°C are reported. 17O NMR data for ten para-substituted E-benzalindanones, enriched with 17O, were recorded in acetonitrile at 75°C. The 17O NMR data for the E-benzalindanones gave good correlations with sigma plus values, with literature carbonyl IR stretching frequencies, and with literature 17O NMR carbonyl data of chalcones and 5-aryl-2,3-furandiones. The carbonyl oxygen atom electron density (AM1) gave good correlation with the carbonyl 17O NMR chemical shift of both β-substituted methyleneindanones and the E-benzalindanones.

Molecular Modeling and Experimental Study of Nonlinear Optical Compounds: Mono-Substituted Derivatives of Dicyanovinylbenzene

NASA Technical Reports Server (NTRS)

Timofeeva, Tatyana V.; Nesterov, Vladimir N.; Antipin, Mikhael Y.; Clark, R. D.; Sanghadasa, M.; Cardelino, B. H.; Moore, C. E.; Frazier, Donald O.

2000-01-01

A search for potential nonlinear optical (NLO) compounds has been performed using the Cambridge Structural Database and molecular modeling. We have studied a series of mono-substituted derivatives of dicyanovinylbenzene as the NLO properties of one of its derivatives (o-methoxy-dicyanovinylbenzene, DIVA) were described earlier. The molecular geometry in the series of the compounds studied was investigated with an X- ray analysis and discussed along with results of molecular mechanics and ab initio quantum chemical calculations. The influence of crystal packing on the molecular planarity has been revealed. Two new compounds from the series studied were found to be active for second harmonic generation (SHG) in the powder. The measurements of SHG efficiency have shown that the o-F- and p-Cl-derivatives of dicyanovinylbenzene are about 10 and 20- times more active than urea, respectively. The peculiarities of crystal structure formation in the framework of balance between the van der Waals and electrostatic interactions have been discussed. The crystal morphology of DIVA and two new SHG-active compounds have been calculated on the basis of their known crystal structures.

Design and synthesis of new potent PTP1B inhibitors with the skeleton of 2-substituted imino-3-substituted-5-heteroarylidene-1,3-thiazolidine-4-one: Part I.

PubMed

Meng, Ge; Zheng, Meilin; Wang, Mei; Tong, Jing; Ge, Weijuan; Zhang, Jiehe; Zheng, Aqun; Li, Jingya; Gao, Lixin; Li, Jia

2016-10-21

A new series of 2-substituted imino-3-substituted-5- heteroarylidene-1,3-thiazolidine-4-ones as the potent bidentate PTP1B inhibitors were designed and synthesized in this paper. All of the new compounds were characterized and identified by spectra analysis. The biological screening test against PTP1B showed that some of these compounds have the positive inhibitory activity against PTP1B. The activity of the compounds with 5-substituted pyrrole on 5-postion of 1,3-thiazolidine-4-one are more potent than that of those compounds with 5-substituted pyridine group. Compound 14b, 14h and 14i showed IC50 values of 8.66 μM, 6.83 μM and 6.09 μM against PTP1B, respectively. Docking analysis of these active compounds with PTP1B showed the possible interaction modes of these biheterocyclic compounds with the active sites of PTP1B. The inhibition tests against oncogenetic CDC25B were also conducted on this set of compounds to evaluate the selectivity and possible anti-neoplastic activity. Compound 14b also showed the lowest IC50 of 1.66 μM against CDC25B among all the possible inhibitors, including 14g, 14h, 14i and 15c. Some pharmacological parameters including VolSurf, steric and electric descriptors of all the compounds were calculated to give some hints about the relative relationship with the biological activity. The result of this study might give some light on designing the possible anti-cancer drugs targeting at phosphatases. The most active compound 14i might be used as the lead compound for further structure modification of the new low molecular weight PTP1B inhibitors with the N-containing heterocyclic skeleton. Copyright © 2016. Published by Elsevier Masson SAS.

Fluorine bearing sydnones with styryl ketone group: synthesis and their possible analgesic and anti-inflammatory activities.

PubMed

Deshpande, Shreenivas Ramachandrarao; Pai, Karkala Vasantakumar

2012-04-01

In continuation of structure activity relationship studies, a panel of fluorine containing sydnones with styryl ketone group 4-[1-oxo-3-(substituted aryl)-2-propenyl]-3-(3-chloro-4-fluorophenyl)sydnones 2a-i, was synthesized as better analgesic and anti-inflammatory agents. The title compounds were formed by condensing 4-acetyl-3-(3-chloro-4-fluorophenyl)sydnone with various substituted aryl aldehydes, characterized by spectral studies and evaluated at 100 mg\\kg b.w., p.o. for analgesic, anti-inflammatory and ulcerogenic activities. Compounds 2c and 2e showed good analgesic effect in acetic acid-induced writhing while none showed significant activity in hot plate assay in mice. In carrageenan-induced rat paw oedema test, compound 2c and 2f exhibited good anti-inflammatory effect at 3rd h, whereas compounds 2c, 2e, 2d, 2g and 2h showed activity in croton oil induced ear oedema assay in mice. Compounds 2c and 2e were less ulcerogenic than ibuprofen in rats, when tested by ulcer index method. Compounds with electron attracting substituents such as 2c and 2e were found to be promising in terms of the ratio of efficacy and adverse effect. These compounds generally exhibited better activity than those of earlier series signifying fluorine substitution.

High-resolution NMR spectroscopic trends and assignment rules of metal-free, metallated and substituted corroles.

PubMed

Balazs, Yael S; Saltsman, Irena; Mahammed, Atif; Tkachenko, Elena; Golubkov, Galina; Levine, Joshua; Gross, Zeev

2004-07-01

Major advances over the last few years have facilitated the synthesis of a large variety of meso-only substituted corroles that display interesting catalytic, therapeutic and photophysical properties. This work is the first to study extensively the NMR spectral characteristics of both metallated and non-metallated triarylcorroles in various organic solvents and provide guidelines for easy and reliable assignments of 1D 1H spectra from trends of J coupling constants and chemical shifts. An excellent correlation is found between C=C bond lengths derived from 3J(H,H) values and experimental lengths determined by x-ray crystallography of the same molecules. The nuclear Overhauser effect provides a robust 1D 1H NMR tool for determining the selectivity of electrophilic substitutions. Variable-temperature NMR and isotopic labelling reveal a single preferred tautomerization state and unsymmetric ring orientations at -70 degrees C. The beta-pyrrole protons demonstrate long-range heteronuclear couplings with the coordination core (15N) and with the ortho-19F nuclei of the meso-carbon aryl rings. In sum, application of multinuclear magnetic resonance to corroles and their metal complexes, through the compilation of chemical shifts and J couplings and the recognition of trends therein, provides basic information essential to reliable spectral assignments. Additionally, the conclusions drawn about the structures of corroles and the electron densities at various positions of the corrole macrocycle resulting from the application of high-resolution NMR techniques are of importance to an in-depth understanding of the molecular interactions and processes of this relatively new and rapidly expanding class of compounds. Copyright 2004 John Wiley & Sons, Ltd.

The 3,7-diazabicyclo[3.3.1]nonane scaffold for subtype selective nicotinic acetylcholine receptor ligands. Part 2: carboxamide derivatives with different spacer motifs.

PubMed

Eibl, Christoph; Munoz, Lenka; Tomassoli, Isabelle; Stokes, Clare; Papke, Roger L; Gündisch, Daniela

2013-12-01

3,7-Diazabicyclo[3.3.1]nonane (bispidine) based nicotinic acetylcholine receptor (nAChR) ligands have been synthesized and evaluated for nAChRs interaction. Diverse spacer motifs were incorporated between the hydrogen bond acceptor (HBA) part and a variety of substituted (hetero)aryl moieties. Bispidine carboxamides bearing spacer motifs often showed high affinity in the low nanomolar range and selectivity for the α4β2(∗) nAChR. Compounds 15, 25, and 47 with Ki values of about 1 nM displayed the highest affinities for α4β2(∗) nAChR. All evaluated compounds are partial agonists or antagonists at α4β2(∗), with reduced or no effects on α3β4(∗) with the exception of compound 15 (agonist), and reduced or no effect at α7 and muscle subtypes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ligand-Specific Transcriptional Mechanisms Underlie Aryl Hydrocarbon Receptor-Mediated Developmental Toxicity of Oxygenated PAHs

PubMed Central

Goodale, B. C.; La Du, J.; Tilton, S. C.; Sullivan, C. M.; Bisson, W. H.; Waters, K. M.; Tanguay, R. L.

2015-01-01

Polycyclic aromatic hydrocarbons (PAHs) are priority environmental contaminants that exhibit mutagenic, carcinogenic, proinflammatory, and teratogenic properties. Oxygen-substituted PAHs (OPAHs) are formed during combustion processes and via phototoxidation and biological degradation of parent (unsubstituted) PAHs. Despite their prevalence both in contaminated industrial sites and in urban air, OPAH mechanisms of action in biological systems are relatively understudied. Like parent PAHs, OPAHs exert structure-dependent mutagenic activities and activation of the aryl hydrocarbon receptor (AHR) and cytochrome p450 metabolic pathway. Four-ring OPAHs 1,9-benz-10-anthrone (BEZO) and benz(a)anthracene-7,12-dione (7,12-B[a]AQ) cause morphological aberrations and induce markers of oxidative stress in developing zebrafish with similar potency, but only 7,12-B[a]AQ induces robust Cyp1a protein expression. We investigated the role of the AHR in mediating the toxicity of BEZO and 7,12-B[a]AQ, and found that knockdown of AHR2 rescued developmental effects caused by both compounds. Using RNA-seq and molecular docking, we identified transcriptional responses that precede developmental toxicity induced via differential interaction with AHR2. Redox-homeostasis genes were affected similarly by these OPAHs, while 7,12-B[a]AQ preferentially activated phase 1 metabolism and BEZO uniquely decreased visual system genes. Analysis of biological functions and upstream regulators suggests that BEZO is a weak AHR agonist, but interacts with other transcriptional regulators to cause developmental toxicity in an AHR-dependent manner. Identifying ligand-dependent AHR interactions and signaling pathways is essential for understanding toxicity of this class of environmentally relevant compounds. PMID:26141390

Copper(II)-Catalyzed Conversion of Aryl/Heteroaryl Boronic Acids, Boronates, and Trifluoroborates into the Corresponding Azides: Substrate Scope and Limitations.

PubMed

Grimes, Kimberly D; Gupte, Amol; Aldrich, Courtney C

2010-05-01

We report the copper(II)-catalyzed conversion of organoboron compounds into the corresponding azide derivatives. A systematic series of phenylboronic acid derivatives is evaluated to examine the importance of steric and electronic effects of the substituents on reaction yield as well as functional group compatibility. Heterocyclic substrates are also shown to participate in this mild reaction while compounds incorporating B-C(sp(3)) bonds are unreactive under the reaction conditions. The copper(II)-catalyzed boronic acid-azide coupling reaction is further extended to both boronate esters and potassium organotrifluoroborate salts. The method described herein complements existing procedures for the preparation of aryl azides from the respective amino, triazene, and halide derivatives and we expect that it will greatly facilitate copper- and ruthenium-catalyzed azide-alkyne cycloaddition reactions for the preparation of diversely functionalized 1-aryl- or 1-heteroaryl-1,2,3-triazoles derivatives.

Copper-catalyzed C(sp3)-OH cleavage with concomitant C-C coupling: synthesis of 3-substituted isoindolinones.

PubMed

Rao, H Surya Prakash; Rao, A Veera Bhadra

2015-02-06

Copper(II) trifluoromethanesulfonate (Cu(OTf)2) efficiently catalyzes the C-C coupling of 3-hydoxyisoindolinones with a variety of aryl-, heteroaryl-, and alkenylboronic acids to furnish C(3) aryl-, heteroaryl-, and alkenyl-substituted isoindolinones. The coupling reactions work smoothly in 1,2-dicholoroethane (DCE) reflux, to effect both inter- and intramolecular versions. This is the first report on C(sp(3))-OH cleavage with concomitant C-C coupling. The photolabile 2-nitrobenzyl protecting group is most appropriate for promotion of the coupling reaction and for deprotection. The tetracyclic ring motif of the alkaloid neuvamine was prepared by applying the newly developed copper-catalyzed C-C coupling.

A facile iodine(III)-mediated synthesis of 3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)-[1,2,4]triazolo[4,3-a]pyridines via oxidation of 2-((3-aryl-1-phenyl-1H-pyrazol-4-yl)methylene)-1-(pyridin-2-yl)hydrazines and their antimicrobial evaluations

PubMed Central

2011-01-01

Background Fused heterocyclic 1,2,4-triazoles have acquired much importance because of their interesting biological properties. Although a number of methods have been reported in the literature which includes oxidation with phosphorus oxychloride, lead tetraacetate, bromine, etc., hypervalent iodine reagents have emerged as reagents of choice for various synthetically useful transformations due to their low toxicity, ready availability and ease of handling. Results A series of new 3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)-[1,2,4]triazolo[4,3-a]pyridines 4 has been conveniently synthesized by oxidative cyclization of 2-(3-aryl-1-phenyl-1H-pyrazol-4-yl)methylene)-1-(pyridin-2-yl)hydrazines 3 promoted with iodobenzene diacetate under mild conditions (up to 90% isolated yields). All the new compounds were tested in vitro for their antimicrobial activity. Conclusions Iodine(III)-mediated oxidative approach has offered an easy access to new 3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)-[1,2,4]triazolo[4,3-a]pyridines 4. The antibacterial and antifungal activities of newly synthesized compounds have proved them potent antimicrobial agents. PMID:22373059

Characterization of an aryl-alcohol oxidase from the plant saprophytic basidiomycete Coprinopsis cinerea with broad substrate specificity against aromatic alcohols.

PubMed

Tamaru, Yoshiaki; Umezawa, Kiwamu; Yoshida, Makoto

2018-07-01

The aim of the study was to obtain information about the enzymatic properties of aryl-alcohol oxidase from the plant saprophytic basidiomycete Coprinopsis cinerea (rCcAAO), which is classified into the auxiliary activities family 3 subfamily 2 (AA3_2). The gene encoding AAO from the plant saprophytic basidiomycete Coprinopsis cinerea (CcAAO) was cloned, and the recombinant CcAAO (rCcAAO) was heterologously expressed in the methylotrophic yeast Pichia pastoris. The purified rCcAAO showed significant activity not only against trans,trans-2,4-hexadien-1-ol but also against a broad range of aromatic alcohols including aromatic compounds that were reported to be poor substrates for known AAOs. Moreover, site-directed mutagenesis analysis demonstrated that mutants with substitutions from leucine to phenylalanine and tryptophan at position 416 exhibited decreases of activity for aromatic alcohols but still maintained the activity for trans,trans-2,4-hexadien-1-ol. Leucine 416 in CcAAO contributes to the broad substrate specificity against various aromatic alcohols, which is useful for the production of hydrogen peroxide using this enzyme.

Novosphingobium aromaticivorans uses a Nu-class glutathione S-transferase as a glutathione lyase in breaking the β-aryl ether bond of lignin

PubMed Central

Kontur, Wayne S.; Bingman, Craig A.; Olmsted, Charles N.; Wassarman, Douglas R.; Ulbrich, Arne; Gall, Daniel L.; Smith, Robert W.; Yusko, Larissa M.; Fox, Brian G.; Noguera, Daniel R.; Coon, Joshua J.; Donohue, Timothy J.

2018-01-01

As a major component of plant cell walls, lignin is a potential renewable source of valuable chemicals. Several sphingomonad bacteria have been identified that can break the β-aryl ether bond connecting most phenylpropanoid units of the lignin heteropolymer. Here, we tested three sphingomonads predicted to be capable of breaking the β-aryl ether bond of the dimeric aromatic compound guaiacylglycerol-β-guaiacyl ether (GGE) and found that Novosphingobium aromaticivorans metabolizes GGE at one of the fastest rates thus far reported. After the ether bond of racemic GGE is broken by replacement with a thioether bond involving glutathione, the glutathione moiety must be removed from the resulting two stereoisomers of the phenylpropanoid conjugate β-glutathionyl-γ-hydroxypropiovanillone (GS-HPV). We found that the Nu-class glutathione S-transferase NaGSTNu is the only enzyme needed to remove glutathione from both (R)- and (S)-GS-HPV in N. aromaticivorans. We solved the crystal structure of NaGSTNu and used molecular modeling to propose a mechanism for the glutathione lyase (deglutathionylation) reaction in which an enzyme-stabilized glutathione thiolate attacks the thioether bond of GS-HPV, and the reaction proceeds through an enzyme-stabilized enolate intermediate. Three residues implicated in the proposed mechanism (Thr51, Tyr166, and Tyr224) were found to be critical for the lyase reaction. We also found that Nu-class GSTs from Sphingobium sp. SYK-6 (which can also break the β-aryl ether bond) and Escherichia coli (which cannot break the β-aryl ether bond) can also cleave (R)- and (S)-GS-HPV, suggesting that glutathione lyase activity may be common throughout this widespread but largely uncharacterized class of glutathione S-transferases. PMID:29449375

Rate and Equilibrium Constants for the Addition of N-Heterocyclic Carbenes into Benzaldehydes: A Remarkable 2-Substituent Effect**

PubMed Central

Collett, Christopher J; Massey, Richard S; Taylor, James E; Maguire, Oliver R; O'Donoghue, AnnMarie C; Smith, Andrew D

2015-01-01

Rate and equilibrium constants for the reaction between N-aryl triazolium N-heterocyclic carbene (NHC) precatalysts and substituted benzaldehyde derivatives to form 3-(hydroxybenzyl)azolium adducts under both catalytic and stoichiometric conditions have been measured. Kinetic analysis and reaction profile fitting of both the forward and reverse reactions, plus onwards reaction to the Breslow intermediate, demonstrate the remarkable effect of the benzaldehyde 2-substituent in these reactions and provide insight into the chemoselectivity of cross-benzoin reactions. PMID:25908493

Urea Derivatives of 2-Aryl-benzothiazol-5-amines: A New Class of Potential Drugs for Human African Trypanosomiasis.

PubMed

Patrick, Donald A; Gillespie, J Robert; McQueen, Joshua; Hulverson, Matthew A; Ranade, Ranae M; Creason, Sharon A; Herbst, Zackary M; Gelb, Michael H; Buckner, Frederick S; Tidwell, Richard R

2017-02-09

A previous publication from this lab (Patrick, et al. Bioorg. Med. Chem. 2016, 24 , 2451 - 2465 ) explored the antitrypanosomal activities of novel derivatives of 2-(2-benzamido)ethyl-4-phenylthiazole (1), which had been identified as a hit against Trypanosoma brucei, the causative agent of human African trypanosomiasis. While a number of these compounds, particularly the urea analogues, were quite potent, these molecules as a whole exhibited poor metabolic stability. The present work describes the synthesis of 65 new analogues arising from medicinal chemistry optimization at different sites on the molecule. The most promising compounds were the urea derivatives of 2-aryl-benzothiazol-5-amines. One such analogue, (S)-2-(3,4-difluorophenyl)-5-(3-fluoro-N-pyrrolidylamido)benzothiazole (57) was chosen for in vivo efficacy studies based upon in vitro activity, metabolic stability, and brain penetration. This compound attained 5/5 cures in murine models of both early and late stage human African trypanosomiasis, representing a new lead for the development of drugs to combat this neglected disease.

6-Substituted 3,4-dihydro-naphthalene-2-carboxylic acids: synthesis and structure-activity studies in a novel class of human 5alpha reductase inhibitors.

PubMed

Baston, Eckhard; Salem, Ola I A; Hartmann, Rolf W

2002-10-01

Novel 3,4-dihydro-naphthalene-2-carboxylic acids were synthesized and evaluated for 5alpha reductase inhibitory activity. This enzyme exists in two isoforms and is a pharmacological target for the treatment of benign prostatic hyperplasia, male pattern baldness and acne. In the present study non-steroidal compounds capable of mimicking the transition state of the steroidal substrates were prepared. The synthetic strategy for the preparation of compounds 1-6 consisted of triflation followed by subsequent Heck-type carboxylation or methoxy carbonylation for 6-phenyl-3,4-dihydronaphthalen-2(1H)-one 1c. A Negishi-type coupling reaction between 6-(trifluoro-methanesulfonyloxy)-3,4-dihydro-naphthalene-2-carboxylic acid methyl ester 7b and various aryl bromides led, after further transformations, to 6-substituted 3,4-dihydro-naphthalene-2-carboxylic acids 7-15. In a similar way the corresponding naphthalene-2-carboxylic acids 16 and 17 were obtained. The DU 145 cell line and prostate homogenates served as enzyme sources for the human type 1 and type 2 isozymes, whereas ventral prostate was employed to evaluate rat isozyme inhibitory potency. The most active inhibitors identified in this study were 6-[4-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (3) (IC50 = 0.09 microM, rat type 1), 6-[3-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (13) (IC50 = 0.75 microM, human type 2; IC50 = 0.81 microM, human type 1) and 6-[4-(N,N-diisopropylamino-carbonyl)phenyl]naphthalene-2-carboxylic acid (16) (IC50 = 0.2 microM, human type 2). The latter compound was shown to deactivate the enzyme in an uncompetitive manner (Ki = 90 nM; Km, Testosterone = 0.8-1.0 microM) similar to the steroidal inhibitor Epristeride. Select inhibitors (13 and 16) were tested in vivo using testosterone propionate-treated, juvenile, orchiectomized SD-rats. None of the compounds was active at a dose of 25 mg/kg. This result might in part be

Biodegradation of pentafluorosulfanyl-substituted aminophenol in Pseudomonas spp.

PubMed

Saccomanno, Marta; Hussain, Sabir; O'Connor, Neil K; Beier, Petr; Somlyay, Mate; Konrat, Robert; Murphy, Cormac D

2018-06-01

The pentafluorosulfanyl (SF 5 -) substituent conveys properties that are beneficial to drugs and agrochemicals. As synthetic methodologies improve the number of compounds containing this group will expand and these chemicals may be viewed as emerging pollutants. As many microorganisms can degrade aromatic xenobiotics, we investigated the catabolism of SF 5 -substituted aminophenols by bacteria and found that some Pseudomonas spp. can utilise these compounds as sole carbon and energy sources. GC-MS analysis of the culture supernatants from cultures grown in 5-(pentafluorosulfanyl) 2-aminophenol demonstrated the presence of the N-acetylated derivative of the starting substrate and 4-(pentafluorosulfanyl)catechol. Biotransformation experiments with re-suspended cells were also conducted and fluorine-19 NMR analyses of the organic extract and aqueous fraction from suspended cell experiments revealed new resonances of SF 5 -substituted intermediates. Supplementation of suspended cell cultures with yeast extract dramatically improved the degradation of the substrate as well as the release of fluoride ion. 4-(Pentafluorosulfanyl)catechol was shown to be a shunt metabolite and toxic to some of the bacteria. This is the first study to demonstrate that microorganisms can biodegrade SF 5 -substituted aromatic compounds releasing fluoride ion, and biotransform them generating a toxic metabolite.

Structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogs in a microbial antitumor prescreen I: Derivatives of o-fluoro-DL-phenylalanine.

PubMed

Otani, T T; Briley, M R

1982-02-01

Twelve derivatives of 0-fluoro-dl-phenylalanine containing fluorine, chlorine, methoxy, and nitro radicals in various positions of the aromatic ring of the benzoyl group were prepared and tested in a Lactobacillus casei system. It was found that most substitutions in the benzoyl phenyl ring resulted in a compound exhibiting greater growth-inhibiting activity than the nonsubstituted benzoyl-o-fluorophenylalanine. The greatest activity was observed in the ortho-substituted fluoro compound and the meta- and para-substituted chloro and nitro compounds. With the methoxy group, the position of substitution appeared unimportant, since all three methoxy isomers exhibited essentially equal inhibition. Nitro substitution in the ortho position had a protective effect in that the product was less active than the unsubstituted benzoyl-o-fluoro-dl-phenylalanine.

Antimalarial activity of novel 5-aryl-8-aminoquinoline derivatives.

PubMed

Shiraki, Hiroaki; Kozar, Michael P; Melendez, Victor; Hudson, Thomas H; Ohrt, Colin; Magill, Alan J; Lin, Ai J

2011-01-13

In an attempt to separate the antimalarial activity of tafenoquine (3) from its hemolytic side effects in glucose-6-phosphate dehydrogenase (G6PD) deficiency patients, a series of 5-aryl-8-aminoquinoline derivatives was prepared and assessed for antimalarial activities. The new compounds were found metabolically stable in human and mouse microsomal preparations, with t(1/2) > 60 min, and were equal to or more potent than primaquine (2) and 3 against Plasmodium falciparum cell growth. The new agents were more active against the chloroquine (CQ) resistant clone than to the CQ-sensitive clone. Analogues with electron donating groups showed better activity than those with electron withdrawing substituents. Compounds 4bc, 4bd, and 4be showed comparable therapeutic index (TI) to that of 2 and 3, with TI ranging from 5 to 8 based on IC(50) data. The new compounds showed no significant causal prophylactic activity in mice infected with Plasmodium berghei sporozoites, but are substantially less toxic than 2 and 3 in mouse tests.

Fragmentation of negative ions from N-linked carbohydrates, part 4. Fragmentation of complex glycans lacking substitution on the 6-antenna.

PubMed

Harvey, David J; Jaeken, Jaak; Butler, Mike; Armitage, Alison J; Rudd, Pauline M; Dwek, Raymond A

2010-05-01

Negative ion CID spectra of N-linked glycans released from glycoproteins contain many ions that are diagnostic for specific structural features such as the detailed arrangement of antennae and the location of fucose residues. Identification of such ions requires reference glycans that are often difficult to acquire in a pure state. The recent acquisition of a sample of N-glycans from a patient lacking the enzyme N-acetylglucosaminyltransferase-2 provided an opportunity to investigate fragmentation of glycans lacking a 6-antenna. These glycans contained one or two galactose-N-acetylglucosamine-chains attached to the 3-linked mannose residue of the trimannosyl-chitobiose core with and without fucose substitution. The spectra from the patient sample clearly defined the antenna distribution and showed striking differences from the spectra of isomeric compounds obtained from normal subjects. Furthermore, they provided additional information on previously identified antenna-specific fragment ions and indicated the presence of additional ions that were diagnostic of fucose substitution. Glycans obtained from such enzyme-deficient patients can, thus, be a valuable way of obtaining spectra of specific isomers in a relatively pure state for interpretation of mass spectra. 2010 John Wiley & Sons, Ltd.

Photoaddition of N-substituted piperazines to C60: an efficient approach to the synthesis of water-soluble fullerene derivatives.

PubMed

Troshina, Olesya A; Troshin, Pavel A; Peregudov, Alexander S; Kozlovski, Viacheslav I; Lyubovskaya, Rimma N

2006-07-17

An oxidative radical photoaddition of mono N-substituted piperazines to [60]fullerene was systematically investigated. Reactions of C60 with piperazines bearing bulky electron-withdrawing groups (2-pyridyl, 2-pyrimidinyl) were found to be the most selective and yielded C60(amine)4O as major products along with small amounts of C60(amine)2. In contrast, interactions of fullerene with N-methylpiperazine and N-(tert-butoxycarbonyl)piperazine were found to have low selectivity due to different side reactions. Tetraaminofullerene derivative C60(N-(2-pyridyl)piperazine)4O was found to react readily with organic and inorganic acids to yield highly water-soluble salts (solubility approximately 150 mg mL(-1)). In contrast, C60(N-(2-pyrimidinyl)piperazine)4O undergoes hydrolysis under the same conditions and results in a complex mixture of compounds with an average composition of C60(N-(2-pyrimidinyl)piperazine)2(OH)2O. Radical photoaddition of N-(2-pyridyl)piperazine to fullerene derivatives can be used as a facile route for their transformation into water-soluble compounds. Two model fullerene cycloadducts (a methanofullerene and a pyrrolidinofullerene) were easily converted into mixtures of regioisomers of A=C60(N-(2-pyridyl)piperazine)4O (A=cyclic addend) that give highly water-soluble salts under acid treatment.

Boron compounds as anion binding agents for nonaqueous battery electrolytes

DOEpatents

Lee, Hung Sui; Yang, Xia-Oing; McBreen, James; Xiang, Caili

2000-02-08

Novel fluorinated boron-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boron-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boron-based anion receptors include borane and borate compounds bearing different fluorinated alkyl and aryl groups.

Structure-Based Design: Synthesis, X-ray Crystallography, and Biological Evaluation of N-Substituted-4-Hydroxy-2-Quinolone-3-Carboxamides as Potential Cytotoxic Agents.

PubMed

Sabbah, Dima A; Hishmah, Bayan; Sweidan, Kamal; Bardaweel, Sanaa; AlDamen, Murad; Zhong, Haizhen A; Abu Khalaf, Reema; Hasan Ibrahim, Ameerah; Al-Qirim, Tariq; Abu Sheikha, Ghassan; Mubarak, Mohammad S

2018-01-01

Oncogenic potential of phosphatidylinositol 3-kinase (PI3Kα) has been highlighted as a therapeutic target for anticancer drug design. Target compounds were designed to address the effect of different substitution patterns at the N atom of the carboxamide moiety on the bioactivity of this series. Synthesis of the targeted compounds, crystallography, biological evaluation tests against human colon carcinoma (HCT-116), and Glide docking studies. A new series of N-substituted- 4-hydroxy-2-quinolone-3-carboxamides was prepared and characterized by means of FT-IR, 1H and 13C NMR, and elemental analysis. In addition, the identity of the core nucleus 5 was successfully characterized with the aid of X-ray crystallography. Biological activity of prepared compounds was investigated in vitro against human colon carcinoma (HCT-116) cell line. Results revealed that these compounds inhibit cell proliferation and induce apoptosis through an increase in caspase-3 activity and a decrease in DNA cellular content. Compounds 7, 14, and 17 which have H-bond acceptor moiety on p-position displayed promising PI3Kα inhibitory activity. On the other hand, derivatives tailored with bulky and hydrophobic motifs (16 and 18) on o- and m-positions exhibited moderate activity. Molecular docking studies against PI3Kα and caspase-3 showed an agreement between the predicted binding affinity (ΔGobsd) and IC50 values of the derivatives for the caspase-3 model. Furthermore, Glide docking studies against PI3Kα demonstrated that the newly synthesized compounds accommodate PI3Kα kinase catalytic domain and form H-bonding with key binding residues. The series exhibited a potential PI3Kα inhibitory activity in HCT-116 cell line. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Visible‐Light‐Mediated Selective Arylation of Cysteine in Batch and Flow

PubMed Central

Bottecchia, Cecilia; Rubens, Maarten; Gunnoo, Smita B.; Hessel, Volker; Madder, Annemieke

2017-01-01

Abstract A mild visible‐light‐mediated strategy for cysteine arylation is presented. The method relies on the use of eosin Y as a metal‐free photocatalyst and aryldiazonium salts as arylating agents. The reaction can be significantly accelerated in a microflow reactor, whilst allowing the in situ formation of the required diazonium salts. The batch and flow protocol described herein can be applied to obtain a broad series of arylated cysteine derivatives and arylated cysteine‐containing dipeptides. Moreover, the method was applied to the chemoselective arylation of a model peptide in biocompatible reaction conditions (room temperature, phosphate‐buffered saline (PBS) buffer) within a short reaction time. PMID:28805276

Stimulation of aryl metabolite production in the basidiomycete Bjerkandera sp. strain BOS55 with biosynthetic precursors and lignin degradation products.

PubMed Central

Mester, T; Swarts, H J; Romero i Sole, S; de Bont, J A; Field, J A

1997-01-01

Aryl metabolites are known to have an important role in the ligninolytic system of white rot fungi. The addition of known precursors and aromatic acids representing lignin degradation products stimulated the production of aryl metabolites (veratryl alcohol, veratraldehyde, p-anisaldehyde, and 3-chloro-p-anisaldehyde) in the white rot fungus Bjerkandera sp. strain BOS55. The presence of manganese (Mn) is known to inhibit the biosynthesis of veratryl alcohol (T. Mester, E. de Jong, and J.A. Field, Appl. Environ. Microbiol. 61:1881-1887, 1995). A new finding of this study was that the production of the other aryl metabolites, p-anisaldehyde and 3-chloro-p-anisaldehyde, was also inhibited by Mn. We attempted to bypass the Mn-inhibited step in the biosynthesis of aryl metabolites by the addition of known and suspected precursors. Most of these compounds were not able to bypass the inhibiting effect of Mn. Only the fully methylated precursors (veratrate, p-anisate, and 3-chloro-p-anisate) provided similar concentrations of aryl metabolites in the presence and absence of Mn, indicating that Mn does not influence the reduction of the benzylic acid group. The addition of deuterated benzoate and 4-hydroxybenzoate resulted in the formation of deuterated aryl metabolites, indicating that these aromatic acids entered into the biosynthetic pathway and were common intermediates to all aryl metabolites. Only deuterated chlorinated anisyl metabolites were produced when the cultures were supplemented with deuterated 3-chloro-4-hydroxybenzoate. This observation combined with the fact that 3-chloro-4-hydroxybenzoate is a natural product of Bjerkandera spp. (H. J. Swarts, F. J. M. Verhagen, J. A. Field, and J. B. P. A. Wijnberg, Phytochemistry 42:1699-1701, 1996) suggest that it is a possible intermediate in chlorinated anisyl metabolite biosynthesis. PMID:9143129

Cloning, expression and characterization of an aryl-alcohol dehydrogenase from the white-rot fungus Phanerochaete chrysosporium strain BKM-F-1767

PubMed Central

2012-01-01

Background The white-rot fungus Phanerochaete chrysosporium is among the small group of fungi that can degrade lignin to carbon dioxide while leaving the crystalline cellulose untouched. The efficient lignin oxidation system of this fungus requires cyclic redox reactions involving the reduction of aryl-aldehydes to the corresponding alcohols by aryl-alcohol dehydrogenase. However, the biochemical properties of this enzyme have not been extensively studied. These are of most interest for the design of metabolic engineering/synthetic biology strategies in the field of biotechnological applications of this enzyme. Results We report here the cloning of an aryl-alcohol dehydrogenase cDNA from the white-rot fungus Phanerochaete chrysosporium, its expression in Escherichia coli and the biochemical characterization of the encoded GST and His6 tagged protein. The purified recombinant enzyme showed optimal activity at 37°C and at pH 6.4 for the reduction of aryl- and linear aldehydes with NADPH as coenzyme. NADH could also be the electron donor, while having a higher Km (220 μM) compared to that of NADPH (39 μM). The purified recombinant enzyme was found to be active in the reduction of more than 20 different aryl- and linear aldehydes showing highest specificity for mono- and dimethoxylated Benzaldehyde at positions 3, 4, 3,4 and 3,5. The enzyme was also capable of oxidizing aryl-alcohols with NADP + at 30°C and an optimum pH of 10.3 but with 15 to 100-fold lower catalytic efficiency than for the reduction reaction. Conclusions In this work, we have characterized the biochemical properties of an aryl-alcohol dehydrogenase from the white-rot fungus Phanerochaete chrysosporium. We show that this enzyme functions in the reductive sense under physiological conditions and that it displays relatively large substrate specificity with highest activity towards the natural compound Veratraldehyde. PMID:22742413

Deciphering the Origin, Evolution, and Physiological Function of the Subtelomeric Aryl-Alcohol Dehydrogenase Gene Family in the Yeast Saccharomyces cerevisiae.

PubMed

Yang, Dong-Dong; de Billerbeck, Gustavo M; Zhang, Jin-Jing; Rosenzweig, Frank; Francois, Jean-Marie

2018-01-01

Homology searches indicate that Saccharomyces cerevisiae strain BY4741 contains seven redundant genes that encode putative aryl-alcohol dehydrogenases (AAD). Yeast AAD genes are located in subtelomeric regions of different chromosomes, and their functional role(s) remain enigmatic. Here, we show that two of these genes, AAD4 and AAD14 , encode functional enzymes that reduce aliphatic and aryl-aldehydes concomitant with the oxidation of cofactor NADPH, and that Aad4p and Aad14p exhibit different substrate preference patterns. Other yeast AAD genes are undergoing pseudogenization. The 5' sequence of AAD15 has been deleted from the genome. Repair of an AAD3 missense mutation at the catalytically essential Tyr 73 residue did not result in a functional enzyme. However, ancestral-state reconstruction by fusing Aad6 with Aad16 and by N-terminal repair of Aad10 restores NADPH-dependent aryl-alcohol dehydrogenase activities. Phylogenetic analysis indicates that AAD genes are narrowly distributed in wood-saprophyte fungi and in yeast that occupy lignocellulosic niches. Because yeast AAD genes exhibit activity on veratraldehyde, cinnamaldehyde, and vanillin, they could serve to detoxify aryl-aldehydes released during lignin degradation. However, none of these compounds induce yeast AAD gene expression, and Aad activities do not relieve aryl-aldehyde growth inhibition. Our data suggest an ancestral role for AAD genes in lignin degradation that is degenerating as a result of yeast's domestication and use in brewing, baking, and other industrial applications. IMPORTANCE Functional characterization of hypothetical genes remains one of the chief tasks of the postgenomic era. Although the first Saccharomyces cerevisiae genome sequence was published over 20 years ago, 22% of its estimated 6,603 open reading frames (ORFs) remain unverified. One outstanding example of this category of genes is the enigmatic seven-member AAD family. Here, we demonstrate that proteins encoded by two

Deciphering the Origin, Evolution, and Physiological Function of the Subtelomeric Aryl-Alcohol Dehydrogenase Gene Family in the Yeast Saccharomyces cerevisiae

PubMed Central

de Billerbeck, Gustavo M.; Zhang, Jin-jing; Rosenzweig, Frank

2017-01-01

ABSTRACT Homology searches indicate that Saccharomyces cerevisiae strain BY4741 contains seven redundant genes that encode putative aryl-alcohol dehydrogenases (AAD). Yeast AAD genes are located in subtelomeric regions of different chromosomes, and their functional role(s) remain enigmatic. Here, we show that two of these genes, AAD4 and AAD14, encode functional enzymes that reduce aliphatic and aryl-aldehydes concomitant with the oxidation of cofactor NADPH, and that Aad4p and Aad14p exhibit different substrate preference patterns. Other yeast AAD genes are undergoing pseudogenization. The 5′ sequence of AAD15 has been deleted from the genome. Repair of an AAD3 missense mutation at the catalytically essential Tyr73 residue did not result in a functional enzyme. However, ancestral-state reconstruction by fusing Aad6 with Aad16 and by N-terminal repair of Aad10 restores NADPH-dependent aryl-alcohol dehydrogenase activities. Phylogenetic analysis indicates that AAD genes are narrowly distributed in wood-saprophyte fungi and in yeast that occupy lignocellulosic niches. Because yeast AAD genes exhibit activity on veratraldehyde, cinnamaldehyde, and vanillin, they could serve to detoxify aryl-aldehydes released during lignin degradation. However, none of these compounds induce yeast AAD gene expression, and Aad activities do not relieve aryl-aldehyde growth inhibition. Our data suggest an ancestral role for AAD genes in lignin degradation that is degenerating as a result of yeast's domestication and use in brewing, baking, and other industrial applications. IMPORTANCE Functional characterization of hypothetical genes remains one of the chief tasks of the postgenomic era. Although the first Saccharomyces cerevisiae genome sequence was published over 20 years ago, 22% of its estimated 6,603 open reading frames (ORFs) remain unverified. One outstanding example of this category of genes is the enigmatic seven-member AAD family. Here, we demonstrate that proteins encoded

Suppression of gyrase-mediated resistance by C7 aryl fluoroquinolones

PubMed Central

Malik, Muhammad; Mustaev, Arkady; Schwanz, Heidi A.; Luan, Gan; Shah, Nirali; Oppegard, Lisa M.; de Souza, Ernane C.; Hiasa, Hiroshi; Zhao, Xilin; Kerns, Robert J.; Drlica, Karl

2016-01-01

Fluoroquinolones form drug-topoisomerase-DNA complexes that rapidly block transcription and replication. Crystallographic and biochemical studies show that quinolone binding involves a water/metal-ion bridge between the quinolone C3-C4 keto-acid and amino acids in helix-4 of the target proteins, GyrA (gyrase) and ParC (topoisomerase IV). A recent cross-linking study revealed a second drug-binding mode in which the other end of the quinolone, the C7 ring system, interacts with GyrA. We report that addition of a dinitrophenyl (DNP) moiety to the C7 end of ciprofloxacin (Cip-DNP) reduced protection due to resistance substitutions in Escherichia coli GyrA helix-4, consistent with the existence of a second drug-binding mode not evident in X-ray structures of drug-topoisomerase-DNA complexes. Several other C7 aryl fluoroquinolones behaved in a similar manner with particular GyrA mutants. Treatment of E. coli cultures with Cip-DNP selectively enriched an uncommon variant, GyrA-A119E, a change that may impede binding of the dinitrophenyl group at or near the GyrA-GyrA interface. Collectively the data support the existence of a secondary quinolone-binding mode in which the quinolone C7 ring system interacts with GyrA; the data also identify C7 aryl derivatives as a new way to obtain fluoroquinolones that overcome existing GyrA-mediated quinolone resistance. PMID:26984528

Novel 4-(4-substituted-thiazol-2-ylamino)-N-(pyridin-2-yl)-benzenesulfonamides as cytotoxic and radiosensitizing agents.

PubMed

Ghorab, Mostafa M; Ragab, Fatma A; Heiba, Helmy I; Agha, Hebaallah M; Nissan, Yassin M

2012-01-01

A series of novel 4-(4-substituted-thiazol-2-ylamino)-N-(pyridin-2-yl) benzene-sulfonamides were synthesized and screened for their cytotoxic activity against human breast cancer cell line (MCF-7). Compounds 6, 7, 9, 10, 11, and 14 displayed significant activity against MCF-7 when compared to doxorubicin, which was used as a reference drug. The synergistic effect of Gamma radiation for the most active derivatives 7, 9, and 11 was also studied and their IC(50) values markedly decreased to 11.9 μM, 11.7 μM, and 11.6 μM, respectively.

Iron-Catalyzed Enantioselective Cross-Coupling Reactions of α-Chloroesters with Aryl Grignard Reagents.

PubMed

Jin, Masayoshi; Adak, Laksmikanta; Nakamura, Masaharu

2015-06-10

The first iron-catalyzed enantioselective cross-coupling reaction between an organometallic compound and an organic electrophile is reported. Synthetically versatile racemic α-chloro- and α-bromoalkanoates were coupled with aryl Grignard reagents in the presence of catalytic amounts of an iron salt and a chiral bisphosphine ligand, giving the products in high yields with acceptable and synthetically useful enantioselectivities (er up to 91:9). The produced α-arylalkanoates were readily converted to the corresponding α-arylalkanoic acids with high optical enrichment (er up to >99:1) via simple deprotections/recrystallizations. The results of radical probe experiments are consistent with a mechanism that involves the formation of an alkyl radical intermediate, which undergoes subsequent enantioconvergent arylation in an intermolecular manner. The developed asymmetric coupling offers not only facile and practical access to various chiral α-arylalkanoic acid derivatives, which are of significant pharmaceutical importance, but also a basis of controlling enantioselectivity in an iron-catalyzed organometallic transformation.

Comparison of Nootropic and Neuroprotective Features of Aryl-Substituted Analogs of Gamma-Aminobutyric Acid.

PubMed

Tyurenkov, I N; Borodkina, L E; Bagmetova, V V; Berestovitskaya, V M; Vasil'eva, O S

2016-02-01

GABA analogs containing phenyl (phenibut) or para-chlorophenyl (baclofen) substituents demonstrated nootropic activity in a dose of 20 mg/kg: they improved passive avoidance conditioning, decelerated its natural extinction, and exerted antiamnestic effect on the models of amnesia provoked by scopolamine or electroshock. Tolyl-containing GABA analog (tolibut, 20 mg/kg) exhibited antiamnestic activity only on the model of electroshock-induced amnesia. Baclofen and, to a lesser extent, tolibut alleviated seizures provoked by electroshock, i.e. both agents exerted anticonvulsant effect. All examined GABA aryl derivatives demonstrated neuroprotective properties on the maximum electroshock model: they shortened the duration of coma and shortened the period of spontaneous motor activity recovery. In addition, these agents decreased the severity of passive avoidance amnesia and behavioral deficit in the open field test in rats exposed to electroshock. The greatest neuroprotective properties were exhibited by phenyl-containing GABA analog phenibut.

Quantitative High-Throughput Screening and Confirmation Studies for Identification of Compounds that Activate the Aryl Hydrocarbon Receptor Pathway (SETAC)

EPA Science Inventory

The aryl hydrocarbon receptor (AhR) is a transcription factor that mediates adaptive responses to known environmental pollutants, such as aromatic hydrocarbons, through regulation of Phase I and II xenobiotic metabolizing enzymes as well as important growth and differentiation pa...

Asymmetric Catalysis with Organic Azides and Diazo Compounds Initiated by Photoinduced Electron Transfer.

PubMed

Huang, Xiaoqiang; Webster, Richard D; Harms, Klaus; Meggers, Eric

2016-09-28

Electron-acceptor-substituted aryl azides and α-diazo carboxylic esters are used as substrates for visible-light-activated asymmetric α-amination and α-alkylation, respectively, of 2-acyl imidazoles catalyzed by a chiral-at-metal rhodium-based Lewis acid in combination with a photoredox sensitizer. This novel proton- and redox-neutral method provides yields of up to 99% and excellent enantioselectivities of up to >99% ee with broad functional group compatibility. Mechanistic investigations suggest that an intermediate rhodium enolate complex acts as a reductive quencher to initiate a radical process with the aryl azides and α-diazo carboxylic esters serving as precursors for nitrogen and carbon-centered radicals, respectively. This is the first report on using aryl azides and α-diazo carboxylic esters as substrates for asymmetric catalysis under photoredox conditions. These reagents have the advantage that molecular nitrogen is the leaving group and sole byproduct in this reaction.

Rhodium Catalyzed Intramolecular C-H Insertion of α-Aryl-α-diazo Ketones

PubMed Central

Taber, Douglass F.; Tian, Weiwei

2011-01-01

Direct diazo transfer proceeds smoothly with α-aryl ketones. The derived α-aryl-α-diazo ketones cyclize efficiently with Rh catalysis to give the corresponding α-aryl cyclopentanones. PMID:17385917

Palladium-Catalyzed Coupling of Ammonia with Aryl Chlorides, Bromides, Iodides and Sulfonates: A General Method for the Preparation of Primary Arylamines

PubMed Central

Vo, Giang D.

2010-01-01

We report that the complex generated from Pd[P(o-tol)3]2 and the alkylbisphosphine CyPF-t-Bu is a highly active and selective catalyst for the coupling of ammonia with aryl chlorides, bromides, iodides, and sulfonates. The couplings of ammonia with this catalyst conducted with a solution of ammonia in dioxane form primary arylamines from a variety of aryl electrophiles in high yields. Catalyst loadings as low as 0.1 mol % were sufficient for reactions of many aryl chlorides and bromides. In the presence of this catalyst, aryl sulfonates also coupled with ammonia for the first time in high yields. A comparison of reactions in the presence of this catalyst versus those in the presence of existing copper and palladium systems revealed a complementary, if not broader substrate scope. The utility of this method to generate amides, imides and carbamates is illustrated by a one-pot synthesis of a small library of these carbonyl compounds from aryl bromides and chlorides. Mechanistic studies show that Pd[P(o-tol)3]2 and CyPF-t-Bu generate a more active and general catalyst than that generated from CyPF-t-Bu and palladiun(II) precursors because of the low concentration of active catalyst that is generated from the combination of palladium(II), ammonia and base. PMID:19591470

Fine-tuning the nucleophilic reactivities of boron ate complexes derived from aryl and heteroaryl boronic esters.

PubMed

Berionni, Guillaume; Leonov, Artem I; Mayer, Peter; Ofial, Armin R; Mayr, Herbert

2015-02-23

Boron ate complexes derived from thienyl and furyl boronic esters and aryllithium compounds have been isolated and characterized by X-ray crystallography. Products and mechanisms of their reactions with carbenium and iminium ions have been analyzed. Kinetics of these reactions were monitored by UV/Vis spectroscopy, and the influence of the aryl substituents, the diol ligands (pinacol, ethylene glycol, neopentyl glycol, catechol), and the counterions on the nucleophilic reactivity of the boron ate complexes were examined. A Hammett correlation confirmed the polar nature of their reactions with benzhydrylium ions, and the correlation lg k(20 °C)=sN (E+N) was employed to determine the nucleophilicities of the boron ate complexes and to compare them with those of other borates and boronates. The neopentyl and ethylene glycol derivatives were found to be 10(4) times more reactive than the pinacol and catechol derivatives. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ligand-specific transcriptional mechanisms underlie aryl hydrocarbon receptor-mediated developmental toxicity of oxygenated PAHs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodale, B. C.; Geisel School of Medicine at Dartmouth, Hanover, NH; La Du, J.

Polycyclic aromatic hydrocarbons (PAHs) are priority environmental contaminants that exhibit mutagenic, carcinogenic, proinflammatory, and teratogenic properties. Oxygen-substituted PAHs (OPAHs) are formed during combustion processes and via phototoxidation and biological degradation of parent (unsubstituted) PAHs. Despite their prevalence both in contaminated industrial sites and in urban air, OPAH mechanisms of action in biological systems are relatively understudied. Like parent PAHs, OPAHs exert structure-dependent mutagenic activities and activation of the aryl hydrocarbon receptor (AHR) and cytochrome p450 metabolic pathway. Four-ring OPAHs 1,9-benz-10-anthrone (BEZO) and benz(a)anthracene-7,12-dione (7,12-B[a]AQ) cause morphological aberrations and induce markers of oxidative stress in developing zebrafish with similar potency, butmore » only 7,12-B[a]AQ induces robust Cyp1a protein expression. We investigated the role of the AHR in mediating the toxicity of BEZO and 7,12-B[a]AQ, and found that knockdown of AHR2 rescued developmental effects caused by both compounds. Using RNA-seq and molecular docking, we identified transcriptional responses that precede developmental toxicity induced via differential interaction with AHR2. Redox-homeostasis genes were affected similarly by these OPAHs, while 7,12-B[a]AQ preferentially activated phase 1 metabolism and BEZO uniquely decreased visual system genes. Analysis of biological functions and upstream regulators suggests that BEZO is a weak AHR agonist, but interacts with other transcriptional regulators to cause developmental toxicity in an AHR-dependent manner. Furthermore, identifying ligand-dependent AHR interactions and signaling pathways is essential for understanding toxicity of this class of environmentally relevant compounds.« less