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1

Absorption of Carbon Dioxide in Aqueous Piperazine/Methyldiethanolamine  

E-print Network

Absorption of Carbon Dioxide in Aqueous Piperazine/Methyldiethanolamine Sanjay Bishnoi and Gary T dioxide absorption in 0.6 M piperazine PZ r4 M methyldiethanolamine ( )MDEA was measured in a wetted wall loading. The absorption rate did not follow pseudo first-order beha®ior except at ®ery low loading. All

Rochelle, Gary T.

2

Aerobic biodegradability of methyldiethanolamine (MDEA) used in natural gas sweetening plants in batch tests and continuous flow experiments.  

PubMed

Mixtures of different amines including tertiary amines (methyldiethanolamine, MDEA) are commonly used for the removal of CO2 from gas mixtures or in gas sweetening processes for the extraction of CO2 and H2S. The absorber solutions used can be released into the industrial waste water due to continuous substitution of degraded MDEA, periodically cleaning processes or an accidental spill. In this study, the aerobic biodegradability of MDEA was investigated in a standardised batch test and a continuous flow experiment (40 l/d). The results of the batch test indicated that the MDEA-solution was non-biodegradable during the test period of 28 days, whereas the continuous flow experiments showed biodegradation of more than 96% based on TOC-measurements. This was probably due to the adaptation of the microorganisms to this particular waste water contamination during continuous flow experiment. PMID:12871741

Frhacker, M; Pressl, A; Allabashi, R

2003-09-01

3

Molecular dynamics simulation studies of absorption in piperazine activated MDEA solution.  

PubMed

Development of more efficient solvent solutions for removal of CO(2) from natural gas and flue gases is a major task, which contributes to improved design of process plants and leads to decreased costs for its removal. Understanding the mechanisms of CO(2) absorption as well as analysis of undesired simultaneous processes is crucially important in this regard. In this work, we have applied Molecular Dynamics (MD) to investigate the absorption of CO(2) from a binary mixture of CO(2) and CH(4) into aqueous piperazine activated MDEA solution. The MD simulations were performed at a constant temperature of 298 K for five different systems with a loading factor of 0.07 to provide insight into molecular distribution in the amine solution and to enhance understanding of absorption mechanisms on the molecular scale. Force field parameters that were missing from the OPLS-AA force field, as well as charge distribution of piperazine (PZ), protonated piperazine (PZH(+)), piperazine carbamate (PZCOO(-)) and MDEA were obtained by QM calculations. The results of our simulations emphasize the importance of piperazine and piperazine carbamate in accelerating the absorption process. For the first time, we have shown the undesirable trapping of CH(4) by the amine solution and revealed that amine groups are mainly responsible for both absorption of CO(2) and the undesired trapping of CH(4). PMID:21691636

Farmahini, Amir Hajiahmadi; Kvamme, Bjrn; Kuznetsova, Tatiana

2011-07-28

4

Kinetics, modeling, and simulation of the experimental kinetics data of carbon dioxide absorption into mixed aqueous solutions of MDEA and PZ using laminar jet apparatus with a numerically solved absorption-rate\\/kinetic model  

Microsoft Academic Search

The kinetics of the reaction between carbon dioxide (CO2) and mixed solutions of Methyldiethanolamine (MDEA) and Piperazine (PZ) was investigated experimentally in a laminar jet apparatus. The experimental kinetic data were obtained under no interfacial turbulence and over a temperature range from 313 to 333K, MDEA\\/PZwt% concentration ratio of 27\\/3, 24\\/6 and 21\\/9, and CO2 loading from 0.0095 to 0.33

Raphael Idem; Mohamed Edali; Ahmed Aboudheir

2009-01-01

5

1D and 2D absorption-rate\\/kinetic modeling and simulation of carbon dioxide absorption into mixed aqueous solutions of MDEA and PZ in a laminar jet apparatus  

Microsoft Academic Search

The kinetics of the reaction between carbon dioxide (CO2) and mixed solutions of methyldiethanolamine (MDEA) and piperazine (PZ) was investigated experimentally in a laminar jet apparatus. The experimental kinetic data were obtained under no interfacial turbulence and over a temperature range from 313 to 333K, MDEA\\/PZ wt% concentration ratios of 27\\/3, 24\\/6 and 21\\/9, and CO2 loadings from 0.0095 to

Mohamed Edali; Raphael Idem; Ahmed Aboudheir

2010-01-01

6

Absorption of carbon dioxide with piperazine and its mixtures in a rotating packed bed  

Microsoft Academic Search

The removal efficiency of carbon dioxide from gases containing 10% CO2 by the aqueous solutions containing piperazine (PZ) and its mixture with monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP), and methyldiethanolamine (MDEA) in a rotating packed bed was investigated in this study. The efficiency was assessed in terms of an overall volumetric mass transfer coefficient (KGa) that was found to be a strong

Chung-Sung Tan; Jung-En Chen

2006-01-01

7

Absorption of carbonyl sulfide in aqueous methyldiethanolamine  

Microsoft Academic Search

The absorption of carbonyl sulfide in aqueous methyldiethanolamine (MDEA) was studied over a range of temperatures and MDEA concentrations. MDEA is commonly used for selective absorption of hydrogen sulfide in the presence of carbon dioxide. However, sulfur in the form of COS may also be present and it is necessary that estimates of absorption rates of this compound be made.

H. A. Al-Ghawas; G. Ruiz-Ibanez; O. C. Sandall

1988-01-01

8

Diffusivity of nitrous oxide in N-methyldiethanolamine + diethanolamine + water  

SciTech Connect

The tertiary amine N-methyldiethanolamine and the secondary amine diethanolamine are commonly used in the gas-treating industry as chemical solvents for the removal of acid gases such as CO{sub 2} and H{sub 2}S. The diffusion coefficients for nitrous oxide in aqueous solutions consisting of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) were measured over the temperature range 293--353 K for a total amine concentration of 50 mass % and for the mass ratio of DEA to MDEA varying from 0.0441 to 0.588. The experimental diffusion coefficients were found to be relatively insensitive to the mass ratio of amines.

Rinker, E.B.; Russell, J.W.; Tamimi, A.; Sandall, O.C. [Univ. of California, Santa Barbara, CA (United States). Dept. of Chemical Engineering

1995-05-01

9

Kinetics of absorption of carbon dioxide into solutions of N-methyldiethanolamine+water  

Microsoft Academic Search

Kinetics of the absorption of CO2 into N-methyldiethanolamine (MDEA)+water were investigated at 30, 35, and 40C using a laboratory wetted wall column. Four systems of which 1.0, 1.5, 2.0, and 2.5kmolm?3 MDEA aqueous solutions were studied. The solubility and the diffusivity of N2O in amine systems were also studied. The N2O analogy was applied to estimate the solubility and the

Jiun-Jie Ko; Meng-Hui Li

2000-01-01

10

Modeling CO2 mass transfer in amine mixtures: PZ-AMP and PZ-MDEA.  

PubMed

The most common method of carbon dioxide (CO(2)) capture is the absorption of CO(2) into a falling thin film of an aqueous amine solution. Modeling of mass transfer during CO(2) absorption is an important way to gain insight and understanding about the underlying processes that are occurring. In this work a new software tool has been used to model CO(2) absorption into aqueous piperazine (PZ) and binary mixtures of PZ with 2-amino-2-methyl-1-propanol (AMP) or methyldiethanolamine (MDEA). The tool solves partial differential and simultaneous equations describing diffusion and chemical reaction automatically derived from reactions written using chemical notation. It has been demonstrated that by using reactions that are chemically plausible the mass transfer in binary mixtures can be fully described by combining the chemical reactions and their associated parameters determined for single amines. The observed enhanced mass transfer in binary mixtures can be explained through chemical interactions occurring in the mixture without need to resort to using additional reactions or unusual transport phenomena such as the "shuttle mechanism". PMID:21329341

Puxty, Graeme; Rowland, Robert

2011-03-15

11

Diffusivity of nitrous oxide in aqueous solutions of N-methyldiethanolamine and diethanolamine from 293 to 368 K  

SciTech Connect

The diffusion coefficients for nitrous oxide in aqueous solutions of diethanolamine (DEA) and N-methyldiethanolamine (MDEA) were determined using a wetted-sphere absorber over the temperature range 293--368 K. The ranges of amine concentrations covered in the experiments were 10--30 mass % for DEA and 10--50 mass % for MDEA. The diffusion coefficients indicated a linear dependence on amine concentration, but the temperature dependence was nonlinear. It was found that the diffusivity of N[sub 2]O in aqueous DEA is always less than that in aqueous MDEA under equivalent conditions of amine concentration and temperature.

Tamimi, A.; Rinker, E.B.; Sandall, O.C. (Univ. of California, Santa Barbara, CA (United States). Dept. of Chemical and Nuclear Engineering)

1994-04-01

12

Kinetics study of carbon dioxide absorption into aqueous solutions containing N-methyldiethanolamine + diethanolamine  

Microsoft Academic Search

Kinetics of the absorption of CO2 into N-methyldiethanolamine (MDEA)+diethanolamine (DEA)+water were investigated at 30, 35, and 40C using a wetted wall column apparatus. Eight systems of which 1.0 and 1.5kmol\\/m3 MDEA mixed with various DEA concentrations (0.1, 0.2, 0.3, and 0.4) kmol\\/m3 were studied. Densities and viscosities of eight blended amine systems were measured. The solubilities and diffusivities of N2O

Chih-Yuan Lin; Allan N. Soriano; Meng-Hui Li

2009-01-01

13

Kinetics of absorption of carbon dioxide into aqueous solutions of monoethanolamine+ N-methyldiethanolamine  

Microsoft Academic Search

Kinetics of the absorption of CO2 into monoethanolamine(MEA)+N-methyldiethanolamine(MDEA)+water were investigated at 30C,35C, and 40C using a laboratory wetted wall column. Ten systems with various MEA concentrations (0.1, 0.2, 0.3, 0.4, and 0.5kmolm?3) mixed with aqueous MDEA (1.0 and 1.5kmolm?3) solutions were studied. Densities and viscosities of the solutions and the solubilities and diffusivities of N2O in the aqueous blended amine

Chen-Hung Liao; Meng-Hui Li

2002-01-01

14

A RIGOROUS MODEL FOR ABSORPTION OF CARBON DIOXIDE INTO AQUEOUS N-METHYLDIETHANOLAMINE SOLUTION  

Microsoft Academic Search

A rigorous model for absorption of carbon dioxide into aqueous N-methyldiethanolamine (MDEA) based on the assumption of reversible reactions and the simplified model with a pseudo-first order irreversible reaction hypothesis were employed to compare with experimental data. The experimental absorption rates were obtained from a characterized double stirred-cell absorber with a planar gas-liquid interface. It was demonstrated that the numerical

Yao Shi; Zhantie Zhong

2005-01-01

15

Absorption of carbon dioxide in the aqueous mixtures of methyldiethanolamine with three types of imidazolium-based ionic liquids  

Microsoft Academic Search

The absorption of carbon dioxide in the 4mol\\/L aqueous solution of methyldiethanolamine (MDEA) mixed with three types of ionic liquids, 1-butyl-3-methyl-imidazolium tetrafluoroborate ([bmim][BF 4]), 1-butyl-3-methyl-imidazolium acetate ([bmim][Ac]) and 1-butyl-3-methyl-imidazolium dicyanamide ([bmim][DCA]) were measured as a function of temperature, CO 2 partial pressure and concentration of ionic liquids in the solution. The data for aqueous MDEA+ILs solutions were obtained for temperature,

Afshin Ahmady; M. A. Hashim; Mohamed Kheireddine Aroua

2011-01-01

16

Kinetics of carbon dioxide absorption into mixed aqueous solutions of MDEA and MEA using a laminar jet apparatus and a numerically solved 2D absorption rate\\/kinetics model  

Microsoft Academic Search

New comprehensive numerically solved 1D and 2D absorption rate\\/kinetics models have been developed, for the first time, to interpret the experimental kinetic data obtained with a laminar jet apparatus for the absorption of carbon dioxide (CO2) in CO2 loaded mixed solutions of mixed amine system of methyldiethanolamine (MDEA) and monoethanolamine (MEA). Three MDEA\\/MEA weight ratios ranging from 27\\/03 to 23\\/07,

Mohamed Edali; Ahmed Aboudheir; Raphael Idem

2009-01-01

17

N-methyldiethanolamine: A multifunctional structure-directing agent for the synthesis of SAPO and AlPO molecular sieves.  

PubMed

In the present study, N-methyldiethanolamine (MDEA) is demonstrated to be a multifunctional structure-directing agent for the synthesis of aluminophosphate-based molecular sieves. Four types of molecular sieves, including SAPO-34, -35, AlPO-9 and -22, are for the first time acquired with MDEA as a novel template. The phase selectivity of the present synthesis is found to be condition-dependent. SAPO-34 (CHA) crystallizes from a conventional hydrothermal system with a higher MDEA concentration. When using MDEA as both the template and solvent, pure SAPO-35 (LEV) is obtained from the synthetic gel with a high P2O5/Al2O3 ratio of (2-3), in which the concentration of MDEA could be varied in a wide range. AlPO-9 and AlPO-22 (AWW) are synthesized under the similar conditions to SAPO-35, except without the addition of Si source. The physicochemical properties of the obtained samples are investigated by XRD, XRF, SEM, N2 physisorption, TG-DSC, and various NMR spectra ((13)C, (29)Si, (27)Al and (31)P). Both SAPO-34 and SAPO-35 show good thermal stability, large surface area, and high pore volume. The catalytic performance of SAPO-34 is evaluated by the methanol-to-olefins (MTO) reaction and a good (C2H4+C3H6) selectivity of 82.7% has been achieved. PMID:25616250

Wang, Dehua; Tian, Peng; Fan, Dong; Yang, Miao; Gao, Beibei; Qiao, Yuyan; Wang, Chan; Liu, Zhongmin

2015-05-01

18

Removal of carbon dioxide by absorption in mixed amines: modelling of absorption in aqueous MDEA\\/MEA and AMP\\/MEA solutions  

Microsoft Academic Search

This work presents an investigation of CO2 absorption into aqueous blends of methyldiethanolamine (MDEA) and monoethanolamine (MEA), as well as 2-amino-2-methyl-1-propanol (AMP) and monoethanolamine (MEA). The combined mass transferreaction kineticsequilibrium model to describe CO2 absorption into the amine blends has been developed according to Higbie's penetration theory following the work of Hagewiesche et al. (Chem. Eng. Sci. 50 (1995) 1071).

B. P. Mandal; M. Guha; A. K. Biswas; S. S. Bandyopadhyay

2001-01-01

19

Kinetics of the Absorption of CO{sub 2} in Aqueous Solutions of N-Methyldiethanolamine plus Triethylene Tetramine  

SciTech Connect

This work focuses on the development of a new solvent for CO{sub 2} capture. This new solvent is an aqueous solution with a blend of N-methyldiethanolamine (MDEA) and triethylene tetramine (TETA), an amine with four amino groups. CO{sub 2} absorption was investigated between 298 and 333 K using a Lewis cell with a constant interfacial area. Several concentrations of MDEA (17.5 and 40 wt %) and TETA (3 and 6 wt %) were assessed. The influence of the CO{sub 2} partial pressure on the absorption rate was pointed out. The addition of small amount of TETA leads to a high increase in the CO{sub 2} absorption rates. A numerical model based on the film theory was used to determine the rate coefficients between CO{sub 2} and TETA for the different solvents. The physicochemical parameters have a huge influence on the determination of the rate coefficients.

Amann, J.M.G.; Bouallou, C. [Centre Energetique et Procedes CEP, Paris (France)

2009-04-15

20

Study on corrosion in CO 2 chemical absorption process using amine solution  

Microsoft Academic Search

This work explores the promise of aqueous solutions of blended methyldiethanolamine (MDEA) and piperazine (PZ) as a costeffective absorbent for carbon dioxide (CO2) capture from power plant flue gas streams. The hanging film experiment is used to study the law of the corrosion of blended MDEA\\/PZ containing different CO2 loading with carbon steel and stainless steel. Electrochemical corrosion experiments were

Bo Zhao; Yuekun Sun; Yang Yuan; Jubao Gao; Shujuan Wang; Yuqun Zhuo; Changhe Chen

2011-01-01

21

Determination of diethanolamine or N-methyldiethanolamine in high ammonium concentration matrices by capillary electrophoresis with indirect UV detection: application to the analysis of refinery process waters.  

PubMed

Alkanolamines such as diethanolamine (DEA) and N-methyldiethanolamine (MDEA) are used in desulfurization processes in crude oil refineries. These compounds may be found in process waters following an accidental contamination. The analysis of alkanolamines in refinery process waters is very difficult due to the high ammonium concentration of the samples. This paper describes a method for the determination of DEA in high ammonium concentration refinery process waters by using capillary electrophoresis (CE) with indirect UV detection. The same method can be used for the determination of MDEA. Best results were achieved with a background electrolyte (BGE) comprising 10 mM histidine adjusted to pH 5.0 with acetic acid. The development of this electrolyte and the analytical performances are discussed. The quantification was performed by using internal standardization, by which triethanolamine (TEA) was used as internal standard. A matrix effect due to the high ammonium content has been highlighted and standard addition was therefore used. The developed method was characterized in terms of repeatability of migration times and corrected peak areas, linearity, and accuracy. Limits of detection (LODs) and quantification (LOQs) obtained were 0.2 and 0.7 ppm, respectively. The CE method was applied to the determination of DEA or MDEA in refinery process waters spiked with known amounts of analytes and it gave excellent results, since uncertainties obtained were 8 and 5%, respectively. PMID:15338092

Bord, N; Crtier, G; Rocca, J-L; Bailly, C; Souchez, J-P

2004-09-01

22

Lethal monointoxication by overdosage of MDEA.  

PubMed

A 19-year-old man died after the intake of ten tablets of Ecstasy containing 3,4-methyl-enedioxy-N-ethylamphetamine (MDEA) as the main active ingredient. According to an eyewitness the symptoms of intoxication were strong sweating, sudden aggressiveness followed by hallucinations, subsequent failure of motoric coordination, severe spasms of arms and back, complete depression of the respiratory system, unconsciousness, and collapse. Resuscitation by an emergency doctor failed. Major autopsy findings were severe vascular congestion of all internal organs, liquid post-mortem blood, numerous subpleural and subepicardial petechial haemorrhages. By GC/MS analysis, MDEA was found in large amounts in serum (12 mg/l in femoral vein, 22 mg/l in heart blood serum), urine (201 mg/l), brain (18 to 28 mg/l) and in other tissue samples. Scalp-hair was highly positive for MDEA (17 ng/mg). Besides MDEA and its metabolites only trace amounts of MDMA could be found in urine and blood; no other drugs were detected. It can be concluded that the cause of death was a monointoxication by overdosage of MDEA. PMID:9549899

Weinmann, W; Bohnert, M

1998-01-30

23

Improvement of amine-modification with piperazine for the adsorption of CO2  

NASA Astrophysics Data System (ADS)

Both selectivity and capacity of CO2 adsorption were considerably increased when PZ (piperazine) was added in MDEA (methyldiethylamine) that used to modify the surface of silica gels. The adsorbent saturated with CO2 was regenerated at ambient temperature through nitrogen purge. A set of PSA (pressure swing adsorption) operation with 200 cycles was carried out and applicability of the modified adsorbent was thus illustrated. The CO2 content in the column-top stream decreased from 13% to below 0.05% at steady state.

Xue, Quanmin; Wu, Di; Zhou, Yaping; Zhou, Li

2012-02-01

24

Simultaneous absorption of CO2 and H2S into aqueous blends of N-methyldiethanolamine and diethanolamine.  

PubMed

Removal of CO2 from gaseous streams by absorption with chemical reaction in the liquid phase is usually employed in industry as a method to retain atmospheric CO2 to combat the greenhouse effect. A broad spectrum of alkanolamines and, more recently, their mixtures are being employed for the removal of acid gases such as CO2, H2S, and COS from natural and industrial gas streams. In this research, simultaneous absorption of CO2 and H2S into aqueous blends of N-methyldiethanolamine and diethanolamine is studied theoretically and experimentally. The effect of contact time, temperature, and amine concentration on the rate of absorption and the selectivity were studied by absorption experiments in a wetted wall column at atmospheric pressure and constant feed gas ratio. The diffusion-reaction processes for CO2 and H2S mass transfer in blended amines are modeled according to Higbie's penetration theory with the assumption that all reactions are reversible. A rigorous parametric sensitivity test is done to quantify the effects of possible errors in the pertinent model parameters on the prediction accuracy of the absorption rates and enhancement factors. Model results based on the kinetics-equilibrium-mass transfer coupled model developed in this work are found to be in good agreement with the experimental results of rates of absorption of CO2 and H2S into (MDEA + DEA + H2O). PMID:17051803

Mandald, Bishnupada; Bandyopadhyay, Shyamalendu S

2006-10-01

25

21 CFR 520.1804 - Piperazine phosphate capsules.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Piperazine phosphate capsules. 520.1804 Section 520...ANIMAL DRUGS 520.1804 Piperazine phosphate capsules. (a) Specifications...300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor....

2011-04-01

26

21 CFR 520.1804 - Piperazine phosphate capsules.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Piperazine phosphate capsules. 520.1804 Section 520...ANIMAL DRUGS 520.1804 Piperazine phosphate capsules. (a) Specifications...300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor....

2010-04-01

27

21 CFR 520.1804 - Piperazine phosphate capsules.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Piperazine phosphate capsules. 520.1804 Section 520...ANIMAL DRUGS 520.1804 Piperazine phosphate capsules. (a) Specifications...300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor....

2013-04-01

28

21 CFR 520.1804 - Piperazine phosphate capsules.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 false Piperazine phosphate capsules. 520.1804 Section 520...ANIMAL DRUGS 520.1804 Piperazine phosphate capsules. (a) Specifications...300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor....

2012-04-01

29

21 CFR 520.1804 - Piperazine phosphate capsules.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 false Piperazine phosphate capsules. 520.1804 Section 520...ANIMAL DRUGS 520.1804 Piperazine phosphate capsules. (a) Specifications...300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor....

2014-04-01

30

Piperazine-induced occupational asthma  

SciTech Connect

Asthmatic reactions were studied among some 130 factory workers who handled amines and other chemicals. Among present employees, we found 15 cases of asthma associated with occupational exposure to chemicals; among former employees there were at least 18. The inducing agent was judged to be piperazine in 29 persons and ethylenediamine (EDA) in three. The asthma was of the late or dual type; immediate reactions alone were to seen. No one had attacks of asthma before employment, and atopic subjects were not preferentially affected. Routine spirometry revealed airway obstruction in fewer than half of the recent cases. Tests of nonspecific bronchial reactivity with methacholine in six subjects with recent asthma showed hyperactivity in five, while tow subjects with earlier asthma did not have hyperactivity. Bronchial provocation tests with piperazine in one subject were positive both in the factory and in the laboratory. The level of piperazine was 1.2 mg/m3 time-weighted average (TWA) in a work place associated with induction of the asthmatic state, and 0.3 mg/m3 in a place connected with attacks in ''sensitized'' subjects.

Hagmar, L.; Bellander, T.; Bergoeoe, B.; Simonsson, B.G.

1982-03-01

31

Determination of rate constants for the reaction between methyldiethanolamine and carbon dioxide  

E-print Network

DETERMINATION OF RATE CONSTANTS FOR THE REACTION BETWEEN METHYLDIETHANOLAMINE AND CARBON DIOXIDE A Thesis by CHARLES MEADE BRABSON, JR. Submitted to the Graduate College of Texas A6M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1985 Major Subject: Chemical Engineering DETERMINATION OF RATE CONSTANTS FOR THE REACTION BETWEEN METHYLDIETHANOLAMINE AND CARBON DIOXIDE A Thesis by CHARLES MEADE BRABSONp JR. Approved as to style and content...

Brabson, Charles Meade

1985-01-01

32

Design considerations in the development and application of microdisc electrode arrays (MDEAs) for implantable biosensors.  

PubMed

The use of microlithographically fabricated Microdisc Electrode Arrays (MDEAs) in the development of implantable voltammetric biosensors necessitates design criteria that balances the overall footprint of the device with the advantages to be derived from large separation distances between non-interacting microdisc elements. Using the dynamic electroanalytical techniques of Multiple Scan Rate Cyclic Voltammetry (MSRCV) experiments with finite element simulations and Electrochemical Impedance Spectroscopy with equivalent circuit modeling, three unique MDEA designs; MDEA 050 (r = 25 microm, 5,184 discs), MDEA 100 (r = 50 microm, 1,296 discs) and MDEA 250 (r = 125 microm, 207 discs) of constant critical dimensions (center-to-center d/r = 4) and area (A = 0.1 cm(2)) were studied in 1.0 mM ferrocene monocarboxylic acid (FcCO(2)H) solution (in 0.1 M Tris/0.1 M KCl buffer, pH = 7.2). The critical disc-to-disc spacing (d/r) required to archive 67% of maximal current response was defined as optimal. Based on the predictive model, new MDEA designs; MDEA 001 (r = 0.5 microm, 127,324 discs), MDEA 002.5 (r = 1.25 microm, 20,372 discs), MDEA 005 (r = 2.5 microm, 5,093 discs), MDEA 010 (r = 5 microm, 1,273 discs), MDEA 015 (r = 7.5 microm, 566 discs), MDEA 020 (r = 10 microm, 318 discs) were simulated at 10 and 100 mV/s. The final disc count of each MDEA was dictated by the need to maintain a comparable electroactive area between the MDEAs, which was chosen to be 0.001 cm(2), which in turn was dictated by the need to generate sufficient electrochemical current to be comfortably measured by common electrochemical detectors. PMID:19165603

Rahman, Abdur Rub Abdur; Guiseppi-Elie, Anthony

2009-06-01

33

Fatal poisoning by MDMA (ecstasy) and MDEA: a case report.  

PubMed

The first observation of lethal recreational use of MDMA (ecstasy) and MDEA in Italy is reported, together with extensive toxicological and histopathological documentation. Findings such as disseminated intravascular coagulation, rarely reported before, are colocated in the framework of the toxic syndrome for a better definition of criteria for forensic diagnosis. PMID:8721431

Fineschi, V; Masti, A

1996-01-01

34

Novel Chromosomally Encoded Multidrug Efflux Transporter MdeA in Staphylococcus aureus  

PubMed Central

Antibiotic efflux is an important mechanism of resistance in pathogenic bacteria. Here we describe the identification and characterization of a novel chromosomally encoded multidrug resistance efflux protein in Staphylococcus aureus, MdeA (multidrug efflux A). MdeA was identified from screening an S. aureus open reading frame expression library for resistance to antibiotic compounds. When overexpressed, MdeA confers resistance on S. aureus to a range of quaternary ammonium compounds and antibiotics, but not fluoroquinolones. MdeA is a 52-kDa protein with 14 predicted transmembrane segments. It belongs to the major facilitator superfamily and is most closely related, among known efflux proteins, to LmrB of Bacillus subtilis and EmrB of Escherichia coli. Overexpression of mdeA in S. aureus reduced ethidium bromide uptake and enhanced its efflux, which could be inhibited by reserpine and abolished by an uncoupler. The mdeA promoter was identified by primer extension. Spontaneous mutants selected for increased resistance to an MdeA substrate had undergone mutations in the promoter for mdeA, and their mdeA transcription levels were increased by as much as 15-fold. The mdeA gene was present in the genomes of all six strains of S. aureus examined. Uncharacterized homologs of MdeA were present elsewhere in the S. aureus genome, but their overexpression did not mediate resistance to the antibacterials tested. However, MdeA homologs were identified in other bacteria, including Bacillus anthracis, some of which were shown to be functional orthologs of MdeA. PMID:14982783

Huang, Jianzhong; O'Toole, Paul W.; Shen, Wei; Amrine-Madsen, Heather; Jiang, Xinhe; Lobo, Neethan; Palmer, Leslie M.; Voelker, LeRoy; Fan, Frank; Gwynn, Michael N.; McDevitt, Damien

2004-01-01

35

Novel chromosomally encoded multidrug efflux transporter MdeA in Staphylococcus aureus.  

PubMed

Antibiotic efflux is an important mechanism of resistance in pathogenic bacteria. Here we describe the identification and characterization of a novel chromosomally encoded multidrug resistance efflux protein in Staphylococcus aureus, MdeA (multidrug efflux A). MdeA was identified from screening an S. aureus open reading frame expression library for resistance to antibiotic compounds. When overexpressed, MdeA confers resistance on S. aureus to a range of quaternary ammonium compounds and antibiotics, but not fluoroquinolones. MdeA is a 52-kDa protein with 14 predicted transmembrane segments. It belongs to the major facilitator superfamily and is most closely related, among known efflux proteins, to LmrB of Bacillus subtilis and EmrB of Escherichia coli. Overexpression of mdeA in S. aureus reduced ethidium bromide uptake and enhanced its efflux, which could be inhibited by reserpine and abolished by an uncoupler. The mdeA promoter was identified by primer extension. Spontaneous mutants selected for increased resistance to an MdeA substrate had undergone mutations in the promoter for mdeA, and their mdeA transcription levels were increased by as much as 15-fold. The mdeA gene was present in the genomes of all six strains of S. aureus examined. Uncharacterized homologs of MdeA were present elsewhere in the S. aureus genome, but their overexpression did not mediate resistance to the antibacterials tested. However, MdeA homologs were identified in other bacteria, including Bacillus anthracis, some of which were shown to be functional orthologs of MdeA. PMID:14982783

Huang, Jianzhong; O'Toole, Paul W; Shen, Wei; Amrine-Madsen, Heather; Jiang, Xinhe; Lobo, Neethan; Palmer, Leslie M; Voelker, LeRoy; Fan, Frank; Gwynn, Michael N; McDevitt, Damien

2004-03-01

36

21 CFR 520.1806 - Piperazine suspension.  

Code of Federal Regulations, 2010 CFR

...this chapter. (d) Conditions of use in dogs (1) Indications for use . For the removal of roundworms (Toxocara canis and Toxascaris leonina ). (2) Dosage . Administer 20 to 30 mg piperazine base per pound body weight...

2010-04-01

37

21 CFR 520.1807 - Piperazine.  

Code of Federal Regulations, 2010 CFR

...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS 520.1807 Piperazine...015565 in 510.600(c) of this chapter. (c) Related tolerances. See 556.513 of this chapter. (d) Conditions...

2010-04-01

38

MDEA related death in Crete: a case report and literature review.  

PubMed

"Designer drugs" are derivatives of approved drugs abused for recreational effect and created by underground laboratories to circumvent legal restriction. By far the most controversial drug has been MDMA (3,4-methylenedioxymethamphetamine) and the newer derivative MDEA (3,4-methylenedioxymethamphetamine) often called "Eve". MDEA-related deaths have not been reported in the US, but there have been a death of MDMA and MDEA severe poisonings. Convulsions, collapse, hyperpyrexia, disseminated intravascular coagulation rhabdomyolysis, and acute liver and renal damage result from the ingestion of the drug. Complications may occur and severity and death possibly result. The case of a 31-y-old male, the first victim of MDEA in Greece, is reported. Blood MDEA was 3.1 micrograms/mL; MDEA concentrations in liver, lung and kidney were 4.8, 5.2, and 4.8 micrograms/g respectively. PMID:9251177

Tsatsakis, A M; Michalodimitrakis, M N; Patsalis, A N

1997-08-01

39

Mathematical Model of Carbon Dioxide Absorption into Mixed Aqueous Solutions  

Microsoft Academic Search

In this paper, a mathematical model of CO2 chemical absorption system using MDEA (MethylDiEthanolAmine) and PZ (Piperazine) aqueous solutions is investigated. Precisely, the complex reactive absorption behavior is modeled by an NLP mathematical model. The resulting mathematical model is implemented in GAMS and CONOPT is used as NLP solver. The proposed model will allow to optimize the operating conditions to

Patricia Mores; Nicolas Scenna; Sergio Mussati

2009-01-01

40

Piperazine pivoted transition metal dithiocarbamates  

NASA Astrophysics Data System (ADS)

A quadridentate ligand disodium bis(2,2'-dithiopiperazinato-2,2'-diamino diethylamine) Na 2L 2 and its self assembled transition metal complexes of the type, M 2(L 2) 2 {M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)} have been reported. The piperazine pivoted homodinuclear complexes have been characterized by a range of spectral, thermal, microanalytical and conductometric techniques. On the basis of IR and 1HNMR data a symmetrical bidentate coordination of the dithiocarbamato moiety has been observed in all the cases. The TGA profile of the ligand exhibits two stage thermolytic pattern although the complexes decompose in three steps, respectively. Metal sulfide is found to be the end product. The formation of homodinuclear complexes has been ascertained on the basis of FAB mass spectral data and a probable fragmentation pattern has been proposed. On the basis of UV-visible spectroscopic results and room temperature magnetic moment data a tetrahedral geometry has been proposed for all the complexes except for the Ni(II) and Cu(II) which are found to be square-planar.

Khan, Sadaf; Nami, Shahab A. A.; Siddiqi, K. S.

2008-03-01

41

Piperazine-based nucleic acid analogs  

DOEpatents

A novel nucleoside analog is disclosed which comprises a piperazine ring in the place of the ring ribose or deoxyribose sugar. Monomers utilizing a broad variety of nucleobases are disclosed, as well as oligomers comprising the monomers disclosed herein linked by a variety of linkages, including amide, phosphonamide, and sulfonamide linkages. A method of synthesizing the nucleoside analogs is also disclosed.

Schmidt, Jurgen; Silks, Louis A.; Michalczyk, Ryszard

2005-01-11

42

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 false Piperazine-carbon disulfide complex suspension. 520...ANIMAL DRUGS 520.1802a Piperazine-carbon disulfide complex suspension. (a...suspension contains 7.5 grams of piperazine-carbon disulfide complex. The...

2014-04-01

43

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Piperazine-carbon disulfide complex suspension. 520...ANIMAL DRUGS 520.1802a Piperazine-carbon disulfide complex suspension. (a...suspension contains 7.5 grams of piperazine-carbon disulfide complex. The...

2013-04-01

44

21 CFR 520.1802c - Piperazine-carbon disulfide complex with phenothiazine suspension.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Piperazine-carbon disulfide complex with phenothiazine... 520.1802c Piperazine-carbon disulfide complex with phenothiazine...contains 5 grams of piperazine-carbon disulfide complex and 0.83 gram...

2010-04-01

45

Serotonergic deficits and impaired passive-avoidance learning in rats by MDEA: a comparison with MDMA.  

PubMed

The serotonergic deficits induced by 3,4-methylenedioxyethamphetamine (MDEA, "eve"), were examined and compared with 3,4 methylenedioxymethamphetamine (MDMA, "ecstasy"). A single dose of MDEA (10, 20, or 40 mg/kg IP) induced a dose-related hyperthermia, but only the highest dose significantly reduced 5-HT content and 5-HT transporter density in the frontal cortex and in the hippocampus 7 days later. Long-term serotonergic deficits were much more marked when MDEA was given repeatedly (40 mg/kg IP., b.i.d., for 4 consecutive days). Single or repeated administration of MDEA induced no change on 5-HT1A receptor density in the frontal cortex, brain stem, or hippocampus, although 3 h after both treatments plasma corticosterone levels were significantly increased. MDEA (5-20 mg/kg, IP) produced significant retention deficits in a passive-avoidance learning task. Conversely, 7 days after the repeated administration of MDEA (40 mg/kg b.i.d., for 4 consecutive days) no effect on passive-avoidance performance was observed unless rats were treated again with another dose of MDEA (20 mg/kg IP) 30 min before the training trial. The 5-HT1A receptor antagonist, WAY 100635, prevented the impairment in retention performance induced by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), but not by MDEA or MDMA, indicating that the effect of these amphetamine derivates was not mediated by 5-HT1A receptor activation. The results suggest the risk of serotonergic dysfunction associated with MDEA abuse in humans. PMID:10672974

Barrionuevo, M; Aguirre, N; Del Ro, J D; Lasheras, B

2000-02-01

46

The Neuropsychopharmacology and Toxicology of 3,4-methylenedioxy-N-ethyl-amphetamine (MDEA).  

PubMed

This paper reviews the pharmacology and toxicology of 3,4-methylenedioxy-N-ethylamphetamine (MDEA, "eve"). MDEA is a ring-substituted amphetamine (RSA) like MDMA, its well known N-methyl analog. Both have become very popular substances of abuse in the techno- and house-music scene. They can evoke psychomotor stimulation, mild alterations of perception, sensations of closeness and a positive emotional state as well as sympathomimetic physical effects. At present, the name "ecstasy" is no longer used only for MDMA, but for the whole group of RSAs (MDA, MDMA, MDEA and MBDB) as they are chemically and pharmacologically nearly identical; moreover, many ecstasy pills contain mixtures of the RSAs. Hence, for a selective review on MDEA, it is crucial to strictly differentiate between: 1) street and chemical names, and 2) studies with or without chemically defined substances. In order to present MDEA-specific information, the pharmacodynamics and kinetics are described on the basis of MDEA challenge studies in animals and humans. In the toxicology section, we present a collection of case reports on fatalities where MDEA was toxicologically confirmed. On the question of serotonergic neurotoxicity and possible long-term consequences, however, MDEA-specific information is available from animal studies only. The neurotoxic potential of MDEA in humans is difficult to estimate, as ecstasy users do not consume pure substances. For future research, challenge studies in animals using dosing regimens adapted to human consumption patterns are needed. Such challenge studies should directly compare individual RSAs. They will represent the most viable and fruitful approach to the resolution of the highly controversial issues of serotonergic neurotoxicity and its functional consequences. PMID:15179441

Freudenmann, Roland W; Spitzer, Manfred

2004-01-01

47

Intentional overdose and death with 3,4-methylenedioxyethamphetamine (MDEA; "Eve"): case report.  

PubMed

We report a case of suicide following ingestion of a large dose of 3,4-methylenedioxyethamphetamine (MDEA, "Eve") in a 27-year-old woman with a history of depression. Several days before her death, she had attempted suicide with benzodiazepines resulting in a 24-hour hospital admission; at that time, no physiologic abnormalities were detected. Findings on autopsy were nonspecific. Toxicologic analysis showed a high concentration of MDEA and the appearance of benzodiazepines in body fluids. Ethanol and other drugs of abuse were not found. We discuss the clinical manifestations, toxicologic syndromes, and mechanisms of death with amphetamine intoxication. MDEA intoxication in young people may result in sudden death. PMID:9662110

Arimany, J; Medallo, J; Pujol, A; Vingut, A; Borondo, J C; Valverde, J L

1998-06-01

48

Carbon dioxide capture with concentrated, aqueous piperazine  

Microsoft Academic Search

Concentrated, aqueous piperazine (PZ) has been investigated as a novel amine solvent for carbon dioxide (CO2) absorption. The CO2 absorption rate of aqueous PZ is more than double that of 7m MEA and the amine volatility at 40C ranges from 11 to 21ppm. Thermal degradation is negligible in concentrated, aqueous PZ up to a temperature of 150C, a significant advantage

Stephanie A. Freeman; Ross Dugas; David H. Van Wagener; Thu Nguyen; Gary T. Rochelle

2010-01-01

49

Engineering of copper molybdates: Piperazine dictated pseudopolymorphs  

NASA Astrophysics Data System (ADS)

The hydrothermal syntheses, crystal structures and magnetic behavior of two compositionally different piperazine pillared copper molybdates, [{Cu( pip) 0.5}MoO 4] ( 1) and a hitherto unknown [Cu( pip)MoO 4] ( pip = piperazine) ( 2), are reported. Both 1 and 2 exhibit three-dimensional covalent frameworks constructed from bimetallic oxide layers pillared by piperazine; however, the {CuMoO 4} networks are quite distinct. The Cu-Mo-O layers in 1 are made of edge-shared {CuO 4N} square pyramidal pairs linked through {MoO 4} tetrahedra, in contrast to the sheets in 2 that are built of corner-sharing {MoO 4} tetrahedra and {CuO 3N 2} square pyramids. Self assembly of the two pseudopolymorphs, 1 and 2, is interpreted in terms of molecular recognition between reasonable soluble molecular species in the supramolecular reaction along the mechanistic approach proposed by Ramanan and Whittingham for rationalizing metal-organic framework structures. Crystal data: 1, Triclinic, space group P-1, a = 5.5765(8) , b = 6.8304(10) , c = 9.2379(14) , ? = 100.688(2), ? = 101.462(2), ? = 112.624(2), Z = 2; 2, Orthorhombic, space group Pbca, a = 11.3899(11) , b = 10.7726(10) , c = 13.2541(12) , Z = 8.

Pavani, Katikaneani; Singh, Monika; Ramanan, Arunachalam; Lofland, Samuel E.; Ramanujachary, Kandalam V.

2009-09-01

50

40 CFR 721.10047 - Polyphosphoric acids, compds. with piperazine.  

Code of Federal Regulations, 2010 CFR

40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyphosphoric acids, compds. with piperazine...721.10047 Protection of Environment ENVIRONMENTAL PROTECTION...721.10047 Polyphosphoric acids, compds. with...

2010-07-01

51

40 CFR 721.10047 - Polyphosphoric acids, compds. with piperazine.  

Code of Federal Regulations, 2011 CFR

40 Protection of Environment 31 2011-07-01 2011-07-01 false Polyphosphoric acids, compds. with piperazine...721.10047 Protection of Environment ENVIRONMENTAL PROTECTION...721.10047 Polyphosphoric acids, compds. with...

2011-07-01

52

Determination of MDMA, MDEA and MDA in urine by high performance liquid chromatography with fluorescence detection.  

PubMed

This paper describes the development and validation of analytical methodology for the determination of the use of MDMA, MDEA and MDA in urine. After a simple liquid extraction, the analyses were carried out on a high performance liquid chromatography (HPLC) in an octadecyl column, with fluorescence detection. The mobile phase using a sodium dodecyl sulfate ion-pairing reagent allows good separation and efficiency. The method showed good linearity and precision. Recovery was between 85 and 102% and detection limits were 10, 15 and 20 ng/ml for MDA, MDMA and MDEA, respectively. No interfering substances were detected with fluorescence detection. PMID:15458720

da Costa, Jos Luiz; da Matta Chasin, Alice Aparecida

2004-11-01

53

Adam (MDMA) and Eve (MDEA) misuse: an immunohistochemical study on three fatal cases.  

PubMed

Three fatal cases of MDMA/MDEA misuse have been examined. These referred to white males between 19 and 20 years of age, in which post-mortem toxicology showed the presence of MDMA (in one case), MDEA (in one case) and both (in one case). The clinical data were analysed and the histopathological findings were studied following immunohistochemical investigations. A complete immunohistochemical study has made it possible to demonstrate rhabdomyolysis and myoglobinuria with alterations of the organs typical of a DIC. Clinical, histopathological and toxicological data suggest that severe or fatal complications following ecstasy ingestion could be related to idiosyncratic response. PMID:10533279

Fineschi, V; Centini, F; Mazzeo, E; Turillazzi, E

1999-09-30

54

Kinetics of absorption of carbon dioxide in aqueous piperazine solutions  

Microsoft Academic Search

In the present work the absorption of carbon dioxide into aqueous piperazine (PZ) solutions has been studied in a stirred cell, at low to moderate temperatures, piperazine concentrations ranging from 0.6 to 1.5kmolm-3, and carbon dioxide pressures up to 500mbar, respectively. The obtained experimental results were interpreted using the DeCoursey equation [DeCoursey, W., 1974. Absorption with chemical reaction: development of

P. W. J. Derks; T. Kleingeld; C. van Aken; J. A. Hogendoorn; G. F. Versteeg

2006-01-01

55

The effect of phosphoric acid on the absorption of carbon dioxide into solutions of methyldiethanolamine  

E-print Network

. The specific equipment required for each setup is described below in detail. Kinetic and Mass Transfer Experimental Setup Both the kinetics and mass transfer of the solutions were studied with a liquid batch and a continuous flow of gas through the reactor...: Nitrous Oxide Absorption into MDEA/HsPO4 Solutions . . . 17. Ideal Solution Equilibrium Concentrations at 25'C 18. Comparison of Ideal and Actual Solution pH Values. . 19. Ionic Ratio Criteria for Solutions with Overall Activity Coefficients Less...

Cordi, Eric Marshall

1991-01-01

56

Functional gene cloning and characterization of MdeA, a multidrug efflux pump from Staphylococcus aureus.  

PubMed

A DNA fragment conferring drug resistance was cloned from the chromosomal DNA of Staphylococcus aureus N315 using a drug hypersensitive Escherichia coli KAM32 as the host. Although E. coli KAM32 cells were sensitive to many antimicrobial agents, transformed cells harboring a recombinant plasmid carrying the DNA region became resistant to several structurally unrelated antimicrobial agents, such as tetraphenylphosphonium chloride, Hoechst 33342 and norfloxacin. These results suggest that the cloned DNA fragment carries a gene(s) encoding a multidrug efflux pump. We partially determined the nucleotide sequence of the cloned DNA and found the mdeA gene within it. The E. coli cells transformed with the mdeA gene showed efflux activity of Hoechst 33342. On the other hand, S. aureus cells transformed with mdeA showed elevated resistance to doxorubicin, daunorubicin, tetraphenylphosphonium chloride, Hoechst 33342, ethidium bromide and rhodamine 6G. Elevated energy-dependent efflux of ethidium was observed with transformed S. aureus. We found that the mdeA gene was expressed under normal growth conditions in S. aureus N315. PMID:16595922

Yamada, Youichi; Shiota, Sumiko; Mizushima, Tohru; Kuroda, Teruo; Tsuchiya, Tomofusa

2006-04-01

57

21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.  

Code of Federal Regulations, 2014 CFR

...Piperazine phosphate with thenium closylate tablets. 520.1805 Section 520.1805 Food...Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250...

2014-04-01

58

21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.  

Code of Federal Regulations, 2011 CFR

...Piperazine phosphate with thenium closylate tablets. 520.1805 Section 520.1805 Food...Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250...

2011-04-01

59

21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.  

Code of Federal Regulations, 2012 CFR

...Piperazine phosphate with thenium closylate tablets. 520.1805 Section 520.1805 Food...Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250...

2012-04-01

60

21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.  

Code of Federal Regulations, 2013 CFR

...Piperazine phosphate with thenium closylate tablets. 520.1805 Section 520.1805 Food...Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250...

2013-04-01

61

40 CFR 721.9800 - Poly(substituted triazinyl) piperazine (generic name).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Poly(substituted triazinyl) piperazine...Specific Chemical Substances 721.9800 Poly(substituted triazinyl) piperazine...reporting. (1) The chemical substance poly(substituted triazinyl)...

2011-07-01

62

40 CFR 721.9800 - Poly(substituted triazinyl) piperazine (generic name).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Poly(substituted triazinyl) piperazine...Specific Chemical Substances 721.9800 Poly(substituted triazinyl) piperazine...reporting. (1) The chemical substance poly(substituted triazinyl)...

2010-07-01

63

A Linear Piperazine-Containing Ligand and Its Hg Coordination Polymer  

Microsoft Academic Search

Reactions of piperazine hexahydrate with triazol and paraformaldehyde afford a new piperazine-containing ligand: (N,N?-bis(1-H-1,2,4-triazole-1-yl)piperazine) (btp). X-ray crystal diffraction reveals that btp is an overall linear structure. Its Hg polymer displays a zigzag chain in which piperazine is held in the chair conformation. In addition, the spectra properties of the btp and 1 are investigated, the strong luminescence characteristics of btp

Wen-Juan Chu; Rui-Jun Li; Yao-Ting Fan; Hong-Wei Hou

2012-01-01

64

Pilot plant for CO2 capture with aqueous piperazine/potassium carbonate , Gary T. Rochelle1  

E-print Network

GHGT-8 1 Pilot plant for CO2 capture with aqueous piperazine/potassium carbonate Eric Chen1 , Gary pilot for CO2 capture was successfully operated using potassium carbonate promoted with piperazine, potassium carbonate, piperazine Introduction Several amine-promoted potassium carbonate solvents have been

Rochelle, Gary T.

65

Acute poisoning with amphetamines (MDEA) and heroin: antagonistic effects between the two drugs.  

PubMed

A case of oral ingestion of large doses of both the amphetamine-derivative 3,4-methylene dioxyethamphetamine (MDEA) and heroin is reported. Despite high serum levels of both drugs, the patient did not present with the classic signs and symptoms normally seen during intoxication with these drugs. The patient recovered after symptomatic treatment. The possibility that opposite pharmacological properties of the two drugs prevented the patients death is discussed. PMID:8796401

Jorens, P G; Heytens, L; Demey, H E; Andries, S; Ricaurte, G A; Bossaert, L; Schepens, P J

1996-05-01

66

'Eve' and 'Ecstasy'. A report of five deaths associated with the use of MDEA and MDMA.  

PubMed

3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy"), a synthetic analogue of 3,4-methylenedioxyamphetamine, has been the center of recent debate over its potential for abuse vs its use as a psychotherapeutic agent. Following its emergency classification in Schedule 1 by the Drug Enforcement Administration in 1985, 3,4-methylenedioxyethamphetamine (MDEA, "Eve") has appeared as MDMA's legal replacement. MDMA is thought to be safe by recreational users and by psychotherapists who support its use. The details of five deaths associated with the use of MDMA and MDEA are reported. In three patients, MDMA or MDEA may have contributed to death by the induction of arrhythmias in individuals with underlying natural disease. In another patient, use of MDMA preceded an episode of bizarre and risky behavior that resulted in accidental death. In another patient, MDMA was thought to be the immediate cause of death. Death as a consequence of the use of these drugs appears to be rare, but it does occur; this outcome may be more common in individuals with underlying cardiac disease. PMID:2881002

Dowling, G P; McDonough, E T; Bost, R O

1987-03-27

67

Absorption of carbon dioxide into aqueous piperazine: reaction kinetics, mass transfer and solubility  

Microsoft Academic Search

This work studies the absorption of carbon dioxide into aqueous solutions of piperazine in a wetted wall contactor. Absorption was studied from 298 to 333K in solutions of 0.6 and 0.2M aqueous piperazine. The apparent reaction rate is first order in both carbon dioxide and piperazine with a value of 53,700m3\\/kmols at 25C. The apparent second-order rate constant follows an

Sanjay Bishnoi; Gary T. Rochelle

2000-01-01

68

Absorption of Carbon Dioxide Characterized by Using the Absorbent Composed of Piperazine and Triethanolamine  

Microsoft Academic Search

This work studies the CO2 absorption of alkanolamine, piperazine, and TEA (triethanolamine), and the chemical reaction kinetics of CO2 by using the mixed solution of piperazine and TEA in polyvinylidine?fluoride hollow fiber membrane contactor?stripper hybrid process. Absorption was studied from 303K to 382K in the mixed solution of piperazine 0.26M, 0.64M, and TEA 0.38M, 1.13M, 2.26M. Also, absorption rates were

Bongkuk Sea

2004-01-01

69

Degradation of aqueous piperazine in carbon dioxide capture  

Microsoft Academic Search

Concentrated, aqueous piperazine (PZ) is a novel solvent for carbon dioxide (CO2) capture by absorption\\/stripping. One of the major advantages of PZ is its resistance to thermal degradation and oxidation.At 135 and 150C, 8m PZ is up to two orders of magnitude more resistant to thermal degradation than 7m monoethanolamine (MEA). After 18 weeks at 150C, only 6.3% of the

Stephanie A. Freeman; Jason Davis; Gary T. Rochelle

2010-01-01

70

Three-dimensional network in piperazine-1,4-diiumpicratepiperazine (1/2/1)  

PubMed Central

In the title compound, C4H12N2 2+2C6H2N3O7 ?C4H10N2, the piperazine-1,4-diium cations and piperazine molecules lie on crystallographic inversion centres. In the crystal structure, intermolecular NH?O and NH?N hydrogen bonds link the components to form two-dimensional layers parallel to the (001) plane. These layers are, in turn, connected by weak intermolecular CH?O hydrogen bonds and ?? stacking interactions [centroidcentroid distance between parallel aryl rings = 3.764?(2)?, interplanar spacing = 3.500?(2)? and ring offset = 1.387?(2)?], forming a three-dimensional framework. PMID:21202060

Wang, Zhong-Long; Jia, Li-Hui

2008-01-01

71

Prepulse inhibition of the acoustic startle response is disrupted by N-ethyl-3,4-methylenedioxyamphetamine (MDEA) in the rat.  

PubMed

N-Ethyl-3,4-methylenedioxyamphetamine (MDEA) is a derivative of methylenedioxyamphetamine (MDA), a substituted amphetamine with demonstrated abuse liability. MDA, MDEA and a third substituted amphetamine, methylenedioxymethamphetamine (MDMA), all produce a destructive action on central serotonin neurons and appear to induce some similar behavioral effects. The present study investigated the effects of racemic MDEA and its stereoisomers on prepulse inhibition of the acoustic startle response, a behavioral model of sensorimotor gating that is sensitive to psychostimulant drugs. Rats were subjected to 122 dB[A] acoustic noises, some of which were preceded by a weak 80 dB[A] prepulse noise. In vehicle-injected control rats, the prepulse induced a significant decrease in startle amplitude when compared to trials in which startle stimuli were not preceded by prepulses. Administration of racemic MDEA (0.3-10.0 mg/kg) and (+) MDEA (0.1-3.0 mg/kg) induced a significant attenuation in prepulse inhibition, while (-) MDEA (0.3-10.0 mg/kg) did not. Racemic MDMA (0.3-10.0 mg/kg) produced similar though not significant effects. These results confirm a stimulant-like behavioral effect of MDEA despite its relatively modest effects on dopamine markers, and support findings that the (+) stereoisomers of substituted amphetamines are more potent than tha (-) stereoisomers in producing psychostimulant-like biochemical and behavioral effects. PMID:2776841

Mansbach, R S; Braff, D L; Geyer, M A

1989-08-11

72

Gene cloning and characterization of MdeA, a novel multidrug efflux pump in Streptococcus mutans.  

PubMed

Multidrug resistance, especially multidrug efflux mechanisms that extrude structurally unrelated cytotoxic compounds from the cell by multidrug transporters, is a serious problem and one of the main reasons for the failure of therapeutic treatment of infections by pathogenic microorganisms as well as of cancer cells. Streptococcus mutans is considered one of the primary causative agents of dental caries and periodontal disease, which comprise the most common oral diseases. A fragment of chromosomal DNA from S. mutans KCTC3065 was cloned using Escherichia coli KAM32 as host cells lacking major multidrug efflux pumps. Although E. coli KAM32 cells were very sensitive to many antimicrobial agents, the transformed cells harboring a recombinant plasmid became resistant to several structurally unrelated antimicrobial agents such as tetracycline, kanamycin, rhodamin 6G, ampicillin, acriflavine, ethidium bromide, and tetraphenylphosphonium chloride. This suggested that the cloned DNA fragment carries a gene encoding a multidrug efflux pump. Among 49 of the multidrug-resistant transformants, we report the functional gene cloning and characterization of the function of one multidrug efflux pump, namely MdeA from S. mutans, which was expressed in E. coli KAM32. Judging from the structural and biochemical properties, we concluded that MdeA is the first cloned and characterized multidrug efflux pump using the proton motive force as the energy for efflux drugs. PMID:23462018

Kim, Do Kyun; Kim, Kyoung Hoon; Cho, Eun Ji; Joo, Seoung-Je; Chung, Jung-Min; Son, Byoung Yil; Yum, Jong Hwa; Kim, Young-Man; Kwon, Hyun-Ju; Kim, Byung-Woo; Kim, Tae Hoon; Lee, Eun-Woo

2013-03-01

73

13C CP/MAS NMR study of a genistein/piperazine complex  

NASA Astrophysics Data System (ADS)

13C CP/MAS NMR indicates that piperazine forms a hydrogen bond with the C7?OH group of genistein. The hydroxyl proton is transferred to the piperazine nitrogen atom. It is shown that the I- I*- S model of the polarization transfer in isolated spin clusters is also valid for quaternary carbon atoms.

Kolodziejski, Waclaw; Mazurek, Aleksander P.; Kasprzycka-Guttman, Teresa

2000-09-01

74

Synthesis and characterization of the novel phosphonates- and phosphonothioate-piperazine as flame retardants for cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tetraethyl piperazine-1,4-diyldiphosphonate (PDP) and O,O,O',O'-tetramethyl piperazine-1,4-diyldiphosphonothioate (PDSP) were synthesized in one simple step and their structures were confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and elemental analysis (EA). Print cloth, twil...

75

Fast LC-MS/MS method for the determination of amphetamine, methamphetamine, MDA, MDMA, MDEA, MBDB and PMA in urine.  

PubMed

A fast method was designed for the simultaneous determination of amphetamine (A), methamphetamine (MA), PMA, MDA, MDMA, MDEA and MBDB in urine. The drugs were analysed by LC (ESI)-MS/MS, after a simple liquid-liquid extraction in the presence of the deuterated analogues. Reverse phase separation on an Atlantis dC18 Intelligent Speed column was achieved in less than 4 min under gradient conditions, and the total run time was 8 min. The method was fully validated, including linearity (1-1000 ng/mL for A, MDMA, MDEA and MBDB; 2-1000 ng/mL for MDA and PMA; 1-200 ng/mL for MA; r2>0.99 for all compounds), recovery (>80%), within-day and between-day precision and accuracy (CV and MRE<12.7% for intermediate level and ULOQ, and <17.2% for LLOQ), limit of detection (0.2 ng/mL for MDMA, MDEA and MBDB; 0.5 ng/mL for A, MA and PMA; 1 ng/mL for MDA) and quantitation (1 ng/mL for A, MA, MDMA, MDEA and MBDB; 2 ng/mL for MDA and PMA) and relative ion intensities. No matrix effect was observed. The procedure proved to be sensitive, specific and rapid, and was applied to real forensic cases. PMID:17097252

Concheiro, Marta; Simes, Susana Maria dos Santos Sadler; Quintela, Oscar; de Castro, Ana; Dias, Mrio Joo Rodrigues; Cruz, Angelines; Lpez-Rivadulla, Manuel

2007-08-24

76

Effects of MDMA, MDA and MDEA on blood pressure, heart rate, locomotor activity and body temperature in the rat involve alpha-adrenoceptors.  

PubMed

The effects of injection of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and N-ethyl-3,4-methylenedioxyamphetamine (MDEA) (all 20 mg kg(-1)) on blood pressure, heart rate, core body temperature and locomotor activity in conscious rats were investigated using radiotelemetry. MDMA and MDA produced a prolonged increase in both systolic and diastolic pressures, with MDA causing the most marked rise. MDEA produced a transient but nonsignificant fall in diastolic pressure. The pressor response produced by MDA was accompanied by bradycardia. All three amphetamine derivatives caused an initial hypothermic response; however, MDA also produced a subsequent hyperthermia, and the speed of recovery from hypothermia was MDA>MDMA>MDEA. The alpha2A-adrenoceptor antagonist 2-((4,5-dihydro-1H-imidazol-2-yl)methyl)-2,3-dihydro-1-methyl-1H-isoindole (BRL 44408) (1 mg kg(-1)) prolonged the hypothermic response to MDMA. Only MDA induced locomotor activity when given alone, but in the presence of BRL 44408, MDMA produced increased locomotor activity. The order of potency for producing isometric contractions of rat aorta (alpha1D) and vas deferens (alpha1A) was MDA>MDMA>MDEA, with MDEA acting as an alpha1-adrenoceptor antagonist with a pK(B) of 4.79+/-0.12 (n = 4) in aorta. The order of potency for prejunctional inhibition of stimulation-evoked contractions in rat vas deferens (alpha2A-adrenoceptor mediated) was MDA>MDMA>MDEA. Blood pressure actions of the three amphetamine derivatives may be at least partly due to alpha1-adrenoceptor agonism or antagonism. The reversal of the hypothermic actions are at least partly due to alpha2A-adrenoceptor agonism since the hypothermic response was more prolonged with MDEA which exhibits low alpha2A-adrenoceptor potency, and effects of MDMA after alpha2A-adrenoceptor antagonism were similar to those of MDEA. PMID:16491100

Bexis, Sotiria; Docherty, James R

2006-04-01

77

Effects of MDMA, MDA and MDEA on blood pressure, heart rate, locomotor activity and body temperature in the rat involve ?-adrenoceptors  

PubMed Central

The effects of injection of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and N-ethyl-3,4-methylenedioxyamphetamine (MDEA) (all 20?mg?kg?1) on blood pressure, heart rate, core body temperature and locomotor activity in conscious rats were investigated using radiotelemetry. MDMA and MDA produced a prolonged increase in both systolic and diastolic pressures, with MDA causing the most marked rise. MDEA produced a transient but nonsignificant fall in diastolic pressure. The pressor response produced by MDA was accompanied by bradycardia. All three amphetamine derivatives caused an initial hypothermic response; however, MDA also produced a subsequent hyperthermia, and the speed of recovery from hypothermia was MDA>MDMA>MDEA. The ?2A-adrenoceptor antagonist 2-((4,5-dihydro-1H-imidazol-2-yl)methyl)-2,3-dihydro-1-methyl-1H-isoindole (BRL 44408) (1?mg?kg?1) prolonged the hypothermic response to MDMA. Only MDA induced locomotor activity when given alone, but in the presence of BRL 44408, MDMA produced increased locomotor activity. The order of potency for producing isometric contractions of rat aorta (?1D) and vas deferens (?1A) was MDA>MDMA>MDEA, with MDEA acting as an ?1-adrenoceptor antagonist with a pKB of 4.790.12 (n=4) in aorta. The order of potency for prejunctional inhibition of stimulation-evoked contractions in rat vas deferens (?2A-adrenoceptor mediated) was MDA>MDMA>MDEA. Blood pressure actions of the three amphetamine derivatives may be at least partly due to ?1-adrenoceptor agonism or antagonism. The reversal of the hypothermic actions are at least partly due to ?2A-adrenoceptor agonism since the hypothermic response was more prolonged with MDEA which exhibits low ?2A-adrenoceptor potency, and effects of MDMA after ?2A-adrenoceptor antagonism were similar to those of MDEA. PMID:16491100

Bexis, Sotiria; Docherty, James R

2006-01-01

78

1-Methylpiperazine-1,4-diium dipicrate  

PubMed Central

In the crystal structure of the title compound [systematic name: 1-methylpiperazine-1,4-diium bis(2,4,6-trinitrophenolate)], C5H14N2 2+2C6H2N3O7 ?, the ionic components are connected by relatively strong NH?O hydrogen bonds into centrosymmetric six-membered conglomerates, which comprise two dications and four anions. Besides Coulombic interactions, only weak CH?O interactions and some stacking between picrates (separation between the planes of ca. 3.4? but only a small overlapping) can be identified between these building blocks of the crystal structure. The piperazine ring adopts a chair conformation with the methyl substituent in the equatorial position. In the picrate anions, the twist angles of the nitro groups depend on their positions relative to the phenolate O atom: it is much smaller for the NO2 groups para to the CO? group [15.23?(9)and 3.92?(14)] than for the groups in the ortho positions [28.76?(13)39.84?(11)]. PMID:21523064

Dutkiewicz, Grzegorz; Samshuddin, S.; Narayana, B.; Yathirajan, H. S.; Kubicki, Maciej

2011-01-01

79

Heteroleptic titanium(IV) catecholato/piperazine systems and their anti-cancer properties.  

PubMed

In this paper we report the synthesis and full characterisation of a range of Ti(IV)-catecholato systems complexed to piperazine or homopiperazine salan ligands. The steric/electronic environment of the catecholate moiety has been varied and the effect this has on cytotoxicity discussed. It was observed that the 7-membered homopiperazine complexes are more stable to hydrolysis than their piperazine cousins in biological media. In general the homopiperazine complexes show higher cytotoxicity than the piperazine complexes, with the most cytotoxic complex exhibiting IC50 (?M) values of 3 0.5 ?M (HT-29) and 4 1 ?M (OVCAR). PMID:24201896

Hancock, Stuart L; Gati, Rachel; Mahon, Mary F; Tshuva, Edit Y; Jones, Matthew D

2014-01-21

80

Synthesis and Properties of Piperazine Derivatives and Their Quaternary Ammonium Amphiphilic Salts  

Microsoft Academic Search

A series of long-chain piperazine derivatives,N-alkyl-N?-methyl piperazine and their amphiphilic salts,N-alkyl-N?-ethyl-N?-methyl piperazinium bromide, and the relatedN-alkyl-N,N?-dimethyl piperazinium bromide were synthesized and characterized by1H and13C NMR and FTIR spectroscopy. Under the experimental conditions used, the NMR data showed unequivocally that quaternarization ofN-alkyl-N?-methyl piperazine by the reaction with ethyl bromide occurred exclusively at the nitrogen atom bearing the methyl group due to

L. H. Gan; G. Roshan Deen; Y. Y. Gan; C. H. Chew

1996-01-01

81

Genistein complexes with amines. Part II: ab initio study of the complexes with piperazine and triethylamine  

NASA Astrophysics Data System (ADS)

The piperazine and triethylamine complexes of genistein, exhibiting high immunosuppressant activity, were ab initio modeled at RHF/6-31G ?? level and results were compared with those obtained for genistein-morpholine complexes by X-ray, NMR, and theoretical methods. The most stable genistein-piperazine complex is formed due to hydrogen bonding of genistein's OH group at position C7 to piperazine's nitrogen atom. In the most stable genistein-triethylamine complex genistein's OH group at position C4' (position para to phenyl substituent) and trimethylamine nitrogen atom are engaged in hydrogen bond formation. The calculations confirmed our previous NMR conclusion that piperazine is more strongly complexed by genistein than is morpholine or triethylamine. The theoretical 13C NMR spectra correlate fairly well with the experimental spectra.

Mazurek, A. P.; Dobrowolski, J. Cz.; Sadlej, J.; Bednarek, E.; Kozerski, L.

2000-03-01

82

Determination of the metabolites of the new designer drugs bk-MBDB and bk-MDEA in human urine.  

PubMed

This is the first report on identifying the specific metabolites of the new designer drugs 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one (bk-MBDB) and 2-ethylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (bk-MDEA) in human urine using synthesized standards. Based on GC/MS and LC/MS, we identified N-dealkylation, demethylenation followed by O-methylation, and beta-ketone reduction as their major metabolic pathways. The quantitative analyses by LC/MS revealed that both demethylenation followed by O-methylation and beta-ketone reduction were superior to N-dealkylation and that both bk-MBDB and bk-MDEA were mainly metabolized into their corresponding 4-hydroxy-3-methoxy metabolites (4-OH-3MeO metabolites). After hydrolysis, the concentrations of 4-OH-3MeO metabolites and 3-hydroxy-4-methoxy metabolites of both bk-MBDB and bk-MDEA dramatically increased, suggesting that the metabolites mainly exist as their conjugates. PMID:19406592

Zaitsu, Kei; Katagi, Munehiro; Kamata, Hiroe T; Kamata, Tooru; Shima, Noriaki; Miki, Akihiro; Tsuchihashi, Hitoshi; Mori, Yasushige

2009-07-01

83

1-(2-Azaniumylethyl)piperazine-1,4-diium trinitrate  

PubMed Central

In the title salt, C6H18N3 3+3NO3 ?, the piperazine ring adopts a chair conformation and the ethylammonium group is equatorial relative to the piperazine ring, and in an all-trans conformation. In the crystal, strong charge-assisted NH?O hydrogen bonds link the piperazinediium trications and the nitrate anions into a three-dimensional network PMID:22199803

Rademeyer, M.

2011-01-01

84

CO2 Absorption Rate and Solubility in Monoethanolamine\\/Piperazine\\/Water  

Microsoft Academic Search

The solubility and absorption rate of carbon dioxide into monoethanolamine\\/ piperazine\\/water were measured in a wetted wall column at 40-60C. The total amine concentration was varied from 1.0 M to 5.0 M with monoethanolamine blends containing 0 to 1.2 M piperazine. CO2 solubility and solution speciation were simulated by nine equilibrium reactions. Two of the equilibrium constants were adjusted to

Gary T. Rochelle

2003-01-01

85

CO2 Absorption Rate and Solubility in Monoethanolamine\\/Piperazine\\/Water  

Microsoft Academic Search

The solubility and absorption rate of carbon dioxide into monoethanolamine\\/piperazine\\/water were measured in a wetted wall column at 4060C. The total amine concentration was varied from 1.0M to 5.0M, with monoethanolamine blends containing 0 to 1.2M piperazine. CO2 solubility and solution speciation were simulated by nine equilibrium reactions. Two of the equilibrium constants were adjusted to match literature data. The

Hongyi Dang; Gary T. Rochelle

2003-01-01

86

Synthesis and antifungal activity of novel triazole compounds containing piperazine moiety.  

PubMed

Design and synthesis of triazole library antifungal agents having piperazine side chains, analogues to fluconazole were documented. The synthesis highlighted utilization of the click chemistry on the basis of the active site of the cytochrome P450 14?-demethylase (CYP51). Their structures were characterized by (1)H-NMR, (13)C-NMR, MS and IR. The influences of piperazine moiety on in vitro antifungal activities of all the target compounds were evaluated against eight human pathogenic fungi. PMID:25090121

Wang, Yanwei; Xu, Kehan; Bai, Guojing; Huang, Lei; Wu, Qiuye; Pan, Weihua; Yu, Shichong

2014-01-01

87

Modeling and Kinetic Study on Absorption of CO 2 by Aqueous Solutions of N-methyldiethanolamine in a Modified Wetted Wall Column  

Microsoft Academic Search

To get more accurate kinetic data of the absorption of CO2 into aqueous solution of N-methyldiethanolamine, a wetted wall column was modified to more uniformly distribute the liquid on the column surface and gas in the absorbing chamber and change the length of the column. The average liquid film thickness and the liquid-phase mass transfer coefficient were measured, and a

Zhi QIAN; Kai GUO

2009-01-01

88

Pharmacological profiles of aminoindanes, piperazines, and pipradrol derivatives.  

PubMed

Aminoindanes, piperazines, and pipradrol derivatives are novel psychoactive substances found in "Ecstasy" tablets as replacements for 3,4-methylenedioxymethamphetamine (MDMA) or substances sold as "ivory wave." The pharmacology of these MDMA- and methylphenidate-like substances is poorly known. We characterized the pharmacology of the aminoindanes 5,6-methylenedioxy-2-aminoindane (MDAI), 5-iodoaminoindane (5-IAI), and 2-aminoindane (2-AI), the piperazines meta-chlorophenylpiperazine (m-CPP), trifluoromethylphenylpiperazine (TFMPP), and 1-benzylpiperazine (BZP), and the pipradrol derivatives desoxypipradrol (2-diphenylmethylpiperidine [2-DPMP]), diphenylprolinol (diphenyl-2-pyrrolidinemethanol [D2PM]), and methylphenidate. We investigated norepinephrine (NE), dopamine (DA), and serotonin (5-hydroxytryptamine [5-HT]) uptake inhibition using human embryonic kidney 293 (HEK 293) cells that express the respective human monoamine transporters (NET, DAT, and SERT). We also evaluated the drug-induced efflux of NE, DA, and 5-HT from monoamine-preloaded cells and the binding affinity to monoamine transporters and receptors, including trace amine-associated receptor 1 (TAAR1). 5-IAI and MDAI preferentially inhibited the SERT and NET and released 5-HT. 2-AI interacted with the NET. BZP blocked the NET and released DA. m-CPP and TFMPP interacted with the SERT and serotonergic receptors. The pipradrol derivatives were potent and selective catecholamine transporter blockers without substrate releasing properties. BZP, D2PM, and 2-DPMP lacked serotonergic activity and TAAR1 binding, in contrast to the aminoindanes and phenylpiperazines. In summary, all of the substances were monoamine transporter inhibitors, but marked differences were found in their DAT vs. SERT inhibition profiles, release properties, and receptor interactions. The pharmacological profiles of D2PM and 2-DPMP likely predict a high abuse liability. PMID:24486525

Simmler, Linda D; Rickli, Anna; Schramm, York; Hoener, Marius C; Liechti, Matthias E

2014-03-15

89

GC-MS studies on side chain regioisomers related to substituted methylenedioxyphenethylamines: MDEA, MDMMA, and MBDB.  

PubMed

Three regioisomeric 3,4-methylenedioxyphenethylamines having the same molecular weight and major mass spectral fragments of equal mass have been reported as drugs of abuse in forensic studies in recent years. These compounds are 3,4-methylenedioxy-N-ethylamphetamine (MDEA), 3,4-methylenedioxy-N,N-dimethylamphetamine (MDMMA), and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB). A series of seven additional side chain regioisomers have mass spectra essentially equivalent to the three controlled drug substances, all have molecular weight of 207 and major fragment ions in their electron ionization mass spectra at m/z 72 and 135/136. The trifluoroacetyl, pentafluoropropionyl, and heptafluorobutryl derivatives of the primary and secondary regioisomeric amines were evaluated in GC-MS studies. The mass spectra for these derivatives were significantly individualized, and the resulting unique fragment ions allowed for specific side chain identification. The trifluoroacetyl and heptafluorobutryl derivatives provided more specific fragment ions for molecular individualization among these regioisomeric substances. These perfluoroacyl derivatives showed reasonable resolution on the polar stationary phase Rtx-200. PMID:20875234

Awad, Tamer; Belal, Tarek; Maher, Hadir M; DeRuiter, Jack; Clark, C Randall

2010-10-01

90

Structural-chemical transformations during organic self-propagating high-temperature synthesis. Crystal structure of piperazine malonate and its crystal hydrate  

Microsoft Academic Search

An organic salt, piperazine malonate, was prepared by self-propagating high-temperature synthesis (SHS) in a solid-phase piperazine-malonic\\u000a acid (P-M) system. Triclinic crystals of piperazine malonate (PM) hydrate (I) were isolated from an aqueous solution. Monoclinic\\u000a crystals of anhydrous piperazine malonate (2) were isolated from a solution in DMSO. Crystals 1 and 2 were studied by X-ray\\u000a structural analysis. Structures 1 and

V. I. Ponomarev; E. G. Klimchuk; A. G. Merzhanov; O. S. Filipenko

1997-01-01

91

Survey and Down-Selection of Acid Gas Removal Systems for the Thermochemical Conversion of Biomass to Ethanol with a Detailed Analysis of an MDEA System  

SciTech Connect

The first section (Task 1) of this report by Nexant includes a survey and screening of various acid gas removal processes in order to evaluate their capability to meet the specific design requirements for thermochemical ethanol synthesis in NREL's thermochemical ethanol design report (Phillips et al. 2007, NREL/TP-510-41168). MDEA and selexol were short-listed as the most promising acid-gas removal agents based on work described in Task 1. The second report section (Task 2) describes a detailed design of an MDEA (methyl diethanol amine) based acid gas removal system for removing CO2 and H2S from biomass-derived syngas. Only MDEA was chosen for detailed study because of the available resources.

Nexant, Inc., San Francisco, California

2011-05-01

92

2:1 Complex of 4-methylphenol with piperazine, structure in the solid and solution state  

NASA Astrophysics Data System (ADS)

The title complex has been obtained from the solution of 4-methylphenol and piperazine, and the crystal structure has been determined by X-ray diffraction analysis. The complex crystallizes in space group P-1, each piperazine molecule linking two 4-methylphenol molecules via H-bonding between the amine N atoms and the phenol hydroxyl group. 1H NMR spectra indicate that the complex formed with the aid of H-bonding exists also in the solution. The proton peaks assigned to the hydroxyl and amine groups in pure 4-methylphenol and piperazine merge into one in the title complex, which implies that the H-bond between the hydroxyl O and the amine N atoms is involved in a fast proton exchange process. The ESI-MS spectrum of the solution of the title complex also provides evidence for the existence of the 2:1 complex in the solution.

Jin, Zhimin; Xu, Duanjun; Pan, Yuanjiang; Xu, Yuanzhi; Chiang, Michael Yen-Nan

2001-01-01

93

Dehydrogenation of piperazine to pyrazine on oxide surfaces under chromatographic conditions  

Microsoft Academic Search

The conversion of piperazine under pulse-chromatographic conditions on catalysts anhydrides of polyvalent acids and metal oxides of variable valence (P2O5, Cr2O3, MoO3, WO3, CuO, CoO, NiO, MoO3 + P2O5 andWO3 + B2O3 + CoO) applied on Chromsorb W was investigated. The principal reaction direction in all cases is dehydrogenation of piperazine to pyrazine (9094% yields). The most selective catalyst

A. A. Anderson; M. V. Shimanskaya

1974-01-01

94

1-Phenylpiperazine-1,4-diium tetrachloridocobalt(II)  

PubMed Central

In the title molecular salt, (C10H16N2)[CoCl4], the piperazine ring of the phenylpiperazine dication adopts a chair conformation and the phenyl ring occupies an equatorial orientation. In the tetrachloridocobaltate(II) dianion, the CoCl bond lengths for the chloride ions not accepting hydrogen bonds are significantly shorter than those for the chloride ions accepting such bonds. In the crystal, the components are linked by NH?Cl hydrogen bonds, generating [001] chains. PMID:24826100

Dhieb, Abdelhamid Chiheb; Janzen, Daron E.; Rzaigui, Mohamed; Smirani Sta, Wajda

2014-01-01

95

The acute effect in rats of 3,4-methylenedioxyethamphetamine (MDEA, "eve") on body temperature and long term degeneration of 5-HT neurones in brain: a comparison with MDMA ("ecstasy").  

PubMed

Administration of a single dose of the recreationally used drug 3,4-methylenedioxyethamphetamine (MDEA or "eve") to Dark Agouti rats resulted in an acute dose-dependent hyperthermic response. The peak effect and duration of hyperthermia of a dose of MDEA of 35 mg/kg intraperitoneally was similar to a dose of 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") of 15 mg/kg intraperitoneally. Seven days later this dose of MDMA produced a marked (approximately 50%) loss of 5-HT and its metabolite 5-HIAA in cortex, hippocampus and striatum and a similar loss of [3H]-paroxetine binding in cortex: these losses reflecting the MDMA-induced neurotoxic degeneration of 5-HT nerve endings. In contrast, administration of MDEA (15, 25 or 35 mg/kg), even at the highest dose, produced only a 20% loss in cortex and hippocampus and no decrease in striatum. The neurotoxic effect of MDEA was only weakly dose-dependent. Neither MDEA (35 mg/kg) nor MDMA (15 mg/kg) altered striatal dopamine content 7 days later. MDEA appeared to have about half the potency of MDMA in inducing acute hyperthermia and 25% of the potency in inducing degeneration of cerebral 5-HT neurones. However since higher doses of MDEA (compared to MDMA) are probably necessary to induce mood changing effects, these data do not support any contention that this compound is a "safer" recreational drug than MDMA in terms of either acute toxicity or long term neurodegeneration. PMID:10401727

Colado, M I; Granados, R; O'Shea, E; Esteban, B; Green, A R

1999-06-01

96

Simultaneous determination of amphetamine, methamphetamine, methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), and methylenedioxyethylamphetamine (MDEA) enantiomers by GC-MS.  

PubMed

A method is described for the simultaneous determination of the ratio of l- and d-enantiomers of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) in urine. The assay uses liquid-liquid extraction followed by derivatization with trifluoroacetyl-l-prolyl chloride (l-TPC) and analysis by gas chromatography-mass spectrometry. The assay was developed using prepared samples containing varying concentrations of each of the analytes over a range of percentages of each enantiomer. Results showed the method to provide accurate and reliable results in samples containing > or = 10 ng/mL amphetamine and methamphetamine and > or = 25 ng/mL MDA, MDMA, and MDEA. The assay was used to analyze urine samples from subjects of a controlled MDMA study. Results for each of the eight subjects showed a greater percentage of the l-enantiomer of MDMA initially, and the percentage increased with time postdose. Analysis of the metabolite MDA revealed that the proportion of d-enantiomer was initially greater than the l-enantiomer followed by a gradual increase in the proportion of l-enantiomer until it exceeded the amount of the d-enantiomer. In all cases, the l-MDA exceeded the d-MDA within the first 36 h postdose. PMID:10517560

Hensley, D; Cody, J T

1999-10-01

97

Application of ORAL.screen saliva drug test for the screening of methamphetamine, MDMA, and MDEA incorporated in hair.  

PubMed

By the use of a one-step immunoassay drug test for oral fluid, a convenient and fairly sensitive screening method has been devised for methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) incorporated in hair. These drugs, in a 10-mg portion of hair, were extracted into 5M HCl/methanol (1:20, v/v), and the extract reconstituted in 100 micro L water was assayed with the saliva drug test ORAL.screen trade mark. The limits of detection were 0.5 ng/mg hair for d-MA, 0.8 ng/mg for dl-MDMA, and 1.0 ng/mg for dl-MDEA. The results are in good agreement with those of gas chromatography-mass spectrometry (GC-MS) determination. Although all positive results must be confirmed by either GC-MS or a specific alternative methodology, this method provided a simple screening, suitable for drug enforcement purposes, while requiring only a 10-mg hair specimen. PMID:15068568

Miki, Akihiro; Katagi, Munehiro; Shima, Noriaki; Tsuchihashi, Hitoshi

2004-03-01

98

Antiproliferative and erythroid differentiation of piperazine and triphenyl derivatives against k-562 human chronic myelogenous leukemia.  

PubMed

Five piperazine derivatives (S)-4-benzyl-1-(4-bromo-3-methylphenyl)-2 methylpiperazine (A), (S)-1-benzyl-3-isobutylpiperazine-2,5-dione (B), (S)-1-benzyl-3 methylpiperazine-2,5-dione (C), (S)-1,3-dibenzylpiperazine-2,5-dione (D), (E)-1-(3-methyl 4-((E)-3-(2-methylpropylidene) piperazin-1-yl) phenyl)-2-(2 methylpropylidene) piperazine (E) and triphenyl derivative ammonium 2-((2,3',3''-trimethyl-[1,1':4',1''-terphenyl]-4 yl)oxy)acetate (F) were tested for inhibition of K-562 cell proliferation and for induction of erythroid differentiation. Among them, two piperazine and one triphenyl derivatives, compounds A, E, and F inhibited the proliferation of the K562 cell lines exhibiting inhibition concentration 50 (IC50) (IC50) of values 30.101.6, 4.600.4 and 25.701.10 ?g ml(-1), respectively. If compound A and F were added to suboptimal concentrations of the established anticancer drugs cytosine arabinoside or mithramycin, pronounced synergic effects were observed. PMID:23898056

Saab, Antoine Michael; Dobmeier, Michael; Koenig, Burkhard; Fabri, Enrica; Finotti, Alessia; Borgatti, Monica; Lampronti, Ilaria; Bernardi, Francesco; Efferth, Thomas; Gambari, Roberto

2013-08-01

99

Integration of enabling methods for the automated flow preparation of piperazine-2-carboxamide.  

PubMed

Here we describe the use of a new open-source software package and a Raspberry Pi() computer for the simultaneous control of multiple flow chemistry devices and its application to a machine-assisted, multi-step flow preparation of pyrazine-2-carboxamide - a component of Rifater(), used in the treatment of tuberculosis - and its reduced derivative piperazine-2-carboxamide. PMID:24778715

Ingham, Richard J; Battilocchio, Claudio; Hawkins, Joel M; Ley, Steven V

2014-01-01

100

Thermal decomposition reactions of cotton fabric treated with piperazine-phosphonates derivatives as a flame retardant  

Technology Transfer Automated Retrieval System (TEKTRAN)

There has been a great scientific interest in exploring the great potential of the piperazine-phosphonates in flame retardant (FR) application on cotton fabric by investigating the thermal decomposition of cotton fabric treated with them. This research tries to understand the mode of action of the t...

101

Integration of enabling methods for the automated flow preparation of piperazine-2-carboxamide  

PubMed Central

Summary Here we describe the use of a new open-source software package and a Raspberry Pi computer for the simultaneous control of multiple flow chemistry devices and its application to a machine-assisted, multi-step flow preparation of pyrazine-2-carboxamide a component of Rifater, used in the treatment of tuberculosis and its reduced derivative piperazine-2-carboxamide. PMID:24778715

Ingham, Richard J; Battilocchio, Claudio; Hawkins, Joel M

2014-01-01

102

1,2-cyclic sulfamidates as versatile precursors to thiomorpholines and piperazines.  

PubMed

[reaction: see text] 1,2-Cyclic sulfamidates undergo regiospecific nucleophilic displacement with either methyl thioglycolate or alpha-amino esters, followed by lactamization (thermal, base-mediated, or cyanide-catalyzed), to give thiomorpholin-3-ones and piperazin-2-ones. PMID:12633078

Williams, Andrew J; Chakthong, Suda; Gray, Diane; Lawrence, Ron M; Gallagher, Timothy

2003-03-20

103

The mechanism of action of piperazine-phosphonates derivatives in cotton fabric  

Technology Transfer Automated Retrieval System (TEKTRAN)

Piperazine-phosphonates additives are known to be very effective flame retardants on different polymeric systems, especially cotton cellulose. In order to understand their mechanism of action, we carried out the investigation of their thermal behavior on cotton fabric by, first, employing the attenu...

104

The influences of piperazine-phosphonates derivatives on flame retardancy and thermal behaviors of cotton cellulose  

Technology Transfer Automated Retrieval System (TEKTRAN)

In an effort to create the environmentally-friendly flame retardants (FRs) for cotton cellulose, two phosphoramidates derivatives, tetraethyl piperazine-1,4-diyldiphosphonate (PDP) and diethyl 4-methylpiperazin-1-ylphosphoramidate (PAP), have been developed. Both were synthesized in high yield and ...

105

Theoretical study of differential enthalpy of absorption of CO2 with MEA and MDEA as a function of temperature.  

PubMed

Temperature dependent correlations for enthalpy of deprotonation, carbamate formation, and heat of absorption of the overall reaction between aqueous MEA and MDEA and gaseous CO2 are calculated on the basis of computational chemistry based ln K values input to the Gibbs-Helmholtz equation. Temperature dependency of reaction equilibrium constants for deprotonation and carbamate formation reactions is calculated with the SM8T continuum solvation model coupled with density functional theoretical calculations at the B3LYP/6-311++G(d,p) level of theory. Calculated reaction equilibrium constants and enthalpies of individual reactions and overall heat of absorption are compared against experimental data in the temperature range 273.15-373 K. Temperature dependent correlations for different reaction equilibrium constants and enthalpies of reactions are given. These correlated results can be used in thermodynamic models such as UNIQUAC and NRTL for better understanding of post-combustion CO2 capture solvent chemistry. PMID:23855311

Gupta, Mayuri; da Silva, Eirik F; Hartono, Ardi; Svendsen, Hallvard F

2013-08-15

106

Ecstasy (MDMA, MDA, MDEA, MBDB) consumption, seizures, related offences, prices, dosage levels and deaths in the UK (1994-2003).  

PubMed

In the last decade, a global trend of escalating ecstasy (MDMA, MDA, MDEA, MBDB) use was observed. Mentions on medical death certificates, last year's ecstasy use, number of drug offenders, seizures, prices and dosage levels figures were used for this descriptive and correlational study. Figures (1994-2003) were taken from the UK General Mortality Registers, from the Home Office Statistical Bulletins, from the British Crime Survey and from those reported to both the National Crime Intelligence and Forensic Science Services. A total of 394 ecstasy deaths mentions were here identified from the UK; in 42% of cases ecstasy was the sole drug mentioned. Overall, number of fatalities showed a year-per-year increase and positively correlated with: prevalence of last year's use (p < 0.01); number of offenders (p < 0.01) and number of seizures (p < 0.01) but negatively correlated with ecstasy price (p < 0.05). Price negatively correlated with: prevalence of last year's use (p < 0.001) and number of seizures (p < 0.01); but positively correlated with average MDMA dosage per tablet (p < 0.01). MDA, MDEA and MBDB accounted for a significant proportion of tablets only up to 1997, but not afterwards. Increasing production with a concomitant decrease in ecstasy price may have facilitated an increase in consumption levels and this, in turn, may have determined an increase in number of ecstasy deaths mentions. Only medical death certificates and not coroners' reports at the end of their inquests were here analysed; no data were available in respect of other drugs use and toxicology results. PMID:16574720

Schifano, Fabrizio; Corkery, John; Deluca, Paolo; Oyefeso, Adenekan; Ghodse, A Hamid

2006-05-01

107

Differences in binding affinities of MDA, MDMA, MDEA, Amphetamine, Methamphetamine, and their deuterated analogues to solid-phase extraction cartridges.  

PubMed

This study evaluated the potential for partial separation of drugs from their deuterated internal standards using Cerex() Polycrom CLIN II solid-phase extraction (SPE) cartridges. After elution from the column and derivatization, gas chromatography-mass spectrometry results showed that the target compound eluted from the SPE cartridge prior to its deuterated form. This elution separation effect was greater for 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine (MAMP) than for the other drugs studied. When the drugs were eluted in 0.5 mL increments from a 50 mg sorbent bed, no drug appeared in the first fraction. The drug to internal standard ratios (expected value 1.00) for subsequent fractions collected were 1.30, 1.07, and 0.83 for MDA/MDA-d(5); 1.65, 1.18, 0.67, and 0.56 for MDMA/MDMAd(5); and 1.37, 1.18, and 0.95 for MDEA/MDEA-d(6). For d-AMP and d-MAMP, the expected ratio was 0.40. The subsequent ratios were 0.63, 0.46, 0.35, and 0.34 for d-AMP/d-AMP-d(11); and 1.00, 0.59, 0.25, and 0.18 for d-MAMP/d-MAMP-d(14). The affinity of d-MAMPd(14) was shown to be greater than that of d-MAMP-d(5), and deuteration at the propyl end of the molecule was shown to increase binding more than deuteration on the phenyl group. PMID:21219698

Romberg, R W; Ntamack, A G; Blacik, L J; Kazarian, C M; Snyder, J Jacob; Welsh, E R

2011-01-01

108

Development and validation of a disk solid phase extraction and gas chromatography-mass spectrometry method for MDMA, MDA, HMMA, HMA, MDEA, methamphetamine and amphetamine in sweat.  

PubMed

We describe the development and validation of a method for the simultaneous quantification of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), 3-hydroxy-4-methoxymethamphetamine (HMMA), 3-hydroxy-4-methoxyamphetamine (HMA), 3,4-methylenedioxyethylamphetamine (MDEA), methamphetamine (MAMP) and amphetamine (AMP) in sweat. Drugs were eluted from PharmChek sweat patches with sodium acetate buffer, extracted with disk solid phase extraction and analyzed using GC/MS-EI with selected ion monitoring. Limits of quantification (LOQ) for MDMA, MDEA, MAMP and AMP were 2.5 ng/patch, and 5 ng/patch for MDA, HMA and HMMA. This fully validated procedure was more sensitive than previously published analytical methods and permitted the simultaneous analysis of multiple amphetamine analogs in human sweat. PMID:17369000

De Martinis, Bruno S; Barnes, Allan J; Scheidweiler, Karl B; Huestis, Marilyn A

2007-06-01

109

Development and Validation of a Disk Solid Phase Extraction and Gas Chromatography-Mass Spectrometry Method for MDMA, MDA, HMMA, HMA, MDEA, Methamphetamine and Amphetamine in Sweat  

PubMed Central

We describe the development and validation of a method for the simultaneous quantification of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), 3-hydroxy-4-methoxymethamphetamine (HMMA), 3-hydroxy-4-methoxyamphetamine (HMA), 3,4-methylenedioxyethylamphetamine (MDEA), methamphetamine (MAMP) and amphetamine (AMP) in sweat. Drugs were eluted from PharmChek sweat patches with sodium acetate buffer, extracted with disk solid phase extraction and analyzed using GC/MS-EI with selected ion monitoring. Limits of quantification (LOQ) for MDMA, MDEA, MAMP and AMP were 2.5 ng/patch, and 5 ng/patch for MDA, HMA and HMMA. This fully validated procedure was more sensitive than previously published analytical methods and permitted the simultaneous analysis of multiple amphetamine analogs in human sweat. PMID:17369000

De Martinis, Bruno S.; Barnes, Allan J.; Scheidweiler, Karl B.; Huestis, Marilyn A.

2009-01-01

110

Novel 1-(2-aryl-2-adamantyl)piperazine derivatives with antiproliferative activity.  

PubMed

Novel 1-(2-aryl-2-adamantyl)piperazine derivatives have been synthesized and evaluated invitro for their antitumor properties against HeLa cervical carcinoma, MDA MB 231 breast cancer, MIA PaCa2 pancreatic cancer, and NCI H1975 non-small cell lung cancer. The parent piperazine 6 was found to exhibit a reasonable activity toward the HeLa and MDA MB 231 tumor cell lines (IC50= 9.2 and 8.4 ??, respectively). Concurrent benzene ring C4-fluorination and piperidine acetylation of the piperazino NH of compound 6 resulted in the most active compound 13 of the series in both of the above cell lines (IC50=8.4 and 6.8 ??, respectively). Noticeably, compounds 6 and 13 exhibited a significantly low cytotoxicity level over the normal human cells HUVEC (Human Umbilical Vein Endothelial Cells) and NHDF (Normal Human Dermal Fibroblasts). PMID:25703296

Fytas, Christos; Zoidis, Grigoris; Tsotinis, Andrew; Fytas, George; Khan, Mohsin A; Akhtar, Samar; Rahman, Khondaker M; Thurston, David E

2015-03-26

111

Synthesis and antitubercular evaluation of 4-carbonyl piperazine substituted 1,3-benzothiazin-4-one derivatives.  

PubMed

Tuberculosis (TB) remains a major human health problem. New therapeutic antitubercular agents are urgent needed to control the global tuberculosis pandemic. We synthesized a new series of 4-carbonyl piperazine substituted 1,3-benzothiazin-4-one derivatives and evaluated their anti-mycobacterial activities against Mycobacterium tuberculosis H37Ra as well as their druggabilities. The results showed that most of these derivatives, especially the compounds with simple alkyl side chains, exhibited good antitubercular activities and favorable aqueous solubilities with no obvious cytotoxicity. It suggested that the 4-carbonyl piperazine substituents in benzothiazinone scaffold were well tolerated, in which the compound 8h, with an antitubercular activity of MIC 0.008?M, exhibited an excellent aqueous solubility of 104?g/mL, which was 100-fold better than the potent DprE1 inhibitor Comp.1 (BTZ038), also more soluble than PBTZ169. PMID:25754492

Peng, Cui-Ting; Gao, Chao; Wang, Ning-Yu; You, Xin-Yu; Zhang, Li-Dan; Zhu, Yong-Xia; Xv, Ying; Zuo, Wei-Qiong; Ran, Kai; Deng, Hong-Xia; Lei, Qian; Xiao, Kun-Jie; Yu, Luo-Ting

2015-04-01

112

4-(2-Azaniumylethyl)piperazin-1-ium bis(perchlorate)  

PubMed Central

In the title compound, C6H17N3 2+2ClO4 ?, the piperazine ring adopts a chair conformation with the ethylammonium fragment occupying an equatorial position. In the crystal, the dications and perchlorate anions are linked through NH?O hydrogen bonding and weak CH?O hydrogen bonding into a three-dimensional supramolecular network. PMID:22064357

Reisi, Mohammad Reza; Saleh Salga, Muhammad; Khaledi, Hamid; Mohd Ali, Hapipah

2011-01-01

113

Equilibrium solubility of carbon dioxide in the amine solvent system of (triethanolamine + piperazine + water)  

Microsoft Academic Search

In this study, a new set of data for the equilibrium solubility of carbon dioxide in the amine solvent system that consists of triethanolamine (TEA), piperazine (PZ), and water is presented. Equilibrium solubility values were obtained at T=(313.2, 333.2, and 353.2)K and pressures up to 153kPa using the vapour-recirculation equilibrium cell. The TEA concentrations in the considered ternary (solvent) mixture

Pei-Yuan Chung; Allan N. Soriano; Rhoda B. Leron; Meng-Hui Li

2010-01-01

114

Kinetics and modeling of carbon dioxide absorption into aqueous solutions of piperazine  

Microsoft Academic Search

In this work, the kinetics of the reaction between CO2 and aqueous piperazine (PZ) have been estimated over the temperature range of 298313K from the absorption data obtained in a wetted wall contactor. The absorption data are obtained for the PZ concentrations of 0.20.8kmolm-3 and for CO2 partial pressures up to 5kPa. A coupled mass transfer-kinetics-equilibrium mathematical model based on

Arunkumar Samanta; S. S. Bandyopadhyay

2007-01-01

115

Bis{4-[(1,3-benzodioxol-5-yl)methyl]piperazin-1-yl}methane  

PubMed Central

In the title compound, C25H32N4O4, both piperazine rings adopt a chair conformation. One of dioxolane ring systems is essentially planar [dihedral angle = 0.9?(2)] while the other adopts a slightly disordered envelope conformation, the mean plane of the dioxolane ring being twisted by 3.6?(2) from that of the benzene ring. The dihedral angle between the benzene rings is 69.9?(5). No classical hydrogen bonds were observed. PMID:24454103

Kavitha, Channappa N.; Jasinski, Jerry P.; Anderson, Brian J.; Yathirajan, H. S.; Kaur, Manpreet

2013-01-01

116

Benzothiophene piperazine and piperidine urea inhibitors of fatty acid amide hydrolase (FAAH)  

PubMed Central

The synthesis and structureactivity relationships (SAR) of a series of benzothiophene piperazine and piperidine urea FAAH inhibitors is described. These compounds inhibit FAAH by covalently modifying the enzymes active site serine nucleophile. Activity-based protein profiling (ABPP) revealed that these urea inhibitors were completely selective for FAAH relative to other mammalian serine hydrolases. Several compounds showed in vivo activity in a rat complete Freunds adjuvant (CFA) model of inflammatory pain. PMID:19386497

Johnson, Douglas S.; Ahn, Kay; Kesten, Suzanne; Lazerwith, Scott E.; Song, Yuntao; Morris, Mark; Fay, Lorraine; Gregory, Tracy; Stiff, Cory; Dunbar, James B.; Liimatta, Marya; Beidler, David; Smith, Sarah; Nomanbhoy, Tyzoon K.; Cravatt, Benjamin F.

2011-01-01

117

Benzothiophene piperazine and piperidine urea inhibitors of fatty acid amide hydrolase (FAAH).  

PubMed

The synthesis and structure-activity relationships (SAR) of a series of benzothiophene piperazine and piperidine urea FAAH inhibitors is described. These compounds inhibit FAAH by covalently modifying the enzyme's active site serine nucleophile. Activity-based protein profiling (ABPP) revealed that these urea inhibitors were completely selective for FAAH relative to other mammalian serine hydrolases. Several compounds showed in vivo activity in a rat complete Freund's adjuvant (CFA) model of inflammatory pain. PMID:19386497

Johnson, Douglas S; Ahn, Kay; Kesten, Suzanne; Lazerwith, Scott E; Song, Yuntao; Morris, Mark; Fay, Lorraine; Gregory, Tracy; Stiff, Cory; Dunbar, James B; Liimatta, Marya; Beidler, David; Smith, Sarah; Nomanbhoy, Tyzoon K; Cravatt, Benjamin F

2009-05-15

118

Comparison of impact of the different hydrophilic carriers on the properties of piperazine-containing drug  

Microsoft Academic Search

The objective of this study was to determine the impact of a series of nonionic surfactants on the solubility of piperazine-containing drug (meclizine, MZ) in comparison to that of natural cyclodextrins (?-CD and ?-CD) and dimethyl-?-cyclodextrin (DM-?-CD). The solubility of the drug was studied in either CDs solutions or nonionic surfactant solutions. Three classes of nonionic surfactants were used namely;

Mahrous Osman Ahmed

2001-01-01

119

Investigations on the stereoselectivity of the phase II metabolism of the 3,4-methylenedioxyethylamphetamine (MDEA) metabolites 3,4-dihydroxyethylamphetamine (DHEA) and 4-hydroxy-3-methoxyethylamphetamine (HMEA).  

PubMed

Different elimination was reported for the two enantiomers of the designer drug 3,4-methylenedioxyethylamphetamine (MDEA) in vivo. In the present work, the enantioselectivity of glucuronidation and sulfation of the MDEA phase I metabolites 3,4-dihydroxyethylamphetamine (DHEA) and 4-hydroxy-3-methoxyethylamphetamine (HMEA) was investigated. First, glucuronide standards were synthesized using rat liver microsomes. Incubations were performed with recombinant human UDP-glucuronyltransferases (UGT) and pooled human liver microsomes (pHLM) for glucuronidation and using recombinant human sulfotransferases (SULT) and pooled human liver cytosol (pHLC) for sulfation. Product formation experiments were performed by quantification of the phase II metabolites using liquid chromatography-high-resolution mass spectrometry. Additionally, substrate depletion experiments were conducted by gas chromatography-mass spectrometry after chiral derivatization for sulfation. UGT2B7, 2B15, and 2B17 were involved in glucuronidation of HMEA and SULT1A1 and SULT1A3 and SULT1A3 and SULT1E1 in the sulfation of DHEA and HMEA, respectively. SULTs provided much higher affinity, whereas UGTs showed higher capacities. Marked stereoselectivity could be observed for UGT2B15, UGT2B17, and pHLM toward S-HMEA, for SULT1A3 and pHLC toward S-DHEA and for SULT1A3 and pHLC toward R-HMEA. In conclusion, the phase II metabolism might also contribute to the observed different pharmacokinetic properties of MDEA. PMID:22564759

Schwaninger, Andrea E; Meyer, Markus R; Zapp, Josef; Maurer, Hans H

2012-07-01

120

A case of levocetirizine-induced fixed drug eruption and cross-reaction with piperazine derivatives.  

PubMed

Fixed drug eruption is an uncommon adverse drug reaction caused by delayed cell-mediated hypersensitivity. Levocetirizine is an active (R)-enatiomer of cetirizine and there have been a few reports of fixed drug eruption related to these antihistamines. We experienced a case of levocetirizine-induced fixed drug eruption and cross-reaction with other piperazine derivatives confirmed by patch test. A 73-year-old female patient presented with recurrent generalized itching, cutaneous bullae formation, rash and multiple pigmentation at fixed sites after taking drugs for common cold. She took bepotastine besilate (Talion) and levocetirizine (Xyzal) as antihistamine. She took acetaminophen, pseudoephedrine 60 mg / triprolidine 2.5 mg (Actifed), dihydrocodeinebitartrate 5 mg / di-methylephedrine hydrochloride 17.5 mg / chlorpheniramine maleate 1.5 mg / guaifenesin 50 mg (Codening) and aluminium hydroxide 200 mg / magnesium carbonate 120 mg (Antad) at the same time. Patch test was done with suspected drugs and the result was positive with levocetirizine. We additionally performed patch test for other antihistamines such as cetirizine, hydroxyzine, fexofenadine and loratadine. Piperazine derivatives (cetirizine and hydroxyzine) were positive, but piperidine derivatives (fexofenadine and loratadine) were negative to patch test. There was no adverse drug reaction when she was challenged with fexofenadine. We report a case of levocetirizine-induced fixed drug eruption confirmed by patch test. Cross-reactions were only observed in the piperazine derivatives and piperidine antihistamine was tolerant to the patient. PMID:24260733

Kim, Mi-Yeong; Jo, Eun-Jung; Chang, Yoon-Seok; Cho, Sang-Heon; Min, Kyung-Up; Kim, Sae-Hoon

2013-10-01

121

A case of levocetirizine-induced fixed drug eruption and cross-reaction with piperazine derivatives  

PubMed Central

Fixed drug eruption is an uncommon adverse drug reaction caused by delayed cell-mediated hypersensitivity. Levocetirizine is an active (R)-enatiomer of cetirizine and there have been a few reports of fixed drug eruption related to these antihistamines. We experienced a case of levocetirizine-induced fixed drug eruption and cross-reaction with other piperazine derivatives confirmed by patch test. A 73-year-old female patient presented with recurrent generalized itching, cutaneous bullae formation, rash and multiple pigmentation at fixed sites after taking drugs for common cold. She took bepotastine besilate (Talion) and levocetirizine (Xyzal) as antihistamine. She took acetaminophen, pseudoephedrine 60 mg / triprolidine 2.5 mg (Actifed), dihydrocodeinebitartrate 5 mg / di-methylephedrine hydrochloride 17.5 mg / chlorpheniramine maleate 1.5 mg / guaifenesin 50 mg (Codening) and aluminium hydroxide 200 mg / magnesium carbonate 120 mg (Antad) at the same time. Patch test was done with suspected drugs and the result was positive with levocetirizine. We additionally performed patch test for other antihistamines such as cetirizine, hydroxyzine, fexofenadine and loratadine. Piperazine derivatives (cetirizine and hydroxyzine) were positive, but piperidine derivatives (fexofenadine and loratadine) were negative to patch test. There was no adverse drug reaction when she was challenged with fexofenadine. We report a case of levocetirizine-induced fixed drug eruption confirmed by patch test. Cross-reactions were only observed in the piperazine derivatives and piperidine antihistamine was tolerant to the patient. PMID:24260733

Kim, Mi-Yeong; Jo, Eun-Jung; Chang, Yoon-Seok; Cho, Sang-Heon; Min, Kyung-Up

2013-01-01

122

Multimetallic assemblies using piperazine-based dithiocarbamate building blocks.  

PubMed

Treatment of cis-[RuCl2(dppm)2] (dppm = bis(diphenylphosphino)methane) with dithiocarbamates, NaS2CNR2 (R = Me, Et) and [H2NC5H10][S2CNC5H10], yields cations [Ru(S2CNR2)2(dppm)2](+) and [Ru(S2CNC5H10)2(dppm)2](+), respectively. The zwitterions S2CNC4H8NHR (R = Me, Et) react with the same metal complex in the presence of base to yield [Ru(S2CNC4H8NR)(dppm)2](+). Piperazine or 2,6-dimethylpiperazine reacts with carbon disulfide to give the zwitterionic dithiocarbamate salts H2NC4H6(R2-3,5)NCS2 (R = H; R = Me), which form the complexes [Ru(S2CNC4H6(R2-3,5)NH2)(dppm)2](2+) on reaction with cis-[RuCl2(dppm)2]. Sequential treatment of [Ru(S2CNC4H8NH2)(dppm)2](2+) with triethylamine and carbon disulfide forms the versatile metalla-dithiocarbamate complex [Ru(S2CNC4H8NCS2)(dppm)2] which reacts readily with cis-[RuCl2(dppm)2] to yield [{Ru(dppm)2}2(S2CNC4H8NCS2)]. Reaction of [Ru(S2CNC4H8NCS2)(dppm)2] with [Os(CH=CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] (BTD = 2,1,3-benzothiadiazole), [Pd(C6H4CH2NMe2)Cl]2, [PtCl2(PEt3)2], and [NiCl2(dppp)] (dppp = 1,3-bis(diphenylphosphino)propane) results in the heterobimetallic complexes [(dppm)2Ru(S2CNC4H8NCS2)ML(n))](m+) (ML(n) = Os(CH=CHC6H4Me-4)(CO)(PPh3)2](+), m = 1; ML(n) = Pd(C,N-C6H4CH2NMe2), m = 1; ML(n) = Pt(PEt3)2, m = 2; ML(n) = Ni(dppp), m = 2). Reaction of [NiCl2(dppp)] with H2NC4H8NCS2 yields the structurally characterized compound, [Ni(S2CNC4H8NH2)(dppp)](2+), which reacts with base, CS2, and cis-[RuCl2(dppm)2] to provide an alternative route to [(dppm)2Ru(S2CNC4H8NCS2)Ni(dppp)](+). A further metalla-dithiocarbamate based on cobalt, [CpCo(S2CNC4H8NH2)(PPh3)](2+), is formed by treatment of CpCoI2(CO) with S2CNC4H8NH2 followed by PPh3. Further reaction with NEt3, CS2, and cis-[RuCl2(dppm)2] yields [(Ph3P)CpCo(S2CNC4H8NCS2)Ru(dppm)2](2+). Heterotrimetallic species of the form [{(dppm)2Ru(S2CNC4H8NCS2)}2M](2+) result from the reaction of [Ru(S2CNC4H8NCS2)(dppm)2] and M(OAc)2 (where M = Ni, Cu, Zn). Reaction of [Ru(S2CNC4H8NCS2)(dppm)2] with Co(acac)3 and LaCl3 results in the formation of the compounds [{(dppm)2Ru(S2CNC4H8NCS2)}3Co](3+) and [{(dppm)2Ru(S2CNC4H8NCS2)}3La](3+), respectively. The electrochemical behavior of selected examples is also reported. PMID:18811147

Wilton-Ely, James D E T; Solanki, Dina; Knight, Edward R; Holt, Katherine B; Thompson, Amber L; Hogarth, Graeme

2008-10-20

123

Application of the Syva EMIT and Abbott TDx amphetamine immunoassays to the detection of 3,4-methylene-dioxymethamphetamine (MDMA) and 3,4-methylene-dioxyethamphetamine (MDEA) in urine.  

PubMed

MDMA and MDEA are hallucinogenic analogs of amphetamine. The need for laboratory monitoring of these substances has developed as a result of their increased recreational use. Since the Abbott TDx and Syva EMIT-d.a.u. immunoassays are commonly used tests for urine monitoring of drugs-of-abuse, the amphetamine assay of each manufacturer was assessed to determine the degree of cross-reactivity with MDMA and MDEA. Cross-reactivity was evaluated using a series of MDMA- and MDEA-spiked urine samples. Testing was performed over a two-day period with 3 runs/day and each sample run in duplicate. The Syva EMIT d.a.u. amphetamine assay was positive only at the highest concentration standard (10.0 micrograms/mL) for both MDMA and MDEA. Consequently, no further testing was performed with this assay. Calibration curves were generated for the TDx runs and percent cross-reactivity determinations were made. Precision for the TDx data was evaluated based on within-day and between-day coefficients of variation (CV). CVs for MDMA runs were below 6% for within-day and below 5% for between-day runs. Values of CV for MDEA were below 16% for both within-day and between runs; CVs were less than 2.5% for positive values. Cross-reactivity for MDMA ranged from 18% (10.00 micrograms/mL) to 118% (0.15 microgram/mL). Cross-reactivity for the MDEA standards ranged from 12% (10.00 micrograms/mL) to 47% (0.15 micrograms/mL). The presence of MDMA and/or MDEA in samples resulting in a negative EMIT-d.a.u. test and a positive TDx test was confirmed by GC/MS analysis.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1973747

Kunsman, G W; Manno, J E; Cockerham, K R; Manno, B R

1990-01-01

124

Use of dynamically coated capillaries for the routine analysis of methamphetamine, amphetamine, MDA, MDMA, MDEA, and cocaine using capillary electrophoresis.  

PubMed

A rapid, accurate, precise, reproducible, economical, and environmentally gentle method using capillary electrophoresis (CE) is presented for the routine analysis of methamphetamine, amphetamine, MDA, MDMA, MDEA, and cocaine in seized drugs. The methodology uses a 32 cm by 50 microm capillary (length to detector 23.5 cm) with a commercially available buffer kit and diode array UV detection. Dynamic coating of the capillary surface is accomplished by flushing with base for 1 min, a proprietary polycation for 1 min, and then a proprietary polyanion for 2 min. This approach provides a relatively high and stable electroosmotic flow (EOF), even at low pHs. The background electrolyte (BGE) contains 75 mM phosphate buffer (pH 2.5) with the same polyanion as above. Using this methodology, amphetamine, methamphetamine, MDA, MDMA, MDEA, and an internal standard (n-butylamphetamine) are baseline resolved in less than 5 min. The run-to-run migration time %RSDs and peak area %RSDs are typically <0.3% and <2.1%, respectively. The day-to-day and capillary-to-capillary migration time %RSDs are <1.5% and <2.1%, respectively. The %RSDs of the relative migration times compared with the internal standard on a day-to-day and capillary-to-capillary basis are <0.2% and <0.06%, respectively. The linear dynamic range using peak areas range from 0.003 to 0.10 mg/mL. The correlation coefficients are >0.9998, with all calibration curves passing at or near the origin. Similar data are obtained for cocaine and its internal standard henyltoloxamine. None of the compounds usually encountered in illicit samples interfere with the target compound (e.g., methamphetamine and cocaine) or the internal standard. Quantitative results for synthetic mixtures and seized exhibits are in good agreement with actual values, and also with results obtained from other techniques. The relatively high EOF for the dynamically coated capillary system allows for the screening of basic, acidic, and neutral adulterants in drug seizures; identification is facilitated by the use of automated UV library searches. PMID:11569540

Lurie, I S; Bethea, M J; McKibben, T D; Hays, P A; Pellegrini, P; Sahai, R; Garcia, A D; Weinberger, R

2001-09-01

125

Electrophysiological effects of piperazine and diethylcarbamazine on Ascaris suum somatic muscle.  

PubMed Central

1 Electrophysiological recordings were made from the bag region of Ascaris suum muscle. Membrane potential and input conductance or membrane current under voltage clamp were measured. 2 In high-Cl- Ringer, bath-applied piperazine, at concentrations greater than 10(-4)M, produced a dose-dependent and reversible increase in input conductance associated with a hyperpolarizing potential. The increase in input conductance was reduced when the preparations were bathed in low-Cl- Ringer. Gamma-Aminobutyric acid (GABA) and piperazine reversal potentials were measured with a voltage clamp on the same cells using iontophoretic application of the agonists. The reversal potentials were the same and close to the predicted Nernst Cl- potential (-65 mV). When GABA and piperazine were applied simultaneously piperazine reversibly reduced the amplitude of the control outward GABA current response. It was concluded that piperazine acts as a GABA agonist of low potency on the extra-synaptic GABA receptors of the bag, mediating an increase in Cl- conductance. 3 Acetylcholine was applied iontophoretically within 100 micron of the bag region while the preparation was bathed in a low-Ca2+, low-Cl- Ringer. The response under voltage clamp was a dose-dependent inward current associated with an increase in input conductance. This response was reversibly antagonized by 3 X 10(-5)M tubocurarine, high concentrations of diethylcarbamazine (10(-3) to 10(-2)M) but not high concentrations of piperazine (10(-3) to 10(-2)M). It was concluded that there are extra-synaptic acetylcholine receptors on the bag region of Ascaris muscle and that diethylcarbamazine but not piperazine acts as an antagonist. 4 Bath-applied diethylcarbamazine (10(-4) to 2 X 10(-3)M) produced a reversible dose-dependent depolarization of the membrane potential which was associated with an increase in the amplitude and frequency of spontaneous depolarizing potentials in active preparations at 32 degrees C to 35 degrees C in high-Cl- Ringer. The excitatory action of diethylcarbamazine was not blocked by 3 X 10(-5)M tubocurarine. Diethylcarbamazine (10(-4) to 10(-3)M) had no effect on the outward current response to GABA iontophoresis. Diethylcarbamazine (10(-4) to 10(-2)M) reversibly antagonized in a dose-dependent manner the delayed rectification of the bag membrane. In a low-Ca2+, low-Cl- Ringer, diethylcarbamazine (10(-4) to 2 X 10(-3)M) reversibly antagonized the voltage-sensitive outward current of the bag. This effect was mimicked by high-K+ Ringer or perfusion with 4-aminopyridine (10(-3) to 2 X 10(-3)M). It was concluded that diethylcarbamazine did not react with the GABA receptor but antagonized a voltage-sensitive K+ conductance. PMID:7139188

Martin, R. J.

1982-01-01

126

Threaded structure and blue luminescence of (CuCN)20(Piperazine)7{ Robert D. Pike,* Kathryn E. deKrafft, Amanda N. Ley and Tristan A. Tronic  

E-print Network

Threaded structure and blue luminescence of (CuCN)20(Piperazine)7{ Robert D. Pike,* Kathryn E. de and highly luminescent 20 : 7 complex of CuCN with piperazine (Pip) was formed under aqueous conditions; its of luminescent metalorganic networks based on CuCN,9 we herein report the formation of a copper-rich network

Pike, Robert D.

127

Determination of MDMA, MDA, MDEA and MBDB in oral fluid using high performance liquid chromatography with native fluorescence detection.  

PubMed

This paper describes the analytical methodology for the determination of MDMA, MDA, MDEA and MBDB in oral fluid. After a liquid-liquid extraction, the analysis was carried out by high performance liquid chromatography (HPLC), with fluorescence detection. The detector wavelength was fixed at 285 nm for excitation and 320 nm for emission. The mobile phase, a mixture of phosphate buffer (pH=5) and acetonitrile (75:25), and the column, Kromasil 100 C8 5 microm 250 mm x 4.6mm, allowed good separation of the compounds in an isocratic mode in only 10 min. The method was validated and showed good limits of detection (2 ng/mL) and quantitation (10 ng/mL) for all the amphetamine derivatives. No interfering substances were detected. A stability study of these compounds in oral fluid stored at three different temperatures (-18, 4 and 20 degrees C) over 10 weeks was conducted, showing a time-dependent degradation of the four compounds. PMID:15944063

Concheiro, Marta; de Castro, Ana; Quintela, Oscar; Lpez-Rivadulla, Manuel; Cruz, Angelines

2005-06-10

128

GC-MS studies on the regioisomeric methoxy-methyl-phenethylamines related to MDEA, MDMMA, and MBDB.  

PubMed

Three regioisomeric 3,4-methylenedioxyphenethylamines having the same molecular weight and major mass spectral fragments of equal mass have been reported as drugs of abuse in forensic studies in recent years. These compounds are 3,4-methylenedioxy-N-ethylamphetamine (MDEA), 3,4-methylenedioxy-N-N-dimethylamphetamine (MDMMA), and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB). The mass spectra of the regioisomers (4-methoxy-3-methyl and 4-methoxy-2-methyl-phenethylamines) are essentially equivalent to the three compounds reported as drugs of abuse. This project focused on the synthesis, mass spectral characterization, and chromatographic analysis of these six regioisomeric methoxy methyl phenethylamines. Additionally, the mass spectral and chromatographic properties of these compounds will be compared to the isobaric 2,3- and 3,4-methylenedioxyphenethyl-amines of the same side chain. The six regioisomeric methoxy-methyl-phenethylamines were synthesized from commercially available starting materials. Side chain differentiation by mass spectrometry was possible after the formation of the perfluoroacyl derivatives, pentafluoropropionylamides (PFPA) and heptafluorobutrylamides (HFBA). Gas chromatographic separation on Rtx-1 was successful at resolving the perfluoroacyl derivatives of the 4-methoxy-3-methyl phenethylamines from those of the 4-methoxy-2-methyl phenethylamines. The 4-methoxy-3-methyl-phenethylamine derivatives eluted before the 4-methoxy-2-methyl-phenethylamine derivatives as both the PFPA and HFBA derivatives. PMID:19007498

Thigpen, Ashley; Awad, Tamer; Deruiter, Jack; Clark, C Randall

2008-01-01

129

Advanced Amine Solvent Formulations and Process Integration for Near-Term CO2 Capture Success  

SciTech Connect

This Phase I SBIR project investigated the economic and technical feasibility of advanced amine scrubbing systems for post-combustion CO2 capture at coal-fired power plants. Numerous combinations of advanced solvent formulations and process configurations were screened for energy requirements, and three cases were selected for detailed analysis: a monoethanolamine (MEA) base case and two advanced cases: an MEA/Piperazine (PZ) case, and a methyldiethanolamine (MDEA) / PZ case. The MEA/PZ and MDEA/PZ cases employed an advanced double matrix stripper configuration. The basis for calculations was a model plant with a gross capacity of 500 MWe. Results indicated that CO2 capture increased the base cost of electricity from 5 cents/kWh to 10.7 c/kWh for the MEA base case, 10.1 c/kWh for the MEA / PZ double matrix, and 9.7 c/kWh for the MDEA / PZ double matrix. The corresponding cost per metric tonne CO2 avoided was 67.20 $/tonne CO2, 60.19 $/tonne CO2, and 55.05 $/tonne CO2, respectively. Derated capacities, including base plant auxiliary load of 29 MWe, were 339 MWe for the base case, 356 MWe for the MEA/PZ double matrix, and 378 MWe for the MDEA / PZ double matrix. When compared to the base case, systems employing advanced solvent formulations and process configurations were estimated to reduce reboiler steam requirements by 20 to 44%, to reduce derating due to CO2 capture by 13 to 30%, and to reduce the cost of CO2 avoided by 10 to 18%. These results demonstrate the potential for significant improvements in the overall economics of CO2 capture via advanced solvent formulations and process configurations.

Fisher, Kevin S.; Searcy, Katherine; Rochelle, Gary T.; Ziaii, Sepideh; Schubert, Craig

2007-06-28

130

Utility of chloranil in assay of naphazoline, clemizole, penicillin G sodium, and piperazine.  

PubMed

A simple and sensitive spectrophotometric method is described for the assay of naphazoline, clemizole, penicillin G sodium, and piperazine. The method was based on the formation of a charge transfer complex between these drugs as n-donors and chloranil, the pi-acceptor. Conformity to Beer's law enabled the assay of dosage forms of these drugs. Compared with official methods, the results obtained were of equal accuracy. A more detailed investigation of th naphazoline-chloranil complex was made with respect to its composition, association constant, and free energy change. PMID:6110697

Belal, S; Elsayed, M A; Abdel-Hamid, M E; Abdine, H

1981-02-01

131

1,4-Dimethyl-piperazin-1-ium 3-hy-droxy-2-naphtho-ate.  

PubMed

The reaction of 1,4-dimethyl-piperazine and 3-hy-droxy-2-naphthoic acid gives the title 1:1 salt, C(6)H(15)N(2) (+)C(11)H(7)O(3) (-), with a singly protonated piperazinium cation. In the crystal, a single N-H?O hydrogen bond links the cations and anions into discrete pairs and the aromatic anions stack along the crystallographic a-axis direction. This results in layers of cations and anions alternating along the crystallographic c-axis direction. An intra-molecular O-H?O hydrogen bond is also present. PMID:22412659

Craig, Gemma E; Johnson, Carla; Kennedy, Alan R

2012-03-01

132

4-(Furan-2-carbonyl)piperazin-1-ium 3,5-dinitrobenzoate  

PubMed Central

In the cation of the title salt, C9H13N2O2 +C7H3N2O6 ?, the piperazine ring adopts a slightly distorted chair conformation. Twofold rotational disorder is exhibited by the furan ring in a 0.430?(4):0.570?(4) ratio. In the crystal, NH?O hydrogen bonds link the ions into chains along [010]. Additional weak CH?O interactions are observed, leading to a supramolecular layer parallel to (011). PMID:24940274

Kavitha, Channappa N.; Kaur, Manpreet; Jasinski, Jerry P.; Butcher, Ray J.; Yathirajan, H.S.

2014-01-01

133

4-(4-Carboxybenzyl)-1-methylpiperazin-1-ium picrate  

PubMed Central

The title compound, C13H19N2O2 +C6H2N3O7 ?, is a salt obtained by cocrystallization of 4-[(4-methylpiperazin-1-yl)methyl]benzoic acid and picric acid. The cations adopt an L-shaped conformation and are linked into chains along [010] by OH?N hydrogen bonds. The NH group of each piperazinium ring forms a hydrogen bond to the phenolate O atom of a picrate anion, and the picrate anions form face-to-face contacts with an interplanar separation of 3.023?(1)?. PMID:21582181

Li, Hongqi; Hakim Al-arique, Q. N. M.; Yathirajan, H. S.; Narayana, B.; Ramesha, A. R.

2009-01-01

134

4-(4-Carboxy-benz-yl)-1-methyl-piperazin-1-ium picrate.  

PubMed

The title compound, C(13)H(19)N(2)O(2) (+)C(6)H(2)N(3)O(7) (-), is a salt obtained by cocrystallization of 4-[(4-methyl-piperazin-1-yl)meth-yl]benzoic acid and picric acid. The cations adopt an 'L-shaped' conformation and are linked into chains along [010] by O-H?N hydrogen bonds. The NH group of each piperazinium ring forms a hydrogen bond to the phenolate O atom of a picrate anion, and the picrate anions form face-to-face contacts with an inter-planar separation of 3.023?(1)?. PMID:21582181

Li, Hongqi; Hakim Al-Arique, Q N M; Yathirajan, H S; Narayana, B; Ramesha, A R

2009-01-01

135

1,4-Dimethylpiperazin-1-ium 3-hydroxy-2-naphthoate  

PubMed Central

The reaction of 1,4-dimethylpiperazine and 3-hydroxy-2-naphthoic acid gives the title 1:1 salt, C6H15N2 +C11H7O3 ?, with a singly protonated piperazinium cation. In the crystal, a single NH?O hydrogen bond links the cations and anions into discrete pairs and the aromatic anions stack along the crystallographic a-axis direction. This results in layers of cations and anions alternating along the crystallographic c-axis direction. An intramolecular OH?O hydrogen bond is also present. PMID:22412659

Craig, Gemma E.; Johnson, Carla; Kennedy, Alan R.

2012-01-01

136

N'N'-disubstituted piperazine derivatives as antifilarial antiamoebic and spermicidal agents.  

PubMed

4 derivatives of N',N'-piperazine were tested for spectra of activity against filaria, amoeba, and sperm, in addition to bacteria. All 4 of the desubstituted piperazines stopped movements of sperms within 10 minutes at a concentration of 15.6 mg/ml. 2 of the compounds, coded R-3504 and R-3536, showed activity within 2 minutes. Antifilarial activity was exhibited by all 4 compounds within 5 minutes at 15.6 and 31.2 mg/ml against L. carinii and W. bancroft, respectively, in vitro. 3 of the compounds showed activity against E. histolytica at 5 mg/ml; and R-2916 showed antiamoebal activity at 50 mg/ml in vitro. Up to 200 mg/ml, all 4 compounds exhibited no antibacterial activity against S. typhi, S. aureus, and V. cholerae when tested in vitro. The compounds R-2768, R-3504, and R-3536 inhibited the motility of the microfilariae of W. bancrofti and L. carinii; E. histolyica; and human sperms. This was not due to cytotoxic activity but was specific activity since the compounds did not exhibit any antibacterial activity. PMID:12261318

Sonurlikar, U A; Shanker, B; Kirke, P A; Bhide, M B

1977-12-01

137

Kinetics of N-nitrosopiperazine formation from nitrite and piperazine in CO2 capture.  

PubMed

Piperazine (PZ) is an efficient amine for carbon capture systems, but it can form N-nitrosopiperazine (MNPZ), a carcinogen, from nitrogen oxides (NO(x)) in flue gas from coal or natural gas combustion. The reaction of nitrite with PZ was studied in 0.1 to 5 mol/dm(3) PZ with 0.001 to 0.8 mol CO2/mol PZ at 50 to 135 C. The reaction forming MNPZ is first order in nitrite, piperazine carbamate species, and hydronium ion. The activation energy is 84 2 kJ/mol with a rate constant of 8.5 10(3) 1.4 10(3) dm(6) mol(-2) s(-1) at 100 C. The proposed mechanism involves protonation of the carbamate species, nucleophilic attack of the carbamic acid, and formation of bicarbonate and MNPZ. These kinetics and mechanism will be useful in identifying inhibitors and other strategies to reduce nitrosamine accumulation in CO2 capture by scrubbing with PZ or other amines. PMID:23438967

Goldman, Mark J; Fine, Nathan A; Rochelle, Gary T

2013-04-01

138

Synthesis, pharmacological evaluation, and ?1 receptor interaction analysis of hydroxyethyl substituted piperazines.  

PubMed

Starting from (S)- or (R)-aspartate, three synthetic strategies were explored to prepare hydroxyethyl substituted piperazines with different substituents at the N-atoms. ? receptor affinity was recorded using receptor material from both animal and human origin. ?1 affinities determined with guinea pig brain and human RPMI 8226 tumor cell lines differed slightly but showed the same tendency. (S)-2-[4-(Cyclohexylmethyl)-1-(naphthalene-2-ylmethyl)piperazin-2-yl]ethanol (7c) revealed the highest affinity at human ?1 receptors (Ki = 6.8 nM). The potent ?1 receptor ligand 7c was able to inhibit selectively the growth of three human tumor cell lines with IC50 values in the low micromolar range. The reduced growth of the RPMI-8226 cell line was caused by apoptosis. The interaction of 7c with the ?1 receptor was analyzed in detail using the 3D homology model of the ?1 receptor. The calculated free binding energies of all hydroxyethylpiperazines nicely correlate with their recorded affinities toward the human ?1 receptor. PMID:24617836

Weber, Frauke; Brune, Stefanie; Korpis, Katharina; Bednarski, Patrick J; Laurini, Erik; Dal Col, Valentina; Pricl, Sabrina; Schepmann, Dirk; Wnsch, Bernhard

2014-04-10

139

7-O-[4-methyl piperazine-1-(2-acetyl)]-2H-1-benzopyran-2-one: a novel antifilarial lead compound  

Microsoft Academic Search

In preliminary studies we found that benzopyrones (coumarins), which are known to exert many biological activities including anti-inflammatory effect, possess promising macrofilaricidal action as well. In order to explore the possibility of combining such a macrofilaricidal activity with the microfilaricidal potential of the known piperazine pharmacophore, we synthesized a series of compounds and evaluated their antifilarial effect. In the present

R. P. Tripathi; V. K. Tiwari; S. Misra-Bhattacharya; K. Tyagi; V. M. L. Srivastava; P. K. Murthy

2003-01-01

140

Absorption of carbon dioxide by mixed piperazinealkanolamine absorbent in a plasma-modified polypropylene hollow fiber contactor  

Microsoft Academic Search

This paper examines the enhancement of hydrophobic plasma treatment on the performance of polypropylene (PP) hollow fibers in a gas absorption membrane (GAM) process using aqueous solutions of piperazine (PZ) and alkanolamine. Experiments were conducted at various gas flow rates, liquid flow rates, and absorbent concentrations. The CO2 absorption flux increased with increasing gas flow rates and absorbent concentrations. The

Su-Hsia Lin; Kuo-Lun Tung; Wei-Jie Chen; Hao-Wei Chang

2009-01-01

141

Excretion of N-mononitrosopiperazine after low level exposure to piperazine in air: effects of dietary nitrate and ascorbate  

SciTech Connect

The secondary amine piperazine may be nitrosated in vivo, following oral intake or occupational exposure by inhalation. The suspected carcinogen N-mononitrosopiperazine could be formed in the human stomach, and in part excreted in the urine. In this study, 0.4 microgram N-mononitrosopiperazine, determined by gas chromatography-Thermal Energy Analysis, was observed in the urine in one of four volunteers, at an experimental exposure by inhalation of 0.3 mg piperazine/m3. The intake of spinach and beetroot caused an increased nitrosation of piperazine, and up to 1.7 microgram N-mononitrosopiperazine was excreted in the urine in the four individuals. This excretion indicates that about 5% of the absorbed piperazine dose was converted to N-mononitrosopiperazine. With the same nitrate-rich diet, but with the addition of citrus fruits and fresh vegetables, the highest excretion was 0.6 microgram N-mononitrosopiperazine. The excretion was significantly correlated with the ratio between the maximum level of nitrite in saliva and the ascorbate level in plasma. There was also a significant interindividual variation. N,N'-Dinitrosopiperazine was not found in any sample of urine.

Bellander, T.; Osterdahl, B.G.; Hagmar, L.

1988-04-01

142

(4-(Bis(4-fluorophenyl)methyl)piperazin-1-yl)(cyclohexyl)methanone hydrochloride (LDK1229): a new cannabinoid CB1 receptor inverse agonist from the class of benzhydryl piperazine analogs.  

PubMed

Some inverse agonists of cannabinoid receptor type 1 (CB1) have been demonstrated to be anorectic antiobesity drug candidates. However, the first generation of CB1 inverse agonists, represented by rimonabant (SR141716A), otenabant, and taranabant, are centrally active, with a high level of psychiatric side effects. Hence, the discovery of CB1 inverse agonists with a chemical scaffold distinct from these holds promise for developing peripherally active CB1 inverse agonists with fewer side effects. We generated a new CB1 inverse agonist, (4-(bis(4-fluorophenyl)methyl)piperazin-1-yl)(cyclohexyl)methanone hydrochloride (LDK1229), from the class of benzhydryl piperazine analogs. This compound binds to CB1 more selectively than cannabinoid receptor type 2, with a Ki value of 220 nM. Comparable CB1 binding was also observed by analogs 1-[bis(4-fluorophenyl)methyl]-4-cinnamylpiperazine dihydrochloride (LDK1203) and 1-[bis(4-fluorophenyl)methyl]-4-tosylpiperazine hydrochloride (LDK1222), which differed by the substitution on the piperazine ring where the piperazine of LDK1203 and LDK1222 are substituted by an alkyl group and a tosyl group, respectively. LDK1229 exhibits efficacy comparable with SR141716A in antagonizing the basal G protein coupling activity of CB1, as indicated by a reduction in guanosine 5'-O-(3-thio)triphosphate binding. Consistent with inverse agonist behavior, increased cell surface localization of CB1 upon treatment with LDK1229 was also observed. Although docking and mutational analysis showed that LDK1229 forms similar interactions with the receptor as SR141716A does, the benzhydryl piperazine scaffold is structurally distinct from the first-generation CB1 inverse agonists. It offers new opportunities for developing novel CB1 inverse agonists through the optimization of molecular properties, such as the polar surface area and hydrophilicity, to reduce the central activity observed with SR141716A. PMID:25411367

Mahmoud, Mariam M; Olszewska, Teresa; Liu, Hui; Shore, Derek M; Hurst, Dow P; Reggio, Patricia H; Lu, Dai; Kendall, Debra A

2015-02-01

143

Nitrosamine formation in amine scrubbing at desorber temperatures.  

PubMed

Amine scrubbing is a thermodynamically efficient and industrially proven method for carbon capture, but amine solvents can nitrosate in the desorber, forming potentially carcinogenic nitrosamines. The kinetics of reactions involving nitrite and monoethanolamine (MEA), diethanolamine (DEA), methylethanolamine (MMEA), and methyldiethanolamine (MDEA) were determined under desorber conditions. The nitrosations of MEA, DEA, and MMEA are first order in nitrite, carbamate species, and hydronium ion. Nitrosation of MDEA, a tertiary amine, is not catalyzed by the addition of CO2 since it cannot form a stable carbamate. Concentrated and CO2 loaded MEA was blended with low concentrations of N-(2-hydroxyethyl) glycine (HeGly), hydroxyethyl-ethylenediamine (HEEDA), and DEA, secondary amines common in MEA degradation. Nitrosamine yield was proportional to the concentration of secondary amine and was a function of CO2 loading and temperature. Blends of tertiary amines with piperazine (PZ) showed n-nitrosopiperazine (MNPZ) yields close to unity, validating the slow nitrosation rates hypothesized for tertiary amines. These results provide a useful tool for estimating nitrosamine accumulation over a range of amine solvents. PMID:24956458

Fine, Nathan A; Goldman, Mark J; Rochelle, Gary T

2014-08-01

144

DNA interactions of new cytotoxic tetrafunctional dinuclear platinum complex trans,trans-[{PtCl2(NH3)}2(piperazine)].  

PubMed

A new tetrafunctional dinuclear platinum complex trans,trans-[{PtCl2(NH3)}2(piperazine)] with sterically rigid linking group was designed, synthesized and characterized. In this novel molecule, the DNA-binding features of two classes of the platinum compounds with proven antitumor activity are combined, namely trans oriented bifunctional mononuclear platinum complexes with a heterocyclic ligand and polynuclear platinum complexes. DNA-binding mode of this new complex was analyzed by various methods of molecular biology and biophysics. The complex coordinates DNA in a unique way and interstrand and intrastrand cross-links are the predominant lesions formed in DNA in cell-free media and in absence of proteins. An intriguing aspect of trans,trans-[{PtCl2(NH3)}2(piperazine)] is that, using a semi-rigid linker, interstrand cross-linking is diminished relative to other dinuclear platinum complexes with flexible linking groups and lesions that span several base pairs, such as tri- and tetrafunctional adducts, become unlikely. In addition, in contrast to the inability of trans,trans-[{PtCl2(NH3)}2(piperazine)] to cross-link two DNA duplexes, the results of the present work convincingly demonstrate that this dinuclear platinum complex forms specific DNA lesions which can efficiently cross-link proteins to DNA. The results substantiate the view that trans,trans-[{PtCl2(NH3)}2(piperazine)] or its analogues could be used as a tool for studies of DNA properties and their interactions or as a potential antitumor agent. The latter view is also corroborated by the observation that trans,trans-[{PtCl2(NH3)}2(piperazine)] is a more effective cytotoxic agent than cisplatin against human tumor ovarian cell lines. PMID:17400194

Brabec, Viktor; Christofis, Petros; Slmov, Martina; Kostrhunov, Hana; Novkov, Olga; Najajreh, Yousef; Gibson, Dan; Kasprkov, Jana

2007-06-15

145

Stability study of the designer drugs "MDA, MDMA and MDEA" in water, serum, whole blood, and urine under various storage temperatures.  

PubMed

A controlled study was undertaken to determine the stability of the designer drugs MDA, MDMA and MDEA in pooled serum, whole blood, water and urine samples over a period of 21 weeks. The concentrations of the individual designer drugs in the various matrices were monitored over time, in the dark at various temperatures (-20, 4 or 20 degrees C), for a low (+/- 6 ng/ml for water, serum and whole blood and +/- 150 ng/ml for urine) and a high concentration level (+/- 550 ng/ml for water, serum and whole blood and +/- 2500 ng/ml for urine). Compound concentrations were measured using a validated HPLC assay with fluorescence detection. Our study demonstrated no significant loss of the designer drugs in water and urine at any of the investigated temperatures for 21 weeks. The same results were observed in serum for up to 17 weeks, and up to 5 weeks in whole blood. After that time, the compounds could no longer be analyzed due to matrix degradation, especially in the low concentration samples that were stored at room temperature. This study demonstrates that the designer drugs, MDA, MDMA and MDEA are stable when stored at -20 degrees C for 21 weeks, even in haemolysed whole blood. PMID:11741758

Clauwaert, K M; Van Bocxlaer, J F; De Leenheer, A P

2001-12-15

146

GC-MS and GC-IRD analysis of ring and side chain regioisomers of ethoxyphenethylamines related to the controlled substances MDEA, MDMMA and MBDB.  

PubMed

Three regioisomeric 3, 4-methylenedioxyphenethylamines having the same molecular weight and major mass spectral fragments of equal mass have been reported as drugs of abuse in recent years. These compounds are 3,4-methylenedioxy-N-ethylamphetamine (MDEA), 3,4-methylenedioxy-N,N-dimethylamphetamine (MDMMA), and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB). Ring substituted ethoxy phenethylamines having the same side chain are compounds with an isobaric relationship to these controlled drug substances, all have molecular weight of 207 and major fragment ions in their electron ionization mass spectra at m/z 72 and 135/136. The three methylenedioxyphenethylamines were resolved from the ethoxyphenethylamines by capillary gas chromatography using an Rxi-50 stationary phase. The trifluoroacetyl, pentafluoropropionyl and heptafluorobutryl derivatives of the secondary amines were evaluated in GC-MS studies. The mass spectra for these derivatives were significantly individualized and the resulting unique fragment ions allowed for specific side chain identification. The perfluoroacyl derivatives showed reasonable resolution on a non-polar stationary phase such as Rtx-1. GC-IRD studies provided structure-IR spectra relationships used for the discrimination of the three target drugs (MDEA, MDMMA and MBDB) from the other nine ring substituted ethoxyphenethylamine regioisomers. PMID:20427137

Al-Hossaini, Abdullah M; Awad, Tamer; DeRuiter, Jack; Clark, C Randall

2010-07-15

147

Copper(I) cyanide networks: synthesis, structure, and luminescence behavior. Part 2. Piperazine ligands and hexamethylenetetramine.  

PubMed

A variety of photoluminescent, and in some cases thermochromic, metal-organic networks of CuCN were self-assembled in aqueous reactions with amine ligands: (CuCN) 2(Pip) ( 1a), (CuCN) 20(Pip) 7 ( 1b), (CuCN) 7(MePip) 2 ( 2), (CuCN) 2(Me 2Pip) ( 3a), (CuCN) 4(Me 2Pip) ( 3b), (CuCN) 7(EtPip) 2 ( 4), (CuCN) 4(Et 2Pip) ( 5), (CuCN) 3(BzPip) 2 ( 6a), (CuCN) 5(BzPip) 2 ( 6b), (CuCN) 7(BzPip) 2 ( 6c), (CuCN) 4(BzPip) ( 6d), (CuCN) 2(Bz 2Pip) ( 7), (CuCN)(Ph 2CHPip) ( 8a), (CuCN) 2(Ph 2CHPip) ( 8b), (CuCN) 3(HMTA) 2 ( 9a), (CuCN) 5(HMTA) 2 ( 9b), and (CuCN) 5(HMTA) ( 9c) (Pip = piperazine, MePip = N-methylpiperazine, Me 2Pip = N, N'-dimethylpiperazine, EtPip = N-ethylpiperazine, Et 2Pip = N, N'-diethylpiperazine, BzPip = N-benzylpiperazine, Bz 2Pip = N, N'-dibenzylpiperazine, Ph 2CHPip = N-(diphenylmethyl)piperazine, and HMTA = hexamethylenetetramine). New X-ray structures are reported for 1b, 2, 3b, 4, 5, 6a, 6d, 7, 8b, 9b, and 9c. An important structural theme is the formation of (6,3) (CuCN) 2(piperazine) sheets with or without threading of independent CuCN chains. Strong luminescence at ambient temperature is observed for all but complexes 6 and 7. All luminescent compounds show a broad emission band in the blue region at about 450 nm attributable to metal-to-ligand charge transfer behavior based on the large Stokes shift between excitation and emission maxima. 3, 8, and 9 are thermochromic due to an additional lower energy emission band, which is absent at 77 K. PMID:18597424

Lim, Mi Jung; Murray, Courtney A; Tronic, Tristan A; deKrafft, Kathryn E; Ley, Amanda N; deButts, Jordan C; Pike, Robert D; Lu, Haiyan; Patterson, Howard H

2008-08-01

148

Design, Synthesis and Biological Evaluation of Novel Piperazine Derivatives as CCR5 Antagonists  

PubMed Central

By using a fragment-assembly strategy and bioisosteric-replacement principle, a series of novel piperazine derivatives were designed, synthesized, and evaluated for their cellular target-effector fusion activities and in vitro antiviral activities against HIV-1. Preliminary structure-activity relationships (SARs) of target compounds were concluded in this study, and five compounds were found to exhibited medium to potent CCR5 fusion activities with IC50 values in low micromolar level. Among evaluated compounds, 23 h was found to be a CCR5 antagonist with an IC50 value of 6.29 M and an anti-HIV-1 inhibitor with an IC50 value of 0.44 M. PMID:23308267

Liu, Tao; Weng, Zhiyong; Dong, Xiaowu; Chen, Linjie; Ma, Ling; Cen, Shan; Zhou, Naiming; Hu, Yongzhou

2013-01-01

149

Novel fluorescent pH sensor based on coumarin with piperazine and imidazole substituents  

NASA Astrophysics Data System (ADS)

A new coumarin derivative containing piperazine and imidazole moieties is reported as a fluorophore for hydrogen ions sensing. The fluorescence enhancement of the studied sensor with an increase in hydrogen ions concentration is based on the hindering of photoinduced electron transfer from the piperazinyl amine and the imidazolyl amine to the coumarin fluorophore by protonation. The presented sensor has a novel design of fluorophore-spacer-receptor(1)-receptor(2) format, which is proposed to sense two ranges of pH (from 2.5 to 5.5) and (from 10 to 12) instead of sensing one pH range. A model compound, in which the piperazinyl ring is absent, was synthesized as well to confirm the novel pH sensing of the proposed sensor.

Saleh, Na'il; Al-Soud, Yaseen A.; Nau, Werner M.

2008-12-01

150

Spectroscopic, magnetic and thermogravimetric studies of piperazine-bis-(dithiocarbamate) complexes  

NASA Astrophysics Data System (ADS)

A new 1,4-piperazine-bis-dithiocarbamate sodium salt and its metal complexes have been prepared and characterized by elemental analyses, conductivity measurements, magnetic susceptibilities, thermal analyses (TG and DTG) and spectroscopic (i.r., electronic and EPR) techniques. The ligand is tetrasulphur coordinated to the metals in polymeric structures. The magnetic measurements are indicative of one unpaired electron in the copper(II) complex; a ? value typical of planar low-spin complexes has been obtained in the case of the cobalt(II) derivative, while a distortion from the planarity is suggested in the case of the nickel(II) complex. Tentative structures of the complexes are proposed on the basis of the obtained results.

Fabretti, Antonio Costantino; Forghieri, Fabrizia; Giusti, Aleardo; Preti, Carlo; Tosi, Giuseppe

151

Hypophagic and hypolocomotive effects of metachloro phenyl piperazine in rats treated with theophylline and caffeine.  

PubMed

Long term intake of coffee is known to produce anxiety and suppression of appetite. 5- hydroxytryptamine (5-HT) acting via 5-HT-2C receptors elicits anorexia and anxiety. The present study is design to monitor metachloro phenyl piperazine (m-CPP) at a dose of 3mg/ml/kg, induces hypophagia and hypolocomotion in rats taking a solution of caffeine (a component of coffee and tea) or theophylline (a component of tea) as a sole source of water. We found that hypophagic and hypolocomotive effects of m-CPP were attenuated in theophylline but not in caffeine treated animals suggesting that long term intake of theophylline may attenuate anorexiogenic and anxiogenic effects of 5-HT. A possible role of 5-HT-2C receptors in the modulation of anxiety and appetite in people drinking coffee or tea discussed. PMID:21715256

Alam, Nausheen; Haleem, Darakshan Jabeen; Najam, Rahila; Haider, Syeda; Ahmed, Shahida Perveen

2011-07-01

152

Vibrational spectra, normal coordinate treatment and simulation of the vibrational spectra of piperazine glyoxime and its Co(III) complex  

NASA Astrophysics Data System (ADS)

Newly synthesized Co(III) complexes of piperazine glyoxime (PGO) are examined from the vibrational spectroscopy point of view. A complete interpretation of the vibrational spectra of both the ligand and the complex has been carried out on the basis of normal coordinate analysis. A valence force field has been developed for both of the compounds. The vibrational spectra of the compounds are simulated by a visual basic program prepared to run on an MS Excel data sheet.

zpozan, T.; Kkusta, D.; Bykmumcu, Z.

2003-12-01

153

Substituted piperazines as nootropic agents: 2- or 3-phenyl derivatives structurally related to the cognition-enhancer DM235.  

PubMed

A series of 2-phenyl- or 3-phenyl piperazines, structurally related to DM235 and DM232, two potent nootropic agents, have been prepared and tested in the mouse passive-avoidance test, to assess their ability to revert scopolamine-induced amnesia. Although the newly synthesized molecules were less potent than the parent compounds, some useful information has been obtained from structure-activity relationships. A small but significant enantioselectivity has been found for the most potent compound 5a. PMID:25813160

Guandalini, Luca; Martino, Maria Vittoria; Di Cesare Mannelli, Lorenzo; Bartolucci, Gianluca; Melani, Fabrizio; Malik, Ruchi; Dei, Silvia; Floriddia, Elisa; Manetti, Dina; Orlandi, Francesca; Teodori, Elisabetta; Ghelardini, Carla; Romanelli, Maria Novella

2015-04-15

154

Decomposition of nitrosamines in CO2 capture by aqueous piperazine or monoethanolamine.  

PubMed

Amine scrubbing is an efficient method for carbon capture and sequestration, but secondary amines present in all amine solvents can form carcinogenic nitrosamines. Decomposition kinetics for n-nitrosopiperazine (MNPZ), nitrosodiethanolamine (NDELA), and nitroso-(2-hydroxyethyl) glycine (NHeGly) were measured over a range of temperature, base concentration, base strength, and CO2 loading pertinent to amine scrubbing. MNPZ and NDELA decomposition is first order in the nitrosamine, half order in base concentration, and base-catalyzed with a Brnsted slope of ? = 0.5. The activation energy is 94, 106, and 112 kJ/mol for MNPZ, NDELA, and NHeGly, respectively. MNPZ readily decomposes at 150 C in 5 M piperazine, making thermal decomposition an important mechanism for MNPZ control. However, NHeGly and NDELA are too stable at 120 C in 7 M monoethanolamine (MEA) for thermal decomposition to be important. Base treatment during reclaiming could rapidly and selectively decompose NHeGly and NDELA to mitigate nitrosamine accumulation in MEA. PMID:24730662

Fine, Nathan A; Nielsen, Paul T; Rochelle, Gary T

2014-05-20

155

Charge-transfer complexes of 1-(2-aminoethyl) piperazine with ?- and ?-acceptors  

NASA Astrophysics Data System (ADS)

The solid charge-transfer (CT) molecular complexes formed in the reaction of 1-(2-aminoethyl) piperazine (AEPIP) with the ?-acceptor iodine and ?-acceptors 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 7,7,8,8-tetracyanoquinodi-methane (TCNQ), 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD) and 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL) were studied in chloroform at 25 C. The products were investigated through electronic and infrared spectra as well as elemental analysis. The obtained results showed that the formed solid CT-complexes have the formulas [(AEPIP) I] +I5-, [(AEPIP)(DDQ) 2], [(AEPIP)(TCNQ) 2], [(AEPIP) 2(TBCHD) 3] and [(AEPIP)(CHL)] which are in full agreement with the known reaction stoichiometries in solution as well as the elemental analysis measurements. The formation constant KCT, molar extinction coefficient ?CT, free energy change ? G0 and CT energy ECT have been calculated for the CT-complexes [(AEPIP)(DDQ) 2], [(AEPIP)(TCNQ) 2] and [(AEPIP)(CHL)] as well.

Mostafa, Adel; Bazzi, Hassan S.

2010-11-01

156

Network formation and photoluminescence in copper(I) halide complexes with substituted piperazine ligands.  

PubMed

The synthesis, X-ray structures and photophysics of ten complexes of CuX (X = I or Br) with bridging N-substituted and N,N'-disubstituted piperazines (Pip) are presented. Depending on the steric demand of the Pip substituents, the complexes fall into four categories: (CuX)(4)(Pip)(2), which are networks of linked Cu(4)X(4) cubane units, (CuX)(2)(Pip), which are chains of linked Cu(2)X(2) rhombs, and (CuX)(2)(Pip)(2) or (CuX)(4)(Pip)(4), which are simple rhomboid dimers and cubane tetramers. A combination of spectroscopic studies and DFT calculations was used to investigate the luminescence of the products. The results suggest that the relatively high energy emission seen in dimers is due to cluster-centred (XMLT/metal-centred) excitations for the aliphatic amines and MLCT (d ??*) for aromatic amines, and low energy emission seen in the tetramers is the result of cluster-centred transitions. The (CuI)(2)(Pip) complexes act as sensor materials, undergoing irreversible reaction with aliphatic and aromatic amines (Nu) in the vapour state, irreversibly producing cubanes (CuI)(4)Nu(4), with corresponding production of long wavelength emission. PMID:22859067

Safko, Jason P; Kuperstock, Jacob E; McCullough, Shannon M; Noviello, Andrew M; Li, Xiaobo; Killarney, James P; Murphy, Caitlin; Patterson, Howard H; Bayse, Craig A; Pike, Robert D

2012-10-14

157

Quantitative determination of some pharmaceutical piperazine derivatives through complexation with iron(III) chloride.  

PubMed

A simple, accurate and sensitive spectrophotometric method has been developed for the determination of three pharmaceutical piperazine derivatives, namely ketoconazole (KC), trimetazidine hydrochloride (TMH) and piribedil (PD). This method is based on the formation of yellow orange complexes between iron(III) chloride and the investigated drugs. The optimum reaction conditions, spectral characteristics, conditional stability constants and composition of the water soluble complexes have been established. The method permits the determination of KC, TMH and PD over a concentration range 1-15, 1-12 and 1-12 microg ml(-1), respectively. Sandell sensitivity is found to be 0.016, 0.013 and 0.013 microg cm(-2) for KC, TMH and PD, respectively. The method was sensitive, simple, reproducible and accurate within +/-1.5%. The method is applicable to the assay of the three drugs under investigation in different dosage forms and the results are in good agreement with those obtained by the official methods (USP and JP). PMID:12875888

Abou-Attia, F M; Issa, Y M; Abdel-Gawad, F M; Abdel-Hamid, S M

2003-08-01

158

A chemical genetic approach identifies piperazine antipsychotics as promoters of CNS neurite growth on inhibitory substrates  

PubMed Central

Injury to the central nervous system (CNS) can result in lifelong loss of function due in part to the regenerative failure of CNS neurons. Inhibitory proteins derived from myelin and the astroglial scar are major barriers for the successful regeneration of injured CNS neurons. Previously, we described the identification of a novel compound, F05, which promotes neurite growth from neurons challenged with inhibitory substrates in vitro, and promotes axonal regeneration in vivo (Usher et al., 2010). To identify additional regeneration-promoting compounds, we used F05-induced gene expression profiles to query the Broad Institute Connectivity Map, a gene expression database of cells treated with >1,300 compounds. Despite no shared chemical similarity, F05-induced changes in gene expression were remarkably similar to those seen with a group of piperazine phenothiazine antipsychotics (PhAPs). In contrast to antipsychotics of other structural classes, PhAPs promoted neurite growth of CNS neurons challenged with two different glial derived inhibitory substrates. Our pharmacological studies suggest a mechanism whereby PhAPs promote growth through antagonism of calmodulin signaling, independent of dopamine receptor antagonism. These findings shed light on mechanisms underlying neurite-inhibitory signaling, and suggest that clinically approved antipsychotic compounds may be repurposed for use in CNS injured patients. PMID:22561309

Johnstone, AL; Reierson, GW; Smith, RP; Goldberg, JL; Lemmon, VP; Bixby, JL

2012-01-01

159

Prevalence of use study for amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxy-amphetamine (MDA), 3,4-methylenedioxy-methamphetamine (MDMA), and 3,4-methylenedioxy-ethylamphetamine (MDEA) in military entrance processing stations (MEPS) specimens.  

PubMed

The Roche Abuscreen Onlinetrade mark Amphetamine immunoassay (IA), modified to include sodium periodate, and the Microgenics DRI Ecstasy IA were used to determine the prevalence of amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) in urine specimens from applicants seeking to join the United States Armed Forces. Over a 4-month period, a total of 85,658 specimens were IA screened using the Department of Defense 500 ng/mL administrative cutoff level for AMP and MDMA. All presumptively positive specimens were confirmed using a solid-phase extraction procedure coupled with simultaneous analysis of AMP, MAMP, MDA, MDMA, and MDEA by fast gas chromatography-mass spectrometry using the same cutoff levels as the IA. The Roche Online Amphetamine IA identified 216 specimens as presumptively positive; of these, 70 specimens confirmed positive for AMP and 87 specimens confirmed positive for AMP and/or MAMP, resulting in a confirmation rate of 73%. The Microgenics DRI Ecstasy IA identified eight specimens as presumptively positive; of these, five specimens confirmed positive for MDMA and/or MDA, resulting in a confirmation rate of 63%. The total use prevalence for AMP, MAMP, MDA, MDMA, and/or MDEA in military entrance processing stations specimens over the testing period was determined to be 0.19%. PMID:16839469

Klette, Kevin L; Kettle, Aaron R; Jamerson, Matthew H

2006-06-01

160

Acid gas treating by aqueous alkanolamines. Annual report, July-December 1992  

SciTech Connect

The objective of the work is to investigate the simultaneous absorption or desorption of CO2 and H2S into and from a mixed aqueous amine solvent consisting of methyldiethanolamine (MDEA) and diethanolamine (DEA). In work completed thus far models have been developed for single gas (either H2S or CO2) absorption into a single amine solution (MDEA or DEA). Density and viscosity measurements have been made for aqueous MDEA, DEA and MDEA/DEA mixtures over the temperature range 20 to 100 C and for concentrations up to 50 weight %.

Sandall, O.C.; Rinker, E.B.; Tamimi, A.; Davis, R.A.; Oelschlager, D.W.

1992-12-01

161

Formation of p-cresol:piperazine complex in solution monitored by spin-lattice relaxation times and pulsed field gradient NMR diffusion measurements  

NASA Astrophysics Data System (ADS)

A study of the nature of the anthelmintic p-cresol:piperazine complex in chloroform solution has been conducted using different NMR techniques: self-diffusion coefficients using DOSY; NOE, NULL, and double-selective T1 measurements to determine inter-molecular distances; and selective and non-selective T1 measurements to determine correlation times. The experimental results in solution and CP-MAS were compared to literature X-ray diffraction data using molecular modeling. It was shown that the p-cresol:piperazine complex exists in solution in a very similar manner as it does in the solid state, with one p-cresol molecule hydrogen bonded through the hydroxyl hydrogen to each nitrogen atom of piperazine. The close correspondence between the X-ray diffraction data and the inter-proton distances obtained by NULL and double selective excitation techniques indicate that those methodologies can be used to determine inter-molecular distances in solution.

de Carvalho, Erika Martins; Velloso, Marcia Helena Rodrigues; Tinoco, Luzineide Wanderley; Figueroa-Villar, Jos Daniel

2003-10-01

162

Effect of the piperazine unit and metal-binding site position on the solubility and anti-proliferative activity of ruthenium(II)- and osmium(II)- arene complexes of isomeric indolo[3,2-c]quinoline-piperazine hybrids.  

PubMed

In this study, the indoloquinoline backbone and piperazine were combined to prepare indoloquinoline-piperazine hybrids and their ruthenium- and osmium-arene complexes in an effort to generate novel antitumor agents with improved aqueous solubility. In addition, the position of the metal-binding unit was varied, and the effect of these structural alterations on the aqueous solubility and antiproliferative activity of their ruthenium- and osmium-arene complexes was studied. The indoloquinoline-piperazine hybrids L(1-3) were prepared in situ and isolated as six ruthenium and osmium complexes [(?(6)-p-cymene)M(L(1-3))Cl]Cl, where L(1) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-2-N-amine, M = Ru ([1a]Cl), Os ([1b]Cl), L(2) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-4-N-amine, M = Ru ([2a]Cl), Os ([2b]Cl), L(3) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-8-N-amine, M = Ru ([3a]Cl), Os ([3b]Cl). The compounds were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, ESI mass spectrometry, IR and UV-vis spectroscopy, and single-crystal X-ray diffraction. The antiproliferative activity of the isomeric ruthenium and osmium complexes [1a,b]Cl-[3a,b]Cl was examined in vitro and showed the importance of the position of the metal-binding site for their cytotoxicity. Those complexes containing the metal-binding site located at the position 4 of the indoloquinoline scaffold ([2a]Cl and [2b]Cl) demonstrated the most potent antiproliferative activity. The results provide important insight into the structure-activity relationships of ruthenium- and osmium-arene complexes with indoloquinoline-piperazine hybrid ligands. These studies can be further utilized for the design and development of more potent chemotherapeutic agents. PMID:24927493

Filak, Lukas K; Kalinowski, Danuta S; Bauer, Theresa J; Richardson, Des R; Arion, Vladimir B

2014-07-01

163

Effect of the Piperazine Unit and Metal-Binding Site Position on the Solubility and Anti-Proliferative Activity of Ruthenium(II)- and Osmium(II)- Arene Complexes of Isomeric Indolo[3,2-c]quinolinePiperazine Hybrids  

PubMed Central

In this study, the indoloquinoline backbone and piperazine were combined to prepare indoloquinolinepiperazine hybrids and their ruthenium- and osmium-arene complexes in an effort to generate novel antitumor agents with improved aqueous solubility. In addition, the position of the metal-binding unit was varied, and the effect of these structural alterations on the aqueous solubility and antiproliferative activity of their ruthenium- and osmium-arene complexes was studied. The indoloquinolinepiperazine hybrids L13 were prepared in situ and isolated as six ruthenium and osmium complexes [(?6-p-cymene)M(L13)Cl]Cl, where L1 = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-2-N-amine, M = Ru ([1a]Cl), Os ([1b]Cl), L2 = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-4-N-amine, M = Ru ([2a]Cl), Os ([2b]Cl), L3 = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-8-N-amine, M = Ru ([3a]Cl), Os ([3b]Cl). The compounds were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, ESI mass spectrometry, IR and UVvis spectroscopy, and single-crystal X-ray diffraction. The antiproliferative activity of the isomeric ruthenium and osmium complexes [1a,b]Cl[3a,b]Cl was examined in vitro and showed the importance of the position of the metal-binding site for their cytotoxicity. Those complexes containing the metal-binding site located at the position 4 of the indoloquinoline scaffold ([2a]Cl and [2b]Cl) demonstrated the most potent antiproliferative activity. The results provide important insight into the structureactivity relationships of ruthenium- and osmium-arene complexes with indoloquinolinepiperazine hybrid ligands. These studies can be further utilized for the design and development of more potent chemotherapeutic agents. PMID:24927493

2014-01-01

164

Control of water molecule aggregations in copper 1,4-cyclohexanedicarboxylate coordination polymers containing pyridyl-piperazine type ligands  

NASA Astrophysics Data System (ADS)

A series of layered divalent copper coordination polymers containing 1,4-cyclohexanedicarboxylate and long-spanning pyridyl-piperazine type ligands exhibits greatly different co-crystallized water molecule aggregations depending on the specific ligands used. Both [Cu(t-14cdc)(4-bpmp)]n (1, t-14cdc = trans-1,4-cyclohexanedicarboxylate, 4-bpmp = bis(4-pyridylmethyl)piperazine) and {[Cu(t-14cdc)(4-bpfp)(H2O)2]6H2O}n (2, 4-bpfp = bis(4-pyridylformyl)piperazine) possess 2D (4,4) coordination polymer grids. However 1 lacks any co-crystallized water and has pinched grid apertures, while 2 manifests infinite water tapes with T6(2)4(2) classification and rectangular grid apertures. {[Cu2(c-14cdc)2(4-bpmp)]2H2O}n (3, c-14cdc = cis-1,4-cyclohexanedicarboxylate) has [Cu2(c-14cdc)]2 ribbons with paddlewheel dimeric units linked into 2D slabs by 4-bpmp tethers, along with isolated water molecule pairs. In contrast, {[Cu2(c-14cdc)2(4-bpfp)]10H2O}n (4) shows a very similar underlying coordination polymer topology but entrains unique decameric water molecule clusters. The minor product {[Cu2(c-14cdcH)2(t-1,4-cdc)(4-bpfp)2(H2O)2]2H2O}n (5) was isolated along with 4; this compound underwent some in situ cis to trans cyclohexane-dicarboxylate ligand isomerization and exhibits a ladder polymer motif.

Qiblawi, Sultan H.; LaDuca, Robert L.

2014-01-01

165

Synthesis of New N,N-Bis(5-arylidene-4-oxo-4,5-dihydrothiazolin-2-yl)piperazine Derivatives Under Microwave Irradiation and Preliminary Biological Evaluation  

PubMed Central

New N,N-bis(5-arylidene-4-oxo-4,5-dihydrothiazoline-2-yl)diamine derivatives 5 were prepared in two steps from rhodanine and piperazine, or 1,4-bis(3-amino-propyl)piperazine, under microwave reaction conditions with retention of configuration. Some of these compounds were tested for in vitro antiproliferative activities and for their kinase inhibitory potencies towards six kinases (CDK5/p25, GSK3?/?, DYRK1A, DYRK2, CLK1, and CLK2). The compound 5d showed nanomolar activity towards DYRK1A kinase (IC50 = 0.041 ?M). PMID:23264934

Coulibaly, Wacothon Karime; Paquin, Ludovic; Bni, Anoubil; Bekro, Yves-Alain; Durieux, Emilie; Meijer, Laurent; Le Guvel, Rmy; Corlu, Anne; Bazureau, Jean-Pierre

2012-01-01

166

Synthesis of New N,N'-Bis(5-arylidene-4-oxo-4,5-dihydrothiazolin-2-yl)piperazine Derivatives Under Microwave Irradiation and Preliminary Biological Evaluation.  

PubMed

New N,N'-bis(5-arylidene-4-oxo-4,5-dihydrothiazoline-2-yl)diamine derivatives 5 were prepared in two steps from rhodanine and piperazine, or 1,4-bis(3-amino-propyl)piperazine, under microwave reaction conditions with retention of configuration. Some of these compounds were tested for in vitro antiproliferative activities and for their kinase inhibitory potencies towards six kinases (CDK5/p25, GSK3?/?, DYRK1A, DYRK2, CLK1, and CLK2). The compound 5d showed nanomolar activity towards DYRK1A kinase (IC(50) = 0.041 ?M). PMID:23264934

Coulibaly, Wacothon Karime; Paquin, Ludovic; Bni, Anoubil; Bekro, Yves-Alain; Durieux, Emilie; Meijer, Laurent; Le Guvel, Rmy; Corlu, Anne; Bazureau, Jean-Pierre

2012-12-01

167

Acceleration of the reaction of carbon dioxide into aqueous 2-amino-2-hydroxymethyl-1,3-propanediol solutions by piperazine addition  

Microsoft Academic Search

In this work, the kinetics of the reaction between CO2 and piperazine-activated aqueous solutions of a sterically hindered alkanolamine, 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) was studied in a wetted wall column contactor at 303.15, 313.15 and 323.15K. The AHPD concentration in the aqueous solutions was kept at 1kmolm-3 while the piperazine (PZ) concentration varied in the range 0.10.4kmolm-3. Under pseudo-first-order CO2 absorption conditions,

Francis Bougie; Julien Lauzon-Gauthier; Maria C. Iliuta

2009-01-01

168

Design and synthesis of piperazine derivatives as a novel class of ?-secretase modulators that selectively lower A?42 production.  

PubMed

Novel piperazine derivatives as ?-secretase modulators (GSMs) were prepared and tested for their ability to selectively lower A?42 production. Lead compound 3, with selective A?42-lowering activity, was modified by replacing its imidazolylphenyl moiety with an oxazolylphenyl moiety. Optimization of the urea group significantly improved mouse microsomal stability, while retaining both activity and selectivity. These efforts led to the successful identification of an orally available and brain-penetrant GSM, 6j, which selectively reduced brain A?42 in mice. PMID:25842363

Takai, Takafumi; Koike, Tatsuki; Honda, Eiji; Kajita, Yuichi; Nakamura, Minoru; Morimoto, Sachie; Hoashi, Yasutaka; Kamata, Makoto; Watanabe, Tomomichi; Igari, Tomoko; Terauchi, Jun

2015-05-01

169

Tri- and tetraurea piperazine cyclophanes: synthesis and complexation studies of preorganized and folded receptor molecules.  

PubMed

A series of symmetrical tri- and tetrameric N-ethyl- and N-phenylurea-functionalized cyclophanes have been prepared in nearly quantitative yields (86-99?%) from the corresponding tri- and tetraamino-functionalized piperazine cyclophanes and ethyl or phenyl isocyanates. Their conformational and complexation properties have been studied by single-crystal X-ray diffraction, variable-temperature NMR spectroscopy, and ESI-MS analysis. The rigid 27-membered trimeric cyclophane skeleton assisted by a seam of intramolecular hydrogen bonds results in a preorganized ditopic recognition site with an all-syn conformation of the urea moieties that, complemented by a lipophilic cavity of the cyclophane, binds molecular and ionic guests as well as ion pairs. The all-syn conformation persists in acidic conditions and the triprotonated triurea cyclophane binds an unprecedented anion pair, H(2)PO(4)(-)???HPO(4)(2-), in the solid state. The tetra-N-ethylurea cyclophane is less rigid and demonstrates an induced-fit recognition of diisopropyl ether in the solid state. The guest was encapsulated within the lipophilic interior of a quasicapsule, formed by intramolecular hydrogen-bond-driven folding of the 36-membered cyclophane skeleton. In the gas phase, the essential role of the urea moieties in the binding was demonstrated by the formation of monomeric 1:1 complexes with K(+), TMA(+), and TMP(+) as well as the ion-pair complexes [KI+K](+), [TMABr+TMA](+) and [TMPBr+TMP](+). In the positive-mode ESI-MS analysis, ion-pair binding was found to be more pronounced with the larger tetraurea cyclophanes. In the negative mode, owing to the large size of the binding site, a general binding preference towards larger anions, such as the iodide, over smaller anions, such as the fluoride, was observed. PMID:21077059

Raatikainen, Kari; Beyeh, N Kodiah; Rissanen, Kari

2010-12-27

170

Dimethyl phenyl piperazine iodide (DMPP) induces glioma regression by inhibiting angiogenesis  

SciTech Connect

1,1-Dimethyl-4-phenyl piperazine iodide (DMPP) is a synthetic nicotinic acetylcholine receptor (nAChR) agonist that could reduce airway inflammation. In this study, we demonstrated that DMPP could dramatically inhibit glioma size maintained on the chick embryonic chorioallantoic membrane (CAM). We first performed MTT and BrdU incorporation experiments on U87 glioma cells in vitro to understand the mechanism involved. We established that DMPP did not significantly affect U87 cell proliferation and survival. We speculated that DMPP directly caused the tumor to regress by affecting the vasculature in and around the implanted tumor on our chick CAM model. Hence, we conducted detailed analysis of DMPP's inhibitory effects on angiogenesis. Three vasculogenesis and angiogenesis in vivo models were used in the study which included (1) early chick blood islands formation, (2) chick yolk-sac membrane (YSW) and (3) CAM models. The results revealed that DMPP directly suppressed all developmental stages involved in vasculogenesis and angiogenesis possibly by acting through Ang-1 and HIF-2? signaling. In sum, our results show that DMPP could induce glioma regression grown on CAM by inhibiting vasculogenesis and angiogenesis. - Highlights: ?We demonstrated that DMPP inhibited the growth of glioma cells on chick CAM. ?DMPP did not significantly affect the proliferation and survival of U87 cells. ?We revealed that DMPP suppressed vasculogenesis and angiogenesis in chick embryo. ?Angiogenesis in chick CAM was inhibited by DMPP via most probably Ang-1 and HIF-2?. ?DMPP could be potentially developed as an anti-tumor drug in the future.

He, Yan-qing; Li, Yan; Wang, Xiao-yu [Key Laboratory for Regenerative Medicine of the Ministry of Education, Division of Histology and Embryology, Medical College, Jinan University, Guangzhou 510632 (China); He, Xiao-dong [Institute of Vascular Biological Sciences, Guangdong Pharmaceutical University, Guangzhou 510006 (China); Jun, Li [Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Centre of Genetic Medicine, College of Life Science and Technology, Jinan University, Guangzhou 510632 (China); Chuai, Manli [Division of Cell and Developmental Biology, University of Dundee, Dundee, DD1 5EH (United Kingdom); Lee, Kenneth Ka Ho [Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin (Hong Kong); Wang, Ju [Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Centre of Genetic Medicine, College of Life Science and Technology, Jinan University, Guangzhou 510632 (China); Wang, Li-jing, E-mail: wanglijing62@163.com [Institute of Vascular Biological Sciences, Guangdong Pharmaceutical University, Guangzhou 510006 (China); Yang, Xuesong, E-mail: yang_xuesong@126.com [Key Laboratory for Regenerative Medicine of the Ministry of Education, Division of Histology and Embryology, Medical College, Jinan University, Guangzhou 510632 (China)

2014-01-15

171

Protective Effects of a Piperazine Derivative [N-{4-[4-(2-methoxy-phenyl)-piperazin-1-yl]-phenyl} Carbamic Acid Ethyl Ester] Against Aluminium-Induced Neurotoxicity: Insights From In Silico and In Vivo Studies.  

PubMed

The cholinergic hypothesis associated with Alzheimer's disease has spurred the development of numerous structural classes of compounds with different pharmacological profiles aimed at increasing central cholinergic neurotransmission. In the present study, six synthetic piperazine derivatives D1-D6 were screened for their efficacy as acetylcholinesterase inhibitors (AChEIs) through in silico and in vitro studies. Compound D2 was found to be a potential AChEI with adequate pharmacokinetic properties, as supported by in silico study. Further, in vivo studies were designed to examine the protective effect of piperazine derivative D2 (3 and 5mg/kg for 6weeks) in ameliorating the alterations induced by aluminium chloride (AlCl3) on behavioural and neurochemical indices. Behavioural tests (Morris water maze and elevated plus maze) revealed significant alterations in the short-term memory and anxiety levels in rats treated with AlCl3, which was further improved after D2 treatment. Further, D2 treatment attenuated the neurotoxic effects of AlCl3 as shown by the improvement in rats performance in Water maze test and in lowering AChE activity. Besides preventing lipid peroxidation and protein damage, changes in the levels of endogenous antioxidant enzymes (GST, GPx, GR and GSH) associated with AlCl3 administration were also restored upon treatment with D2. Thus, our results support the neuroprotective potential of compound D2, thus validating its use in alleviating toxic effects of aluminium. PMID:25403519

Meena, Poonam; Manral, Apra; Saini, Vikas; Tiwari, Manisha

2015-04-01

172

Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes.  

PubMed

A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, (1)H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand. PMID:21757398

Khan, Shamim Ahmad; Nishat, Nahid; Parveen, Shadma; Rasool, Raza

2011-10-15

173

Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes  

NASA Astrophysics Data System (ADS)

A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, 1H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand.

Khan, Shamim Ahmad; Nishat, Nahid; Parveen, Shadma; Rasool, Raza

2011-10-01

174

Synthesis of linear piperazine/polyether functional polysiloxane and its modification of surface properties on cotton fabrics.  

PubMed

In this work, silicone softener (PTSO-PEG) was synthesized, with piperazine terminated polydimethylsiloxane (PTSO) and epoxy terminated polyethylene glycol (EPEG) as raw materials. Chemical structure of PTSO-PEG was characterized by (1)H NMR, FTIR, GPC, and TGA. Its application on cotton fabrics was studied. Morphologies of silicone modified surfaces on cotton fabrics and silicon wafers were investigated by SEM and AFM, respectively. The morphology images indicated that PTSO-PEG treated surface was macroscopically smooth and microscopically rough. Performance properties of silicone treated cotton fabrics, including hydrophilicity, whiteness, and softness, were tested. The results showed that PTSO-PEG treated cotton fabrics expressed better whiteness and hydrophilicity than traditional amino silicone treated sample. The piperazine and hydrophilic polyether groups on PTSO-PEG molecules disturbed the continuous and orderly arrangement of Si-CH3 groups, giving the cotton a hydrophilic and rough surface. This work provided a cost-effective and environmental method to synthesize and apply high performance silicone softener. PMID:25812599

Jin, Yufen; Pu, Qun; Fan, Hong

2015-04-15

175

Piperazine derivatives: synthesis, inhibition of the Mycobacterium tuberculosis enoyl-acyl carrier protein reductase and SAR studies.  

PubMed

The Mycobacterium tuberculosis NADH-dependent enoyl-acyl carrier protein reductase (MtInhA) catalyzes hydride transfer to long-chain enoyl thioester substrates. MtInhA is a member of the mycobacterial type II dissociated fatty acid biosynthesis system, and is the bona fide target for isoniazid, the most prescribed drug for tuberculosis treatment. Here, a series of piperazine derivatives was synthesized and screened as MtInhA inhibitors, which resulted in the identification of compounds with IC50 values in the submicromolar range. A structure-activity relationship (SAR) evaluation indicated the importance of the chemical environment surrounding the carbonyl group for inhibition. In addition, the structure of one selected compound was supported by crystallographic studies, and experimental geometrical values were compared with semi-empirical quantum chemical calculations. Furthermore, the mode of inhibition and inhibitory dissociation constants were determined for the nine most active compounds. These findings suggest that these 9H-fluoren-9-yl-piperazine-containing compounds interact with MtInhA at the enoyl thioester (2-trans-dodecenoyl-CoA) substrate binding site. PMID:25461892

Rotta, Mariane; Pissinate, Kenia; Villela, Anne Drumond; Back, Davi Fernando; Timmers, Luis Fernando Saraiva Macedo; Bachega, Jos Fernando Ruggiero; de Souza, Osmar Norberto; Santos, Digenes Santiago; Basso, Luiz Augusto; Machado, Pablo

2015-01-27

176

Influence of silica nanospheres on the separation performance of thin film composite poly(piperazine-amide) nanofiltration membranes  

NASA Astrophysics Data System (ADS)

A novel thin film nanocomposite nanofiltration (TFNN) membrane was fabricated by introducing silica nanospheres (ca. 235 11 nm) in the interfacial polymerization process of trimesoyl chloride (TMC) and piperazine (PIP) over polysulfone (PS) support for investigating the effect of silica nanofiller on the separation performance (i.e., permeability and salt rejection) of conventional thin film composite poly(piperazine-amide) nanofiltration (TFCN) membrane. The physicochemical characterization results show that all of the silica nanospheres are uniformly embedded on the surface of TFNN membrane. The introduction of silica nanospheres improves the hydrophilicity of the TFCN membrane and also causes its isoelectric point shift to a lower pH value. Moreover, the active poly(piperazine-amide) barrier layer of TFNN membrane (60.8 2.3 nm) is thinner than that of the pristine TFCN membrane (72.1 2.5 nm) as a control sample. The separation performance tests reveal that the addition of silica nanospheres can obviously elevate the salt rejection of the pristine TFCN membrane from 87.58 0.15 to 94.81 0.17% under 2000 ppm of MgSO4 solution and 0.5 MPa operating pressure, simultaneously accompanied by the increases of permeate flux from 19.36 0.75 to 22.65 0.68 L/m2 h. Additionally, compared with pristine TFCN membrane, the fabricated TFNN membrane has relatively low salt rejection (43.20 0.27%) in 0.5 MPa operating pressure for 500 ppm of NaCl aqueous solution, which demonstrates that the introduction of silica nanospheres can dramatically promote the divalent-ionic separation selectivity. Furthermore, the experimental results suggest that the nanocomposite TFNN membrane possesses stable filtration performance in the softening process of MgSO4 aqueous solution. The separation performance improvement should be attributed to the optimizations of microstructures and surface features of active barrier layer of TFNN membrane, caused by the addition of silica nanospheres.

Li, Qiang; Wang, Yihua; Song, Jie; Guan, Yipeng; Yu, Hui; Pan, Xianhui; Wu, Feiyang; Zhang, Meng

2015-01-01

177

Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt.  

PubMed

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM-INA cocrystal and a binary adduct ACM-PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM-PAM and ACM-CPR, and the piperazine salt ACM-PPZ were solved from high-resolution powder X-ray diffraction data. The ACM-INA cocrystal is sustained by the acid?pyridine heterosynthon and N-H?O catemer hydrogen bonds involving the amide group. The acid?amide heterosynthon is present in the ACM-PAM cocrystal, while ACM-CPR contains carboxamide dimers of caprolactam along with acid-carbonyl (ACM) hydrogen bonds. The cocrystals ACM-INA, ACM-PAM and ACM-CPR are three-dimensional isostructural. The carboxyl?carboxyl synthon in ACM-PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24?h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM-PPZ salt and ACM-nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM-PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug. PMID:25075330

Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

2014-03-01

178

Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt  

PubMed Central

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACMINA cocrystal and a binary adduct ACMPABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACMPAM and ACMCPR, and the piperazine salt ACMPPZ were solved from high-resolution powder X-ray diffraction data. The ACMINA cocrystal is sustained by the acid?pyridine heterosynthon and NH?O catemer hydrogen bonds involving the amide group. The acid?amide heterosynthon is present in the ACMPAM cocrystal, while ACMCPR contains carboxamide dimers of caprolactam along with acidcarbonyl (ACM) hydrogen bonds. The cocrystals ACMINA, ACMPAM and ACMCPR are three-dimensional isostructural. The carboxyl?carboxyl synthon in ACMPABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24?h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACMPPZ salt and ACMnicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACMPABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug. PMID:25075330

Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

2014-01-01

179

GC-MS studies on the regioisomeric 2,3- and 3,4-methylenedioxyphenethylamines related to MDEA, MDMMA, and MBDB.  

PubMed

Three regioisomeric 3,4-methylenedioxyphenethylamines having the same molecular weight and major mass spectral fragments of equal mass have been reported as drugs of abuse in forensic studies in recent years. These compounds are 3,4-methylenedioxy-N-ethylamphetamine (MDEA), 3,4-methylenedioxy-N-N-dimethylamphetamine (MDMMA), and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB). The mass spectra of the regioisomers (2,3-methylenedioxyphenethylamines) are essentially equal to the three compounds reported as drugs of abuse. This paper reports the synthesis, mass spectral characterization, and chromatographic analysis of these six regioisomeric amines. The six regioisomeric methylenedioxyphenethylamines are synthesized from commercially available starting materials. The electron impact mass spectra of these regioisomers show some variation in the relative intensity of the major ions with only a couple of minor ions that may indicate side chain specific fragments. Differentiation by mass spectrometry is only possible after the formation of the perfluoroacyl derivatives, pentafluoropropionylamides (PFPA) and heptafluorobutrylamides (HFBA). Gas chromatographic separation on non-polar stationary phases (Rtx-1 and Rtx-5) is not successful at resolving the three 3,4-methylenedioxyphenethylamines from the three 2,3-methylenedioxyphenethylamines as the underivatized amines. The six underivatized amines are resolved on the more polar trifluoropropylmethyl polysiloxane Rtx-200 stationary phase as well as a permethylated beta-cyclodextran Rtx-bDEX stationary phase. Gas chromatographic separation is successful at resolving the four PFPA and the four HFBA derivatives on the Rtx-200 stationary phase as well as the permethylated beta-cyclodextran stationary phase. The 2,3-methylenedioxyphenethylamine derivatives (compounds 4 and 6) eluted before the 3,4-methylenedioxyphenethylamine derivatives (compounds 1 and 3) as both the PFPA and HFBA derivatives. PMID:17555628

Thigpen, Ashley; DeRuiter, Jack; Clark, C Randall

2007-01-01

180

3-(Adamantan-1-yl)-1-[(4-benzylpiperazin-1-yl)methyl]-4-ethyl-1H-1,2,4-triazole-5(4H)-thione  

PubMed Central

In the title compound, C26H37N5S, the piperazine ring adopts a chair conformation with the exocyclic NC bonds in pseudo-equatorial orientations. The piperazine ring (all atoms) subtends dihedral angles of 79.47?(9) and 73.07?(9) with the triazole and benzene rings, respectively, resulting in an approximate U-shape for the molecule. No significant intermolecular interactions are observed in the crystal. PMID:24454243

Al-Abdullah, Ebtehal S.; Al-Tuwaijri, Hanaa M.; El-Emam, Ali A.; Chidan Kumar, C. S.; Fun, Hoong-Kun

2013-01-01

181

Bis(1-methyl-piperazine-1,4-diium) di-?-bromido-bis-[tetra-bromido-bismuthate(III)] dihydrate.  

PubMed

In the title hydrated salt, (C5H14N2)2[Bi2Br10]2H2O, the com-plete [Bi2Br10](4-) biocta-hedron is generated by crystallographic inversion symmetry. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position. In the crystal, the tetra-anions and water mol-ecules are linked by O-H?Br and O-H?(Br,Br) hydrogen bonds to generate [100] chains. The chains are crosslinked by N-H?Br, N-H?O and C-H?Br hydrogen bonds originating from the piperazinediium dications, thereby forming a three-dimensional network. PMID:24940195

Essid, Manel; Roisnel, Thierry; Marouani, Houda

2014-06-01

182

Bis(1-methylpiperazine-1,4-diium) di-?-bromido-bis[tetrabromidobismuthate(III)] dihydrate  

PubMed Central

In the title hydrated salt, (C5H14N2)2[Bi2Br10]2H2O, the complete [Bi2Br10]4? bioctahedron is generated by crystallographic inversion symmetry. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position. In the crystal, the tetraanions and water molecules are linked by OH?Br and OH?(Br,Br) hydrogen bonds to generate [100] chains. The chains are crosslinked by NH?Br, NH?O and CH?Br hydrogen bonds originating from the piperazinediium dications, thereby forming a three-dimensional network. PMID:24940195

Essid, Manel; Roisnel, Thierry; Marouani, Houda

2014-01-01

183

Thermodynamic Investigation and Mixed Ligand Complex Formation of 1,4-Bis-(3-aminopropyl)-piperazine and Biorelevant Ligands.  

PubMed

Thermodynamic parameters for protonation of 1,4-bis(3-aminopropyl)-piperazine (BAPP) and its metal complexation with some divalent metal ions were determined in aqueous solution at constant ionic strength (0.1?M NaNO(3)) using a potentiometric technique. The order of -?G(0) and -?H(0) was found to obey Co(2+) < Ni(2+) < Cu(2+) > Zn(2+), in accordance with the Irving-Williams order. The formation equilibria of zinc (II) complexes and the ternary complexes Zn(BAPP)L, where L?=?amino acid, amides, or DNA constituents), have been investigated. Ternary complexes are formed by a simultaneous mechanism. The concentration distribution of the complexes in solution was evaluated as a function of pH. Stoichiometry and stability constants for the complexes formed are reported and discussed. The stability of ternary complexes was quantitatively compared with their corresponding binary complexes in terms of the parameter ?log K. PMID:23226992

El-Sherif, Ahmed A; Shehata, Mohamed R; Shoukry, Mohamed M; Barakat, Mohammad H

2012-01-01

184

Crystal structures and luminescent properties of two cadmium complexes containing the N,N?-bis-(4-pyridylmethyl) piperazine ligand  

NASA Astrophysics Data System (ADS)

Two cadmium coordination polymers based on the flexible ligand N, N'-bis-(4-pyridyl-methyl) piperazine (bpmp), formulated as {[Cd(bpmp)(H 2O)(Cl) 2]C 2H 5OH2H 2O} n ( 1) and {[Cd(bpmp)(H 2O) 4]2NO 32H 2O} n ( 2), are reported. The crystal structures of the as-synthesized complexes were determined by single-crystal X-ray diffraction analyses. Complex 1 possesses a chloride-bridged two-dimensional (2-D) wave-like layer structure containing (6,3) networks, with the bpmp ligands displaying a cis-conformation. Complex 2 has a one-dimensional (1-D) chain structure built by octahedral Cd nodes and trans-bpmp bridges. Solid state emission spectra of both the two compounds have also been studied at room temperature.

Xu, Bo; Yang, Hongxun; Lin, Jingxiang; Zhu, Xiandong; Liu, Tianfu; Cao, Rong

2009-12-01

185

Synthesis, spectroscopic and thermal studies of the reactions of the donors piperazine and N,N?-dimethylpiperazine with ?- and ?-acceptors  

NASA Astrophysics Data System (ADS)

The interactions of the electron donors piperazine (PIP) and N, N'-dimethylpiperazine (DMPIP) with the ?-acceptor iodine and the ?-acceptors tetracyanoethylene (TCNE) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) were studied spectrophotometrically in chloroform at 25 C. The electronic and infrared spectra of the resulting charge-transfer complexes were recorded, in addition to thermal analysis. The results obtained showed that the stoichiometries of the reactions are not fixed and depend on the nature of both the donor and the acceptor. The formed CT-complexes have the formulas of [(PIP)2I]+I3-, [(PIP)(TCNE) 2], [(PIP)(DDQ) 2], [(DMPIP)4I]+I3-, [(DMPIP)(TCNE) 2] and [(DMPIP)(DDQ) 2]. A general mechanism explaining the formation of triiodide complexes was suggested.

Bazzi, Hassan S.; AlQaradawi, Siham Y.; Mostafa, Adel; Nour, El-Metwally

2008-05-01

186

Thermodynamic Investigation and Mixed Ligand Complex Formation of 1,4-Bis-(3-aminopropyl)-piperazine and Biorelevant Ligands  

PubMed Central

Thermodynamic parameters for protonation of 1,4-bis(3-aminopropyl)-piperazine (BAPP) and its metal complexation with some divalent metal ions were determined in aqueous solution at constant ionic strength (0.1?M NaNO3) using a potentiometric technique. The order of ?G0 and ?H0 was found to obey Co2+ < Ni2+ < Cu2+ > Zn2+, in accordance with the Irving-Williams order. The formation equilibria of zinc (II) complexes and the ternary complexes Zn(BAPP)L, where L?=?amino acid, amides, or DNA constituents), have been investigated. Ternary complexes are formed by a simultaneous mechanism. The concentration distribution of the complexes in solution was evaluated as a function of pH. Stoichiometry and stability constants for the complexes formed are reported and discussed. The stability of ternary complexes was quantitatively compared with their corresponding binary complexes in terms of the parameter ?log K. PMID:23226992

El-Sherif, Ahmed A.; Shehata, Mohamed R.; Shoukry, Mohamed M.; Barakat, Mohammad H.

2012-01-01

187

Formation of cobalt(II) piperazine supramolecular systems under different organic acid mediums: synthesis, characterization and crystal structures  

NASA Astrophysics Data System (ADS)

The reactions of CoCl 2 salt and piperazine ( L) in the presence of different organic acid mediums afford a series of cobalt(II) complexes, the solid structures (determined by X-ray diffraction techniques) of which are controlled by the nature of the specific acid. When terephthalic acid was used, a novel mononuclear molecule [Co(H L) 2Cl 3]Cl(H 2O) ( 1) was obtained [orthorhombic, Pnma, a=24.604(16) , b=9.882(7) , c=6.609(4) , Z=4], in which the Co II center takes the unusual compressed trigonal-bipyramidal coordination geometry (CoN 2Cl 3) and multiple hydrogen-bonding interactions extend this structure into a three-dimensional supramolecular network. However, with the replacement of terephthalic acid with malonic acid in the above reaction, a one-dimensional coordination polymer [Co LCl 2] n ( 2) was obtained [monoclinic, P2 1/ n, a=6.363(3) , b=10.244(5) , c=12.124(5) , ?=103.560(8), Z=4], in which the tetrahedral Co II centers (CoCl 2N 2) are linked by the bidentate-coordinated piperazine molecules to form a zigzag chain array and these coordination chains are further expanded to a three-dimensional hydrogen-bonding architecture. In addition, a mononuclear complex [Co(gly) 3](H 2O) ( 3) [monoclinic, P2 1/ c, a=6.261(5) , b=14.280(9) , c=12.182(8) , ?=101.450(14), Z=4] was yielded when glycine was used in the similar procedure. A three-dimensional framework is also observed through the hydrogen-bonding interactions between [Co(gly) 3] moieties, in which the guest water molecules are included. These results unequivocally indicate that the nature of the organic acid templates play the key role in formation of these complexes.

Zhao, Xiao-Jun; Du, Miao; Wang, Ying; Bu, Xian-He

2004-04-01

188

Novel Piperazine-based Compounds Inhibit Microtubule Dynamics and Sensitize Colon Cancer Cells to Tumor Necrosis Factor-induced Apoptosis*  

PubMed Central

We recently identified a series of mitotically acting piperazine-based compounds that potently increase the sensitivity of colon cancer cells to apoptotic ligands. Here we describe a structure-activity relationship study on this compound class and identify a highly active derivative ((4-(3-chlorophenyl)piperazin-1-yl)(2-ethoxyphenyl)methanone), referred to as AK301, the activity of which is governed by the positioning of functional groups on the phenyl and benzoyl rings. AK301 induced mitotic arrest in HT29 human colon cancer cells with an ED50 of ?115 nm. Although AK301 inhibited growth of normal lung fibroblast cells, mitotic arrest was more pronounced in the colon cancer cells (50% versus 10%). Cells arrested by AK301 showed the formation of multiple microtubule organizing centers with Aurora kinase A and ?-tubulin. Employing in vitro and in vivo assays, tubulin polymerization was found to be slowed (but not abolished) by AK301. In silico molecular docking suggests that AK301 binds to the colchicine-binding domain on ?-tubulin, but in a novel orientation. Cells arrested by AK301 expressed elevated levels of TNFR1 on their surface and more readily activated caspases-8, -9, and -3 in the presence of TNF. Relative to other microtubule destabilizers, AK301 was the most active TNF-sensitizing agent and also stimulated Fas- and TRAIL-induced apoptosis. In summary, we report a new class of mitosis-targeting agents that effectively sensitizes cancer cells to apoptotic ligands. These compounds should help illuminate the role of microtubules in regulating apoptotic ligand sensitivity and may ultimately be useful for developing agents that augment the anti-cancer activities of the immune response. PMID:24338023

Chopra, Avijeet; Anderson, Amy; Giardina, Charles

2014-01-01

189

Heat of Dissolution Measurements for CO2 in Mixed Alkanolamine Solvents  

SciTech Connect

The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}- alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

Vinayak N. Kabadi

2005-12-01

190

HEAT OF DISSOLUTION MEASUREMENTS FOR CO2 IN MIXED ALKANOLAMINE SOLVENTS  

SciTech Connect

The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

Vinayak N. Kabadi

2005-05-23

191

HEAT OF DISSOLUTION MEASUREMENTS FOR CO2 IN MIXED ALKANOLAMINE SOLVENTS  

SciTech Connect

The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80 C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

Vinayak N. Kabadi

2004-04-27

192

HEAT OF DISSOLUTION MEASUREMENTS FOR CO2 IN MIXED ALKANOLAMINE SOLVENTS  

SciTech Connect

The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80 C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

Vinayak N. Kabadi

2004-11-15

193

Carbon capture and sequestration: an exploratory inhalation toxicity assessment of amine-trapping solvents and their degradation products.  

PubMed

Carbon dioxide (CO2) absorption with aqueous amine solvents is a method of carbon capture and sequestration (CCS) from flue gases. One concern is the possible release of amine solvents and degradation products into the atmosphere, warranting evaluation of potential pulmonary effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP) underwent oxidative and CO2-mediated degradation for 75 days. C57bl/6N mice were exposed for 7 days by inhalation of 25 ppm neat amine or equivalant concentration in the degraded mixture. The aqueous solutions were nebulized to create the inhalation atmospheres. Pulmonary response was measured by changes in inflammatory cells in bronchoalveolar lavage fluid and cytokine expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus assays were applied to assess genotoxicity. Chemical analysis of the test atmosphere and liquid revealed complex mixtures, including acids, aldehydes, and other compounds. Exposure to oxidatively degraded MEA increased (p < 0.05) total cells, neutrophils, and lymphocytes compared to control mice and caused inflammatory cytokine expression (statistical increase at p < 0.05). MEA and CO2-degraded MEA were the only atmospheres to show statistical (p < 0.05) increase in oxidative stress. CO2 degradation resulted in a different composition, less degradation, and lower observed toxicity (less magnitude and number of effects) with no genotoxicity. Overall, oxidative degradation of the amines studied resulted in enhanced toxicity (increased magnitude and number of effects) compared to the neat chemicals. PMID:25167095

McDonald, Jacob D; Kracko, Dean; Doyle-Eisele, Melanie; Garner, C Edwin; Wegerski, Chris; Senft, Al; Knipping, Eladio; Shaw, Stephanie; Rohr, Annette

2014-09-16

194

Temperature- and pH-responsive nanoparticles of biocompatible polyurethanes for doxorubicin delivery.  

PubMed

A series of temperature- and pH-responsive polyurethanes based on hexamethylene diisocyanate (HDI) and 4,4'-diphenylmethane diisocyanate (MDI) were synthesized by a coupling reaction with bis-1,4-(hydroxyethyl) piperazine (HEP), N-methyldiethanolamine (MDEA) and N-butyldiethanolamine (BDEA), respectively. The chemical structure, molecular weight, thermal property and crystallization properties were characterized by Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) spectroscopy. The resulting polyurethanes were then used to prepare nanoparticles either by direct dispersion method or dialysis method. Their pH and temperature responsibilities were evaluated by optical transmittance and size measurement in aqueous media. Interestingly, HDI-based and MDI-based polyurethanes exhibited different pH and temperature responsive properties. Nanoparticles based on HDI-HEP and HDI-MDEA were temperature-responsive, while MDI-based biomaterials were not. All of them showed pH-sensitive behavior. The possible responsive mechanism was investigated by (1)H NMR spectroscopy. The cytotoxicity of the polyurethanes was evaluated using methylthiazoletetrazolium (MTT) assay in vitro. It was shown that the HDI-based polyurethanes were non-toxic, and could be applied to doxorubicin (DOX) encapsulation. The experimental results indicated that DOX could be efficiently encapsulated into polyurethane nanoparticles and uptaken by Huh-7 cells. The loaded DOX molecules could be released from the drug-loaded polyurethane nanoparticles upon pH and temperature changes, responsively. PMID:23262421

Wang, Anning; Gao, Hui; Sun, Yanfang; Sun, Yu-long; Yang, Ying-Wei; Wu, Guolin; Wang, Yinong; Fan, Yunge; Ma, Jianbiao

2013-01-30

195

Chiral separation and quantification of R/S-amphetamine, R/S-methamphetamine, R/S-MDA, R/S-MDMA, and R/S-MDEA in whole blood by GC-EI-MS.  

PubMed

The enantioselective composition of the amphetamines is of interest, as the enantiomers show differences in their pharmacological effects and several methods for chiral separation of amphetamines have been described. Only a few methods have used whole blood as matrix and none of these separates both classic amphetamines (amphetamine and methamphetamine) and designer amphetamines (MDA, MDMA and MDEA). The aim of this study was, therefore, to develop a method for enantioselective analysis of AM, MA, MDA, MDMA, and MDEA in whole blood. The amphetamines were extracted from 0.5 g of whole blood by liquid-liquid extraction. After derivatization with R-MTPCl, the resulting diastereomers were separated by GC on a HP-5MS column and detected by SIM-MS. R-MTPCl was used as derivatization reagent because of the stability of this reagent and good separation of these analytes. Through the method, development time and temperature of the derivatization were optimized, and by admixture of 0.02% triethylamine it became possible to detect the amphetamines in adequately low concentrations as more analytes were derivatized. The method was validated and it was linear from 0.004 to 3 microg/g per enantiomer. The accuracy was within 91-115%, while the repeatability and reproducibility were < or =15% R.S.D. A method suitable for enantioselective separation and analysis of the amphetamines has been achieved, and the method was applied to analysis of whole blood samples originating from traffic and criminal cases and post mortem cases. PMID:16797258

Rasmussen, Louise Bang; Olsen, Kristine Hje; Johansen, Sys Stybe

2006-10-01

196

Structural analysis of complexes formed by ethyl 4-phenylthiocarbamoyl piperazine-1-carboxylate with Ni(II), Zn(II) and Cd(II) through spectroscopic and DFT techniques  

NASA Astrophysics Data System (ADS)

A piperazine derivative, ethyl 4-phenylthiocarbamoyl piperazine-1-carboxylate and its Ni(II), Zn(II) and Cd(II) complexes have been synthesized and characterized by elemental analyses, magnetic susceptibility measurement, UV-Visible, FTIR, Raman spectroscopic and DFT methods. The Ni(II) and Zn(II) bind through the N and S sites of the two ligand Heptpc and N site of two pyridine molecules. However, the Cd(II) binds through the only N sites of the two ligand Heptpc and N site of two pyridine molecules. On the basis of various techniques used for the characterizations of the complexes, we found that the most possible geometry of the Ni(II) and Zn(II) complexes are distorted octahedral and of the Cd(II) complex is distorted tetrahedral.

Prakash, Om; Gautam, Priyanka; Dani, R. K.; Nandi, Abhisikta; Singh, N. K.; Singh, Ranjan K.

2014-04-01

197

1,4-Bis{[hydroxy(phenyl)phosphoryl]methyl}piperazine-1,4-diium tetrachloridocadmate(II) dihydrate and the cobaltate(II) analogue.  

PubMed

The reaction of aminophosphinic acid with CdCl22.5H2O or CoCl26H2O in concentrated hydrochloric acid yielded the isostructural compounds 1,4-bis{[hydroxy(phenyl)phosphoryl]methyl}piperazine-1,4-diium tetrachloridocadmate(II) dihydrate, (C18H26N2O4P2)[CdCl4]2H2O, (I), and 1,4-bis{[hydroxy(phenyl)phosphoryl]methyl}piperazine-1,4-diium tetrachloridocobaltate(II) dihydrate, (C18H26N2O4P2)[CoCl4]2H2O, (II). The asymmetric unit of each contains two half dications, both located on crystallographic centres of inversion, a tetrachloridometallate(II) dianion and two solvent water molecules. The residues are linked into two-dimensional layers in the ab plane by O-HO hydrogen bonds. PMID:23832033

Du, Chao-Jun; Wang, Li-Sheng

2013-07-01

198

Pelanserin: 3-[3-(4-phenylpiperazin-1-yl)propyl]quinazoline-2,4(1H,3H)-dione  

PubMed Central

The title compound, C21H24N4O2, is a potent serotonin 5-HT2 and ?1-adrenoceptor antagonist. The n-propyl chain links the quinazolinedione heterocycle and the phenylpiperazine group in which the benzene ring is equatorially located and the piperazine ring has the expected chair conformation. The dihedral angle between the planes of the benzene ring and the quinazolinedione ring system is 74.1?(1). In the crystal, molecules form centrosymmetric dimers through R 2 2(8) hydrogen-bonded rings involving the amine and one carbonyl group of the quinazolinedione moiety. These dimers are extended into chains extending along the a-axis direction through expanded centrosymmetric cyclic CH?O associations involving the second carbonyl group, giving R 2 2(20) and R 1 2(7) motifs. PMID:25249922

Aguirre Hernndez, Gerardo; Somanathan, Ratnasamy; Berns, Sylvain

2014-01-01

199

Laboratory and greenhouse evaluation of a new systemic fungicide, N,N'-bis-(1-formamido-2,2,2-trichloroethyl)-piperazine (CELA W 524)  

Microsoft Academic Search

The new systemic fungicide N,N'-bis-(1-formamido-2,2,2-trichloroethyl)-piperazine (CELA W 524) was shown to display a moderate to distinct fungitoxic activity in vitro towards several pathogenic and non-pathogenic fungi. Depending on the inert ingredients present2, the available formulations proved to be either rather phytotoxic or virtually non-phytotoxic. Pre-infectional spraying with the non-phytotoxic formulation provided complete protection of barley, bean, cucumber, pea and tomato

A. Fuchs; S. Doma; J. Vrs

1971-01-01

200

Phenyl benzenesulfonamides are novel and selective 5-HT6 antagonists: identification of N-(2,5-dibromo-3-fluorophenyl)-4-methoxy-3-piperazin-1-ylbenzenesulfonamide (SB-357134).  

PubMed

Substituted N-phenyl-4-methoxy-3-piperazin-1-ylbenzenesulfonamides and conformationally restricted analogues have been identified as high affinity and selective 5-HT6 antagonists. Compounds from this series had a range of pharmacokinetic profiles in rat and in general there was a correlation between clearance and CNS penetration. Based on its overall biological profile 2 (SB-357134) was selected for further pre-clinical evaluation. PMID:11140733

Bromidge, S M; Clarke, S E; Gager, T; Griffith, K; Jeffrey, P; Jennings, A J; Joiner, G F; King, F D; Lovell, P J; Moss, S F; Newman, H; Riley, G; Rogers, D; Routledge, C; Serafinowska, H; Smith, D R

2001-01-01

201

Absorption of carbon dioxide by the absorbent composed of piperazine and 2-amino-2-methyl-1-propanol in PVDF membrane contactor  

Microsoft Academic Search

This paper tests the performance of microporous polyvinylidinefluoride (PVDF) hollow fiber in a gas absorption membrane process (GAM) using the aqueous solutions of piperazine (PZ) and 2-amino-2-methyl-1-propanol (AMP). Experiments were conducted at various gas flow rates, liquid flow rates and absorbent concentrations. Experimental results showed that wetting ratio was about 0.036% when used with the aqueous alkanolamine solutions, while that

Su-Hsia Lin; Pen-Chi Chiang; Chun-Fan Hsieh; Meng-Hui Li; Kuo-Lun Tung

2008-01-01

202

Effects of repeated administration of the monoamine oxidase inhibitor phenelzine on the discriminability of d-lysergic acid diethylamide (LSD) and 1-(m-trifluoromethylphenyl) piperazine (TFMPP)  

Microsoft Academic Search

Rats trained to discriminate d-lysergic acid diethylamide (LSD; 0.08 mg\\/kg) or 1-(m-trifluoromethylphenyl) piperazine (TFMPP; 0.8 mg\\/kg) were treated with the monoamine oxidase inhibitor (MAOI) phenelzine (10 mg\\/kg\\/day) for 7 days. After a 24 h washout period, they were challenged with the training drug (and dose) or saline, during extinction test sessions. Following 0.08 mg\\/kg LSD, LSD-trained rats responded primarily on

Kathryn A. Cunningham; Brenda A. Carroll; James B. Appel

1986-01-01

203

Kinetics of the absorption of carbon dioxide into mixed aqueous solutions of 2-amino-2-methyl-l-propanol and piperazine  

Microsoft Academic Search

The reaction kinetics of the absorption of CO2 into aqueous solutions of piperazine (PZ) and into mixed aqueous solutions of 2-amino-2-methyl-l-propanol (AMP) and PZ were investigated by wetted wall column at 3040C. The physical properties such as density, viscosity, solubility, and diffusivity of the aqueous alkanolamine solutions were also measured. The N2O analogy was applied to estimate the solubilities and

Wei-Chen Sun; Chia-Bao Yong; Meng-Hui Li

2005-01-01

204

Conformational analysis of piperazine and piperidine analogs of GBR 12909: stochastic approach to evaluating the effects of force fields and solvent  

Microsoft Academic Search

Analogs of the flexible dopamine reuptake inhibitor, GBR 12909 (1), may have potential utility in the treatment of cocaine abuse. As a first step in the 3D-QSAR modeling of the dopamine transporter\\u000a (DAT)\\/serotonin transporter (SERT) selectivity of these compounds, we carried out conformational analyses of two analogs of\\u000a 1: a piperazine (2) and a related piperidine (3). Ensembles of conformers

Deepangi Pandit; William Roosma; Milind Misra; Kathleen M. Gilbert; William J. Skawinski; Carol A. Venanzi

2011-01-01

205

Proof of a 1-(3-chlorophenyl)piperazine (mCPP) intakeUse as adulterant of cocaine resulting in drugdrug interactions?  

Microsoft Academic Search

Since 2005, increasing numbers of seizures of the designer drug of abuse 1-(3-chlorophenyl)piperazine (mCPP) have been reported. This paper describes the unequivocal proof of a mCPP intake. Differentiation from the intake of its precursor drugs trazodone and nefazodone was performed by a systematic toxicological analysis (STA) procedure using full-scan GCMS after acid hydrolysis, liquidliquid extraction and microwave-assisted acetylation. The found

Roland F. Staack; Liane D. Paul; Dagmar Schmid; Gabriele Roider; Burkhard Rolf

2007-01-01

206

Synthesis and dopamine transporter affinity of chiral 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(2-hydroxypropyl)piperazines as potential cocaine abuse therapeutic agents  

Microsoft Academic Search

A series of optically pure phenyl-and non-phenyl-substituted 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(2-hydroxypropyl)piperazines was synthesized and their binding affinity for dopamine transporter (DAT) was investigated. The analogues with a hydroxyl group in the S configuration were more selective for the DAT over the serotonin transporter (SERT) than the corresponding R enantiomers. Compound (+)-11 showed high affinity and selectivity for DAT over the SERT and, therefore,

Ling-Wei Hsin; Thomas Prisinzano; Chavon R Wilkerson; Christina M Dersch; Robert Horel; Arthur E Jacobson; Richard B Rothman; Kenner C Rice

2003-01-01

207

1,4-Bis(4-nitrosophenyl)piperazine: novel bridging ligand in dinuclear complexes of rhodium(III) and iridium(III).  

PubMed

The synthesis, spectroscopic characterization and crystal structures of the first 1,4-bis(4-nitrosophenyl)piperazine (BNPP) (4) bridged dinuclear complexes of rhodium(III) and iridium(III) are presented. The reaction of the ?(2)-halogenido-bridged dimers [(?(5)-C(5)Me(5))IrX(2)](2) [X = Cl (5a), Br (5b), I (5c)] and [(?(5)- C(5)Me(5))RhCl(2)](2) (6a) with 4 yields the dinuclear complexes [(?(5)-C(5)Me(5))IrX(2)](2)-BNPP (7a-c) and [(?(5)-C(5)Me(5))RhCl(2)](2)-BNPP (8a). All new compounds were characterized by their NMR, IR and mass spectra. The X-ray structure analyses of the obtained half-sandwich complexes revealed a slightly distorted pseudo-octahedral configuration ("three-legged pianostool") for the metal(III) centers. The bridging BNPP ligand is ?-N coordinated by both nitroso groups and shows different conformations of the piperazine ring depending on the solvent used for crystallization. Moreover the crystal structures of 1,4-bis(4-nitrosophenyl)piperazine (4) and its precursor 1,4-diphenylpiperazine (3) are reported. PMID:22183299

Wirth, Stefan; Barth, Florian; Lorenz, Ingo-Peter

2012-02-21

208

Tuning of the dimensional linkage from the complex to the framework by thermal conversion in the system Fe/Cl/piperazine.  

PubMed

An attempt to control the three structural features linkage, structural dimensionality and coordination mode is presented for the combination of Fe(II) and Fe(III) chlorides together with the ditopic ligand piperazine (pipz). Thermal conversion of small units like complexes into highly aggregated structures such as coordination polymers is demonstrated for the framework formation of ?[Fe(II)Cl2(pipz)] starting from both FeCl2 and FeCl3. Depending on the oxidation state of iron, different reaction paths and metastable products are observed. Iron(II)chloride reacts with piperazine to form the previously unknown 2-dimensional network, ?[Fe(II)2Cl4(pipz)3]pipz, which can be thermally converted into the 3-dimensional framework at elevated temperatures by release of piperazine. The use of iron(III)chloride starts with an internal redox reaction giving the divalent complex [Fe(II)Cl3(Hpipz)(pipz)] in the first step, followed by thermal conversion yielding the framework ?[Fe(II)Cl2(pipz)] and the salt [Fe(II)Cl3(Hpipz)(pipz)](Hpipz)Cl2. Both thermal conversion mechanisms were further investigated by in situ IR-spectroscopy, differential thermal analysis and thermogravimetry. PMID:25188834

Schnfeld, F; Wirthensohn, R; Schmitt, H-C; Constantinidis, P; Fischer, I; Mller-Buschbaum, K

2014-11-01

209

An unknown solvate of 1-(2,4-di-chloro-benz-yl)-4-[(4-methyl-phen-yl)sulfon-yl]piperazine.  

PubMed

In the title compound, C18H20Cl2N2O2S, the piperazine ring adopts a chair conformation. The dihedral angle between the sulfonyl-bound benzene ring and the best-fit plane through the six non-H atoms of the piperazine ring is 72.22?(12); those between the di-chloro-benzene ring and the sulfonyl and piperazine rings are 2.44?(13) and 74.16?(2), respectively. In the crystal, mol-ecules are connected through weak C-H?O inter-actions into a hexa-meric unit generating a R 6 (6)(60) motif in the ab plane. The mol-ecules are also connected into C(4) chains through weak C-H?N inter-actions. The solvent used to grow the crystal was a mixture of di-chloro-methane and methanol, but the resulting electron density was uninter-pretable. The solvent contribution to the scattering was removed with the SQUEEZE routine in PLATON [Spek (2009 ?). Acta Cryst. D65, 148-155]. The formula mass and unit-cell characteristics do not take into account the disordered solvent. PMID:23723926

Sreenivasa, S; Manojkumar, K E; Anitha, H C; Suchetan, P A; Palakshamurthy, B S; Jayashree, Yenagi; Tonannavar, J

2013-05-01

210

Enantiomeric separation and quantitation of (+/-)-amphetamine, (+/-)-methamphetamine, (+/-)-MDA, (+/-)-MDMA, and (+/-)-MDEA in urine specimens by GC-EI-MS after derivatization with (R)-(-)- or (S)-(+)-alpha-methoxy-alpha-(trifluoromethy)phenylacetyl chloride (MTPA).  

PubMed

In drug testing, the presence of methamphetamine in urine is generally confirmed by a gas chromatography-mass spectrometry (GC-MS) method. Derivatization of the compound to a perfluoroalkylamide, prior to confirmation, typically yields better chromatographic separation. Once methamphetamine is detected, a second GC-MS test is necessary to distinguish positive results from the use of over-the-counter medication, Vicks inhaler, or from use of a prescription drug, selegiline (Deprenyl). R-(-)-Methamphetamine is the urinary product from legitimate use of these medications. The second GC-MS test is to confirm illicit use of (S)-(+)-methamphetamine. In the procedure, the two methamphetamine isomers are changed to the chromatographically separable diastereomers by a chiral derivatizing agent, (S)-(-)-trifluoroacetylprolyl chloride (TPC). But the method has inherent limitations. Racemization of the reagent produces mixed diastereomers even from pure (S)-(+)-methamphetamine. Instead of using TPC, we utilized (R)-(-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride (MTPA) to prepare the amides of diastereomers of methamphetamine. No racemization was observed with this reagent. The method was extended to resolve GC peaks of (R)-(-)- and (S)-(+)-isomers of amphetamine, 3,4-methylenedioxyamphetamine (MDA), N-methyl-MDA (MDMA), and N-ethyl-MDA (MDEA). Three ions from the drug and two ions from the deuterated internal standard were monitored to characterize and quantitate the drugs. For MDEA, only one ion was used. The quantitation was linear over 25 to 5000 ng/mL for MDEA and 25 to 10,000 ng/mL for all other drugs. Correlation coefficients were > 0.996. Precision calculated as the coefficient of variation at the calibrator concentration of 500 ng/mL was within +/- 11% for all drugs. The method was applied to test 43 urine specimens. In 91% of the methamphetamine-positive specimens, only the (S)-(+)-isomer was detected. In all MDMA-positive specimens, the concentrations of (R)-(-)-isomer were greater than the (S)-(+)-isomer indicating longer retention of (R)-(-)-isomer in the human body. The specimen concentrations (R + S) compared well with that of a non-chiral method that used 4-carboethoxyhexafluorobutyryl chloride as derivatizing agent. But the MTPA method has some advantage. It alone can replace the two GC-MS methods needed to confirm the presence of (S)-(+)-isomers of amphetamine and methamphetamine. PMID:15516295

Paul, Buddha D; Jemionek, John; Lesser, David; Jacobs, Aaron; Searles, Douglas A

2004-09-01

211

HS process: an advanced process for selective H/sub 2/S  

SciTech Connect

Union Carbide's HS process offers improved efficiency in both H/sub 2/S removal and system costs while remaining flexible to diverse gas-conditioning requirements. The process combines three principal elements - an MDEA (methyldiethanolamine) solvent, a multistaged contactor design, and a special selective contactor tray. Prototype pilot-plant operations have demonstrated the superior performance of the HS process over existing methods.

Sigmund, P.W.; Butwell, K.F.; Wussler, A.J.

1981-01-01

212

Studies on the non-covalent interactions between cyclodextrins and aryl alkanol piperazine derivatives by mass spectrometry and fluorescence spectroscopy.  

PubMed

The non-covalent complexes of alpha- and beta-cyclodextrins (alpha-, beta-CDs) with two aryl alkanol piperazine derivatives (Pipe I and Pipe II) have been studied by electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. The ESI-MS experimental results demonstrated that Pipe I can conjugate to beta-CD and form 1:1 or 1:2 stoichiometric non-covalent complexes, and Pipe II can only form 1:1 complexes with alpha- or beta-CD. Fluorescence spectra indicated that the fluorescence intensities of Pipe I and Pipe II can be enhanced by increasing the content of beta-CD. The mass spectrometric titration experiments showed that the dissociation constants K(d1) were 5.77 and 9.52 x 10(-4) mol L(-1) for the complexes of alpha-CD with Pipe I and Pipe II, respectively, revealing that the binding of alpha-CD-Pipe I was stronger than alpha-CD-Pipe II. The K(d1) and K(d2) values were 9.81 x 10(-4) mol L(-1) and 1.11 x 10(-7) (mol L(-1))(2) for 1:1 and 1:2 complexes of Pipe I with beta-CD, respectively. The K(d) values obtained from fluorescence spectroscopy were in agreement with those from ESI-MS titration. PMID:20623479

Chu, Yan-Qiu; Dai, Xin-Hua; Jiang, Dan; Jiang, Gong-Yu; Fang, Xiang; Ding, Chuan-Fan

2010-08-15

213

Complexation, thermal and catalytic studies of N-substituted piperazine, morpholine and thiomorpholine with some metal ions.  

PubMed

Several Cu(II), Pt(II) and Ni(II) complexes of N-substituted, piperazine (NN donor), morpholine (NO donor) and thiomorpholine (NS donor) derivatives were synthesized and their thermal behavior and catalytic activity in epoxidation reaction of cis-diphenylethylene were studied using oxygen sources NaOCl. The coordination compounds of Cu(II), Pt(II) and Ni(II) having general formula [MLCl]Cl, [ML2l]Cl2 or [ML]Cl2 with tetra coordinated geometry around metal ions have been isolated as solid. All the ligands and complexes were identified by spectroscopic methods and elemental analysis, magnetic measurements, electrical conductance and thermal analysis. A square planer structures have been proposed for all complexes. The thermal stability of the complexes discussed in terms of ligands donor atoms, geometry and central metal ions. The complexes have a similar thermal behavior for the selected metal ions. The thermogravimetric analyses suggest high thermal stability for most complexes followed by thermal decomposition in different steps. The decomposition processes were observed as water elimination, chloride anion removal and degradation of the organic ligands. Catalytic ability of the complexes were examined and found that all the complexes can effectively catalyze the epoxidation of cis-stilbene with NaOCl. PMID:24091345

Kacan, Mesut; Turkyilmaz, Murat; Karabulut, Ferhat; Altun, Ozlen; Baran, Yakup

2014-01-24

214

Complexation, thermal and catalytic studies of N-substituted piperazine, morpholine and thiomorpholine with some metal ions  

NASA Astrophysics Data System (ADS)

Several Cu(II), Pt(II) and Ni(II) complexes of N-substituted, piperazine (NN donor), morpholine (NO donor) and thiomorpholine (NS donor) derivatives were synthesized and their thermal behavior and catalytic activity in epoxidation reaction of cis-diphenylethylene were studied using oxygen sources NaOCl. The coordination compounds of Cu(II), Pt(II) and Ni(II) having general formula [MLCl]Cl, [ML2l]Cl2 or [ML]Cl2 with tetra coordinated geometry around metal ions have been isolated as solid. All the ligands and complexes were identified by spectroscopic methods and elemental analysis, magnetic measurements, electrical conductance and thermal analysis. A square planer structures have been proposed for all complexes. The thermal stability of the complexes discussed in terms of ligands donor atoms, geometry and central metal ions. The complexes have a similar thermal behavior for the selected metal ions. The thermogravimetric analyses suggest high thermal stability for most complexes followed by thermal decomposition in different steps. The decomposition processes were observed as water elimination, chloride anion removal and degradation of the organic ligands. Catalytic ability of the complexes were examined and found that all the complexes can effectively catalyze the epoxidation of cis-stilbene with NaOCl.

Kacan, Mesut; Turkyilmaz, Murat; Karabulut, Ferhat; Altun, Ozlen; Baran, Yakup

2014-01-01

215

Investigation on the inclusion interaction of 4-sulfonatocalix[n]arenes with 1-(4-nitrophenyl)piperazine  

NASA Astrophysics Data System (ADS)

The inclusion behaviors of 4-Sulfonatocalix[n]arenes (SCXn) (n = 4, 6, 8) with 1-(4-nitrophenyl)piperazine (NPP) were investigated by UV spectroscopy and fluorescence spectroscopy at different pH values (pH = 3.05, 6.50, 8.40). The UV absorption and fluorescence intensity of NPP remarkably increased in presence of SCXn revealing formation of the inclusion complexes between NPP and SCXn. Moreover, the formation constants (K) of inclusion complexes were also determined by the non-linear fitting method, and the obtained data showed that the formation constants decreased gradually with the increasing of the pH value. When the pH value was 3.05, the formation constant of NPP with SCX8 reached a maximum of 1.7 107 L mol-1. The stoichiometric ratio was verified to be 1:1 by the continuous variation method. Meanwhile FT-IR and DSC analysis also indicated that NPP could form the inclusion complex with SCXn. In order to explore the inclusion mechanism of NPP with SCXn, 1H NMR and molecular modeling studies were carried out and experimental results showed that the part of benzene ring of NPP penetrated into the hydrophobic cavity of SCXn.

Zhang, Yongbin; Chao, Jianbin; Zhao, Shuhui; Xu, Penghao; Wang, Hongfang; Guo, Zhiqiang; Liu, Diansheng

2014-11-01

216

Crystallographic characterisation of Ti(IV) piperazine complexes and their exploitation for the ring opening polymerisation of rac-lactide.  

PubMed

In this paper a series of eight Ti(IV) piperazine based complexes have been prepared and fully characterised in the solid-state by X-ray crystallography and in solution via NMR spectroscopy. In the solid-state either Ti(2)(L)(O(i)Pr)(6) or Ti(2)(L)(2)(O(i)Pr)(4) were observed depending upon the nature of the starting ligand. For complexes with less sterically demanding ligands (1H(2) and 2H(2)) an equilibrium was observed: 2 Ti(2)(L)(O(i)Pr)(6) ? Ti(2)(L)(2)(O(i)Pr)(4) + 2 Ti(O(i)Pr)(4). The thermodynamic properties (?G, ?H and ?S) have been investigated via variable temperature NMR spectroscopy. With more sterically demanding ligands (3-8H(2)) the Ti(2)(L)(O(i)Pr)(6) form was the most prevalent in the solid-state and in solution. These complexes have been tested for the production of polylactide under melt and solution conditions with high conversions being obtained. PMID:21246147

Hancock, Stuart L; Mahon, Mary F; Jones, Matthew D

2011-03-01

217

Novel amide and sulphonamide derivatives of 6-(piperazin-1-yl)phenanthridine as potent Mycobacterium tuberculosis H37Rv inhibitors.  

PubMed

A series of thirty three novel 6-(piperazin-1-yl)phenanthridine amide and sulphonamide analogues were synthesized, characterized and screened for their invitro antimycobacterial activity against Mycobacterium tuberculosis (MTB) H37Rv strain. These compounds exhibited minimum inhibitory concentration (MIC) between 1.56 and ?50?g/mL. Out of these derivatives, few compounds 6l, 6r, 7b, 7f, 7g and 7k exhibited moderate activity (MIC=6.25?g/mL) and compounds 6b, 6e, 6k, 6n, 7h, 7i and 7n displayed good activity (MIC=3.13?g/mL), whereas compounds 6m, 6s and 7d exhibited excellent anti-tubercular activity (MIC=1.56?g/mL). In addition, MTT assay was accomplished on the active analogues of the series against mouse macrophage (RAW 264.7) cells to evaluate the toxicity profile of the newly synthesized compounds and selectivity index of the compounds was determined. Additionally, compounds 6b and 7d were docked to the ATPase domain of M. tuberculosis GyrB protein to know the interaction profile and structures of compounds 6b and 7d were further substantiated through single crystal XRD. PMID:25590862

Naidu, Kalaga Mahalakshmi; Nagesh, Hunsur Nagendra; Singh, Manjeet; Sriram, Dharmarajan; Yogeeswari, Perumal; Gowri Chandra Sekhar, Kondapalli Venkata

2015-03-01

218

Design, synthesis and antimycobacterial activity of various 3-(4-(substitutedsulfonyl)piperazin-1-yl)benzo[d]isoxazole derivatives.  

PubMed

In this communication, we synthesized a series of twenty four novel 3-(4-(substitutedsulfonyl)piperazin-1-yl)benzo[d]isoxazole analogues, characterized using various spectroscopic techniques and evaluated for their in vitro anti-tubercular activity against Mycobacterium tuberculosis (MTB) H37Rv strain. The titled compounds exhibited Minimum inhibitory concentration (MIC) between 3.125 and >50 ?g/mL. Among the tested compounds, 5c, 6a, 6j and 6p exhibited moderate activity (MIC = 12.5 ?g/mL), while 5a and 6i exhibited good activity (MIC = 6.25 ?g/mL) and 6b (MIC = 3.125 ?g/mL) exhibited very good anti-tubercular activity. In addition, the analogues 5a, 5c, 6a, 6b, 6i, 6j and 6p were subjected to toxicity studies against mouse macrophage (RAW 264.7) cell lines to analyse the selectivity profile of the newly synthesized compounds and selectivity index of the most active compound was found to be >130 indicating suitability of the compound for further drug development. Structure of 6b was further substantiated through single crystal XRD. PMID:25240097

Naidu, Kalaga Mahalakshmi; Suresh, Amaroju; Subbalakshmi, Jayanty; Sriram, Dharmarajan; Yogeeswari, Perumal; Raghavaiah, Pallepogu; Chandra Sekhar, Kondapalli Venkata Gowri

2014-11-24

219

Piperazine-2,3-dicarboxylic acid Derivatives as Dual Antagonists of NMDA and GluK1-Containing Kainate Receptors  

PubMed Central

Competitive N-methyl-D-aspartate receptor (NMDAR) antagonists bind to the GluN2 subunit, of which there are four types (GluN2A-D). We report that some N1-substituted derivatives of cis-piperazine-2,3-dicarboxylic acid display improved relative affinity for GluN2C and GluN2D versus GluN2A and GluN2B. These derivatives also display subtype-selectivity among the more distantly related kainate receptor family. Compounds 18i and (?)-4 were the most potent kainate receptor antagonists and 18i was selective for GluK1 versus GluK2, GluK3 and AMPA receptors. Modeling studies revealed structural features required for activity at GluK1 subunits and suggested that S674 was vital for antagonist activity. Consistent with this hypothesis, replacing the equivalent residue in GluK3 (alanine) with a serine imparts 18i antagonist activity. Antagonists with dual GluN2D and GluK1 antagonist activity may have beneficial effects in various neurological disorders. Consistent with this idea, antagonist 18i (30 mg/Kg i.p.) showed antinociceptive effects in an animal model of mild nerve injury. PMID:22111545

Irvine, Mark W.; Costa, Blaise M.; Dlaboga, Daniel; Culley, Georgia; Hulse, Richard; Scholefield, Caroline L.; Atlason, Palmi; Fang, Guangyu; Eaves, Richard; Morley, Richard; Mayo-Martin, Maria B.; Amici, Mascia; Bortolotto, Zuner A.; Donaldson, Lucy; Collingridge, Graham L.; Molnr, Elek; Monaghan, Daniel T.; Jane, David E.

2011-01-01

220

Investigation on the inclusion interaction of 4-sulfonatocalix[n]arenes with 1-(4-nitrophenyl)piperazine.  

PubMed

The inclusion behaviors of 4-Sulfonatocalix[n]arenes (SCXn) (n=4, 6, 8) with 1-(4-nitrophenyl)piperazine (NPP) were investigated by UV spectroscopy and fluorescence spectroscopy at different pH values (pH=3.05, 6.50, 8.40). The UV absorption and fluorescence intensity of NPP remarkably increased in presence of SCXn revealing formation of the inclusion complexes between NPP and SCXn. Moreover, the formation constants (K) of inclusion complexes were also determined by the non-linear fitting method, and the obtained data showed that the formation constants decreasedgradually with the increasing of the pH value. When the pH value was 3.05, the formation constant of NPP with SCX8 reached a maximum of 1.710(7) L mol(-1). The stoichiometric ratio was verified to be 1:1 by the continuous variation method. Meanwhile FT-IR and DSC analysis also indicated that NPP could form the inclusion complex with SCXn. In order to explore the inclusion mechanism of NPP with SCXn, 1H NMR and molecular modeling studies were carried out and experimental results showed that the part of benzene ring of NPP penetrated into the hydrophobic cavity of SCXn. PMID:24858345

Zhang, Yongbin; Chao, Jianbin; Zhao, Shuhui; Xu, Penghao; Wang, Hongfang; Guo, Zhiqiang; Liu, Diansheng

2014-11-11

221

Further delineation of hydrophobic binding sites in dopamine D(2)/D(3) receptors for N-4 substituents on the piperazine ring of the hybrid template 5/7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-2-ol.  

PubMed

Here we report a structure-activity relationship (SAR) study of analogues of 5/7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-2-ol. Our SAR is focused on introduction of various substitutions in the piperazine ring of the hybrid template. The goal behind this study is to delineate the nature of the binding pocket for N-aryl substitution in the piperazine ring by observing the effect of various hydrophobic and other heteroaromatic substitutions on binding affinity (K(i)), as measured with tritiated spiperone and HEK-293 cells expressing either D(2) or D(3) receptors. Functional activity of selected compounds was assessed with the GTPgammaS binding assay. Compound 8d was the most selective for the D(3) receptor in the spiperone binding assay. An interesting similarity in binding affinity was observed between isoquinoline derivative D-301 and the 2-substituted pyridine derivative 8d, suggesting the importance of relative spatial relationships between the N-atom of the ligand and the molecular determinants of the binding pocket in D(2)/D(3) receptors. Functional activity assays demonstrated high potency and selectivity of (+)-8a and (-)-28b (D(2)/D(3) (ratio of EC(50)): 105 and 202, respectively) for the D(3) receptor and both compounds were more selective compared to the reference drug ropinirole (D(2)/D(3) (ratio of EC(50)): 29.5). PMID:20605099

Ghosh, Balaram; Antonio, Tamara; Gopishetty, Bhaskar; Reith, Maarten; Dutta, Aloke

2010-08-01

222

Discriminating octahedral transition metal ions: highly selective tripodal tris-(2,2'-bipyridine) functionalized piperazine cyclophane receptor for Cu2+ ions.  

PubMed

New tripodal transition metal ion receptors, tris(5-ethoxycarbonyl-2,2'-bipyridine) and tris(5-carboxylate-2,2'-bipyridine) substituted 27-membered trimeric piperazine cyclophanes 5 and 7 as well as tetra(5-ethoxycarbonyl-2,2'-bipyridine) substituted 36-membered tetrameric piperazine cyclophane 6, have been prepared and their transition metal ion complexing properties studied in solution by UV-vis spectroscopy and in the solid state by single-crystal X-ray diffraction. The crystal structures of [H(3)5(3+)Fe(2+)]4(ClO(4)(-))CF(3)COO(-) (V), [H(3)7(2+)Fe(2+)]2(SO(4)(2-)) (VII) and the reference complex [tris(5,5'-bis(ethoxycarbonyl)-2,2'-bipyridine)Fe(II) perchlorate] (I) showed that the robust piperazine cyclophane is an optimal platform in preorganizing the 2,2'-bipy moieties to form a very fixed octahedral coordination site. In an acidic water solution, the highly preorganized structure of 5 gives a [5Fe(2+)] complex, the stability of which is comparable with the classical tris(2,2'-bipy) Fe(2+)-complex but it is a significant 3.7 logK units more stable than the non-preorganized tetrameric analog [6Fe(2+)]. Detailed studies with other similar divalent octahedral transition metal cations showed that the restricted octahedral coordination in complexes of 5 results in an unusual selectivity. The selectivity order [Zn(2+)

Raatikainen, Kari; Huuskonen, Juhani; Rissanen, Kari

2011-06-01

223

Assembly and photocatalysis of two novel 3D Anderson-type polyoxometalate-based metal-organic frameworks constructed from isomeric bis(pyridylformyl)piperazine ligands.  

PubMed

Two novel Anderson-type polyoxometalates (POMs)-based metal-organic frameworks (MOFs), namely, H{Cu2(?2-OH)2L(1)[CrMo6(OH)6O18]}4H2O (), {Cu2L(2)[CrMo(VI)5Mo(V)(OH)6O18](H2O)4}4H2O () (L(1) = N,N'-bis(3-pyridinecarboxamide)-piperazine, L(2) = N,N'-bis(4-pyridinecarboxamide)-piperazine), are hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). In complex , the hexadentate [CrMo6(OH)6O18](3-) polyoxoanion bridges the Cu(II) ions to generate a 2D Cu-POM inorganic layer, which is further extended by the ?2-bridging L(1) ligands (via ligation of pyridyl nitrogen atoms) to form a 3D MOF with a 4,6-connected {4(4)6(10)8}{4(4)6(2)} topology. Complex is also a 3D POM-based MOF exhibiting a {4(2)8(4)} topology, which is constructed from the quadridentate [CrMo(VI)5Mo(V)(OH)6O18](4-) polyoxoanions and ?4-bridging L(2) ligands (via ligation of pyridyl nitrogen and carbonyl oxygen atoms). The different coordination modes of POM polyanions and the isomeric bis(pyridylformyl)piperazine ligands play key roles in the construction of the title complexes. In addition, the photocatalytic activities of the title complexes on the degradation of methylene blue (MB) under UV, visible light and sunlight irradiation have been investigated in detail. PMID:24958084

Wang, Xiuli; Chang, Zhihan; Lin, Hongyan; Tian, Aixiang; Liu, Guocheng; Zhang, Juwen

2014-08-28

224

N-Aryl Piperazine Metabotropic Glutamate Receptor 5 Positive Allosteric Modulators Possess Efficacy in Preclinical Models of NMDA Hypofunction and Cognitive Enhancement  

PubMed Central

Impaired transmission through glutamatergic circuits has been postulated to play a role in the underlying pathophysiology of schizophrenia. Furthermore, inhibition of the N-methyl-d-aspartate (NMDA) subtype of ionotropic glutamate receptors (NMDAR) induces a syndrome that recapitulates many of the symptoms observed in patients with schizophrenia. Selective activation of metabotropic glutamate receptor subtype 5 (mGlu5) may provide a novel therapeutic approach for treatment of symptoms associated with schizophrenia through facilitation of transmission through central glutamatergic circuits. Here, we describe the characterization of two novel N-aryl piperazine mGlu5 positive allosteric modulators (PAMs): 2-(4-(2-(benzyloxy)acetyl)piperazin-1-yl)benzonitrile (VU0364289) and 1-(4-(2,4-difluorophenyl)piperazin-1-yl)-2-((4-fluorobenzyl)oxy)ethanone (DPFE). VU0364289 and DPFE induced robust leftward shifts in the glutamate concentration-response curves for Ca2+ mobilization and extracellular signal-regulated kinases 1 and 2 phosphorylation. Both PAMs displayed micromolar affinity for the common mGlu5 allosteric binding site and high selectivity for mGlu5. VU0364289 and DPFE possessed suitable pharmacokinetic properties for dosing in vivo and produced robust dose-related effects in reversing amphetamine-induced hyperlocomotion, a preclinical model predictive of antipsychotic-like activity. In addition, DPFE enhanced acquisition of contextual fear conditioning in rats and reversed behavioral deficits in a mouse model of NMDAR hypofunction. In contrast, DPFE had no effect on reversing apomorphine-induced disruptions of prepulse inhibition of the acoustic startle reflex. These mGlu5 PAMs also increased monoamine levels in the prefrontal cortex, enhanced performance in a hippocampal-mediated memory task, and elicited changes in electroencephalogram dynamics commensurate with procognitive effects. Collectively, these data support and extend the role for the development of novel mGlu5 PAMs for the treatment of psychosis and cognitive deficits observed in individuals with schizophrenia. PMID:23965381

Gregory, K.J.; Herman, E.J.; Ramsey, A.J.; Hammond, A.S.; Byun, N.E.; Stauffer, S.R.; Manka, J.T.; Jadhav, S.; Bridges, T.M.; Weaver, C.D.; Niswender, C.M.; Steckler, T.; Drinkenburg, W.H.; Ahnaou, A.; Lavreysen, H.; Macdonald, G.J.; Bartolom, J.M.; Mackie, C.; Hrupka, B.J.; Caron, M.G.; Daigle, T.L.; Lindsley, C.W.; Conn, P.J.

2013-01-01

225

Structure and dimensionality of coordination complexes correlated to piperazine conformation: from discrete [CuII2] and [CuII4] complexes to a micro1,3-N3- bridged [CuII2]n chain.  

PubMed

Three different types of copper(II) complexes have been studied of the hexadentate Schiff base ligand N,N'-bis[2-{(salicylidenimine)amino}ethyl] piperazine (H2L) having the piperazine backbone in the chair form and axial-axial (a,a) N-atom lone pairs in the free state. The structure of the products is influenced by the reaction conditions and by the exogenous ligands, affecting the conformation of the piperazine moiety (primary structure) and the topology and nuclearity of the resulting complexes (secondary structure). In [Cu2L(DMF)2]X2 (X = ClO4-, la; NO3-, 1b), the lone-pairs of chair-piperazine adopt the equatorial-equatorial (e,e) conformation. In the presence of NEt3 and NaN3, two types of [CuII4] complexes [Cu4(L)2(OH)2(H2O)2]X2 x nH2O (X = ClO4-, n = 1, 2a; X = NO3-, n = 4, 2b) and [Cu4(L)2(N3)2(H2O)2]X2 x H2O (X = ClO4-, 3a; NO3-, 3b) are obtained where four copper(II) ions are bridged by two hexadentate micro3-piperazine ligands, this time in chair-e,a conformation, and by two OH and N3 groups. In CH3CN, reactions of 1, 2 or 3 with NaN3 always produce the double end-to-end azido bridged 1D polymer [Cu2L(N3)2], (4) having a chair-e,e piperazine backbone. All studied conformations of the piperazine bridge mediate antiferromagnetic interactions between the Cu(II) ions, as revealed by bulk magnetization measurements. The striking difference in intensity of the coupling through trans-e,e piperazine observed for complexes la and 4 might be due to complementarily effects between the ligands involved. PMID:19462656

Paital, Alok Ranjan; Mandal, Debashree; Huang, Xiaoying; Li, Jing; Arom, Guillem; Ray, Debashis

2009-02-28

226

3-(Adamantan-1-yl)-4-ethyl-1-{[4-(2-methoxyphenyl)piperazin-1-yl]methyl}-1H-1,2,4-triazole-5(4H)-thione  

PubMed Central

In the title compound, C26H37N5OS, the piperazine ring adopts a chair conformation. The triazole ring forms dihedral angles of 67.85?(9) and 59.41?(9) with the piperazine and benzene rings, respectively, resulting in an approximate V-shaped conformation for the molecule. An intramolecular CH?O hydrogen bond generates an S(6) ring motif. The crystal structure features CH?? interactions, producing a two-dimensional supramolecular architecture. PMID:24526973

El-Emam, Ali A.; Al-Tuwaijri, Hanaa M.; Al-Abdullah, Ebtehal S.; Chidan Kumar, C. S.; Fun, Hoong-Kun

2014-01-01

227

Investigation of the mode of binding of a novel series of N-benzyl-4-heteroaryl-1-(phenylsulfonyl)piperazine-2-carboxamides to the hepatitis C virus polymerase  

SciTech Connect

Structure based rationales for the activities of potent N-benzyl-4-heteroaryl-1-(phenylsulfonyl)piperazine-2-carboxamide inhibitors of the hepatitis C viral polymerase are described herein. These compounds bind to the hepatitis C virus non-structural protein 5B (NS5B), and co-crystal structures of select examples from this series with NS5B are reported. Comparison of co-crystal structures of a potent analog with both NS5B genotype 1a and genotype 1b provides a possible explanation for the genotype-selectivity observed with this compound class and suggests opportunities for the further optimization of the series.

Gentles, Robert G.; Sheriff, Steven; Beno, Brett R.; Wan, Changhong; Kish, Kevin; Ding, Min; Zheng, Xiaofan; Chupak, Louis; Poss, Michael A.; Witmer, Mark R.; Morin, Paul; Wang, Ying-Kai; Rigat, Karen; Lemm, Julie; Voss, Stacey; Liu, Mengping; Pelosi, Lenore; Roberts, Susan B.; Gao, Min; Kadow, John F. (BMS) [BMS

2013-11-20

228

A novel mixed valence copper(I) copper(II) bis(antipyryl-methyl)-piperazine complex: synthesis, molecular structure and spectroscopic characterization  

NASA Astrophysics Data System (ADS)

This paper describes a new case of the bis(antipyryl-methyl)-piperazine [BAMP] ligand being in the "boat"-conformation and acting as a tetradentate. But unlike in Co(BAMP)(NCS) 2, which is the only complex with BAMP acting as tetradentate known so far, the coordinated copper(II) is connected via a iodo-bridge to a Cu II 2-moiety. The synthesis, elemental analysis, spectroscopic (far- and mid-FTIR, UV-Vis) and structural characterization (X-ray diffraction) as well as magnetochemical and conductivity data of this novel mixed valence binuclear complex Cu ICu II(BAMP)I 3 are presented.

Weinberger, P.; Costisor, O.; Tudose, R.; Baumgartner, O.; Linert, W.

2000-02-01

229

4-[Bis(4-fluorophenyl)methyl]piperazin-1-ium 2-hydroxybenzoate 2-hydroxybenzoic acid monosolvate  

PubMed Central

The title compound, C17H19F2N2 +C7H5O3 ?C7H6O3, is a co-crystal from 4-[bis(4-fluorophenyl)methyl]piperazin-1-ium, salicylate anion and salicylic acid in a 1:1:1 ratio. In addition to an intramolecular OH?O hydrogen bond, the crystal packing shows hydrogen bonds between the piperazinium cation and salicylate anion (NH?O), as well as between the salicylic acid molecule and anion (OH?O), giving rise to a three-dimensional network. PMID:22606121

Dayananda, A. S.; Yathirajan, H. S.; Flrke, Ulrich

2012-01-01

230

Synthesis of N-(6-(4-(Piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide Derivatives for the Treatment of Metabolic Syndrome.  

PubMed

Metabolic syndrome is a widely prevalent multifactorial disorder associated with an increased risk of cardiovascular disease and type 2 diabetes mellitus. High plasma levels of insulin and glucose due to insulin resistance are a major component of the metabolic disorder. Thiazolidinediones (TZDs) are potent PPAR? ligand and used as insulin sensitizers in the treatment of type 2 diabetes mellitus. They are potent insulin-sensitizing agents but due to adverse effects like hepatotoxicity, a safer alternative of TZDs is highly demanded. Here we report synthesis of N-(6-(4-(piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide derivatives as an alternate remedy for insulin resistance. PMID:25374688

Deka, Nabajyoti; Bajare, Swapnil; Anthony, Jessy; Nair, Amrutha; Damre, Anagha; Patel, Dharmeshkumar; B-Rao, Chandrika; Sivaramakrishnan, H; Mutt, Shivaprakash Jagalur; Wilankar, Chandan; Marita, Rosalind

2013-01-01

231

Synthesis of N-(6-(4-(Piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide Derivatives for the Treatment of Metabolic Syndrome  

PubMed Central

Metabolic syndrome is a widely prevalent multifactorial disorder associated with an increased risk of cardiovascular disease and type 2 diabetes mellitus. High plasma levels of insulin and glucose due to insulin resistance are a major component of the metabolic disorder. Thiazolidinediones (TZDs) are potent PPAR? ligand and used as insulin sensitizers in the treatment of type 2 diabetes mellitus. They are potent insulin-sensitizing agents but due to adverse effects like hepatotoxicity, a safer alternative of TZDs is highly demanded. Here we report synthesis of N-(6-(4-(piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide derivatives as an alternate remedy for insulin resistance. PMID:25374688

Bajare, Swapnil; Anthony, Jessy; Nair, Amrutha; Damre, Anagha; B-Rao, Chandrika; Sivaramakrishnan, H.; Wilankar, Chandan; Marita, Rosalind

2013-01-01

232

N-Phenylpropyl-N?-(3-methoxyphenethyl)piperazine (YZ-185) Attenuates the Conditioned-Rewarding Properties of Cocaine in Mice  

PubMed Central

Sigma receptor antagonists diminish the effects of cocaine in behavioral assays, including conditioned place preference. Previous locomotor activity experiments in mice determined that the sigma receptor ligand YZ-185 (N-phenylpropyl-N?-(3-methoxyphenethyl)piperazine) enhanced cocaine-induced hyperactivity at a lower (0.1??mol/kg) dose and dose-dependently attenuated cocaine-induced hyperactivity at higher (3.1631.6??mol/kg) doses. The present study investigated the effect of YZ-185 on cocaine's conditioned-rewarding properties in mice. YZ-185 (0.1, 0.316, 3.16, and 31.6??mol/kg) did not have intrinsic activity to produce conditioned place preference or aversion. A higher (31.6??mol/kg) YZ-185 dose, but not lower (0.13.16??mol/kg) YZ-185 doses, prevented the development of place preference to cocaine (66??mol/kg). YZ-185 did not alter the expression of cocaine place preference. To further characterize YZ-185's behavioral profile, its effects in the elevated zero maze and rotarod procedures were also determined; YZ-185 produced no significant change from baseline in either assay, indicating that the sigma receptors probed by YZ-185 do not regulate anxiety-like or coordinated motor skill behaviors. Overall, these results suggest that YZ-185 is a sigma receptor antagonist at the 31.6??mol/kg dose and demonstrate that sigma receptors can mediate the development of the conditioned-rewarding properties of cocaine. PMID:24089641

Sage, Andrew S.; Vannest, Scott C.; Fan, Kuo-Hsien; Will, Matthew J.; Lever, Susan Z.; Lever, John R.; Miller, Dennis K.

2013-01-01

233

N-Phenylpropyl-N'-(3-methoxyphenethyl)piperazine (YZ-185) Attenuates the Conditioned-Rewarding Properties of Cocaine in Mice.  

PubMed

Sigma receptor antagonists diminish the effects of cocaine in behavioral assays, including conditioned place preference. Previous locomotor activity experiments in mice determined that the sigma receptor ligand YZ-185 (N-phenylpropyl-N'-(3-methoxyphenethyl)piperazine) enhanced cocaine-induced hyperactivity at a lower (0.1? ? mol/kg) dose and dose-dependently attenuated cocaine-induced hyperactivity at higher (3.16-31.6? ? mol/kg) doses. The present study investigated the effect of YZ-185 on cocaine's conditioned-rewarding properties in mice. YZ-185 (0.1, 0.316, 3.16, and 31.6? ? mol/kg) did not have intrinsic activity to produce conditioned place preference or aversion. A higher (31.6? ? mol/kg) YZ-185 dose, but not lower (0.1-3.16? ? mol/kg) YZ-185 doses, prevented the development of place preference to cocaine (66? ? mol/kg). YZ-185 did not alter the expression of cocaine place preference. To further characterize YZ-185's behavioral profile, its effects in the elevated zero maze and rotarod procedures were also determined; YZ-185 produced no significant change from baseline in either assay, indicating that the sigma receptors probed by YZ-185 do not regulate anxiety-like or coordinated motor skill behaviors. Overall, these results suggest that YZ-185 is a sigma receptor antagonist at the 31.6? ? mol/kg dose and demonstrate that sigma receptors can mediate the development of the conditioned-rewarding properties of cocaine. PMID:24089641

Sage, Andrew S; Vannest, Scott C; Fan, Kuo-Hsien; Will, Matthew J; Lever, Susan Z; Lever, John R; Miller, Dennis K

2013-01-01

234

Mechanism-based inactivation of human cytochrome P450 3A4 by two piperazine-containing compounds.  

PubMed

Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of more than half of pharmaceutic drugs, and inactivation of CYP3A4 can lead to adverse drug-drug interactions. The substituted imidazole compounds 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine (SCH 66712) and 1-[(2-ethyl-4-methyl-1H-imidazol-5-yl)methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazine (EMTPP) have been previously identified as mechanism-based inactivators (MBI) of CYP2D6. The present study shows that both SCH 66712 and EMTPP are also MBIs of CYP3A4. Inhibition of CYP3A4 by SCH 66712 and EMTPP was determined to be concentration, time, and NADPH dependent. In addition, inactivation of CYP3A4 by SCH 66712 was shown to be unaffected by the presence of electrophile scavengers. SCH 66712 displays type I binding to CYP3A4 with a spectral binding constant (Ks) of 42.9 2.9 M. The partition ratios for SCH 66712 and EMTPP were 11 and 94, respectively. Whole protein mass spectrum analysis revealed 1:1 binding stoichiometry of SCH 66712 and EMTPP to CYP3A4 and a mass increase consistent with adduction by the inactivators without addition of oxygen. Heme adduction was not apparent. Multiple mono-oxygenation products with each inactivator were observed; no other products were apparent. These are the first MBIs to be shown to be potent inactivators of both CYP2D6 and CYP3A4. PMID:25273356

Bolles, Amanda K; Fujiwara, Rina; Briggs, Erran D; Nomeir, Amin A; Furge, Laura Lowe

2014-12-01

235

Synthesis and characterization of Ni(II), Cu(II) and Zn(II) complexes with new macrocyclic Schiff base ligands containing piperazine moiety  

NASA Astrophysics Data System (ADS)

Two new macrocyclic Schiff base ligands L 1 and L 2 from [1 + 1] and [2 + 2] condensation reaction, respectively, have been obtained in a one-pot synthesis starting from 1,4-bis(2-formylphenyl)piperazine and 2,2-dimethyl-propylendiamine. Unfortunately, because of the low solubility of two products, we were unable to separate them effectively. Macrocyclic Schiff base complexes [NiL 1](ClO 4) 2, [CuL 1](ClO 4) 2 and [ZnL 1](ClO 4) 2 were prepared from the reaction of a mixture of L 1 and L 2 in the presence of nickel(II), copper(II) and zinc(II) metal ions, respectively. In all cases, only [1 + 1] condensation products were obtained and no metal complexes were isolated with the L 2 macrocycle. All of complexes have been characterized by elemental analysis, IR spectra, FAB-MS, conductivity measurements and in the case of Zn(II) complex by 1H and 13C NMR spectroscopy. Crystal structures of [NiL 1](ClO 4) 2 and [NiL 1'](ClO 4) 2 complexes have been also determined. The Ni(II) is coordinated to the ligand L 1 and L 1' by two nitrogen atoms of piperazine group and two nitrogen atoms of the imine groups, in a slightly distorted square-planar geometry.

Keypour, Hassan; Arzhangi, Parisa; Rahpeyma, Nasibeh; Rezaeivala, Majid; Elerman, Yalcin; Bykgngr, Orhan; Valencia, Laura; Khavasi, Hamid Reza

2010-08-01

236

Design, Synthesis, Biological Screening, and Molecular Docking Studies of Piperazine-Derived Constrained Inhibitors of DPP-IV for the Treatment of Type 2 Diabetes.  

PubMed

Novel piperazine-derived conformationally constrained compounds were designed, synthesized, and evaluated for in vitro Dipeptidyl peptidase-IV (DPP-IV) inhibitory activities. From a library of compounds synthesized, 1-(2-(4-(7-Chloro-4-quinolyl)piperazin-1-yl)acetyl)pyrrolidine (2g) was identified as a potential DPP-IV inhibitor exhibiting better inhibitory activity than P32/98, reference inhibitor. The in vivo studies carried out in STZ and db/db mice models indicated that the compound 2g showed moderate antihyperglycemic activity as compared to the marketed drug Sitagliptin. A two-week repeated dose study in db/db mice revealed that compound 2g significantly declined blood glucose levels with no evidence of hypoglycemia risk. Furthermore, it showed improvement in insulin resistance reversal and antidyslipidemic properties. Molecular docking studies established good binding affinity of compound 2g at the DPP-IV active site and are in favor of the observed biological data. These data collectively suggest that compound 2g is a good lead molecule for further optimization studies. PMID:25216392

Kushwaha, Ram N; Srivastava, Rohit; Mishra, Akansha; Rawat, Arun K; Srivastava, Arvind K; Haq, Wahajul; Katti, Seturam B

2015-04-01

237

Here today, gone tomorrowand back again? A review of herbal marijuana alternatives (K2, Spice), synthetic cathinones (bath salts), kratom, Salvia divinorum, methoxetamine, and piperazines.  

PubMed

Despite their widespread Internet availability and use, many of the new drugs of abuse remain unfamiliar to health care providers. The herbal marijuana alternatives, like K2 or Spice, are a group of herbal blends that contain a mixture of plant matter in addition to chemical grade synthetic cannabinoids. The synthetic cathinones, commonly called "bath salts," have resulted in nationwide emergency department visits for severe agitation, sympathomimetic toxicity, and death. Kratom, a plant product derived from Mitragyna speciosa Korth, has opioid-like effects, and has been used for the treatment of chronic pain and amelioration of opioid-withdrawal symptoms. Salvia divinorum is a hallucinogen with unique pharmacology that has therapeutic potential but has been banned in many states due to concerns regarding its psychiatric effects. Methoxetamine has recently become available via the Internet and is marked as "legal ketamine." Moreover, the piperazine derivatives, a class of amphetamine-like compounds that includes BZP and TMFPP, are making a resurgence as "legal Ecstasy." These psychoactives are available via the Internet, frequently legal, and often perceived as safe by the public. Unfortunately, these drugs often have adverse effects, which range from minimal to life-threatening. Health care providers must be familiar with these important new classes of drugs. This paper discusses the background, pharmacology, clinical effects, detection, and management of synthetic cannabinoid, synthetic cathinone, methoxetamine, and piperazine exposures. PMID:22271566

Rosenbaum, Christopher D; Carreiro, Stephanie P; Babu, Kavita M

2012-03-01

238

Crystal structure of 1-(3-chlorophenyl)piperazin-1-ium picratepicric acid (2/1)  

PubMed Central

The title salt {systematic name: bis[1-(3-chlorophenyl)piperazinium 2,4,6-trinitrophenolate]picric acid (2/1)}, 2C10H14ClN2 +2C6H5N3O7 ?C6H6N3O7, crystallized with two independent 1-(3-chlorophenyl)piperazinium cations, two picrate anions and a picric acid molecule in the asymmetric unit. The six-membered piperazine ring in each cation adopts a slightly distorted chair conformation and contains a protonated N atom. In the picric acid molecule, the mean planes of the nitro groups in the ortho-, meta-, and para-positions are twisted from the benzene ring by 31.5?(3), 7.7?(1), and 3.8?(2), respectively. In the anions, the dihedral angles between the benzene ring and the ortho-, meta-, and para-nitro groups are 36.7?(1), 5.0?(6), 4.8?(2), and 34.4?(9), 15.3?(8), 4.5?(1), respectively. The nitro group in one anion is disordered and was modeled with two sites for one O atom with an occupancy ratio of 0.627?(7):0.373?(7). In the crystal, the picric acid molecule interacts with the picrate anion through a trifurcated OH?O four-centre hydrogen bond involving an intramolecular OH?O hydrogen bond and a weak CH?O interaction. Weak intermolecular CH?O interactions are responsible for the formation of cationanioncation trimers resulting in a chain along [010]. In addition, weak CH?Cl and weak ?? interactions [centroidcentroid distances of 3.532?(3), 3.756?(4) and 3.705?(3)?] are observed and contribute to the stability of the crystal packing. PMID:25484834

Kavitha, Channappa N.; Jasinski, Jerry P.; Kaur, Manpreet; Anderson, Brian J.; Yathirajan, H. S.

2014-01-01

239

Crystal structure of 1-(3-chloro-phen-yl)piperazin-1-ium picrate-picric acid (2/1).  

PubMed

The title salt {systematic name: bis-[1-(3-chloro-phen-yl)piperazinium 2,4,6-tri-nitro-phenolate]-picric acid (2/1)}, 2C10H14ClN2 (+)2C6H5N3O7 (-)C6H6N3O7, crystallized with two independent 1-(3-chloro-phen-yl)piperazinium cations, two picrate anions and a picric acid mol-ecule in the asymmetric unit. The six-membered piperazine ring in each cation adopts a slightly distorted chair conformation and contains a protonated N atom. In the picric acid mol-ecule, the mean planes of the nitro groups in the ortho-, meta-, and para-positions are twisted from the benzene ring by 31.5?(3), 7.7?(1), and 3.8?(2), respectively. In the anions, the dihedral angles between the benzene ring and the ortho-, meta-, and para-nitro groups are 36.7?(1), 5.0?(6), 4.8?(2), and 34.4?(9), 15.3?(8), 4.5?(1), respectively. The nitro group in one anion is disordered and was modeled with two sites for one O atom with an occupancy ratio of 0.627?(7):0.373?(7). In the crystal, the picric acid mol-ecule inter-acts with the picrate anion through a trifurcated O-H?O four-centre hydrogen bond involving an intra-molecular O-H?O hydrogen bond and a weak C-H?O inter-action. Weak inter-molecular C-H?O inter-actions are responsible for the formation of cation-anion-cation trimers resulting in a chain along [010]. In addition, weak C-H?Cl and weak ?-? inter-actions [centroid-centroid distances of 3.532?(3), 3.756?(4) and 3.705?(3)?] are observed and contribute to the stability of the crystal packing. PMID:25484834

Kavitha, Channappa N; Jasinski, Jerry P; Kaur, Manpreet; Anderson, Brian J; Yathirajan, H S

2014-11-01

240

Concentrations and ratios of amphetamine, methamphetamine, MDA, MDMA, and MDEA enantiomers determined in plasma samples from clinical toxicology and driving under the influence of drugs cases by GC-NICI-MS.  

PubMed

Enantiomers of amphetamine (AM), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) exhibit different pharmacological properties. This may be important for the interpretation of analytical results. Plasma samples were analyzed using validated negative ion chemical ionization gas chromatography-mass spectrometry procedures. The results for clinical toxicology cases, divided into screening (SCR) and intoxication (ITX) cases, and those of driving under the influence of drugs (DUID) cases were compared. The concentrations of all enantiomers, except R-(-)-MDA and R-(-)- and S-(+)-MA, in the SCR samples were lower than in ITX and DUID samples. Differences between concentrations in ITX and DUID samples were only significant for both enantiomers of AM (DUID higher). These findings suggested impairment in drugged drivers. Different enantiomer ratios (R vs. S) were found for AM between DUID and SCR samples, for MDMA between ITX and SCR samples, and for MDA between DUID and ITX and DUID and SCR samples. Higher MDMA enantiomer ratios in SCR compared to ITX samples are in accordance with a previously described increase of those ratios over time, possibly allowing differentiation of recent from nonrecent ingestion. Pharmacokinetic analysis of a MDMA poisoning yielded elimination half-lives of 6.0 h for R-(-)-MDMA and 4.1 h for S-(+)-MDMA. The enantiomer ratios rose exponentially over time. PMID:14670133

Peters, F T; Samyn, N; Wahl, M; Kraemer, T; De Boeck, G; Maurer, H H

2003-01-01

241

Studies of tricyclic piperazine/piperidine furnished molecules as novel integrin ?v?3/?IIb?3 dual antagonists using 3D-QSAR and molecular docking.  

PubMed

The development of injectable integrin ?(v)?(3)/?(IIb)?(3) dual antagonists attracts much attention of research for treating of acute ischemic diseases in recent years. In this work, based on a dataset composed of 102 tricyclic piperazine/piperidine furnished dual ?(v)?(3) and ?(IIb)?(3) antagonists, a variety of in silico modeling approaches including the comparative molecular field analysis (CoMFA), comparative similarity indices analysis (CoMSIA), and molecular docking were applied to reveal the requisite 3D structural features impacting the biological activities. Our statistical results show that the ligand-based 3D-QSAR models for both the ?(v)?(3) and ?(IIb)?(3) studies exhibited satisfactory internal and external predictability, i.e., for the CoMFA models, results of Q(2)=0.48, R(ncv)(2)=0.87, R(pred)(2)=0.71 for ?(v)?(3) and Q(2)=0.50, R(ncv)(2)=0.85, R(pred)(2)=0.72 for ?(IIb)?(3) analysis were obtained, and for the CoMSIA ones, the outcomes of Q(2)=0.55, R(ncv)(2)=0.90, R(pred)(2)=0.72 for ?(v)?(3) and Q(2)=0.52, R(ncv)(2)=0.88, R(pred)(2)=0.74 for ?(IIb)?(3) were achieved respectively. In addition, through a comparison between 3D-QSAR contour maps and docking results, it is revealed that that the most crucial interactions occurring between the tricyclic piperazine/piperidine derivatives and ?(v)?(3)/?(IIb)?(3) receptor ligand binding pocket are H-bonding, and the key amino acids impacting the interactions are Arg214, Asn215, Ser123, and Lys253 for ?(v)?(3), but Arg214, Asn215, Ser123 and Tyr190 for ?(IIb)?(3) receptors, respectively. Halogen-containing groups at position 15 and 16, benzene sulfonamide substituent at position 23, and the replacement of piperazine with 4-aminopiperidine of ring B may increase the ?(v)?(3)/?(IIb)?(3) antagonistic activity. The potencies for antagonists to inhibit isolated ?(v)?(3) and ?(IIb)?(3) are linear correlated, indicating that similar interaction mechanisms may exist for the series of molecules. To our best knowledge this is the first report on 3D-QSAR modeling of these dual ?(v)?(3)/?(IIb)?(3) antagonists. The results obtained should provide information for better understanding of the mechanism of antagonism and thus be helpful in design of novel potent dual ?(v)?(3)/?(IIb)?(3) antagonists. PMID:21273104

Yan, Yulian; Li, Yan; Zhang, Shuwei; Ai, Chunzhi

2011-02-01

242

Synthesis and binding properties of new long-chain 4-substituted piperazine derivatives as 5-HT1A and 5-HT7 receptor ligands.  

PubMed

New long-chain 4-substituted piperazines linked to a thienopyrimidine or a quinazoline system were synthesized and tested for their binding properties on human cloned 5-HT1A and 5-HT7 serotonin receptors. Some structural modifications, concerning tree main portions, that is, terminal fragment, chain length, and aryl substituents, were examined. The 2- and 3-substituted thienopyrimidinone and quinazolinone systems were selected as terminal fragment and a chain length of four or five methylene units was set. Explored aryl substituents were phenyl, phenylmethyl, 3- or 4-chlorophenyl, and 2-ethoxyphenyl. Title compounds showed affinity for 5-HT1A and 5-HT7 receptors. In particular, 2-ethoxyphenyl derivatives 40 and 45 displayed Ki values in the nanomolar range on both receptors, acting as dual ligands. PMID:25759032

Modica, Maria N; Intagliata, Sebastiano; Pittal, Valeria; Salerno, Loredana; Siracusa, Maria A; Cagnotto, Alfredo; Salmona, Mario; Romeo, Giuseppe

2015-04-01

243

Aqua-{4,4',6,6'-tetra-fluoro-2,2'-[(piperazine-1,4-di-yl)dimethyl-ene]diphenolato}copper(II).  

PubMed

In the title compound, [Cu(C(18)H(16)F(4)N(2)O(2))(H(2)O)], the Cu(II) atom shows a distorted square-pyramidal coordination geometry with the N,N',O,O'-tetra-dentate piperazine-diphenolate ligand forming the basal plane. The apical site is occupied by the O atom of a coordinated water mol-ecule. Neighbouring complexes are associated through inter-molecular O-H?O and O-H?F hydrogen bonds between the water mol-ecule and a phenolate O atom or an F atom from an adjacent ligand, respectively, forming a centrosymmetric dimer. Dimers are linked by additional inter-molecular C-H?O and C-H?F hydrogen bonds, giving infinite chains propagating along the a axis. PMID:21588831

Kubono, Koji; Tsuno, Yuki; Tani, Keita; Yokoi, Kunihiko

2010-01-01

244

EPR, mass, electronic, IR spectroscopic and thermal studies of bimetallic copper(II) complexes with tetradentate ligand, 1,4-diformyl piperazine bis(carbohydrazone)  

NASA Astrophysics Data System (ADS)

The synthesis of novel bimetallic Cu(II) complexes with general stoichiometry [Cu 2(H 2L)X 2(H 2O) 2], [Cu 2(H 2L)(CH 3COO) 2] and [Cu 2(H 2L)SO 4(H 2O) 2] (where H 2L = dideprotonated ligand and X = NO 3- and Cl -) derived from tetradentate ligand obtained by the condensation of 1,4-diformyl piperazine with carbohydrazide has been discussed. The complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, UV, EPR spectral studies and thermogravimetric analyses. The value of magnetic moments indicates that the complexes are paramagnetic and show the antiferromagnetic interaction between the two metal centres. The complexes possess the square planar coordination environment. The values of covalency measurements, i.e., in-plane ?-bonding ? 2, in-plane ?-bonding ? 2 and orbital reduction factor k indicate the covalent nature of complexes.

Chandra, Sulekh; Jain, Deepali; Sharma, Amit Kumar

2009-01-01

245

Bis[1-(2,3-dimethylphenyl)piperazine-1,4-diium] bis(oxonium) cyclohexaphosphate dihydrate  

PubMed Central

In the title compound, 2C12H20N2 2+2H3O+P6O18 6?2H2O, a protonated water molecule bridges the centrosymmetrical anionic P6O18 ring via OH?O hydrogen bonds. The centrosymmetric hydrogen-bonded rings formed by four oxonium cations and four phosphate anions can be described by an R 4 8(36) graph-set motif. The ring motifs are connected by hydrogen bonds into inorganic layers perpendicular to [100]. The 1-(2,3-dimethylphenyl)piperazine-1,4-diium cations are located between the layers, compensating their negative charge and establishing NH?O hydrogen bonds with the O atoms of the anionic framework. PMID:24046694

Ameur, Iness; Abid, Sonia; Al-Deyab, Salem S; Rzaigui, Mohamed

2013-01-01

246

4-(2-Methoxyphenyl)piperazin-1-ium 6-chloro-5-isopropyl-2,4-dioxopyrimidin-1-ide  

PubMed Central

In the cation of the title salt, C11H17N2O+C7H8ClN2O2 ?, the piperazine ring adopts a distorted chair conformation and contains a positively charged N atom with quaternary character. Its mean plane makes a dihedral angle of 42.36?(8) with the phenyl ring of its 2-methoxyphenyl substituent. The 2,4-dioxopyrimidin-1-ide anion is generated by deprotonation of the N atom at the 1-position of the pyrimidinedione ring. Intramolecular CH?O hydrogen bonds generate S(6) ring motifs in both the cation and the anion. In the crystal, NH?O, NH?N and CH?O hydrogen bonds are also observed, resulting in a two-dimensional network parallel to the ab plane. The crystal stability is further consolidated by weak CH?? interactions. PMID:24764966

Al-Omary, Fatmah A. M.; Ghabbour, Hazem A.; El-Emam, Ali A.; Chidan Kumar, C. S.; Fun, Hoong-Kun

2014-01-01

247

Efficient approach to improving the flame retardancy of poly(vinyl alcohol)/clay aerogels: incorporating piperazine-modified ammonium polyphosphate.  

PubMed

Ammonium polyphosphates (APP) modified with piperazine (PA-APP) was used to improve the flame retardancy of poly(vinyl alcohol) (PVA)/montmorillonite (MMT) aerogels, which were prepared via an environmentally friendly freeze-drying method. The thermal stabilities of the samples were evaluated by thermogravimetric analysis (TG); the flammability behaviors of samples were investigated by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter (CC) tests. TG test results showed that the 5% weight loss temperature (T5%) of PVA/MMT/PA-APP was 10 C higher than that of PVA/MMT/APP. In combustion testing, all of PVA/MMT/PA-APP aerogels achieved V-0 ratings and have a higher LOI values than the unmodified PVA/MMT aerogel. Moreover, the aerogel with 1% PA-APP5, which means that the content of piperazine is 5% in PA-APP, decreased the cone calorimetry THR value to 5.71 MJ/m(2), and increased the char residue to 52%. The compressive modulus of PVA/MMT/PA-APP was increased by 93.4% compared with PVA/MMT/APP because of the increase in interfacial adhesion between matrix and PA-APP fillers. The densities of the PVA/MMT/PA-APP samples were slightly lower than those of the unmodified aerogels because of reduced shrinkage in the presence of PA-APP. All the tests results indicated that the incorporation of PA-APP not only improved the thermal stability and flame retardancy of aerogels but also maintained their mechanical properties. PMID:25588129

Wang, Yu-Tao; Liao, Shi-Fu; Shang, Ke; Chen, Ming-Jun; Huang, Jian-Qian; Wang, Yu-Zhong; Schiraldi, David A

2015-01-28

248

N-(omega-(4-(2-methoxyphenyl)piperazin-1-yl)alkyl)carboxamides as dopamine D2 and D3 receptor ligands.  

PubMed

The dopamine D(3) receptor is recognized as a potential therapeutic target for the treatment of various neurological and psychiatric disorders. Targetting high affinity and D(3) versus D(2) receptor-preferring ligands, the partial agonist BP 897 was taken as a lead structure. Variations in the spacer and the aryl moiety led to N-alkylated 1-(2-methyoxyphenyl)piperazines with markedly improved affinity and selectivity. Molecular modeling studies supported the structural development. Pharmacophore models for dopamine D(2) and D(3) receptor ligands were developed from their potentially bioactive conformation and were compared in order to get insight into molecular properties of importance for D(2)/D(3) receptor selectivity. For the 72 compounds presented here, an extended and more linear conformation in the aliphatic or aryl spacers turned out to be crucial for dopamine D(3) receptor selectivity. Structural diversity in the aryl moiety (benzamides, heteroarylamides, arylimides) had a major influence on (sub)nanomolar D(3) receptor affinity, which was optimized with more rigid aryl acrylamide derivatives. Compound 38 (ST 280, (E)-4-iodo-N-(4-(4-(2-methoxyphenyl)piperazin-1-yl)butyl)cinnamoylamide) displayed a most promising pharmacological profile (K(i) (hD(3)) = 0.5 nM; K(i) (hD(2L)) = 76.4 nM; selectivity ratio of 153), and above that, compound 38 offered the prospect of a novel radioligand as a pharmacological tool for various D(3) receptor-related in vitro and in vivo investigation. PMID:12930150

Hackling, Anneke; Ghosh, Robin; Perachon, Sylvie; Mann, Andr; Hltje, Hans-Dieter; Wermuth, Camille G; Schwartz, Jean-Charles; Sippl, Wolfgang; Sokoloff, Pierre; Stark, Holger

2003-08-28

249

An azide-bridged copper(II) complex: poly[piperazine-1,4-dium [tetra-??-azido-?N:N:N-hexa-??-azido-?N:N-di-??-azido-??N:N-pentacopper(II)] tetrahydrate].  

PubMed

A new Cu(II)-azide complex, {(C4H12N2)[Cu5(N3)12]4H2O}n, has been synthesized by the reaction of piperazine, Cu(OAc)22H2O (OAc is acetate) and NaN3. In the structure, ?2-1,1- and ?3-1,1,1-azide anions bridge five Cu(II) cations to form a linear pentanuclear cluster unit, which is further linked by ?2-1,1- and ?2-1,3-azide anions to form a two-dimensional condensed [Cu5(N3)12]n layer. The diprotonated piperazine and the solvent water molecules are hydrogen bonded to the coordination layers to form a three-dimensional supramolecular network. PMID:25370112

Liu, Hou-Ting; Lu, Jing

2014-11-01

250

Measurement of nitrosamine and nitramine formation from NOx reactions with amines during amine-based carbon dioxide capture for postcombustion carbon sequestration.  

PubMed

With years of full-scale experience for precombustion CO(2) capture, amine-based technologies are emerging as the prime contender for postcombustion CO(2) capture. However, concerns for postcombustion applications have focused on the possible contamination of air or drinking water supplies downwind by potentially carcinogenic N-nitrosamines and N-nitramines released following their formation by NO(x) reactions with amines within the capture unit. Analytical methods for N-nitrosamines in drinking waters were adapted to measure specific N-nitrosamines and N-nitramines and total N-nitrosamines in solvent and washwater samples. The high levels of amines, aldehydes, and nitrite in these samples presented a risk for the artifactual formation of N-nitrosamines during sample storage or analysis. Application of a 30-fold molar excess of sulfamic acid to nitrite at pH 2 destroyed nitrite with no significant risk of artifactual nitrosation of amines. Analysis of aqueous morpholine solutions purged with different gas-phase NO and NO(2) concentrations indicated that N-nitrosamine formation generally exceeds N-nitramine formation. The total N-nitrosamine formation rate was at least an order of magnitude higher for the secondary amine piperazine (PZ) than for the primary amines 2-amino-2-methyl-1-propanol (AMP) and monoethanolamine (MEA) and the tertiary amine methyldiethanolamine (MDEA). Analysis of pilot washwater samples indicated a 59 ?M total N-nitrosamine concentration for a system operated with a 25% AMP/15% PZ solvent, but only 0.73 ?M for a 35% MEA solvent. Unfortunately, a greater fraction of the total N-nitrosamine signal was uncharacterized for the MEA-associated washwater. At a 0.73 ?M total N-nitrosamine concentration, a ~25000-fold reduction in concentration is needed between washwater units and downwind drinking water supplies to meet proposed permit limits. PMID:22831707

Dai, Ning; Shah, Amisha D; Hu, Lanhua; Plewa, Michael J; McKague, Bruce; Mitch, William A

2012-09-01

251

Toward understanding amines and their degradation products from postcombustion CO2 capture processes with aerosol mass spectrometry.  

PubMed

Amine-based postcombustion CO2 capture (PCCC) is a promising technique for reducing CO2 emissions from fossil fuel burning plants. A concern of the technique, however, is the emission of amines and their degradation byproducts. To assess the environmental risk of this technique, standardized stack sampling and analytical methods are needed. Here we report on the development of an integrated approach that centers on the application of a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) for characterizing amines and PCCC-relevant species. Molecular characterization is achieved via ion chromatography (IC) and electrospray ionization high-resolution mass spectrometry (ESI-MS). The method has been optimized, particularly, by decreasing the AMS vaporizer temperature, to gain quantitative information on the elemental composition and major nitrogen-containing species in laboratory-degraded amine solvents commonly tested for PCCC applications, including ethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP). The AMS-derived nitrogen-to-carbon (N/C) ratios for the degraded solvent and product mixtures agree well with the results from a total organic carbon and total nitrogen (TOC/TN) analyzer. In addition, marker ions identified in the AMS spectra are used to estimate the mass contributions of individual species. Overall, our results indicate that this new approach is suitable for characterizing PCCC-related mixtures as well as organic nitrogen species in other sample types. As an online instrument, AMS can be used for both real-time characterization of emissions from operating PCCC plants and ambient particles in the vicinity of the facilities. PMID:24617831

Ge, Xinlei; Shaw, Stephanie L; Zhang, Qi

2014-05-01

252

Toward Understanding Amines and Their Degradation Products from Postcombustion CO2 Capture Processes with Aerosol Mass Spectrometry  

PubMed Central

Amine-based postcombustion CO2 capture (PCCC) is a promising technique for reducing CO2 emissions from fossil fuel burning plants. A concern of the technique, however, is the emission of amines and their degradation byproducts. To assess the environmental risk of this technique, standardized stack sampling and analytical methods are needed. Here we report on the development of an integrated approach that centers on the application of a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) for characterizing amines and PCCC-relevant species. Molecular characterization is achieved via ion chromatography (IC) and electrospray ionization high-resolution mass spectrometry (ESI-MS). The method has been optimized, particularly, by decreasing the AMS vaporizer temperature, to gain quantitative information on the elemental composition and major nitrogen-containing species in laboratory-degraded amine solvents commonly tested for PCCC applications, including ethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP). The AMS-derived nitrogen-to-carbon (N/C) ratios for the degraded solvent and product mixtures agree well with the results from a total organic carbon and total nitrogen (TOC/TN) analyzer. In addition, marker ions identified in the AMS spectra are used to estimate the mass contributions of individual species. Overall, our results indicate that this new approach is suitable for characterizing PCCC-related mixtures as well as organic nitrogen species in other sample types. As an online instrument, AMS can be used for both real-time characterization of emissions from operating PCCC plants and ambient particles in the vicinity of the facilities. PMID:24617831

2015-01-01

253

Solid-state variable-temperature NMR study of the phase separation of polybutadiene polyurethane zwitterionomers  

NASA Astrophysics Data System (ADS)

Polybutadiene polyurethane (PBDPU) zwitterionomers based on 4,4'-diphenylmethane diisocyanate (MDI), methyl-diethanolamine (MDEA), and hydroxy terminated polybutadiene are studied with variable-temperature (VT) wide-line 1H NMR. Spinspin relaxation times ( T2) and spinlattice relaxation times ( T1) are measured. It is found that phase separation of PBDPU does not change significantly upon ionization. The initial incorporation of ionization groups destroys the crystallinity of the hard segment while further ionization enhances physical crosslinks in the hard phase. The results are compared with a previous VT NMR study on polyether polyurethane zwitterionomers based on MDI, MDEA and 1000 Da molecular weight polytetramethylene oxide.

Yang, G.; Chen, Q.; Wang, Y.; Yang, C.; Wu, X.

1994-07-01

254

Synthesis, growth, structural and optical studies of organic nonlinear optical material--piperazine-1,4-diium bis 2,4,6-trinitrophenolate.  

PubMed

Piperazine-1,4-diium bis 2,4,6-trinitrophenolate is one of the useful organic materials with nonlinear optical (NLO) and pharmaceutical applications. The material was grown by slow evaporation solution growth method at room temperature. The crystal system and lattice parameters were identified by single crystal XRD analysis. The grown material crystallizes in monoclinic system with P21/n space group. The main functional groups NH2, NO2, CN, CC, and phenolic 'O' atom were identified using FTIR analysis. The protons and carbons of grown crystal with various chemical environments were studied by 1H and 13C NMR spectroscopy to confirm the molecular structure. The optical properties of the crystal were studied by UV-vis-NIR spectroscopy and the transmission 100% range starts from 532 nm onwards. The optical band gap was measured as 2.63 eV from the plot of (?h?)2 versus h?. The thermal stability was detected at 304.1C using TG-DTA analysis. The dielectric studies of the sample were carried out at different temperatures in the frequency range from 50 Hz to 5 MHz to establish the dielectric nature of the crystal. Photoconductivity measurements were carried out on the grown crystal. The Second Harmonic Generation (SHG) of the crystal was tested to confirm the nonlinear optical property. PMID:24878440

Suguna, S; Anbuselvi, D; Jayaraman, D; Nagaraja, K S; Jeyaraj, B

2014-11-11

255

A tetramethylpyrazine piperazine derivate CXC137 prevents cell injury in SH-SY5Y cells and improves memory dysfunction of rats with vascular Dementia.  

PubMed

We investigated the effects of CXC137, a tetramethylpyrazine piperazine derivate, on cell damage induced by N-methyl-D-aspartate (NMDA) in human derived neuroblastoma cells (SH-SY5Y) and its effect on memory dysfunction of rats with vascular dementia. It was found that the presence of CXC137 increased SH-SY5Y cells viability by inhibition of cell apoptosis induced by NMDA. These effects of CXC137 were accompanied by increases of the antioxidant superoxide dismutase activity and the level of reduced glutathione, and a decrease of lipid peroxidation product, malondialdehyde. The presence of CXC137 also showed to produce strong inhibition of cellular lactate dehydrogenase leakage, cell apoptosis and intracellular calcium overload. In a vascular dementia rat model established by bilateral common carotid arteries occlusion, treatment with CXC137 from 2 to 35day of post-operation significantly improves the motor performance, spatial learning and memory capability of rats in both the prehensile traction test and Morris water maze test, an effect that was companied by reductions of the animal glutamic acid levels and the degree of brain mitochondrial swelling. These results suggest that CXC137 can improve the memory dysfunction in dementia and thus has important therapeutic potential for the treatment of dementia. PMID:24357351

Zhang, Hao; Sun, Rong; Liu, Xin-Yong; Shi, Xiao-Ming; Wang, Wen-Fang; Yu, Lu-Gang; Guo, Xiu-Li

2014-02-01

256

EPR, mass, electronic, IR spectroscopic and thermal studies of bimetallic copper(II) complexes with tetradentate ligand, 1,4-diformyl piperazine bis(carbohydrazone).  

PubMed

The synthesis of novel bimetallic Cu(II) complexes with general stoichiometry [Cu(2)(H(2)L)X(2)(H(2)O)(2)], [Cu(2)(H(2)L)(CH(3)COO)(2)] and [Cu(2)(H(2)L)SO(4)(H(2)O)(2)] (where H(2)L=dideprotonated ligand and X=NO(3)(-) and Cl(-)) derived from tetradentate ligand obtained by the condensation of 1,4-diformyl piperazine with carbohydrazide has been discussed. The complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, UV, EPR spectral studies and thermogravimetric analyses. The value of magnetic moments indicates that the complexes are paramagnetic and show the antiferromagnetic interaction between the two metal centres. The complexes possess the square planar coordination environment. The values of covalency measurements, i.e., in-plane sigma-bonding alpha(2), in-plane pi-bonding beta(2) and orbital reduction factor k indicate the covalent nature of complexes. PMID:18678523

Chandra, Sulekh; Jain, Deepali; Sharma, Amit Kumar

2009-01-01

257

Synthesis, spectroscopic and thermal studies of charge-transfer molecular complexes formed in the reaction of 1,4-bis (3-aminopropyl) piperazine with ?- and ? acceptors  

NASA Astrophysics Data System (ADS)

In the present study, solid charge-transfer (CT) molecular complexes formed in the reaction of the electron donor 1,4-bis (3-aminopropyl) piperazine (APPIP) with the ?-electron acceptor iodine and ?-acceptors 7,7,8,8-tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD) have been investigated spectrophotometrically in chloroform at 25 C. These were characterized through electronic and infrared spectra as well as elemental and thermal analysis. The obtained results showed that the formed solid CT-complexes have the formulas [(APPIP) I]+I3-, [(APPIP)(TCNQ)], [(APPIP)2(TCNE)3], [(APPIP)(DDQ)] and [(APPIP)(TBCHD)] in full agreement with the known reaction stoichiometries in solution as well as the elemental measurements. The formation constant KCT, molar extinction coefficient ?CT, free energy change ?G0, CT energy ECT and the ionization potential Ip have been calculated for the CT complexes [(APPIP) I]+I3-, [(APPIP)(TCNQ)], [(APPIP)(DDQ)] and [(APPIP)(TBCHD)].

AlQaradawi, Siham Y.; Mostafa, Adel; Bazzi, Hassan S.

2012-03-01

258

Gastroprotective activity and mechanism of novel dichlorido-zinc(II)-4-(2-(5-methoxybenzylideneamino)ethyl)piperazin-1-iumphenolate complex on ethanol-induced gastric ulceration.  

PubMed

Zinc complexes were reported to have anti-ulcer activity and used as drug for the treatment of gastrointestinal disorders. A novel compound dichlorido-zinc(II)-4-(2-(5-methoxybenzylidene amino)ethyl)piperazin-1-iumphenolate (ZnHMS) was synthesized, characterized and evaluated for its gastroprotective activity against ethanol-induced ulcer in rats. Gross and microscopic lesions, histochemical staining of glycogen storage, biochemical and immunological parameters were taken into consideration. Oral administration of ZnHMS (30 and 60 mg/kg; 14 days) dose-dependently inhibited gastric lesions. It significantly increased the mucus content and total acidity compared to the control group (P<0.01). Serum levels of aspartate (AST), alanine (ALT) transaminases, pro-inflammatory interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-?) and anti-inflammatory interleukin-10 (IL-10) in the rats exposed to ethanol induced ulceration have been altered. ZnHMS considerably enhances (P<0.05) the protection of gastric epithelia by modulating the acute alterations of AST, ALT, IL-6, IL-10, TNF-? and stomach glycogen. Interestingly, ZnHMS did interfere with the natural release of nitric oxide. In addition, acute toxicity study revealed no abnormal sign to the rats treated with ZnHMS (2000 mg/kg). These findings suggest that the gastroprotective activity of ZnHMS might contribute in adjusting the inflammatory cytokine-mediated oxidative damage to the gastric mucosa. PMID:22178775

Salga, Muhammad Saleh; Ali, Hapipah Mohd; Abdulla, Mahmood Ameen; Abdelwahab, Siddig Ibrahim

2012-01-25

259

Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines  

NASA Astrophysics Data System (ADS)

A series of heteroleptic copper(II) complexes of the type [CuL1-4(diimine)](ClO4)2 (1-8) [L1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2?-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172 10-4 cm-1) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in dx-y ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA.

Ravichandran, J.; Gurumoorthy, P.; Imran Musthafa, M. A.; Kalilur Rahiman, A.

2014-12-01

260

Single-walled carbon nanotubes functionalized with aptamer and piperazine-polyethylenimine derivative for targeted siRNA delivery into breast cancer cells.  

PubMed

Epithelial cell adhesion molecule (EpCAM) is a glycosylated type 1 membrane protein which is frequently over expressed in most solid tumors and it has recently been identified as a cancer stem cell (CSC) marker. Specific targeting of CSCs using nano-carriers would enhance treatment efficacy of cancer. In this study, we used a RNA aptamer against EpCAM (EpDT3) attached physically to our newly synthesized non-viral vector, based on single-walled carbon nanotube (SWNT) conjugated to piperazine-polyethylenimine derivative. The DNA transfection efficiency and siRNA delivery activity of the synthesized vector was investigated against upregulated BCL9l, which has been associated with breast and colorectal cancers. The complexes of the vector-aptamer/siRNA could specifically induce apoptosis by more than 20% in MCF-7 cell line as a positive EpCAM than MDA-MB-231 cells which are EpCAM negative. The decrease of BCL9l protein level was observed with western blot analysis in MCF-7 cells indicating the targeted silencing activity of the complex. PMID:25712164

Mohammadi, Marzieh; Salmasi, Zahra; Hashemi, Maryam; Mosaffa, Fatemeh; Abnous, Khalil; Ramezani, Mohammad

2015-05-15

261

Potential antidepressants: pharmacology of 2-(4-methyl piperazin-1-yl)-1,8-naphthyridine-3-carbonitrile in rodent behavioural models.  

PubMed

Serotonin type 3 (5-HT3) antagonists, which find an unflinching place in the management of nausea and emesis are presently screened for their neuro-pharmacological potential in various animal models. In the present study, 2-(4-methyl piperazin-1-yl)-1,8-naphthyridine-3-carbonitrile (NA-2) with an optimal log P and pA2 value comparable to that of ondansetron was screened in rodent models of depression. The acute and chronic (14 days) treatment of the synthetic compound exhibited antidepressant-like effects at the lower dose levels in mice forced swim test (FST). A typical and similar dose-immobility profile was observed in both mice FST and tail suspension test (TST). Interaction studies in FST revealed the reversal of mCPP induced immobility, attenuation of antidepressant effects of fluoxetine and desipramine. Chronic NA-2 treatment restored the behavioural deficits in olfactory bulbectomized (OBX) rats as indicated by reduction in hyperactivity in novel open field test. This preliminary study points to a serotonergic mechanism behind the antidepressant-like effects of NA-2 and invigorates further investigation of analogous compounds in various other models of depression. PMID:18214343

Mahesh, R; Rajkumar, R; Minasri, B; Venkatesha Perumal, R

2007-12-01

262

Design, synthesis and antimycobacterial evaluation of 1-(4-(2-substitutedthiazol-4-yl)phenethyl)-4-(3-(4-substitutedpiperazin-1-yl)alkyl)piperazine hybrid analogues.  

PubMed

A series of twenty six new 1-(4-(2-substitutedthiazol-4-yl)phenethyl)-4-(3-(4-substitutedpiperazin-1-yl)alkyl)piperazine analogues were synthesized by seven steps and evaluated for their anti-tubercular activity against Mycobacterium tuberculosis H37Rv strain. Among the tested compounds, 7j, 7p, and 7r exhibited moderate activity (MIC = 6.25 ?g/mL) and compounds 7a, 7f, 7g, 7n and 7v exhibited good activity (MIC = 3.125 ?g/mL), while 7h displayed excellent activity (MIC = 1.56 ?g/mL) by inhibiting 99% growth of M. tuberculosis H37Rv strain. In addition, all the active compounds were subjected to cytotoxic studies against mouse macrophage (RAW264.7) cell lines and the selectivity index values for most of the compounds is >10 indicating suitability of compounds in an endeavour to attain lead molecule for further drug development. PMID:25062011

Nagesh, Hunsur Nagendra; Suresh, Amaroju; Sairam, Sirigina Devesh Sathya Sri; Sriram, Dharmarajan; Yogeeswari, Perumal; Chandra Sekhar, Kondapalli Venkata Gowri

2014-09-12

263

Synthesis, growth, structural and optical studies of organic nonlinear optical material - Piperazine-1,4-diium bis 2,4,6-trinitrophenolate  

NASA Astrophysics Data System (ADS)

Piperazine-1,4-diium bis 2,4,6-trinitrophenolate is one of the useful organic materials with nonlinear optical (NLO) and pharmaceutical applications. The material was grown by slow evaporation solution growth method at room temperature. The crystal system and lattice parameters were identified by single crystal XRD analysis. The grown material crystallizes in monoclinic system with P21/n space group. The main functional groups NH2, NO2, Csbnd N, Cdbnd C, and phenolic O' atom were identified using FTIR analysis. The protons and carbons of grown crystal with various chemical environments were studied by 1H and 13C NMR spectroscopy to confirm the molecular structure. The optical properties of the crystal were studied by UV-vis-NIR spectroscopy and the transmission 100% range starts from 532 nm onwards. The optical band gap was measured as 2.63 eV from the plot of (?h?)2 versus h?. The thermal stability was detected at 304.1 C using TG-DTA analysis. The dielectric studies of the sample were carried out at different temperatures in the frequency range from 50 Hz to 5 MHz to establish the dielectric nature of the crystal. Photoconductivity measurements were carried out on the grown crystal. The Second Harmonic Generation (SHG) of the crystal was tested to confirm the nonlinear optical property.

Suguna, S.; Anbuselvi, D.; Jayaraman, D.; Nagaraja, K. S.; Jeyaraj, B.

2014-11-01

264

(?-Piperazine-1,4-dicarbodithioato-?4 S 1,S 1?:S 4,S 4?)bis[bis(triphenylphosphane-?P)gold(I)] chloroform disolvate  

PubMed Central

In the title compound, [Au2(C6H8N2S4)(C18H15P)4]2CHCl3, the digold complex resides on a crystallographic inversion center and co-crystallizes with two molecules of chloroform solvent. The piperazine-1,4-dicarbodithioate linker has an almost ideal chair conformation. The geometry about the gold atoms is severely distorted tetrahedral punctuated by a very acute SAuS bite angle. PMID:22219852

Guzei, Ilia A.; Spencer, Lara C.; Lillywhite, Stacy; Darkwa, James

2011-01-01

265

(3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone: A potent, selective, orally active dipeptidyl peptidase IV inhibitor  

SciTech Connect

A series of 4-substituted proline amides was synthesized and evaluated as inhibitors of dipeptidyl pepdidase IV for the treatment of type 2 diabetes. (3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone (5) emerged as a potent (IC{sub 50} = 13 nM) and selective compound, with high oral bioavailability in preclinical species and low plasma protein binding. Compound 5, PF-00734200, was selected for development as a potential new treatment for type 2 diabetes.

Ammirati, Mark J.; Andrews, Kim M.; Boyer, David D.; Brodeur, Anne M.; Danley, Dennis E.; Doran, Shawn D.; Hulin, Bernard; Liu, Shenping; McPherson, R. Kirk; Orena, Stephen J.; Parker, Janice C.; Polivkova, Jana; Qiu, Xiayang; Soglia, Carolyn B.; Treadway, Judith L.; VanVolkenburg, Maria A.; Wilder, Donald C.; Piotrowski, David W.; Pfizer

2010-10-01

266

Synthesis, biological evaluation and molecular docking study of novel piperidine and piperazine derivatives as multi-targeted agents to treat Alzheimer's disease.  

PubMed

Development of Multi-Target Directed Ligands (MTDLs) has emerged as a promising approach for targeting complex etiology of Alzheimer's disease (AD). Following this approach, a new series of N'-(4-benzylpiperidin-/piperazin-/benzhydrylpiperazin-1-yl)alkylamine derivatives were designed, synthesized and biologically evaluated as inhibitors of cholinesterases (ChEs), amyloid-beta (A?) self aggregation and also for their radical scavenging activity. The in vitro studies showed that the majority of synthesized derivatives strongly inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) with IC50 values in the low-nanomolar range, and were clearly more potent than the reference compound donepezil in this regard. Among them, inhibitors 5h and 5k, strongly inhibited AChE, with IC50 value of 6.83nM and 2.13nM, respectively, and particularly, compound 5k was found to be highly selective for AChE (?38-fold). Moreover, both kinetic analysis of AChE inhibition and the docking study suggested that 5k binds simultaneously to catalytic active site and peripheral anionic site of AChE. Besides, these compounds also exhibited greater ability to inhibit self-induced A?1-42 aggregation at 25?M with percentage inhibition from ?54% to 89% and specially compound 5k provided highest inhibition (88.81%). Also, the derivatives containing methoxy and hydroxy groups showed potent oxygen radical absorbance capacity (ORAC) ranging from 2.2- to 4.4-fold of the Trolox value. Furthermore, results of ADMET studies suggested that all compounds exhibited appropriate drug like properties. Taken together, these results suggest that 5k might be a promising lead compound for further AD drug development. PMID:25624107

Meena, Poonam; Nemaysh, Vishal; Khatri, Manisha; Manral, Apra; Luthra, Pratibha Mehta; Tiwari, Manisha

2015-03-01

267

Two new three-dimensional zinc phosphites templated by piperazine: [H2pip][Zn3(HPO3)4(H2O)2] and K[H2pip]0.5[Zn3(HPO3)4  

NASA Astrophysics Data System (ADS)

Two three-dimensional open-framework zinc phosphites with the same organically templated, [H2pip][Zn3(HPO3)4(H2O)2] (1) and K[H2pip]0.5[Zn3(HPO3)4] (2) (pip = piperazine), have been solvothermally synthesized and structurally characterized by IR, elemental analysis, thermogravimetric analysis, powder and single-crystal X-ray diffractions. Compound 1 consists of ZnO4 tetrahedra, [HPO3] pseudopyramids and [ZnO4(H2O)2] octahedra, which are linked through their vertexes to generate three-dimensional architecture with intersecting 8-membered channels along the [1 0 0], [0 0 1] and [1 0 1] directions. Compound 2 is constructed from strictly alternating ZnO4 tetrahedra and [HPO3] pseudopyramids, and exhibits (3,4)-connected inorganic framework with 8-, and 12-membered channels, in which the K+ and diprotonated H2pip2+ extra-framework cations reside, respectively. The coexistence of inorganic K+ and organic piperazine mixed templates in the structure is unique and, to the best of our knowledge, firstly observed in metal-phosphite materials. In addition, the participation of left-handed and right-handed helical chains in construction of the puckered 4.82 sheet structure in 2 is also noteworthy.

Zhang, Xiao; Wang, Guo-Ming; Wang, Zong-Hua; Wang, Ying-Xia; Lin, Jian-Hua

2014-01-01

268

The effects of intraventricular administration of eltoprazine, 1-(3-trifluoromethylphenyl)piperazine hydrochloride and 8-hydroxy-2-(di-n-propylamino)tetralin on resident intruder aggression in the rat.  

PubMed

Various serotonergic agents may reduce aggression in rats, but how they act in different parts of the brain is unknown. This study attempted to unravel part of this question by application of different serotonergic ligands into the lateral ventricle (i.c.v.) of male rats (resident-intruder aggression). 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin; 1 and 10 micrograms), a specific 5-HT1A agonist, affected neither aggression nor any other behaviour. The mixed 5-HT1A,B,C agonist, TFMPP (1-(3-trifluoromethylphenyl)piperazine hydrochloride), and the 5-HT1A/1B agonist, eltoprazine ((1-(2,3)-dihydro-1,4-benzodioxin-5-yl)piperazine hydrochloride), suppressed aggression at i.c.v. doses of 10 and 30 micrograms. This reduction was not caused by sedation. These data suggest a role of postsynaptic 5-HT1B receptors in mediating the anti-aggressive effects of mixed 5-HT1 agonists. PMID:1534769

Mos, J; Olivier, B; Poth, M; van Aken, H

1992-03-01

269

4-(3-Chloro-5-(trifluoromethyl)pyridin-2-yl)-N-(4-methoxypyridin-2-yl)piperazine-1-carbothioamide (ML267), a Potent Inhibitor of Bacterial Phosphopantetheinyl Transferase That Attenuates Secondary Metabolism and Thwarts Bacterial Growth  

PubMed Central

4?-Phosphopantetheinyl transferases (PPTases) catalyze a post-translational modification essential to bacterial cell viability and virulence. We present the discovery and medicinal chemistry optimization of 2-pyridinyl-N-(4-aryl)piperazine-1-carbothioamides, which exhibit submicromolar inhibition of bacterial Sfp-PPTase with no activity toward the human orthologue. Moreover, compounds within this class possess antibacterial activity in the absence of a rapid cytotoxic response in human cells. An advanced analogue of this series, ML267 (55), was found to attenuate production of an Sfp-PPTase-dependent metabolite when applied to Bacillus subtilis at sublethal doses. Additional testing revealed antibacterial activity against methicillin-resistant Staphylococcus aureus, and chemical genetic studies implicated efflux as a mechanism for resistance in Escherichia coli. Additionally, we highlight the in vitro absorption, distribution, metabolism, and excretion and in vivo pharmacokinetic profiles of compound 55 to further demonstrate the potential utility of this small-molecule inhibitor. PMID:24450337

2015-01-01

270

3-(Adamantan-1-yl)-4-methyl-1-({4-[3-(trifluoromethyl)phenyl]piperazin-1-yl}methyl)-4,5-dihydro-1H-1,2,4-triazole-5-thione  

PubMed Central

In the title compound, C25H32F3N5S, two independent molecules comprise the asymmetric unit and are related across a pseudo-centre of inversion. The piperazine rings have chair conformations with each N-bound substituent occupying an equatorial position so that the dihedral angles between the planes of the triazole and benzene ring are 78.20?(19) and 79.10?(19) for the two independent molecules, indicating that the molecules have an L-shape. In the crystal, a three-dimensional architecture is stabilized by CH?? interactions. The crystal studied was an inversion twin with the fractional contribution of the minor component being 0.27?(9). PMID:23723852

El-Emam, Ali A.; Al-Tamimi, Abdul-Malek S.; Alrashood, Khalid A.; Ng, Seik Weng; Tiekink, Edward R. T.

2013-01-01

271

N-(4-(4-(2,3-Dichloro- or 2-methoxyphenyl)piperazin-1-yl)-butyl)-heterobiarylcarboxamides with Functionalized Linking Chains as High Affinity and Enantioselective D3 Receptor Antagonists?  

PubMed Central

In the present report, the D3 receptor pharmacophore is modified in the 2,3-diCl-and 2-OCH3-phenyl piperazine class of compounds with the goal to improve D3 receptor affinity and selectivity. This extension of structure-activity relationships (SAR) has resulted in the identification of the first enantioselective D3 antagonists (R- and S-22) to be reported, wherein enantioselectivity is more pronounced at D3 than at D2, and that a binding region on the second extracellular loop (E2) may play a role in both enantioselectivity and D3 receptor selectivity. Moreover, we have discovered some of the most D3-selective compounds reported to date that show high affinity (Ki =1 nM) for D3 and ?400-fold selectivity over the D2 receptor subtype. Several of these analogues showed exquisite selectivity for D3 receptors over >60 other receptors further underscoring their value as in vivo research tools. These lead compounds also have appropriate physical characteristics for in vivo exploration and therefore will be useful in determining how intrinsic activity at D3 receptors tested in vitro is related to behaviors in animal models of addiction and other neuropsychiatric disorders. PMID:19331412

Newman, Amy Hauck; Grundt, Peter; Cyriac, George; Deschamps, Jeffrey R.; Taylor, Michelle; Kumar, Rakesh; Ho, David; Luedtke, Robert R.

2009-01-01

272

Poly[[di-aqua-[?-1,4-bis(pyridin-4-ylmeth-yl)piperazine-?(2) N:N']{?-2,2'-[(1,4-phenyl-ene)bis(-oxy)]di-acetato-?(2) O:O'}cobalt(II)] penta-hydrate].  

PubMed

In the title compound, {[Co(C10H8O6)(C16H20N4)(H2O)2]5H2O} n , octa-hedrally coordinated Co(II) ions on crystallographic inversion centres are bound by trans O atoms belonging to two hydro-quinone-O,O'-di-acetate (hqda) anions {systematic name: 2,2'-[(1,4-phenyl-ene)bis-(-oxy)]di-acetate}, two trans-pyridine N-donor atoms from two bis-(pyridin-4-ylmeth-yl)piperazine (4-bpmp) ligands, and two trans aqua ligands. The exobidentate hqda and 4-bpmp ligands form [Co(hqda)(4-bpmp)(H2O)2] n coordination polymer layers parallel to (110) that are anchored into the full crystal structure by O-H?O hydrogen bonding between aqua ligands and ligated hqda O atoms. Disordered water mol-ecules of crystallization occupy incipient channels along [100]. However, these could not modeled reliably and so they were treated with SQUEEZE in PLATON [Spek (2009 ?). Acta Cryst. D65, 148-155]; the crystal data take the presence of these mol-ecules into account. The crystal under investigation was twinned by non-merohedry, the twin fraction of the components being 53.3% and 46.7%. Only data from the major twin component were used in the refinement. PMID:24940193

Sample, Alexander D; LaDuca, Robert L

2014-06-01

273

Novel derivatives of 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (PB28) with improved fluorescent and ? receptors binding properties.  

PubMed

Despite the promising potentials of ?2 receptors in cancer therapy and diagnosis, there are still ambiguities related to the nature and physiological role of the ?2 protein. With the aim of providing potent and reliable tools to be used in ?2 receptor research, we developed a novel series of fluorescent ?2 ligands on the basis of our previous work, where high-affinity ?2 ligand 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)-n-propyl]piperazine (1, PB28) was used as the pharmacophore. Compared to the previous compounds, these novel ligands displayed improved fluorescence and ?2 binding properties, were ?2-specifically taken up by breast tumor cells, and were successfully employed in confocal microscopy. Compound 14, which was the best compromise between pharmacological and fluorescent properties, was successfully employed in flow cytometry, demonstrating its potential to be used as a tool in nonradioactive binding assays for studying the affinity of putative ?2 receptor ligands. PMID:24697311

Abate, Carmen; Niso, Mauro; Marottoli, Roberta; Riganti, Chiara; Ghigo, Dario; Ferorelli, Savina; Ossato, Giulia; Perrone, Roberto; Lacivita, Enza; Lamb, Don C; Berardi, Francesco

2014-04-24

274

Poly[[diaqua[?-1,4-bis(pyridin-4-ylmethyl)piperazine-?2 N:N?]{?-2,2?-[(1,4-phenylene)bis(oxy)]diacetato-?2 O:O?}cobalt(II)] pentahydrate  

PubMed Central

In the title compound, {[Co(C10H8O6)(C16H20N4)(H2O)2]5H2O}n, octahedrally coordinated CoII ions on crystallographic inversion centres are bound by trans O atoms belonging to two hydroquinone-O,O?-diacetate (hqda) anions {systematic name: 2,2?-[(1,4-phenylene)bis(oxy)]diacetate}, two trans-pyridine N-donor atoms from two bis(pyridin-4-ylmethyl)piperazine (4-bpmp) ligands, and two trans aqua ligands. The exobidentate hqda and 4-bpmp ligands form [Co(hqda)(4-bpmp)(H2O)2]n coordination polymer layers parallel to (110) that are anchored into the full crystal structure by OH?O hydrogen bonding between aqua ligands and ligated hqda O atoms. Disordered water molecules of crystallization occupy incipient channels along [100]. However, these could not modeled reliably and so they were treated with SQUEEZE in PLATON [Spek (2009 ?). Acta Cryst. D65, 148155]; the crystal data take the presence of these molecules into account. The crystal under investigation was twinned by non-merohedry, the twin fraction of the components being 53.3% and 46.7%. Only data from the major twin component were used in the refinement. PMID:24940193

Sample, Alexander D.; LaDuca, Robert L.

2014-01-01

275

Layer silicates modified with 1,4-bis(3-aminopropyl)piperazine for the removal of Th(IV), U(VI) and Eu(III) from aqueous media.  

PubMed

Natural montmorillonite (M) and synthetic kanemite (K) have been functionalized with 1,4-bis(3-aminopropyl)piperazine reacted with methylacrylate to yield new inorganic-organic chelating materials. The original and modified materials were characterized by X-ray diffractometry, textural analysis, SEM and nuclear magnetic nuclei of carbon-13 and silicon-29. The chemically modified clay samples (M-APPMA and K-APPMA) showed modification of its physical-chemical properties including: specific area 45.0m(2)g(-1) (M) to 978.8 m(2)g(-1) (M-APPMA) and 23.5m(2)g(-1) (K) to 898.9 m(2)g(-1) (K-APPMA). The ability of these materials to remove thorium(IV), uranyl(VI) and europium(III) from aqueous solution was followed by a series of adsorption isotherms, which were fitted to non-linear Sips adsorption isotherm model. To achieve the best adsorption conditions the influence of pH and variation of metal concentration were investigated. The energetic effects (Delta(int)H degrees , Delta(int)G degrees and Delta(int)S degrees ) caused by metal ions adsorption were determined through calorimetric titrations. PMID:19604631

Guerra, Denis L; Pinto, Alane A; Viana, Rbia R; Airoldi, Claudio

2009-11-15

276

Neuroprotective targets through which 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), a sigma receptor ligand, mitigates the effects of methamphetamine in vitro  

PubMed Central

Exposure to high or repeated doses of methamphetamine can cause hyperthermia and neurotoxicity, which are thought to increase the risk of developing a variety of neurological conditions. Sigma receptor antagonism can prevent methamphetamine-induced hyperthermia and neurotoxicity, but the underlying cellular targets through which the neuroprotection is conveyed remain unknown. Differentiated NG108-15 cells were thus used as a model system to begin elucidating the neuroprotective mechanisms targeted by sigma receptor antagonists to mitigate the effects of methamphetamine. In differentiated NG108-15 cells, methamphetamine caused the generation of reactive oxygen/nitrogen species, an increase in PERK-mediated endoplasmic reticulum stress and the activation of caspase-3, -8 and -9, ultimately resulting in apoptosis at micromolar concentrations, and necrotic cell death at higher concentrations. The sigma receptor antagonist, 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), attenuated methamphetamine-induced increases in reactive oxygen/nitrogen species, activation of caspase-3,-8 and-9 and accompanying cellular toxicity. In contrast, 1,3-di(2-tolyl)-guanidine (DTG), a sigma receptor agonist, shifted the dose response curve of methamphetamine-induced cell death towards the left. To probe the effect of temperature on neurotoxicity, NG108-15 cells maintained at an elevated temperature (40 C) exhibited a significant and synergistic increase in cell death in response to methamphetamine, compared to cells maintained at a normal cell culture temperature (37 C). SN79 attenuated the enhanced cell death observed in the methamphetamine-treated cells at 40 C. Together, the data demonstrate that SN79 reduces methamphetamine-induced reactive oxygen/nitrogen species generation and caspase activation, thereby conveying neuroprotective effects against methamphetamine under regular and elevated temperature conditions. PMID:24380829

Kaushal, Nidhi; Robson, Matthew J.; Rosen, Abagail; McCurdy, Christopher R.; Matsumoto, Rae R.

2014-01-01

277

Neuroprotective targets through which 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), a sigma receptor ligand, mitigates the effects of methamphetamine in vitro.  

PubMed

Exposure to high or repeated doses of methamphetamine can cause hyperthermia and neurotoxicity, which are thought to increase the risk of developing a variety of neurological conditions. Sigma receptor antagonism can prevent methamphetamine-induced hyperthermia and neurotoxicity, but the underlying cellular targets through which the neuroprotection is conveyed remain unknown. Differentiated NG108-15 cells were thus used as a model system to begin elucidating the neuroprotective mechanisms targeted by sigma receptor antagonists to mitigate the effects of methamphetamine. In differentiated NG108-15 cells, methamphetamine caused the generation of reactive oxygen/nitrogen species, an increase in PERK-mediated endoplasmic reticulum stress and the activation of caspase-3, -8 and -9, ultimately resulting in apoptosis at micromolar concentrations, and necrotic cell death at higher concentrations. The sigma receptor antagonist, 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), attenuated methamphetamine-induced increases in reactive oxygen/nitrogen species, activation of caspase-3, -8 and -9 and accompanying cellular toxicity. In contrast, 1,3-di(2-tolyl)-guanidine (DTG), a sigma receptor agonist, shifted the dose response curve of methamphetamine-induced cell death towards the left. To probe the effect of temperature on neurotoxicity, NG108-15 cells maintained at an elevated temperature (40 C) exhibited a significant and synergistic increase in cell death in response to methamphetamine, compared to cells maintained at a normal cell culture temperature (37 C). SN79 attenuated the enhanced cell death observed in the methamphetamine-treated cells at 40 C. Together, the data demonstrate that SN79 reduces methamphetamine-induced reactive oxygen/nitrogen species generation and caspase activation, thereby conveying neuroprotective effects against methamphetamine under regular and elevated temperature conditions. PMID:24380829

Kaushal, Nidhi; Robson, Matthew J; Rosen, Abagail; McCurdy, Christopher R; Matsumoto, Rae R

2014-02-01

278

Exploring the Solid State Properties of Enzymatic Poly(amine-co-ester) Terpolymers to Expand their Applications in Gene Transfection.  

PubMed

Polymers bearing amino functional groups are an important class of materials capable of serving as non-viral carriers for DNA delivery to living cells. In this work biodegradable poly(amine-co-ester) terpolymers were synthesized via ring-opening and polycondensation copolymerization of lactone (?-caprolactone (CL), ?-dodecalactone, ?-pentadecalactone (PDL), and ?-hexadecalactone) with diethyl sebacate (DES) and N-methyldiethanolamine (MDEA) in diphenyl ether, catalyzed by Candida antarctica lipase B (CALB). All lactone-DES-MDEA terpolymers had random distributions of lactone, sebacate, MDEA repeat units in the polymer chains. PDL-DES-MDEA terpolymers were studied in the composition range from 21 mol% to 90 mol% PDL whereas the terpolymers with other lactones were investigated at a single composition (80 mol% lactone). DSC and WAXS analyses showed that all investigated terpolymers crystallize in their respective homopolylactone crystal lattice. Terpolymers with large lactones and a high lactone content melt well above room temperature and are hard solids, whereas terpolymers with small lactones (e.g. CL) or with a low lactone content melt below/around ambient temperature and are waxy/gluey materials. Given the importance of hydrophobicity in influencing gene delivery, water contact angle measurements were carried out on lactone-DES-MDEA terpolymers showing that it is possible to tune the hydrophilic-to-hydrophobic balance by varying polymer composition and size of lactone units. To demonstrate the feasibility of using solid terpolymers as nanocarriers for DNA delivery, PDL-DES-MDEA copolymers with 65-90% PDL were successfully transformed into free-standing nanoparticles with average particle size ranging from 163 to 175 nm. Our preliminary results showed that LucDNA-loaded nanoparticles of the terpolymer with 65% PDL were effective for luciferase gene transfection of HEK293 cells. PMID:24683469

Voevodina, Irina; Scandola, Mariastella; Zhang, Junwei; Jiang, Zhaozhong

2014-01-01

279

Exploring the Solid State Properties of Enzymatic Poly(amine-co-ester) Terpolymers to Expand their Applications in Gene Transfection  

PubMed Central

Polymers bearing amino functional groups are an important class of materials capable of serving as non-viral carriers for DNA delivery to living cells. In this work biodegradable poly(amine-co-ester) terpolymers were synthesized via ring-opening and polycondensation copolymerization of lactone (?-caprolactone (CL), ?-dodecalactone, ?-pentadecalactone (PDL), and ?-hexadecalactone) with diethyl sebacate (DES) and N-methyldiethanolamine (MDEA) in diphenyl ether, catalyzed by Candida antarctica lipase B (CALB). All lactone-DES-MDEA terpolymers had random distributions of lactone, sebacate, MDEA repeat units in the polymer chains. PDL-DES-MDEA terpolymers were studied in the composition range from 21 mol% to 90 mol% PDL whereas the terpolymers with other lactones were investigated at a single composition (80 mol% lactone). DSC and WAXS analyses showed that all investigated terpolymers crystallize in their respective homopolylactone crystal lattice. Terpolymers with large lactones and a high lactone content melt well above room temperature and are hard solids, whereas terpolymers with small lactones (e.g. CL) or with a low lactone content melt below/around ambient temperature and are waxy/gluey materials. Given the importance of hydrophobicity in influencing gene delivery, water contact angle measurements were carried out on lactone-DES-MDEA terpolymers showing that it is possible to tune the hydrophilic-to-hydrophobic balance by varying polymer composition and size of lactone units. To demonstrate the feasibility of using solid terpolymers as nanocarriers for DNA delivery, PDL-DES-MDEA copolymers with 6590% PDL were successfully transformed into free-standing nanoparticles with average particle size ranging from 163 to 175 nm. Our preliminary results showed that LucDNA-loaded nanoparticles of the terpolymer with 65% PDL were effective for luciferase gene transfection of HEK293 cells. PMID:24683469

Voevodina, Irina; Scandola, Mariastella; Zhang, Junwei; Jiang, Zhaozhong

2014-01-01

280

Buffer Standards for pH Measurement of N-(2-Hydroxyethyl)piperazine-N-2-ethanesulfonic Acid (HEPES) for I = 0.16 molkg?1 from 5 to 55C  

PubMed Central

The values of the second dissociation constant, pK2 of N-(2-hydroxyethyl) piperazine-N-2-ethanesulfonic acid (HEPES) have been reported at 12 temperatures over the temperature range 5 to 55C, including 37C. This paper reports the results for the paH of eight isotonic saline buffer solutions with an I = 0.16 molkg?1 including compositions: (a) HEPES (0.01 molkg?1) + NaHEPES (0.01 molkg?1) + NaCl (0.15 molkg?1); (b) HEPES (0.02 molkg?1) + NaHEPES (0.02 molkg?1) + NaCl (0.14 molkg?1); (c) HEPES (0.03 molkg?1) + NaHEPES (0.03 molkg?1) + NaCl (0.13 molkg?1); (d) HEPES (0.04 molkg?1) + NaHEPES (0.04 molkg?1) + NaCl (0.12 molkg?1); (e) HEPES (0.05 molkg?1) + NaHEPES (0.05 molkg?1) + NaCl (0.11 molkg?1); (f) HEPES (0.06 molkg?1) + NaHEPES (0.06 molkg?1) + NaCl (0.10 molkg?1); (g) HEPES (0.07 molkg?1) + NaHEPES (0.07 molkg?1) + NaCl (0.09 molkg?1); and (h) HEPES (0.08 molkg?1) + NaHEPES (0.08 molkg?1) + NaCl (0.08 molkg?1). Conventional paH values, for all eight buffer solutions from 5 to 55C have been calculated. The operational pH values with liquid junction corrections, at 25 and 37C have been determined based on the NBS/NIST standard between the physiological phosphate standard and four buffer solutions. These are recommended as pH standards for physiological fluids in the range of pH 7.3 to 7.5 at I = 0.16 molkg?1. PMID:20161485

Roy, Rabindra N.; Roy, Lakshmi N.; Ashkenazi, Shahaf; Wollen, Joshua T.; Dunseth, Craig D.; Fuge, Michael S.; Durden, Jared L.; Roy, Chandra N.; Hughes, Hannah M.; Morris, Brett T.; Cline, Kevin L.

2009-01-01

281

Ether modifications to 1-[2-(3,4-dimethoxyphenyl)ethyl]-4-(3-phenylpropyl)piperazine (SA4503): effects on binding affinity and selectivity for sigma receptors and monoamine transporters.  

PubMed

Two series of novel ether analogs of the sigma (?) receptor ligand 1-[2-(3,4-dimethoxyphenyl)ethyl]-4-(3-phenylpropyl)piperazine (SA4503) have been prepared. In one series, the alkyl portion of the 4-methoxy group was replaced with allyl, propyl, bromoethyl, benzyl, phenethyl, and phenylpropyl moieties. In the second series, the 3,4-dimethoxy was replaced with cyclic methylenedioxy, ethylenedioxy and propylenedioxy groups. These ligands, along with 4-O-des-methyl SA4503, were evaluated for ?1 and ?2 receptor affinity, and compared to SA4503 and several known ether analogs. SA4503 and a subset of ether analogs were also evaluated for dopamine transporter (DAT) and serotonin transporter (SERT) affinity. The highest ?1 receptor affinities, Ki values of 1.75-4.63 nM, were observed for 4-O-des-methyl SA4503, SA4503 and the methylenedioxy analog. As steric bulk increased, ?1 receptor affinity decreased, but only to a point. Allyl, propyl and bromoethyl substitutions gave ?1 receptor Ki values in the 20-30 nM range, while bulkier analogs having phenylalkyl, and Z- and E-iodoallyl, ether substitutions showed higher ?1 affinities, with Ki values in the 13-21 nM range. Most ligands studied exhibited comparable ?1 and ?2 affinities, resulting in little to no subtype selectivity. SA4503, the fluoroethyl analog and the methylenedioxy congener showed modest six- to fourteen-fold selectivity for ?1 sites. DAT and SERT interactions proved much more sensitive than ? receptor interactions to these structural modifications. For example, the benzyl congener (?1Ki=20.8 nM; ?2Ki=16.4 nM) showed over 100-fold higher DAT affinity (Ki=121 nM) and 6-fold higher SERT affinity (Ki=128nM) than the parent SA4503 (DAT Ki=12650 nM; SERT Ki=760 nM). Thus, ether modifications to the SA4503 scaffold can provide polyfunctional ligands having a broader spectrum of possible pharmacological actions. PMID:25468036

Xu, Rong; Lord, Sarah A; Peterson, Ryan M; Fergason-Cantrell, Emily A; Lever, John R; Lever, Susan Z

2015-01-01

282

Piperazine (and derivatives) Copper(II) compounds: 1,4-dimethylpiperazin-1,4-ium tetrachlorocuprate(II) and Cu?N bond formation in trichloro(1-methylpiperazin-1-ium-N 4)copper(II) and trichloro(1,4-dimethylpiperazin-1-ium-N 4)copper(II)  

Microsoft Academic Search

The ionic salt (H2Me2ppz)2+ [CuCl4]2? (1), the pseudotetrahedral zwitterionic [CuCl3(HMe2ppz)] (2) and [CuCl3(H2Meppz)] (3) complexes of copper(II) have been synthesized and characterized, [(H2Me2ppz)2+=1,4-dimethyl-piperazin-1,4-ium; (HMe2ppz)+=1,4-dimethylpiperazin-1-ium; (H2Meppz)+=1-methylpiperazin-1-ium]. The X-ray diffraction analysis of compound (1) shows that the [CuCl4]2? anion possesses a flattened tetrahedral geometry with the two largest Cl?Cu?Cl angles being 125.90(5) and 131.41(5). The Cu?Cl distances range from 2.215(1) to 2.267(1)

Armando Marzotto; Dore A Clemente; Franco Benetollo; Giancarlo Valle

2001-01-01

283

21 CFR 520.1807 - Piperazine.  

Code of Federal Regulations, 2012 CFR

...milligrams per pound of body weight. (ii) Indications for use. For removal of large roundworm (Ascaris suum ) and nodular worms (Oesophagostomum spp.). (iii) Limitations. For use in drinking water or feed. Use as sole source of...

2012-04-01

284

21 CFR 520.1807 - Piperazine.  

Code of Federal Regulations, 2011 CFR

...milligrams per pound of body weight. (ii) Indications for use. For removal of large roundworm (Ascaris suum ) and nodular worms (Oesophagostomum spp.). (iii) Limitations. For use in drinking water or feed. Use as sole source of...

2011-04-01

285

21 CFR 520.1807 - Piperazine.  

Code of Federal Regulations, 2013 CFR

...diagnosis, treatment, and control of parasitism. (2) Turkeys (i) Amount...diagnosis, treatment, and control of parasitism. (3) Swine (i) Amount...diagnosis, treatment, and control of parasitism. [64 FR 23018, Apr. 29,...

2013-04-01

286

21 CFR 520.1807 - Piperazine.  

Code of Federal Regulations, 2014 CFR

...diagnosis, treatment, and control of parasitism. (2) Turkeys (i) Amount...diagnosis, treatment, and control of parasitism. (3) Swine (i) Amount...diagnosis, treatment, and control of parasitism. [64 FR 23018, Apr. 29,...

2014-04-01

287

Discovery of 8-Cyclopentyl-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidine-6-carbonitrile (7x) as a Potent Inhibitor of Cyclin-Dependent Kinase 4 (CDK4) and AMPK-Related Kinase 5 (ARK5)  

PubMed Central

The success of imatinib, a BCR-ABL inhibitor for the treatment of chronic myelogenous leukemia, has created a great impetus for the development of additional kinase inhibitors as therapeutic agents. However, the complexity of cancer has led to recent interest in polypharmacological approaches for developing multikinase inhibitors with low toxicity profiles. With this goal in mind, we analyzed more than 150 novel cyano pyridopyrimidine compounds and identified structureactivity relationship trends that can be exploited in the design of potent kinase inhibitors. One compound, 8-cyclopentyl-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidine-6-carbonitrile (7x), was found to be the most active, inducing apoptosis of tumor cells at a concentration of approximately 30100 nM. In vitro kinase profiling revealed that 7x is a multikinase inhibitor with potent inhibitory activity against the CDK4/CYCLIN D1 and ARK5 kinases. Here, we report the synthesis, structureactivity relationship, kinase inhibitory profile, in vitro cytotoxicity, and in vivo tumor regression studies by this lead compound. PMID:24417566

2015-01-01

288

Diaqua(5-carboxybenzene-1,3-dicarboxylato-?O 1)[8-ethyl-5-oxo-2-(piperazin-4-ium-1-yl)-5,8-dihydropyrido[2,3-d]pyrimidine-6-carboxylato-?2 O 5,O 6]zinc monohydrate  

PubMed Central

In the title compound, [Zn(C14H17N5O3)(C9H4O6)(H2O)2]H2O, the complex molecule exists in a zwitterionic form. The ZnII ion exhibits a distorted tetragonal-pyramidal geometry, being coordinated by two O atoms from the zwitterionic 8-ethyl-5-oxo-2-(piperazin-4-ium-1-yl)-5,8-dihydropyrido[2,3-d]pyrimidine-6-carboxylate (L) ligand, one O atom from the 5-carboxybenzene-1,3-dicarboxylate dianion, [Hbtc]2?, and two O atoms from two aqua ligands. In the crystal, NH?O and OH?O hydrogen bonds link the components into a three-dimensional structure. The crystal packing exhibits ?? interactions between the aromatic rings, with centroidcentroid distances in the range 3.466?(3)3.667?(3)?. PMID:23424417

Ye, Zhong-Li; Xin, Guang-Hua; Zhang, Fu-Tian; Xiao, Dong-Rong

2013-01-01

289

Spectroscopic (FT-IR, FT-Raman) investigations and quantum chemical calculations of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(3-methoxyphenyl)piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione  

NASA Astrophysics Data System (ADS)

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(3-methoxyphenyl) piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione have been investigated experimentally and theoretically using Gaussian09 software package. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. Gauge-including atomic orbital 1H NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular Electrostatic Potential was performed by the DFT method and the infrared and Raman intensities have also been reported. First hyperpolarizability is calculated in order to find its role in non-liner optics. The calculated geometrical parameters (SDD) are in agreement with that of similar derivatives. Mullikens net charges have been calculated and compared with the atomic natural charges.

Renjith, R.; Mary, Y. Sheena; Panicker, C. Yohannan; Varghese, Hema Tresa; Pakosi?ska-Parys, Magdalena; Van Alsenoy, C.; Al-Saadi, Abdulaziz A.

2014-08-01

290

Highly stretchable nanoalginate based polyurethane elastomers.  

PubMed

Highly stretchable elastomeric samples based on cationic polyurethane dispersions-sodium alginate nanoparticles (CPUD/SA) were prepared by the solution blending of sodium alginate and aqueous polyurethane dispersions. CPUDs were synthesized by step growth polymerization technique using N-methyldiethanolamine (MDEA) as a source of cationic emulsifier. The chemical structure and thermal-mechanical properties of these systems were characterized using FTIR and DMTA, respectively. The presence of nanoalginate particles including nanobead and nanorod particles were proved by SEM and EDX. It was observed that thermal properties of composites increased with increasing SA content. All prepared samples were known as thermoplastic-elastomers with high percentages of elongation. Excellent compatibility of prepared nanocomposites was proved by the DMTA data. PMID:23648022

Daemi, Hamed; Barikani, Mehdi; Barmar, Mohammad

2013-06-20

291

Determination of alkanolamines in cattails (Typha latifolia) utilizing electrospray ionization with selected reaction monitoring and ion-exchange chromatography.  

PubMed

Selected reaction monitoring (SRM) with electrospray ionization was used as a specific detection technique for the analysis of alkanolamines in plant tissue extracts. Ion-exchange chromatography was used as the method of separation. Quantification was based on monitoring the loss of either H2O or 2(H2O) from the protonated molecule [M+H]+. The method provided increased selectivity for all analytes and better detection limits for three of the six analytes investigated compared with an earlier method using selected ion monitoring with liquid chromatography. Instrumental detection limits ranged from 6-300 pg injected for monoethanolamine (MEA), monoisopropanolamine (MIPA), diethanolamine (DEA), methyldiethanolamine (MDEA), diisopropanolamine (DIPA), and triethanolamine (TEA). Method robustness and selectivity were demonstrated by the determination of DIPA and a known transformation product MIPA in over 35 plant extract samples derived from a laboratory study of plant uptake mechanisms. PMID:15282789

Peru, Kerry M; Headley, John V; Doucette, William J

2004-01-01

292

The removal of carbon dioxide with activated solutions of methyl-diethanol-amine  

Microsoft Academic Search

The (bulk) removal of carbon-dioxide (CO2) from industrial gases, e.g. natural gas, is usually realized with a reactive absorption technique in which (non-)aqueous solutions of alkanolamines are used.From the absorption rate point of view, primary or secondary amines are preferred. However, in case the costs of regeneration are also taken into account, tertiary amines are much more attractive. In order

S. van Loo; E. P. van Elk; G. F. Versteeg

2007-01-01

293

The removal of carbon dioxide with activated solutions of methyl-diethanol-amine  

Microsoft Academic Search

The (bulk) removal of carbon-dioxide (CO2) from industrial gases, e.g. natural gas, is usually realized with a reactive absorption technique in which (non-)aqueous solutions of alkanolamines are used. From the absorption rate point of view, primary or secondary amines are preferred. However, in case the costs of regeneration are also taken into account, tertiary amines are much more attractive. In

S. van Loo; E. P. van Elk; G. F. Versteeg

294

Ditetraalkylammonium amino acid ionic liquids as CO? absorbents of high capacity.  

PubMed

By grafting butyl or ethyl onto tetramethylethylenediamine, quaternary ammonium salts with two positive charge centers were formed at the first step. Metathesis with Ag(2)O followed. Through neutralization with glycine, l-alanine, or valine, a series of new ditetraalkylammonium amino acid ionic liquids (DILs) for CO(2) capture were generated. The structures of DILs, as shown in Figure 1, were verified by using (1)H NMR and EA. These DILs were found to be of quite high viscosity which militated against their industrial application in CO(2) removal. Drawing on the experience of mixed amines' aqueous solutions, these DILs were blended with water or N-methyldiethanolamine (MDEA) aqueous solutions to act as special absorbents of CO(2). Using a Double-Tank Absorption System, the absorption performance of these DIL solutions was investigated in detail. The experimental results indicated that among the three aqueous solutions of DILs (20%, 40%, and 80 wt %), the solution of 40% DIL had a higher absorption rate of CO(2) than the other two, demonstrating the different effects of concentration and viscosity on the absorption. The solution of 40% DIL or the 15% DIL + 15% MDEA had much higher capacity for CO(2) than the corresponding monocation tetraalkylammonium AAILs, due to the special structure of the dication which could influence the solubility of CO(2) in the aqueous solution. PMID:22066493

Ma, Jing-Wen; Zhou, Zheng; Zhang, Feng; Fang, Cheng-Gang; Wu, You-Ting; Zhang, Zhi-Bing; Li, Ai-Min

2011-12-15

295

High-throughput sample preparation and simultaneous column regeneration liquid chromatography-tandem mass spectrometry method for determination of nitrogen mustard metabolites in human urine.  

PubMed

Nitrogen mustards (NMs) are known to have DNA alkylation and strong vesicant properties. Their availability to terrorist organizations makes them a potential choice for chemical attacks on civilian populations. After an exposure, it is difficult to measure NMs directly because of their rapid metabolism in the human body. Therefore to determine an individual's level of exposure to NMs, it is necessary to analyze for NM metabolites being excreted by the body. The metabolites of NMs are generated by a hydrolysis reaction, and are easily detectable by liquid chromatography tandem mass spectrometry (LC-MS/MS). This work is focused on the development of a high-throughput assay for the quantitation of N-ethyldiethanolamine (EDEA) and N-methyldiethanolamine (MDEA) metabolites of bis (2-chloroethyl) ethylethanamine (HN1) and bis (2-chloroethyl) methylethanamine (HN2), respectively. The method uses automated 96-well plate sample preparation of human urine samples and a 2-position 10-port switching valve to allow for simultaneous regeneration of the liquid chromatography (LC) columns. Using this method, over 18 h was saved through the reduction of sample preparation and analysis time when compared to a conventional method for 96 samples. The validated method provided excellent accuracy for both EDEA (100.9%) and MDEA (100.6%) with precision better than 5.27% for each analyte. PMID:21764395

Reddy, Muntha K; Mills, Grier; Nixon, Christopher; Wyatt, Shane A; Croley, Timothy R

2011-08-15

296

Micelles of enzymatically synthesized PEG-poly(amine-co-ester) block copolymers as pH-responsive nanocarriers for docetaxel delivery.  

PubMed

A series of PEGylated poly(amine-co-ester) terpolymers were successfully synthesized in one step via lipase-catalyzed copolymerization of ?-pentadecalactone (PDL), diethyl sebacate (DES), and N-methyldiethanolamine (MDEA) comonomers in the presence of poly(ethylene glycol) methyl ether as a chain-terminating agent. The resultant amphiphilic poly(ethylene glycol)-poly(PDL-co-MDEA-co-sebacate) (PEG-PPMS) block copolymers consisted of hydrophilic PEG chain segments and hydrophobic random PPMS chain segments, which self-assembled in aqueous medium to form stable, nanosized micelles at physiological pH of 7.4. Upon decreasing the medium pH from 7.4 to 5.0, the copolymer micelles swell significantly due to protonation of the amino groups in the micelle PPMS cores. Correspondingly, docetaxel (DTX)-encapsulated PEG2K-PPMS copolymer micelles showed gradual sustained drug release at pH of 7.4, but remarkably accelerated DTX release at acidic pH of 5.0. The drug-loaded micelle particles were readily internalized by SK-BR-3 cancer cells and, compared to free DTX drug, DTX-loaded micelles of the copolymers with optimal compositions exhibited enhanced potency against the cells. Biodegradable PEG-PPMS copolymer micelles represent a new type of promising, pH-responsive nanocarriers for anticancer drug delivery, and the drug release rate from the micelles can be systematically controlled by both pH and the copolymer composition. PMID:24398083

Zhang, Xiaofang; Liu, Bo; Yang, Zhe; Zhang, Chao; Li, Hao; Luo, Xingen; Luo, Huiyan; Gao, Di; Jiang, Qing; Liu, Jie; Jiang, Zhaozhong

2014-03-01

297

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2010 CFR

...strongyles, pinworms, Strongyloides and ascarids (including members of the genera Strongylus spp., Cyathostomum spp., Cylicobrachytus spp. and related genera Craterostomum spp., Oesophagodontus spp., Poteriostomum spp.,...

2010-04-01

298

21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.  

Code of Federal Regulations, 2013 CFR

...oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water...bears directions for administration by stomach tube or drench, it shall also bear the...veterinarian; if not labeled for use by stomach tube or drench, the label shall bear...

2013-04-01

299

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2012 CFR

... See No. 050604 in 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2012-04-01

300

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2014 CFR

... See No. 050604 in 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2014-04-01

301

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2011 CFR

... See No. 050604 in 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2011-04-01

302

21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.  

Code of Federal Regulations, 2011 CFR

...oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water...bears directions for administration by stomach tube or drench, it shall also bear the...veterinarian; if not labeled for use by stomach tube or drench, the label shall bear...

2011-04-01

303

21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.  

Code of Federal Regulations, 2012 CFR

...oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water...bears directions for administration by stomach tube or drench, it shall also bear the...veterinarian; if not labeled for use by stomach tube or drench, the label shall bear...

2012-04-01

304

21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.  

Code of Federal Regulations, 2014 CFR

...oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water...bears directions for administration by stomach tube or drench, it shall also bear the...veterinarian; if not labeled for use by stomach tube or drench, the label shall bear...

2014-04-01

305

4-(Methyl-sulfon-yl)piperazin-1-ium chloride.  

PubMed

In the title mol-ecular salt, C(5)H(13)N(2)O(2)S(+)Cl(-), the complete cation is generated by crystallographic mirror symmetry, with both N atoms, the S atom and one C atom lying on the reflecting plane. The chloride ion also lies on the mirror plane. The piperazinium ring adopts a chair conformation and the N-S bond adopts an equatorial orientation. In the crystal structure, the component ions are linked into a three-dimensional framework by inter-molecular N-H?Cl and C-H?Cl hydrogen bonds. PMID:21579786

Fun, Hoong-Kun; Yeap, Chin Sing; Chidan Kumar, C S; Yathirajan, H S; Narayana, B

2010-01-01

306

4-(Methylsulfonyl)piperazin-1-ium chloride  

PubMed Central

In the title molecular salt, C5H13N2O2S+Cl?, the complete cation is generated by crystallographic mirror symmetry, with both N atoms, the S atom and one C atom lying on the reflecting plane. The chloride ion also lies on the mirror plane. The piperazinium ring adopts a chair conformation and the NS bond adopts an equatorial orientation. In the crystal structure, the component ions are linked into a three-dimensional framework by intermolecular NH?Cl and CH?Cl hydrogen bonds. PMID:21579786

Fun, Hoong-Kun; Yeap, Chin Sing; Chidan Kumar, C. S.; Yathirajan, H. S.; Narayana, B.

2010-01-01

307

Piperazine-1,4-diium naphthalene-1,5-disulfonate  

PubMed Central

The title molecular salt, C4H12N2 2+C10H6O6S2 2?, consists of a piperazinium cation and a 1,5-naphthalenedisulfonate anion. Crystallographic inversion centers are situated at the center of the ring of the dication as well as at the midpoint of the central carboncarbon bond in the dianion. In the crystal, intermolecular NH?O hydrogen bonds link the cations and anions. PMID:22065696

Wei, Bin

2011-01-01

308

Piperazine-1,4-diium naphthalene-1,5-disulfonate.  

PubMed

The title molecular salt, C(4)H(12)N(2) (2+)C(10)H(6)O(6)S(2) (2-), consists of a piperazinium cation and a 1,5-naphthalene-disulfonate anion. Crystallographic inversion centers are situated at the center of the ring of the dication as well as at the midpoint of the central carbon-carbon bond in the dianion. In the crystal, inter-molecular N-H?O hydrogen bonds link the cations and anions. PMID:22065696

Wei, Bin

2011-10-01

309

21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.  

Code of Federal Regulations, 2013 CFR

... See No. 050604 in 510.600(c) of this chapter. (c) Conditions of use. (1) It is administered to horses by stomach tube or as a drench at the rate of 1 fluid ounce of suspension per 100 pounds of body weight for the control of large...

2013-04-01

310

21 CFR 520.1803 - Piperazine citrate capsules.  

Code of Federal Regulations, 2010 CFR

...this chapter. (c) Conditions of use. (1) It is used in dogs and cats for the removal of large roundworms (Toxocara canis and Toxascaris leonina ). (2) The contents of 1 capsule should be mixed with the food of the animal...

2010-04-01

311

Piperine as an inhibitor of the MdeA efflux pump of Staphylococcus aureus.  

PubMed

Piperine, a trans-trans-isomer of 1-piperoyl-piperidine, was tested in combination with mupirocin for antimicrobial activity against Staphylococcus aureus strains including meticillin-resistant S. aureus. The combination markedly reduced the MIC of mupirocin and also lowered the mutation frequency. Enhanced accumulation and efflux of ethidium bromide from wild-type and mutant (Mup(r)-1) strains in the presence of piperine indicated that inhibition of efflux could be a possible mechanism of potentiation of mupirocin activity by piperine. The combination of piperine with mupirocin in a dermal infection model of mice showed better in vivo efficacy when compared with the commercially available formulation of 2?% mupirocin. PMID:21680766

Mirza, Zahid Mehmood; Kumar, Ashwani; Kalia, Nitin Pal; Zargar, Afzal; Khan, Inshad Ali

2011-10-01

312

A liquid chromatography-electrospray ionization-tandem mass spectrometry study of ethanolamines in high salinity industrial wastewaters.  

PubMed

The detection and quantitation of four ethanolamines, tris(2-hydroxyethyl)amine (triethanolamine, TEA), N,N-bis(2-hydroxyethyl)methylamine (methyldiethanolamine, MDEA), N-(2-aminoethyl)ethanolamine (AEA), and N,N-diethylethanolamine (DEA), were achieved in wastewaters from two aerobic activated sludge bioreactors located in an industrial wastewater treatment plant. The streams had salt concentrations of approximately 3% and 7% by weight in Reactor 1 and Reactor 2, respectively. The use of liquid chromatography-electrospray ionization-tandem mass spectrometry avoided the need for some sample preparation steps such as extraction, concentration, and derivatization. Ion suppression in the electrospray, attributable to the presence of sodium clusters, was attenuated by a 10-fold dilution of the wastewaters with acetonitrile. A matrix-matched calibration model averted other potential interferences. For the compounds analyzed in selected reaction monitoring mode (TEA, MDEA, and DEA), the calibration curves presented linearity in a range of 10-1000microg/L with corresponding detection limits ranging from 2 to 11microg/L, depending upon the specific analyte and aqueous matrix. AEA was calibrated in selected ion monitoring mode (100-1000microg/L), with corresponding detection limits in the two wastewaters of 74.6 and 85.3microg/L, respectively. Overall good precision (<10%) and accuracy (97-110%) were achieved for both matrices, which fell within-laboratory reproducibility. Finally, the amines were introduced into six mixed liquor samples from both reactors and quantified following the reported protocol. Again, recoveries were close to 100% with a relative standard deviation of less than 10% in all cases. PMID:20006060

Campo, Pablo; Suidan, Makram T; Chai, Yunzhou; Davis, John

2010-01-15

313

Synthesis, characterization and antibacterial properties of dihydroxy quaternary ammonium salts with long chain alkyl bromides.  

PubMed

Five N-methyl-N-R-N,N-bis(2-hydroxyethyl) ammonium bromides (R = -benzyl (chloride, BNQAS), -dodecyl (C12QAS), -tetradecyl (C14QAS), -hexadecyl (C16QAS), -octadecyl (C18QAS)) were prepared based on N-methyldiethanolamine (MDEA) and halohydrocarbon. Five QAS were characterized by FTIR, NMR, and MS. BNQAS, C12QAS, C14QAS, and C16QAS were confirmed by X-ray single-crystal diffraction. Their antibacterial properties indicated good antibacterial abilities against E. coli, S. aureus, B. subtilis, especially C12QAS with the best antibacterial ability (100% to E. coli, 95.65% to S. aureus, and 91.41% to B. subtilis). In addition, C12QAS also displayed the best antifungal activities than BNQAS and C18QAS against Cytospora mandshurica, Botryosphaeria ribis, Physalospora piricola, and Glomerella cingulata with the ratio of full marks. The strategy provides a facile way to design and develop new types of antibacterial drugs for application in preventing the fruit rot, especially apple. PMID:25215430

Liu, Wen-Shuai; Wang, Chun-Hua; Sun, Ju-Feng; Hou, Gui-Ge; Wang, Yu-Peng; Qu, Rong-Jun

2015-01-01

314

Electropolymerized carbonic anhydrase immobilization for carbon dioxide capture.  

PubMed

Biomimetic carbonation carried out with carbonic anhydrase (CA) in CO2-absorbing solutions, such as methyldiethanolamine (MDEA), is one approach that has been developed to accelerate the capture of CO2. However, there are several practical issues, such as high cost and limited enzyme stability, that need to be overcome. In this study, the capacity of CA immobilization on a porous solid support was studied to improve the instability in the tertiary amine solvent. We have shown that a 63% porosity macroporous carbon foam support makes separation and reuse facile and allows for an efficient supply and presentation of CO2 to an aqueous solvent and the enzyme catalytic center. These enzymatic supports conserved 40% of their initial activity after 42 days at 70 C in an amine solvent, whereas the free enzyme shows no activity after 1 h in the same conditions. In this work, we have overcome the technical barrier associated with the recovery of the biocatalyst after operation, and most of all, these electropolymerized enzymatic supports have shown a remarkable increase of thermal stability in an amine-based CO2 sequestration solvent. PMID:24856780

Merle, Geraldine; Fradette, Sylvie; Madore, Eric; Barralet, Jake E

2014-06-17

315

A Novel Substituted Piperazine, CM156, Attenuates the Stimulant and Toxic Effects of Cocaine in Mice  

PubMed Central

Cocaine is a highly abused drug without effective pharmacotherapies to treat it. It interacts with sigma (?) receptors, providing logical targets for the development of medications to counteract its actions. Cocaine causes toxic and stimulant effects that can be categorized as acute effects such as convulsions and locomotor hyperactivity and subchronic effects including sensitization and place conditioning. In the present study, 3-(4-(4-cyclohexylpiperazin-1-yl)butyl)benzo[d]thiazole-2(3H)-thione (CM156), a novel compound, was developed and tested for interactions with ? receptors using radioligand binding studies. It was also evaluated against cocaine-induced effects in behavioral studies. The results showed that CM156 has nanomolar affinities for each of the ? receptor subtypes in the brain and much weaker affinities for non-? binding sites. Pretreatment of male Swiss-Webster mice with CM156, before administering either a convulsive or locomotor stimulant dose of cocaine, led to a significant attenuation of these acute effects. CM156 also significantly reduced the expression of behavioral sensitization and place conditioning evoked by subchronic exposure to cocaine. The protective effects of CM156 are consistent with ? receptor-mediated actions. Together with previously reported findings, the data from CM156 and related ? compounds indicate that ? receptors can be targeted to alleviate deleterious actions of cocaine. PMID:20100904

Xu, Yan-Tong; Kaushal, Nidhi; Shaikh, Jamaluddin; Wilson, Lisa L.; Msangeau, Christophe; McCurdy, Christopher R.

2010-01-01

316

A novel substituted piperazine, CM156, attenuates the stimulant and toxic effects of cocaine in mice.  

PubMed

Cocaine is a highly abused drug without effective pharmacotherapies to treat it. It interacts with sigma (sigma) receptors, providing logical targets for the development of medications to counteract its actions. Cocaine causes toxic and stimulant effects that can be categorized as acute effects such as convulsions and locomotor hyperactivity and subchronic effects including sensitization and place conditioning. In the present study, 3-(4-(4-cyclohexylpiperazin-1-yl)butyl)benzo[d]thiazole-2(3H)-thione (CM156), a novel compound, was developed and tested for interactions with sigma receptors using radioligand binding studies. It was also evaluated against cocaine-induced effects in behavioral studies. The results showed that CM156 has nanomolar affinities for each of the sigma receptor subtypes in the brain and much weaker affinities for non-sigma binding sites. Pretreatment of male Swiss-Webster mice with CM156, before administering either a convulsive or locomotor stimulant dose of cocaine, led to a significant attenuation of these acute effects. CM156 also significantly reduced the expression of behavioral sensitization and place conditioning evoked by subchronic exposure to cocaine. The protective effects of CM156 are consistent with sigma receptor-mediated actions. Together with previously reported findings, the data from CM156 and related sigma compounds indicate that sigma receptors can be targeted to alleviate deleterious actions of cocaine. PMID:20100904

Xu, Yan-Tong; Kaushal, Nidhi; Shaikh, Jamaluddin; Wilson, Lisa L; Msangeau, Christophe; McCurdy, Christopher R; Matsumoto, Rae R

2010-05-01

317

21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.  

Code of Federal Regulations, 2013 CFR

...Severely debilitated animals should not be wormed except on the advice of a veterinarian. If the drug is for administration by stomach tube, it shall be labeled: Federal law restricts this drug to use by or on the order of a licensed veterinarian....

2013-04-01

318

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

Code of Federal Regulations, 2014 CFR

... ). (2) Limitations. Aqueous solution: administer by stomach tube or drench 1 fluid ounce per 100 pounds of body weight. Reconstituted soluble powder: administer by stomach tube 1 fluid ounce per 125 pounds of body weight. If...

2014-04-01

319

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2011 CFR

...Oxyuris equi ). (3) Limitations. Mix powder and vial contents together in warm water to form suspension. Administer by stomach tube. Do not fast horses before or after treatment. Treatment of mares in late pregnancy is not recommended....

2011-04-01

320

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2012 CFR

...Oxyuris equi ). (3) Limitations. Mix powder and vial contents together in warm water to form suspension. Administer by stomach tube. Do not fast horses before or after treatment. Treatment of mares in late pregnancy is not recommended....

2012-04-01

321

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

Code of Federal Regulations, 2010 CFR

... ). (2) Limitations. Aqueous solution: administer by stomach tube or drench 1 fluid ounce per 100 pounds of body weight. Reconstituted soluble powder: administer by stomach tube 1 fluid ounce per 125 pounds of body weight. If...

2010-04-01

322

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

Code of Federal Regulations, 2012 CFR

... ). (2) Limitations. Aqueous solution: administer by stomach tube or drench 1 fluid ounce per 100 pounds of body weight. Reconstituted soluble powder: administer by stomach tube 1 fluid ounce per 125 pounds of body weight. If...

2012-04-01

323

21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.  

Code of Federal Regulations, 2011 CFR

...Severely debilitated animals should not be wormed except on the advice of a veterinarian. If the drug is for administration by stomach tube, it shall be labeled: Federal law restricts this drug to use by or on the order of a licensed veterinarian....

2011-04-01

324

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2012 CFR

...strongyles, large strongyles (Strongyles spp.), and pinworms (Oxyuris equi ).1 (3) Limitations. Administer by stomach tube or dose syringe after withholding feed overnight or for 8 to 10 hours. Provide water as usual. Resume...

2012-04-01

325

21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.  

Code of Federal Regulations, 2014 CFR

...Severely debilitated animals should not be wormed except on the advice of a veterinarian. If the drug is for administration by stomach tube, it shall be labeled: Federal law restricts this drug to use by or on the order of a licensed veterinarian....

2014-04-01

326

21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.  

Code of Federal Regulations, 2012 CFR

...Severely debilitated animals should not be wormed except on the advice of a veterinarian. If the drug is for administration by stomach tube, it shall be labeled: Federal law restricts this drug to use by or on the order of a licensed veterinarian....

2012-04-01

327

21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.  

Code of Federal Regulations, 2013 CFR

... ). (2) Limitations. Aqueous solution: administer by stomach tube or drench 1 fluid ounce per 100 pounds of body weight. Reconstituted soluble powder: administer by stomach tube 1 fluid ounce per 125 pounds of body weight. If...

2013-04-01

328

Interaction of organotin with piperazine derived self-assembled cylindrical bisdithiocarbamates: Spectral and thermal investigations  

NASA Astrophysics Data System (ADS)

Few organotin complexes of the type R 4Sn 2L 2 where R = CH 3 ( 2), C 4H 9 ( 3), C 6H 5 ( 4), and Sn 2L 2Cl 4 ( 5) (L = bis(2,2'-dithiopiperazinato-2,2'-diaminodiethylamine)) have been synthesized and suitably characterized by FT-IR, UV-vis, 1H NMR, 119Sn NMR, ESI-MS, TGA/DSC, microanalysis and room temperature molar conductivity data. On the basis of FT-IR spectral studies, a symmetrical bidentate coordination has been proposed for all the complexes while the absence of any higher peak in the ESI-MS may be corroborated with the formation of binuclear complexes. On the basis of 119Sn NMR spectroscopy, six-coordinate geometry has been observed for the Sn-center in all the complexes. The TGA/DSC profile of the complexes implies their higher stability than its precursor. However, on the basis of IDT values the stability order of the organotin complexes was found to be 4 > 3 > 2. The room temperature conductivity values of the 1 mM solution of the ligand and its complexes are found to be comparable with that of non-ionic complexes.

Husain, Ahmad; Nami, Shahab A. A.; Siddiqi, K. S.

2009-07-01

329

Interaction of organotin with piperazine derived self-assembled cylindrical bisdithiocarbamates: spectral and thermal investigations.  

PubMed

Few organotin complexes of the type R4Sn2L2 where R=CH3 (2), C4H9 (3), C6H5 (4), and Sn2L2Cl4 (5) (L=bis(2,2'-dithiopiperazinato-2,2'-diaminodiethylamine)) have been synthesized and suitably characterized by FT-IR, UV-vis, 1H NMR, 119Sn NMR, ESI-MS, TGA/DSC, microanalysis and room temperature molar conductivity data. On the basis of FT-IR spectral studies, a symmetrical bidentate coordination has been proposed for all the complexes while the absence of any higher peak in the ESI-MS may be corroborated with the formation of binuclear complexes. On the basis of 119Sn NMR spectroscopy, six-coordinate geometry has been observed for the Sn-center in all the complexes. The TGA/DSC profile of the complexes implies their higher stability than its precursor. However, on the basis of IDT values the stability order of the organotin complexes was found to be 4>3>2. The room temperature conductivity values of the 1 mM solution of the ligand and its complexes are found to be comparable with that of non-ionic complexes. PMID:19297242

Husain, Ahmad; Nami, Shahab A A; Siddiqi, K S

2009-07-01

330

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2014 CFR

...or within 2 weeks before or after treatment with, or exposure to, neuromuscular depolarizing agents (e.g., succinylcholine) or to cholinesterase-inhibiting drugs, pesticides, or chemicals. (d) Conditions of use (1)...

2014-04-01

331

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2013 CFR

...or within 2 weeks before or after treatment with, or exposure to, neuromuscular depolarizing agents (e.g., succinylcholine) or to cholinesterase-inhibiting drugs, pesticides, or chemicals. (d) Conditions of use (1)...

2013-04-01

332

Crystal structure of 2-methylpiperazine-1,4-diium bis(hydrogen maleate)  

PubMed Central

In the title salt, C5H14N2 2+2C4H3O4 ?, the asymmetric unit contains two independent 2-methylpiperazinium dications, which comprise a racemic pair, and four hydrogen maleate monoanions. In the roughly planar hydrogen maleate anions, intramolecular OH?O hydrogen bonds generate S(7) rings. In the crystal, the four independent anions are linked to the 2-methylpiperazinium cations through NH?O hydrogen bonds, forming two-dimensional layered structures lying parallel to (001). PMID:25844244

Wecharine, Intissar; Valkonen, Arto; Rzaigui, Mohamed; Smirani Sta, Wajda

2015-01-01

333

Tetraaquabis(piperazin-1-ium)cobalt(II) bis(sulfate) dihydrate  

PubMed Central

In the centrosymmetric title compound, [Co(C4H11N2)2(H2O)4](SO4)22H2O, the CoII atom is coordinated in a distorted octahedral geometry by four water O atoms and two piperazinium N atoms. These four water O atoms define an equatorial plane with a maximum deviation of 0.0384?(1)? while the two piperazinium N atoms complete the octahedron in the axial positions. Neighboring complex molecules and sulfate anions are connected through an extensive network of NH?O and OH?O hydrogen bonds, which link the different chemical species into layers in the ab plane. Additional OwaterH?O hydrogen bonds involving the non-coordinating water molecules and CH?O interactions connect these layers into a three-dimensional supramolecular structure. PMID:24454163

Sahbani, Thameur; Smirani Sta, Wajda; Rzaigui, Mohamed

2013-01-01

334

Crystal structure of 2-methyl-piperazine-1,4-diium bis-(hydrogen maleate).  

PubMed

In the title salt, C5H14N2 (2+)2C4H3O4 (-), the asymmetric unit contains two independent 2-methyl-piperazinium dications, which comprise a racemic pair, and four hydrogen maleate monoanions. In the roughly planar hydrogen maleate anions, intra-molecular O-H?O hydrogen bonds generate S(7) rings. In the crystal, the four independent anions are linked to the 2-methyl-piperazinium cations through N-H?O hydrogen bonds, forming two-dimensional layered structures lying parallel to (001). PMID:25844244

Wecharine, Intissar; Valkonen, Arto; Rzaigui, Mohamed; Smirani Sta, Wajda

2015-03-01

335

4-(Pyrimidin-2-yl)piperazin-1-ium (E)-3-carboxyprop-2-enoate  

PubMed Central

In the cation of the title salt, C8H13N4 +C4H3O4 ?, the piperazinium ring adopts a slightly distorteded chair conformation. In the crystal, a single strong OH?O intermolecular hydrogen bond links the anions, forming chains along the c-axis direction. The chains of anions are linked by the cations, via NH?O hydrogen bonds, forming sheets parallel to (100). These layers are linked by weak CH?O hydrogen bonds, forming a three-dimensional structure. In addition, there are weak ?? interactions [centroidcentroid distance = 3.820?(9)?] present involving inversion-related pyrimidine rings. PMID:24940275

Yamuna, Thammarse S.; Kaur, Manpreet; Jasinski, Jerry P.; Yathirajan, H. S.

2014-01-01

336

4-(Pyrimidin-2-yl)piperazin-1-ium (E)-3-carb-oxy-prop-2-enoate.  

PubMed

In the cation of the title salt, C8H13N4 (+)C4H3O4 (-), the piperazinium ring adopts a slightly distorteded chair conformation. In the crystal, a single strong O-H?O inter-molecular hydrogen bond links the anions, forming chains along the c-axis direction. The chains of anions are linked by the cations, via N-H?O hydrogen bonds, forming sheets parallel to (100). These layers are linked by weak C-H?O hydrogen bonds, forming a three-dimensional structure. In addition, there are weak ?-? inter-actions [centroid-centroid distance = 3.820?(9)?] present involving inversion-related pyrimidine rings. PMID:24940275

Yamuna, Thammarse S; Kaur, Manpreet; Jasinski, Jerry P; Yathirajan, H S

2014-06-01

337

Discovery of 1-aryloxyethyl piperazine derivatives as Kv1.5 potassium channel inhibitors (part I).  

PubMed

Kv1.5 potassium channel is an efficacious and safe therapeutic target for the treatment of atrial fibrillation (AF), the most common arrhythmia that threatens human. Herein, by modifying the hit compound 7k from an in-house database, 48 derivatives were synthesized for the assay of their Kv1.5 inhibitory effects by whole cell patch clamp technique. Six compounds which showed better potency than the positive compound dronedarone were selected for the next evaluation of their drug-like properties. Compound 8 exhibited balanced solubility and permeability. It also showed acceptable pharmacodynamics profile with very low acute toxicity. Taking all these data into account, compound 8 can serve as a promising lead for the development of novel therapeutic agent for the treatment of AF. PMID:24824064

Guo, Xiaoke; Ma, Xianglei; Yang, Qian; Xu, Jing; Huang, Lu; Jia, Jianmin; Shan, Jiaojiao; Liu, Li; Chen, Weilin; Chu, Hongxi; Wei, Jinlian; Zhang, Xiaojin; Sun, Haopeng; Tang, Yiqun; You, Qidong

2014-06-23

338

Thermodynamics of carbon dioxide in aqueous piperazine/potassium carbonate systems at stripper conditions  

E-print Network

to equivalent solutions of monoethanolamine (MEA). Cullinane [1] measured CO2 solubility with a wetted wall prepared from distilled water by weight. CO2 Solubility The VLE apparatus consisted of three 300 cm3

Rochelle, Gary T.

339

N-(4-Methylpiperazin-4-ium-1-yl)dithiocarbamate sesquihydrate  

PubMed Central

In the crystal structure of the title compound, C6H13N3S21.5H2O, weak NH?S interactions between the zwitterionic molecules are observed, leading to an extensively folded layered arrangement parallel to (100). There are three crystallographically independent water molecules in the asymmetric unit, which are disordered and only half occupied. PMID:22719506

Mietlarek-Kropid?owska, Anna; Chojnacki, Jaros?aw; Wityk, Pawe?; Wieczr, Mi?osz; Becker, Barbara

2012-01-01

340

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2014 CFR

...are: (i) Industrial, commercial, and consumer activities. Requirements as specified in 721.80(j) (flame retardant). (ii) [Reserved] (b) Specific requirements. The provisions of subpart A of this part apply to...

2014-07-01

341

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2012 CFR

...are: (i) Industrial, commercial, and consumer activities . Requirements as specified in 721.80(j) (flame retardant). (ii) [Reserved] (b) Specific requirements . The provisions of subpart A of this part apply to...

2012-07-01

342

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2010 CFR

...are: (i) Industrial, commercial, and consumer activities . Requirements as specified in 721.80(j) (flame retardant). (ii) [Reserved] (b) Specific requirements . The provisions of subpart A of this part apply to...

2010-07-01

343

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2013 CFR

...are: (i) Industrial, commercial, and consumer activities . Requirements as specified in 721.80(j) (flame retardant). (ii) [Reserved] (b) Specific requirements . The provisions of subpart A of this part apply to...

2013-07-01

344

40 CFR 721.10102 - Diphosphoric acid, compd. with piperazine (1:1).  

Code of Federal Regulations, 2011 CFR

...are: (i) Industrial, commercial, and consumer activities . Requirements as specified in 721.80(j) (flame retardant). (ii) [Reserved] (b) Specific requirements . The provisions of subpart A of this part apply to...

2011-07-01

345

2-{4-[(1,3-Benzodioxol-5-yl)methyl]piperazin-1-yl}pyrimidine  

PubMed Central

In the title compound, C16H18N4O2, known also as peribedil, the dihedral angle between the mean planes of the pyrimidine and benzene rings is 56.5?(8). The 1,3-dioxole fragment adopts an envelope conformation with the methylene C atom forming the flap; this atom deviates by 0.232?(3)? from the plane defined by the remaining atoms of the 1,3-benzodioxole unit. In the crystal, CH?? interactions between c-glide-related molecules arrange them into columns extending along the c-axis direction. The columns related by a unit translation along the b axis are packed into (100) layers via another CH?? interaction involving the pyrimidine ring as an acceptor. PMID:24046690

Wu, Chunli; Li, Jieming; Wei, Huijie; Hang, Ye; Jiang, Yueming

2013-01-01

346

1-acyl-4-benzyl-2,5-transdimethyl-piperazine CCR1 antagonists.  

PubMed

Two applications claim 1-acyl-4-benzyl-2,5-dimethylpiperazine derivatives as CCR1 antagonists useful in the treatment of inflammatory diseases. The two applications respectively claim compounds in which the acyl groups are 2-heteroaryl or cinnamoyl (and certain heterocyclic analogues thereof). Both applications describe compounds with good receptor affinity and good in vivo pharmacokinetic properties, displaying a superior profile relative to closely related prior art compounds. PMID:20144048

Norman, Peter

2006-03-01

347

21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.  

Code of Federal Regulations, 2010 CFR

...520.2520g Section 520.2520g Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...Administer by stomach tube. Do not fast horses before or after treatment...used in horses intended for use as food. Federal law restricts this...

2010-04-01

348

Design, synthesis and preliminary pharmacological evaluation of new piperidine and piperazine derivatives as cognition-enhancers.  

PubMed

A series of 2-oxopiperazine, 4-aminomethyl-, 3-amino- and 3-aminomethylpiperidine analogues of DM235 (sunifiram) and MN19 (sapunifiram), two previously reported potent cognition-enhancers, have been synthesized and tested in the mouse passive-avoidance test. The compounds display minimal effective doses in the range 0.3-10mg/kg. Although the new substances do not show improved activity when compared to the parent compounds, some useful information has been obtained to understand structure-activity relationships. In addition, the 3-aminopiperidine moiety appears to be a promising scaffold to synthesize new drugs endowed with cognition-enhancing activity. PMID:17981042

Martini, Elisabetta; Ghelardini, Carla; Dei, Silvia; Guandalini, Luca; Manetti, Dina; Melchiorre, Michele; Norcini, Monica; Scapecchi, Serena; Teodori, Elisabetta; Romanelli, Maria Novella

2008-02-01

349

Design, synthesis and preliminary pharmacological evaluation of new piperidine and piperazine derivatives as cognition-enhancers  

Microsoft Academic Search

A series of 2-oxopiperazine, 4-aminomethyl-, 3-amino- and 3-aminomethylpiperidine analogues of DM235 (sunifiram) and MN19 (sapunifiram), two previously reported potent cognition-enhancers, have been synthesized and tested in the mouse passive-avoidance test. The compounds display minimal effective doses in the range 0.310mg\\/kg. Although the new substances do not show improved activity when compared to the parent compounds, some useful information has been

Elisabetta Martini; Carla Ghelardini; Silvia Dei; Luca Guandalini; Dina Manetti; Michele Melchiorre; Monica Norcini; Serena Scapecchi; Elisabetta Teodori; Maria Novella Romanelli

2008-01-01

350

21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.  

Code of Federal Regulations, 2011 CFR

...510.600(c) of this chapter. (c) Conditions of use: Horses and ponies (1) Amount. For removal of ascarids...administer to animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious...

2011-04-01

351

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2010 CFR

...510.600(c) of this chapter. (c) Conditions of use. Horses and ponies (1) Amount. One fluid ounce per 100 pounds...administer to animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious...

2010-04-01

352

21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.  

Code of Federal Regulations, 2010 CFR

...510.600(c) of this chapter. (c) Conditions of use: Horses and ponies (1) Amount. For removal of ascarids...administer to animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious...

2010-04-01

353

21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.  

Code of Federal Regulations, 2011 CFR

...510.600(c) of this chapter. (c) Conditions of use. Horses and ponies (1) Amount. One fluid ounce per 100 pounds...administer to animals that are or were recently affected with colic, diarrhea, or infected with a serious infectious...

2011-04-01

354

Self-assembled 3D heterometallic Cu(II)/Fe(II) coordination polymers with octahedral net skeletons: structural features, molecular magnetism, thermal and oxidation catalytic properties.  

PubMed

The new three-dimensional (3D) heterometallic Cu(II)/Fe(II) coordination polymers [Cu(6)(H(2)tea)(6)Fe(CN)(6)](n)(NO(3))(2n)6nH(2)O (1) and [Cu(6)(Hmdea)(6)Fe(CN)(6)](n)(NO(3))(2n)7nH(2)O (2) have been easily generated by aqueous-medium self-assembly reactions of copper(II) nitrate with triethanolamine or N-methyldiethanolamine (H(3)tea or H(2)mdea, respectively), in the presence of potassium ferricyanide and sodium hydroxide. They have been isolated as air-stable crystalline solids and fully characterized including by single-crystal X-ray diffraction analyses. The latter reveal the formation of 3D metal-organic frameworks that are constructed from the [Cu(2)(?-H(2)tea)(2)](2+) or [Cu(2)(?-Hmdea)(2)](2+) nodes and the octahedral [Fe(CN)(6)](4-) linkers, featuring regular (1) or distorted (2) octahedral net skeletons. Upon dehydration, both compounds show reversible escape and binding processes toward water or methanol molecules. Magnetic susceptibility measurements of 1 and 2 reveal strong antiferromagnetic [J = -199(1) cm(-1)] or strong ferromagnetic [J = +153(1) cm(-1)] couplings between the copper(II) ions through the ?-O-alkoxo atoms in 1 or 2, respectively. The differences in magnetic behavior are explained in terms of the dependence of the magnetic coupling constant on the Cu-O-Cu bridging angle. Compounds 1 and 2 also act as efficient catalyst precursors for the mild oxidation of cyclohexane by aqueous hydrogen peroxide to cyclohexanol and cyclohexanone (homogeneous catalytic system), leading to maximum total yields (based on cyclohexane) and turnover numbers (TONs) up to about 22% and 470, respectively. PMID:21028781

Karabach, Yauhen Y; Guedes da Silva, M Ftima C; Kopylovich, Maximilian N; Gil-Hernndez, Beatriz; Sanchiz, Joaquin; Kirillov, Alexander M; Pombeiro, Armando J L

2010-12-01

355

Wipe selection for the analysis of surface materials containing chemical warfare agent nitrogen mustard degradation products by ultra-high pressure liquid chromatography-tandem mass spectrometry.  

PubMed

Degradation products arising from nitrogen mustard chemical warfare agent were deposited on common urban surfaces and determined via surface wiping, wipe extraction, and liquid chromatographytandem mass spectrometry detection. Wipes investigated included cotton gauze, glass fiber filter, non-woven polyester fiber and filter paper, and surfaces included several porous (vinyl tile, painted drywall, wood) and mostly non-porous (laminate, galvanized steel, glass) surfaces. Wipe extracts were analyzed by ultra-high pressure liquid chromatographytandem mass spectrometry (UPLCMS/MS) and compared with high performance liquid chromatographytandem mass spectrometry (HPLCMS/MS) results. An evaluation of both techniques suggests UPLCMS/MS provides a quick and sensitive analysis of targeted degradation products in addition to being nearly four times faster than a single HPLC run, allowing for greater throughput during a wide-spread release concerning large-scale contamination and subsequent remediation events. Based on the overall performance of all tested wipes, filter paper wipes were selected over other wipes because they did not contain interferences or native species (TEA and DEA) associated with the target analytes, resulting in high percent recoveries and low background levels during sample analysis. Other wipes, including cotton gauze, would require a pre-cleaning step due to the presence of large quantities of native species or interferences of the targeted analytes. Percent recoveries obtained from a laminate surface were 4799% for all nitrogen mustard degradation products. The resulting detection limits achieved from wipes were 0.2 ng/cm(2) for triethanolamine (TEA), 0.03 ng/cm(2) for N-ethyldiethanolamine (EDEA), 0.1 ng/cm(2) for N-methyldiethanolamine (MDEA), and 0.1 ng/cm(2) for diethanolamine (DEA). PMID:23218189

Willison, Stuart A

2012-12-28

356

Laser direct-write microfabrication and patterning  

NASA Astrophysics Data System (ADS)

The ability to generate small structures is central to modern science and technology. In this work, four laser direct-write microfabrication and micropatterning techniques were studied: (a) Laser micromachining of channels in PMMA using a CO2 laser was investigated experimentally and theoretically. Heat transfer models for the channel depth, channel profile, laser power and scanning speed were developed and applied in this work. These models, are in excellent agreement with experimental results, with a maximum deviation of approximately 5% for the range of experimental parameters (laser power, scanning speed) tested. (b) A sub-micrometer resolution laser direct-write polymerization system for 1 creating two-dimensional and three-dimensional structures was developed using a frequency-doubled Nd:YAG laser. Experimental studies and Monte Carlo simulations were conducted to understand the detailed microscale optical scattering, chemical reaction, polymerization, and their influence on critical fabrication parameters. The experimental data are in good agreement with the theoretical model. (c) Direct laser interference was developed for rapid and large area fabrication of two-dimensional and three dimensional periodic structures on photopolymerizable materials with 10ns pulses from a frequency-tripled Nd:YAG laser emitting at 355 nm. Three different photopolymerizable materials were investigated: pentaerythritol triacrylate (PETIA) with photoinitiator N-methyldiethanolamine (N-MDEA); SU-8 with absorber TINUVIN 384-2; and Shipley 1813. (d) A new approach to fabricating nanometer sized cavity arrays on Poly(3,4-ethylene dioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) thin films using laser-assisted near-field patterning was investigated. Periodic nano-cavity arrays were patterned by combining direct laser interference technology and laser induced near-field technology. An analytical model based on Mie theory was developed, the predicted intensity distributions on the substrate indicate a strong near-field enhancement confined to a very small area (nanometer scale).

Yuan, Dajun

357

Quantitative and qualitative analysis of MDMA, MDEA, MA and amphetamine in urine by head-space\\/solid phase micro-extraction (SPME) and GC\\/MS  

Microsoft Academic Search

The results of qualitative and quantitative analysis of some amphetamines and their analogs isolated from urine samples by solid phase micro-extraction with polydimethylsiloxane fibers are reported. The analytical method employed was gas-chromatography\\/mass spectrometry of head space samples.

F. Centini; A. Masti; I. Barni Comparini

1996-01-01

358

Chromatographic and spectroscopic methods of identification for the side-chain regioisomers of 3,4-methylenedioxyphenethylamines related to MDEA, MDMMA, and MBDB.  

PubMed

Three regioisomeric 3,4-methylenedioxyphenethylamines having the same molecular weight and major mass spectral fragments of equivalent mass have been reported as components of clandestine drug samples in recent years. These drugs of abuse are 3,4-methylenedioxy-N-ethylamphetamine, 3,4-methylenedioxy-N,N-dimethylamphetamine, and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine. These three compounds are a subset of a total of ten regioisomeric 3,4-methylenedioxyphenethylamines of molecular weight 207, yielding regioisomeric fragment ions of equivalent mass (m/z 72 and 135/136) in the electron impact mass spectrum. The specific identification of one of these compounds in a forensic drug sample depends upon the analyst's ability to eliminate the other regioisomers as possible interfering or coeluting substances. This paper reports the synthesis, mass spectral characterization, and chromatographic analysis of these ten unique regioisomers. The ten regioisomeric methylenedioxyphenethylamines are synthesized from commercially available precursor chemicals. The electron impact mass spectra of these regioisomers show some variation in the relative intensity of the major ions with only one or two minor ions that might be considered side-chain specific fragments. Thus, the ultimate identification of any one of these amines with the elimination of the other nine regioisomeric substances depends heavily upon chromatographic methods. Chromatographic separation of these ten uniquely regioisomeric amines is studied using gas chromatographic temperature program optimization. PMID:12841949

Aalberg, Laura; DeRuiter, Jack; Noggle, F Taylor; Sippola, Erkki; Clark, C Randall

2003-01-01

359

Quantitative and qualitative analysis of MDMA, MDEA, MA and amphetamine in urine by headspace/solid phase micro-extraction (SPME) and GC/MS.  

PubMed

The results of qualitative and quantitative analysis of some amphetamines and their analogs isolated from urine samples by solid phase micro-extraction with polydimethylsiloxane fibers are reported. The analytical method employed was gas-chromatography/mass spectrometry of head space samples. PMID:9032950

Centini, F; Masti, A; Barni Comparini, I

1996-12-27

360

The 5-substituted piperazine as a novel secondary pharmacophore greatly improving the physical properties of urea-based  

E-print Network

- pears selective for epoxides of lipids. In plants and ani- mals, many of these lipid substrates have However, the dialkyl ureas have limited solubility in Bioorganic & Medicinal Chemistry 14 (2006) 6586

Hammock, Bruce D.

361

Synthesis and evaluation of 7-chloro-4-(piperazin-1-yl)quinoline-sulfonamide as hybrid antiprotozoal agents.  

PubMed

A new series of 4-aminochloroquinoline based sulfonamides were synthesized and evaluated for antiamoebic and antimalarial activities. Out of the eleven compounds evaluated (F1-F11), two of them (F3 and F10) showed good activity against Entamoeba histolytica (IC50 <5 ?M). Three of the compounds (F5, F7 and F8) also displayed antimalarial activity against the chloroquine-resistant (FCR-3) strain of Plasmodium falciparum with IC50 values of 2 ?M. Compound F7, whose crystal structure was also determined, inhibited ?-haematin formation more potently than quinine. To further understand the action of hybrid molecules F7 and F8, molecular docking was carried out against the homology model of P. falciparum enzyme dihydropteroate synthase (PfDHPS). The complexes showed that the inhibitors place themselves nicely into the active site of the enzyme and exhibit interaction energy which is in accordance with our activity profile data. Application of Lipinski 'rule of five' on all the compounds (F1-F11) suggested high drug likeness of F7 and F8, similar to quinine. PMID:23602620

Salahuddin, Attar; Inam, Afreen; van Zyl, Robyn L; Heslop, Donovan C; Chen, Chien-Teng; Avecilla, Fernando; Agarwal, Subhash M; Azam, Amir

2013-06-01

362

N-(2-alkylaminoethyl)-4-(1,2,4-oxadiazol-5-yl)piperazine-1-carboxamides as highly potent smoothened antagonists  

Microsoft Academic Search

Smoothened (Smo) antagonists are emerging as new therapies for the treatment of neoplasias with aberrantly reactivated hedgehog (Hh) signaling pathway. A novel series of 4-[3-(quinolin-2-yl)-1,2,4-oxadiazol-5-yl]piperazinyl ureas as smoothened antagonists was recently described, herein the series has been further optimized through the incorporation of a basic amine into the urea. This development resulted in identification of some exceptionally potent smoothened antagonists

Ester Muraglia; Jesus M. Ontoria; Danila Branca; Gabriella Dessole; Alberto Bresciani; Massimiliano Fonsi; Claudio Giuliano; Laura Llauger Bufi; Edith Monteagudo; Maria Cecilia Palumbi; Caterina Torrisi; Michael Rowley; Christian Steinkhler; Philip Jones

2011-01-01

363

N-(2-alkylaminoethyl)-4-(1,2,4-oxadiazol-5-yl)piperazine-1-carboxamides as highly potent smoothened antagonists.  

PubMed

Smoothened (Smo) antagonists are emerging as new therapies for the treatment of neoplasias with aberrantly reactivated hedgehog (Hh) signaling pathway. A novel series of 4-[3-(quinolin-2-yl)-1,2,4-oxadiazol-5-yl]piperazinyl ureas as smoothened antagonists was recently described, herein the series has been further optimized through the incorporation of a basic amine into the urea. This development resulted in identification of some exceptionally potent smoothened antagonists with low serum shifts, however, reductive ring opening on the 1,2,4-oxadiazole in rats limits the applicability of these compounds in in vivo studies. PMID:21802943

Muraglia, Ester; Ontoria, Jesus M; Branca, Danila; Dessole, Gabriella; Bresciani, Alberto; Fonsi, Massimiliano; Giuliano, Claudio; Llauger Bufi, Laura; Monteagudo, Edith; Palumbi, Maria Cecilia; Torrisi, Caterina; Rowley, Michael; Steinkhler, Christian; Jones, Philip

2011-09-15

364

1-(2,3-Dimethylphenyl)piperazine-1,4-diium tetrachloridocuprate(II)  

PubMed Central

In the title salt, (C12H20N2)[CuCl4], the CuII atom occupies a general position in a flattened tetrahedral environment by Cl ligands, characterized by ClCuCl angles of 134.04?(3) and 137.18?(4). The six-membered piperazinediium ring adopts a chair conformation. The organic cation and inorganic anion interact through NH?Cl and CH?Cl hydrogen bonds, forming a three-dimensional network. PMID:24426985

Ben Mabrouk, Safa; Ameur, Iness; Abid, Sonia; Rzaigui, Mohamed

2013-01-01

365

O2-Dependent Efficacy of Novel Piperidine- and Piperazine-Based Chalcones against the Human Parasite Giardia intestinalis  

PubMed Central

Giardia intestinalis is the most frequent protozoan agent of intestinal diseases worldwide. Though commonly regarded as an anaerobic pathogen, it preferentially colonizes the fairly oxygen-rich mucosa of the proximal small intestine. Therefore, when testing new potential antigiardial drugs, O2 should be taken into account, since it also reduces the efficacy of metronidazole, the gold standard drug against giardiasis. In this study, 46 novel chalcones were synthesized by microwave-assisted Claisen-Schmidt condensation, purified, characterized by high-resolution mass spectrometry, 1H and 13C nuclear magnetic resonance, and infrared spectroscopy, and tested for their toxicity against G. intestinalis under standard anaerobic conditions. As a novel approach, compounds showing antigiardial activity under anaerobiosis were also assayed under microaerobic conditions, and their selectivity against parasitic cells was assessed in a counterscreen on human epithelial colorectal adenocarcinoma cells. Among the tested compounds, three [30(a), 31(e), and 33] were more effective in the presence of O2 than under anaerobic conditions and killed the parasite 2 to 4 times more efficiently than metronidazole under anaerobiosis. Two of them [30(a) and 31(e)] proved to be selective against parasitic cells, thus representing potential candidates for the design of novel antigiardial drugs. This study highlights the importance of testing new potential antigiardial agents not only under anaerobic conditions but also at low, more physiological O2 concentrations. PMID:24217695

Bahadur, Vijay; Mastronicola, Daniela; Tiwari, Hemandra Kumar; Kumar, Yogesh; Falabella, Micol; Pucillo, Leopoldo Paolo; Sarti, Paolo

2014-01-01

366

CO 2 capture from power stations running with natural gas (NGCC) and pulverized coal (PC): Assessment of a new chemical solvent based on aqueous solutions of N-methyldiethanolamine + triethylene tetramine  

Microsoft Academic Search

Power plants, except the nuclear ones, release relatively high amounts of carbon dioxide. The increasing use of coal to detriment of natural gas will contribute to increase the anthropogenic CO2 emissions. Improving thermal efficiencies will slightly reduce the CO2 emissions but it is essential to design, in the same time, processes recovering carbon dioxide at low cost. A comparison between

Jean-Marc G. Amann; Chakib Bouallou

2009-01-01

367

Single-molecule magnetism in a family of {Co(III)2Dy(III)2} butterfly complexes: effects of ligand replacement on the dynamics of magnetic relaxation.  

PubMed

The synthesis and structural characterization of four related heterometallic complexes of formulas [Dy(III)2Co(III)2(OMe)2(teaH)2(O2CPh)4(MeOH)4](NO3)2MeOHH2O (1a) and [Dy(III)2Co(III)2(OMe)2(teaH)2(O2CPh)4(MeOH)2(NO3)2]MeOHH2O (1b), [Dy(III)2Co(III)2(OMe)2(dea)2(O2CPh)4(MeOH)4](NO3)2 (2), [Dy(III)2Co(III)2(OMe)2(mdea)2(O2CPh)4(NO3)2] (3), and [Dy(III)2Co(III)2(OMe)2(bdea)2(O2CPh)4(MeOH)4](NO3)20.5MeOHH2O (4a) and [Dy(III)2Co(III)2(OMe)2(bdea)2(O2CPh)4(MeOH)2(NO3)2]MeOH1.5H2O (4b) are reported (teaH3 = triethanolamine, deaH2 = diethanolamine, mdeaH2 = N-methyldiethanolamine, and bdeaH2 = N-n-butyldiethanolamine). Compounds 1 (? 1a and 1b) and 4 (? 4a and 4b) both display two unique molecules within the same crystal and all compounds display a butterfly type core, with the Dy(III) ions occupying the central body positions and the diamagnetic Co(III) ions the outer wing-tip sites. Compounds 1-4 were investigated via direct current and alternating current magnetic susceptibility measurements, and it was found that each complex displayed single-molecule magnet (SMM) behavior. All four compounds display unique coordination and geometric environments around the Dy(III) ions and it was found that each displays a different anisotropy barrier. Ab initio calculations were performed on 1-4 and these determined the low lying electronic structure of each Dy(III) ion and the magnetic interactions for each cluster. It was found that there was a strong correlation between the calculated energy gap between the ground and first excited states of the single-ion ligand-field split Dy(III) levels and the experimentally observed anisotropy barrier. Furthermore, the transverse g factors found for the Dy(III) ions, defining the tunnelling rates within the ground Kramers doublets, are largest for 1, which agrees with the experimental observation of the shortest relaxation time in the high-temperature domain for this complex. The magnetic exchange between the Dy(III) ions revealed overall antiferromagnetic interactions for each compound, derived from the dominant dipolar exchange resulting in nonmagnetic ground states for 1-4. The diamagnetic ground states coupled with small tunneling gaps resulted in quantum tunneling time scales at zero field of between 0.1 and >1.5 s. PMID:24749511

Langley, Stuart K; Ungur, Liviu; Chilton, Nicholas F; Moubaraki, Boujemaa; Chibotaru, Liviu F; Murray, Keith S

2014-05-01

368

Rapid and simple LC-MS/MS screening of 64 novel psychoactive substances using dried blood spots.  

PubMed

The range of novel psychoactive substances (NPS) including phenethylamines, cathinones, piperazines, tryptamines, etc. is continuously growing. Therefore, fast and reliable screening methods for these compounds are essential and needed. The use of dried blood spots (DBS) for a fast straightforward approach helps to simplify and shorten sample preparation significantly. DBS were produced from 10 l of whole blood and extracted offline with 500 l methanol followed by evaporation and reconstitution in mobile phase. Reversed-phase chromatographic separation and mass spectrometric detection (RP-LC-MS/MS) was achieved within a run time of 10 min. The screening method was validated by evaluating the following parameters: limit of detection (LOD), matrix effect, selectivity and specificity, extraction efficiency, and short-term and long-term stability. Furthermore, the method was applied to authentic samples and results were compared with those obtained with a validated whole blood method used for routine analysis of NPS. LOD was between 1 and 10 ng/ml. No interference from matrix compounds was observed. The method was proven to be specific and selective for the analytes, although with limitations for 3-FMC/flephedrone and MDDMA/MDEA. Mean extraction efficiency was 84.6 %. All substances were stable in DBS for at least a week when cooled. Cooling was essential for the stability of cathinones. Prepared samples were stable for at least 3 days. Comparison to the validated whole blood method yielded similar results. DBS were shown to be useful in developing a rapid screening method for NPS with simplified sample preparation. PMID:23868723

Ambach, Lars; Hernndez Redondo, Ana; Knig, Stefan; Weinmann, Wolfgang

2014-04-01

369

CO2 Capture by Absorption with Potassium Carbonate  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The best solvent and process configuration, matrix with MDEA/PZ, offers 22% and 15% energy savings over the baseline and improved baseline, respectively, with stripping and compression to 10 MPa. The energy requirement for stripping and compression to 10 MPa is about 20% of the power output from a 500 MW power plant with 90% CO{sub 2} removal. The stripper rate model shows that a ''short and fat'' stripper requires 7 to 15% less equivalent work than a ''tall and skinny'' one. The stripper model was validated with data obtained from pilot plant experiments at the University of Texas with 5m K{sup +}/2.5m PZ and 6.4m K{sup +}/1.6m PZ under normal pressure and vacuum conditions using Flexipac AQ Style 20 structured packing. Experiments with oxidative degradation at low gas rates confirm the effects of Cu{sup +2} catalysis; in MEA/PZ solutions more formate and acetate is produced in the presence of Cu{sup +2}. At 150 C, the half life of 30% MEA with 0.4 moles CO{sub 2}/mole amine is about 2 weeks. At 100 C, less than 3% degradation occurred in two weeks. The solubility of potassium sulfate in MEA solution increases significantly with CO{sub 2} loading and decreases with MEA concentration. The base case corrosion rate in 5 M MEA/1,2M PZ is 22 mpy. With 1 wt% heat stable salt, the corrosion rate increases by 50% to 160% in the order: thiosulfate< oxalate

Gary T. Rochelle; Eric Chen; Babatunde Oyenekan; Andrew Sexton; Jason Davis; Marus Hiilliard; Qing Xu; David Van Wagener; Jorge M. Plaza

2006-12-31

370

Synthesis and activity of piperazine-containing antirhinoviral agents and crystal structure of SDZ 880-061 bound to human rhinovirus 14.  

PubMed

A series of antipicornaviral agents containing piperazinyl moieties was synthesized with the objective of obtaining a compound with a broad spectrum of antirhinovirus activity, high potency (< or = 0.003 microgram/ml), and low cytotoxicity (> or = 30 micrograms/ml). Five compounds of this series were evaluated in detail for efficacy against various HRV serotypes. The agent SDZ 880-061, containing the benzothiazine moiety SDZ 108-075, which is particularly active against HRV14, and the thiazolyl acetic acid ester group of SDZ 89-124, which is potent against HRV1B, indeed has a relatively broad antiviral spectrum. SDZ 880-061 inhibited 85% of 89 HRV serotypes tested at a concentration of < or = 3 micrograms/ml. The 3.0 A resolution X-ray structure of SDZ 880-061 bound to HRV14 has revealed the binding characteristics of this potent compound. It binds in the same pocket as other capsid-binding antiviral agents characterized to date, leaving the innermost portion of the pocket vacant. The binding causes similar, although less extensive, alterations of the HRV14 VP1 backbone conformation (residues 100 to 110, 151 to 159, and 213 to 224) compared to other antiviral agents analyzed structurally. Although the contacts between SDZ 880-061 and HRV14 are mostly of hydrophobic character, the inhibitor has three relatively short polar interactions with residues of VP1 that represent potential hydrogen bonds. The amount of solvent-accessible surface area of SDZ 880-061 buried in the complex (613 A2) is within the range of that observed in protein-protein interfaces. The observed influence of time of addition or removal of SDZ 880-061 on virus yield and on the infectious-center formation indicates that the compound primarily interferes with HRV14 cellular attachment. Since it is assumed that uncoating requires virion instability and/or flexibility, the finding that SDZ 880-061 has only a marginal effect on uncoating may be due to the fact that it does not completely fill the hydrophobic pocket. PMID:8648640

Oren, D A; Zhang, A; Nesvadba, H; Rosenwirth, B; Arnold, E

1996-05-31

371

Responsive, di-metallic lanthanide complexes of a piperazine-bridged bis-macrocyclic ligand: modulation of visible luminescence and proton relaxivity.  

PubMed

The synthesis of a new functionalised bis-macrocyclic ligand (L1) is described together with the corresponding Ln(III) complexes, Ln(2)- (Ln = Gd(III), Eu(III)). Phosphorescence measurements on Gd(2)- at 77 K allowed the ligand-centred triplet state ((3)pi-pi*) to be estimated at ca. 28500 cm(-1). Steady state and time-resolved measurements confirmed emission from the f-centred excited state ((5)D(0)) for Eu(2)-. (1)H NMRD profiles revealed the longitudinal proton relaxivity (r(1)) of Gd(2)- to be 8.3 mM(-1)s(-1)(30 MHz, 25 degrees C). The interaction of Cu(II) and Hg(II) with the lanthanide complexes was probed using luminescence and relaxivity measurements. Addition of Cu(II) (10 eq.) resulted in quenching of the Eu(III) emission, but no increase in r(1) of the Gd(III) dimer. Addition of Hg(II) (10 eq.) caused changes to the hypersensitive emission bands of Eu(III) together with an increase in r(1) of Gd(2)- to be 10.3 mM(-1)s(-1)(30 MHz, 25 degrees C) suggesting a net increase in hydration at the Gd(III) centres. PMID:20379534

Andrews, Michael; Amoroso, Angelo J; Harding, Lindsay P; Pope, Simon J A

2010-04-14

372

Acute oral toxicity evaluations of some zinc(II) complexes derived from 1-(2-salicylaldiminoethyl)piperazine Schiff bases in rats.  

PubMed

The current study described the synthesis and the in vivo acute oral toxicity evaluations in Sprague Dawley rats. The compounds were characterized by elemental analyses, LC-MS, FTIR, (1)H NMR, (13)C NMR and UV-visible spectroscopy. In the acute toxicity study, a single administration of the compounds was performed orally to the rats at the single doses of 2000 mg/kg and they were then monitored for possible side effects, mortality or behavioral changes up to 14 days. The serum level of aspartate (AST), alanine aminotransferases (ALT), alkaline phosphate (ALP), triglyceride, high density lipoprotein (HDL), immunoglobulins (GAM) and the C-reactive proteins did not significantly change. The hematological indices white blood cells (WBC), haematocrit (HCT), red blood cells (RBC), mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC), and mean corpuscular hemoglobin (MCH) were within the normal range. The renal function indices examined were also within the reference range. Generally, the compounds exhibited low toxic effects as required for further in vivo therapeutic studies. PMID:22408397

Salga, Muhammad Saleh; Ali, Hapipah Mohd; Abdulla, Mahmood Ameen; Abdelwahab, Siddig Ibrahim

2012-01-01

373

New functional copolymers of N -acryloyl- N ?-methyl piperazine and 2-hydroxyethyl methacrylate: synthesis, determination of reactivity ratios and swelling characteristics of gels  

Microsoft Academic Search

Copolymers of N-acryloyl-N?-methylpiperazine (AcrNMP) and 2-hydroxyethyl methacrylate (HEMA) were synthesized by free radical solution polymerization\\u000a in dioxane at 701C, using 2,2?-azobisisobutyronitrile (AIBN) as initiator. The copolymer compositions were analyzed by\\u000a the methods of FTIR spectroscopy and elemental analysis. Both the method of analysis yielded results that agreed reasonably\\u000a well. The monomer reactivity ratios of the copolymerization were determined by the

G. Roshan Deen; Y. Y. Gan; L. H. Gan; S. H. Teng

2011-01-01

374

21 CFR 573.940 - Silicon dioxide.  

Code of Federal Regulations, 2012 CFR

...in feed components as an anticaking agent, and/or grinding aid, as follows: Feed component Limitations (percent) BHT (butylated hydroxytoluene) 2 Methionine hydroxy analog and its calcium salts 1 Piperazine, piperazine salts...

2012-04-01

375

21 CFR 573.940 - Silicon dioxide.  

Code of Federal Regulations, 2014 CFR

...in feed components as an anticaking agent, and/or grinding aid, as follows: Feed component Limitations (percent) BHT (butylated hydroxytoluene) 2 Methionine hydroxy analog and its calcium salts 1 Piperazine, piperazine salts...

2014-04-01

376

21 CFR 573.940 - Silicon dioxide.  

Code of Federal Regulations, 2013 CFR

...in feed components as an anticaking agent, and/or grinding aid, as follows: Feed component Limitations (percent) BHT (butylated hydroxytoluene) 2 Methionine hydroxy analog and its calcium salts 1 Piperazine, piperazine salts...

2013-04-01

377

21 CFR 573.940 - Silicon dioxide.  

Code of Federal Regulations, 2010 CFR

...and/or grinding aid, as follows: Feed component Limitations (percent) BHT (butylated hydroxytoluene) 2 Methionine hydroxy analog and its calcium salts 1 Piperazine, piperazine salts 0.8 Sodium propionate 1 Urea 1...

2010-04-01

378

21 CFR 573.940 - Silicon dioxide.  

Code of Federal Regulations, 2011 CFR

...and/or grinding aid, as follows: Feed component Limitations (percent) BHT (butylated hydroxytoluene) 2 Methionine hydroxy analog and its calcium salts 1 Piperazine, piperazine salts 0.8 Sodium propionate 1 Urea 1...

2011-04-01

379

The effect of the pyridyl nitrogen position in pyridylpiperazine sigma ligands  

PubMed Central

A series of pyridylpiperazines was synthesized and analyzed for sigma receptor binding affinity to determine the optimal pyridyl nitrogen position and chain length for the ?1 and ?2 receptor recognition. The (3-pyridyl)piperazines and (4-pyridyl)piperazines favor ?1 receptors, while previously studied (2-pyridyl)piperazines favor ?2 receptors. PMID:20338757

Stavitskaya, Lidiya; Seminerio, Michael J.; Matthews-Tsourounis, Marilyn M.; Matsumoto, Rae R.

2012-01-01

380

Aminoalkoxo-supported heteroleptic hexanuclear gallium(III) wheel as a synthon for group 13 heterometallics: a rare sol-gel precursor for mixed Al-Ga oxide as support for gold catalysts.  

PubMed

A new heteroleptic gallium(III) complex, Ga(6)Cl(6)(mdea)(6) (1 x 2 CHCl(3)) (mdeaH(2) = N-methyl diethanolamine) was prepared in good yield by a chloro-aminoalkoxo exchange reaction and used as a synthon for the synthesis of a novel group 13 heterometallic derivative, Ga(2)Al(4)(O)(2)(mdea)(2)(OPr(i))(10) (2 x 2 CHCl(3)), the latter acting as a facile single source precursor for the sol-gel preparation of the mixed Al-Ga oxide as a high surface area support for gold catalysts. PMID:20625595

Mishra, Shashank; Jeanneau, Erwann; Daniele, Stphane; Mendez, Violaine

2010-08-28

381

tel-00656691,version1-4Jan2012 tel-00656691,version1-4Jan2012  

E-print Network

ricerca in "Antropologia ed Etnologia", XXII ciclo (Universit degli Studi di Perugia) Dottorato Internazionale in Etnologia e Antropologia (AEDE) Settore scientifico disciplinare M-DEA/01 e de l metodologico ................................................... 1 1.1 Alcune questioni di antropologia

Paris-Sud XI, Universit de

382

Universit degli Studi di Roma "La Sapienza" Via di Grottarossa, 1035 00189 ROMA  

E-print Network

Interna Pedagogia Generale Antropologia Sociale Psicologia Generale ********** MED/09 M-PED/01 M-DEA/01 Infermieristica nelle disabilità MED/45 II-II Infermieristica Materno-Infantile Pediatria Infermieristica Materno-Infantile

Guidoni, Leonardo

383

Variable dimensionality in the uranium fluoride/2-methyl-piperazine system: Synthesis and structures of UFO-5, -6, and -7; Zero-, one-, and two-dimensional materials with unprecedented topologies  

SciTech Connect

Recently, low temperature (T < 300 C) hydrothermal reactions of inorganic precursors in the presence of organic cations have proven highly productive for the synthesis of novel solid-state materials. Interest in these materials is driven by the astonishingly diverse range of structures produced, as well as by their many potential materials chemistry applications. This report describes the high yield, phase pure hydrothermal syntheses of three new uranium fluoride phases with unprecedented structure types. Through the systematic control of the synthesis conditions the authors have successfully controlled the architecture and dimensionality of the phase formed and selectively synthesized novel zero-, one-, and two-dimensional materials.

Francis, R.J.; Halasyamani, P.S.; Bee, J.S.; O'Hare, D.

1999-02-24

384

Synthesis and pharmacological evaluation of 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), a cocaine antagonist, in rodents.  

PubMed

Cocaine interacts with monoamine transporters and sigma (?) receptors, providing logical targets for medication development. In the present study, in vitro and in vivo pharmacological studies were conducted to characterize SN79, a novel compound which was evaluated for cocaine antagonist actions. Radioligand binding studies showed that SN79 had a nanomolar affinity for ? receptors and a notable affinity for 5-HT(2) receptors, and monoamine transporters. It did not inhibit major cytochrome P450 enzymes, including CYP1A2, CYP2A6, CYP2C19, CYP2C9*1, CYP2D6, and CYP3A4, suggesting a low propensity for potential drug-drug interactions. Oral administration of SN79 reached peak in vivo concentrations after 1.5 h and exhibited a half-life of just over 7.5 h in male, Sprague-Dawley rats. Behavioral studies conducted in male, Swiss Webster mice, intraperitoneal or oral dosing with SN79 prior to a convulsive or locomotor stimulant dose of cocaine led to a significant attenuation of cocaine-induced convulsions and locomotor activity. However, SN79 produced sedation and motor incoordination on its own at higher doses, to which animals became tolerant with repeated administration. SN79 also significantly attenuated the development and expression of the sensitized response to repeated cocaine exposures. The ability of SN79 to significantly attenuate the acute and subchronic effects of cocaine provides a promising compound lead to the development of an effective pharmacotherapy against cocaine. PMID:21494909

Kaushal, Nidhi; Robson, Matthew J; Vinnakota, Harsha; Narayanan, Sanju; Avery, Bonnie A; McCurdy, Christopher R; Matsumoto, Rae R

2011-09-01

385

Synthesis of new piperazine derived Cu(II)/Zn(II) metal complexes, their DNA binding studies, electrochemistry and anti-microbial activity: validation for specific recognition of Zn(II) complex to DNA helix by interaction with thymine base.  

PubMed

New 3,4:9,10-dibenzo-2,11-dihydroxy-1,12-bispiperazine-5,8-dioxododecane complexes [C(24)H(36)N(4)O(6)Cu] (1), [C(24)H(32)N(4)O(4)Zn] (2) have been synthesized and characterized by elemental analysis, IR, NMR, Mass, EPR, UV-vis spectroscopy and molar conductance measurements. The complexes are non-ionic in nature and possess octahedral geometry around Cu(2+), Zn(2+) central metal ions. The binding studies of 1 and 2 with calf thymus DNA (CT-DNA) were investigated by UV-vis, fluorescence, cyclic voltammetery and viscosity measurements. The calculated binding constant K(b) for 1 and 2 obtained from UV-vis absorption studies was 7.6x10(3)M(-1), 80.8x10(4)M(-1), respectively. The intrinsic binding constants were also estimated to be 7.0x10(4)M(-1) and 7.53x10(5)M(-1) for 1 and 2, respectively by using emission titrations. These experimental results suggest that complexes are groove binders and interact to CT-DNA with different affinities. Both the complexes in presence and absence of CT-DNA show quasireversible wave corresponding to Cu(II)/Cu(I) and Zn(II)/Zn(I) redox couple. The changes in E(1/2), DeltaE, I(pa)/I(pc) ascertain the interaction of 1 and 2 with CT-DNA. Further, decrease in viscosity of CT-DNA with increasing concentration of complexes was observed. In vitro, antimicrobial activity against fungi A. brassicicola, A. niger and bacteria E. coli, P. aeruginosa of complexes were carried out, which indicate that complex 2 is more active against both fungal and bacterial strains as shown by % inhibition data. PMID:19200776

Bhat, Irshad-Ul-Haq; Tabassum, Sartaj

2009-06-01

386

Spectroscopic, radiochemical, and theoretical studies of the Ga3+-N-2-hydroxyethyl piperazine-N'-2-ethanesulfonic acid (HEPES buffer) system: evidence for the formation of Ga3+ - HEPES complexes in (68) Ga labeling reactions.  

PubMed

Recent reports have claimed a superior performance of HEPES buffer in comparison to alternative buffer systems for (67/68) Ga labeling in aqueous media. In this paper we report spectroscopic ((1) H and (71) Ga NMR), radiochemical, mass spectrometry and theoretical modeling studies on the Ga(3+)/HEPES system (HEPES = N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) performed with the aim of elucidating a potential contribution of HEPES in the (68/67) Ga radiolabeling process. Our results demonstrate that HEPES acts as a weakly but competitive chelator of Ga(3+) and that this interaction depends on the relative Ga(3+): HEPES concentration. A by-product formed in the labeling mixture has been identified as a [(68) Ga]Ga(HEPES) complex via chromatographic comparison with the nonradioactive analog. The formation of this complex was verified to compete with [(68) Ga]Ga(NOTA) complexation at low NOTA concentration. Putative chelation of Ga(3+) by the hydroxyl and adjacent ring nitrogen of HEPES is proposed on the basis of (1)H NMR shifts induced by Ga(3+) and theoretical modeling studies. PMID:23606430

Martins, Andr F; Prata, M I M; Rodrigues, S P J; Geraldes, Carlos F G C; Riss, P J; Amor-Coarasa, A; Burchardt, C; Kroll, C; Roesch, F

2013-01-01

387

Synthesis of new piperazine derived Cu(II)/Zn(II) metal complexes, their DNA binding studies, electrochemistry and anti-microbial activity: Validation for specific recognition of Zn(II) complex to DNA helix by interaction with thymine base  

NASA Astrophysics Data System (ADS)

New 3,4:9,10-dibenzo-2,11-dihydroxy-1,12-bispiperazine-5,8-dioxododecane complexes [C 24H 36N 4O 6Cu] ( 1), [C 24H 32N 4O 4Zn] ( 2) have been synthesized and characterized by elemental analysis, IR, NMR, Mass, EPR, UV-vis spectroscopy and molar conductance measurements. The complexes are non-ionic in nature and possess octahedral geometry around Cu 2+, Zn 2+ central metal ions. The binding studies of 1 and 2 with calf thymus DNA (CT-DNA) were investigated by UV-vis, fluorescence, cyclic voltammetery and viscosity measurements. The calculated binding constant Kb for 1 and 2 obtained from UV-vis absorption studies was 7.6 10 3 M -1, 80.8 10 4 M -1, respectively. The intrinsic binding constants were also estimated to be 7.0 10 4 M -1 and 7.53 10 5 M -1 for 1 and 2, respectively by using emission titrations. These experimental results suggest that complexes are groove binders and interact to CT-DNA with different affinities. Both the complexes in presence and absence of CT-DNA show quasireversible wave corresponding to Cu II/Cu I and Zn II/Zn I redox couple. The changes in E1/2, ? E, Ipa/ Ipc ascertain the interaction of 1 and 2 with CT-DNA. Further, decrease in viscosity of CT-DNA with increasing concentration of complexes was observed. In vitro, antimicrobial activity against fungi A. brassicicola, A. niger and bacteria E. coli, P. aeruginosa of complexes were carried out, which indicate that complex 2 is more active against both fungal and bacterial strains as shown by % inhibition data.

Bhat, Irshad-ul-Haq; Tabassum, Sartaj

2009-06-01

388

New sulfur-oxygen mixed-donor ligand N,N'-dimethyl-piperazine-3-oxo-2-thione (Me2pipto) and its Ni(II) and Fe(II) complexes.  

PubMed

Structural and electronic features of the novel title sulfur-oxygen donor ligand Me(2)pipto (1), are discussed in comparison with those of the corresponding dithione ligand Me(2)pipdt. A tuning of the electronic and coordination properties of the ligand, relatable to the soft/hard power of the donor atoms, is achieved. Coordination properties have been checked towards Ni(II) and Fe(III) cations obtaining [Ni(Me(2)pipto)(3)](BF(4))(2) (2) and [Fe(Me(2)pipto)(3)](BF(4))(2) (4) complexes, which show significant differences when compared with the corresponding reaction products when using Me(2)pipdt. PMID:20689897

Pilia, Luca; Artizzu, Flavia; Espa, Davide; Marchi, Luciano; Mercuri, Maria Laura; Serpe, Angela; Deplano, Paola

2010-09-21

389

Discovery of a novel sub-class of ROMK channel inhibitors typified by 5-(2-(4-(2-(4-(1H-Tetrazol-1-yl)phenyl)acetyl)piperazin-1-yl)ethyl)isobenzofuran-1(3H)-one.  

PubMed

A sub-class of distinct small molecule ROMK inhibitors were developed from the original lead 1. Medicinal chemistry endeavors led to novel ROMK inhibitors with good ROMK functional potency and improved hERG selectivity. Two of the described ROMK inhibitors were characterized for the first in vivo proof-of-concept biology studies, and results from an acute rat diuresis model confirmed the hypothesis that ROMK inhibitors represent new mechanism diuretic and natriuretic agents. PMID:24075732

Tang, Haifeng; de Jesus, Reynald K; Walsh, Shawn P; Zhu, Yuping; Yan, Yan; Priest, Birgit T; Swensen, Andrew M; Alonso-Galicia, Magdalena; Felix, John P; Brochu, Richard M; Bailey, Timothy; Thomas-Fowlkes, Brande; Zhou, Xiaoyan; Pai, Lee-Yuh; Hampton, Caryn; Hernandez, Melba; Owens, Karen; Roy, Sophie; Kaczorowski, Gregory J; Yang, Lihu; Garcia, Maria L; Pasternak, Alexander

2013-11-01

390

Expansion of structure-activity studies of piperidine analogues of 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine (GBR 12935) compounds by altering substitutions in the N-benzyl moiety and behavioral pharmacology of selected molecules.  

PubMed

A series of substituted N-benzyl analogues of the dopamine transporter (DAT) specific compound, 4-[2-(diphenylmethoxy)ethyl]-1-benzylpiperidine were synthesized and biologically characterized. Different 4'-alkyl, 4'-alkenyl, and 4'-alkynyl substituents were introduced in the phenyl ring of the benzyl moiety along with the replacement of the same phenyl ring by the isomeric alpha- and beta-naphthyl groups. Different polar substitutions at the 3'- and 4'-position were also introduced. Novel compounds were tested for their binding affinity at the dopamine, serotonin, and norepinephrine transporter systems in the brain by competing for [(3)H]WIN 35 428, [(3)H]citalopram, and [(3)H]nisoxetine, respectively. Selected compounds were also evaluated for their activity in inhibiting the uptake of [(3)H]dopamine. Binding results demonstrated that alkenyl and alkynyl substitutions at the 4'-position produced potent compounds in which compound 6 with a vinyl substitution was the most potent. In vivo evaluation of three selected compounds indicated that despite their high potency at the DAT, these compounds stimulated locomotor activity (LMA) less than cocaine when tested across similar dose ranges. In a drug discrimination study procedure, none of these three compounds generalized from cocaine in mice trained to discriminate 10 mg/kg cocaine from vehicle. In a 4 h time course LMA experiment, one of our previous lead piperidine derivatives (1a) showed considerable prolonged action. Thus, in this report, we describe a structure-activity relationship study of novel piperidine analogues assessed by both in vitro transporter assays and in vivo behavioral activity measurements. PMID:11806716

Dutta, Aloke K; Davis, Matthew C; Fei, Xiang-Shu; Beardsley, Patrick M; Cook, Charles D; Reith, Maarten E A

2002-01-31

391

Structure-activity relationship studies of highly selective inhibitors of the dopamine transporter: N-benzylpiperidine analogues of 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine.  

PubMed

A series of 4-[2-[bis(4-fluorophenyl)methoxy]ethyl-1-benzylpiperidines were examined for their ability to bind to the dopamine transporter (DAT), the serotonin transporter (SERT), and the norepinephrine transporter (NET). Binding results indicated that the presence of an electron-withdrawing group in the C(4)-position of the N-benzyl group is beneficial for binding to the DAT. Several analogues have been identified with high affinity for the DAT, up to 500-fold selectivity over the SERT and about 170-fold selectivity over the NET in binding and uptake inhibition assays. PMID:12672246

Greiner, Elisabeth; Prisinzano, Thomas; Johnson, Edward M; Dersch, Christina M; Marcus, Jamila; Partilla, John S; Rothman, Richard B; Jacobson, Arthur E; Rice, Kenner C

2003-04-10

392

Synthesis and Evaluation of Anti-acetylcholinesterase Activity of 2-(2-(4-(2-Oxo-2-phenylethyl)piperazin-1-yl) ethyl)Isoindoline-1,3-dione Derivatives with Potential Anti-Alzheimer Effects  

PubMed Central

Objective(s): Alzheimer's disease (AD) is a neurodegenerative disorder in elderly patients. Decrease in cholinergic neurotransmission is the main known cause in the pathophysiology of the disease. Improvement and potentiation of the cholinergic system could be beneficial for treatment of the AD. Acetylcholinesterase inhibitors such as donepezil can enhance the duration of action of acetylcholine (Ach) and therefore, through this mechanism improve the symptoms of AD. Materials and Methods: In the current study, based on the potential inhibitory activity of phthalimide derivatives towards acetylcholinesterase enzyme, a new series of phthalimide-based compounds were synthesized (4a-4e) and anti-acetylcholinesterase effect was assessed using Ellman's test. Compound 4b with 4-Fluorophenyl moiety was the most potent derivative in this series (IC50 = 16.42 1.07 M). It was shown that, none of the synthesized compounds showed superior inhibitory potency compared to donepezil (0.41 0.09 M) as a reference drug. Conclusion: The new synthesized phthalimide based analogs could function as potential acetylcholinesterase inhibitors. Further studies are necessary for development of potent analogs. PMID:24379961

Aliabadi, Alireza; Foroumadi, Alireza; Mohammadi-Farani, Ahmad; Garmsiri Mahvar, Mahdi

2013-01-01

393

Studies on the metabolism and the toxicological analysis of the nootropic drug fipexide in rat urine using gas chromatographymass spectrometry  

Microsoft Academic Search

Qualitative studies are described on the metabolism and the toxicological analysis of the nootropic fipexide (FIP) in rat urine using gas chromatographymass spectrometry (GCMS). FIP was extensively metabolized to 1-(3,4-methylenedioxybenzyl)piperazine (MDBP), 4-chlorophenoxyacetic acid, 1-[2-(4-chlorophenoxy)acetyl]piperazine, N-(4-hydroxy-3-methoxy-benzyl)piperazine, piperazine, N-(3,4-methylenedioxybenzyl)ethylenediamine, and N-[2-(4-chlorophenoxy)acetyl]ethylenediamine. The authors systematic toxicological analysis (STA) procedure using full-scan GCMS after acid hydrolysis of one urine aliquot, liquid-liquid extraction and acetylation

Roland F. Staack; Hans H. Maurer

2004-01-01

394

Carbonic anhydrase promotes the absorption rate of CO2 in post-combustion processes.  

PubMed

The rate of carbon dioxide (CO2) absorption by monoethanol amine (MEA), diethanol amine (DEA), N-methyl-2,2'-iminodiethanol (MDEA), and 2-amino-2-methyl 1-propanol (AMP) solutions was found to be enhanced by the addition of bovine carbonic anhydrase (CA), has been investigated using a vapor-liquid equilibrium (VLE) device. The enthalpy (-?Habs) of CO2 absorption and the absorption capacities of aqueous amines were measured in the presence and/or absence of CA enzyme via differential reaction calorimeter (DRC). The reaction temperature (?T) under adiabatic conditions was determined based on the DRC analysis. Bicarbonate and carbamate species formation mechanisms were elucidated by (1)H and (13)C NMR spectral analysis. The overall CO2 absorption rate (flux) and rate constant (kapp) followed the order MEA > DEA > AMP > MDEA in the absence or presence of CA. Hydration of CO2 by MDEA in the presence of CA directly produced bicarbonate, whereas AMP produced unstable carbamate intermediate, then underwent hydrolytic reaction and converted to bicarbonate. The MDEA > AMP > DEA > MEA reverse ordering of the enhanced CO2 flux and kapp in the presence of CA was due to bicarbonate formation by the tertiary and sterically hindered amines. Thus, CA increased the rate of CO2 absorption by MDEA by a factor of 3 relative to the rate of absorption by MDEA alone. The thermal effects suggested that CA yielded a higher activity at 40 C. PMID:23621860

Vinoba, Mari; Bhagiyalakshmi, Margandan; Grace, Andrews Nirmala; Kim, Dae Hoon; Yoon, Yeoil; Nam, Sung Chan; Baek, Il Hyun; Jeong, Soon Kwan

2013-05-01

395

Design of the Williams Field Services Mobile Bay ethane recovery plant  

SciTech Connect

ABB Randall designed, procured and constructed a two train expander plant with a base case design capacity of 525 MMscfd and a hydraulic design capacity of 600 MMscfd. Randall has used its Recycle Reflux Process, proven in other installations, resulting in a calculated ethane recovery of 93% at 525 MMscfd (78% at 600 MMscfd) and ethane rejection. Liquids production creates a design challenge due to the presence of acid gas components such as CO{sub 2}, H{sub 2}S, mercaptans and COS, with the latter three causing the product to fail the copper strip test. The challenge is to remove the components to the required level with minimum cost and in an operator-friendly manner. The following combinations of processes were reviewed: DGA, MDEA and Merichem, COS Hydrolysis and MDEA, MDEA and KOH, Sulfinol, MDEA and SulfaClean; and MDEA and mol sieve. This paper will give a brief description, an illustration and economic impact information of each one. Lastly, the rationale behind the selection of the COS Hydrolysis bed, MDEA absorber and provisions to add an iron sponge bed is discussed.

Vogel, D.C.; McKenzie, D.

1999-07-01

396

Conformational Dynamics of Charge-Transfer States in Donor Bridge Acceptor Systems  

E-print Network

- sisting of CH2 groups linked to a semiflexible piperidine or piperazine ring or to a rigid 2- ously shown that the photoinduced harpooning process is effectively suppressed when the piperidine at low temperature. In the cases of the piperidine- and piperazine-bridged donor-acceptor compounds, evid

van Stokkum, Ivo

397

Oxidation of fluoroquinolone antibiotics and structurally related amines by chlorine dioxide: Reaction kinetics,  

E-print Network

reactivity of the piperazine moiety also depends strongly on the quinolone ring through electronic effects of FQs, and follow the trend of OFL > ENR > CIP w NOR w LOM > > PIP in reactivity. Comparison among FQs and related amines and product characterization indicate that FQs' piperazine ring is the primary reactive

Huang, Ching-Hua

398

Chukwuemeka I. Okoye Carbon Dioxide Solubility and Absorption Rate in  

E-print Network

Copyright by Chukwuemeka I. Okoye 2005 #12;Carbon Dioxide Solubility and Absorption Rate _______________________ Nicholas A. Peppas #12;Carbon Dioxide Solubility and Absorption Rate in Monoethanolamine/Piperazine/H2O for. #12;iii Carbon Dioxide Solubility and Absorption Rate in Monoethanolamine/Piperazine/H2O

Rochelle, Gary T.

399

An announced suicide with ecstasy.  

PubMed

Most cases of ecstasy overdose turn out to be accidental, whereas suicide attempts with designer drugs occur only sporadically. We report an announced suicide by means of a combination of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA). During autopsy, sampling for toxicological investigation (peripheral blood, urine, cerebrospinal fluid, bile and gastric contents) occurred. Serum concentrations as high as 13.33 mg/l for MDMA, 7.32 mg/l for MDEA and 0.43 mg/l for 3,4-methylenedioxyamphetamine were found. Ecstasy tablets, which were confiscated by the police a few days earlier, showed also a combination of MDMA and MDEA. This fact suggests that the ingested tablets probably came from the same source as the seized pills. PMID:16175411

Libiseller, Kathrin; Pavlic, Marion; Grubwieser, Petra; Rabl, Walter

2007-01-01

400

Determination of nitrogen mustard hydrolysis products in rat urine samples using GC-MS.  

PubMed

A gas chromatographic-mass spectrometric method was developed, validated and demonstrated by measuring the levels of nitrogen mustard hydrolysis products in the urine collected from dosed rats. The recovery values for trimethylsilyl derivatives of EDEA and MDEA are between 82-95% and 88-112%, respectively. In vivo studies performed by using three different doses (0.5 mg/kg, 1.0 mg/kg, and 2.0 mg/kg) of HN2 base of nitrogen mustard. MDEA concentrations were between 43.1-232.2 ng/mL. The limit of detection (S/N = 3) values are 2.5 ng/mL and 1.6 ng/mL for EDEA and MDEA, respectively, and the precision of the method in terms of RSD is between 5-8%. PMID:21549026

Kenar, Levent; Alp, Orkun

2011-05-01

401

Physiologically based pharmacokinetic modeling to predict drug-drug interactions involving inhibitory metabolite: a case study of amiodarone.  

PubMed

Evaluation of drug-drug interaction (DDI) involving circulating inhibitory metabolites of perpetrator drugs has recently drawn more attention from regulatory agencies and pharmaceutical companies. Here, using amiodarone (AMIO) as an example, we demonstrate the use of physiologically based pharmacokinetic (PBPK) modeling to assess how a potential inhibitory metabolite can contribute to clinically significant DDIs. Amiodarone was reported to increase the exposure of simvastatin, dextromethorphan, and warfarin by 1.2- to 2-fold, which was not expected based on its weak inhibition observed in vitro. The major circulating metabolite, mono-desethyl-amiodarone (MDEA), was later identified to have a more potent inhibitory effect. Using a combined "bottom-up" and "top-down" approach, a PBPK model was built to successfully simulate the pharmacokinetic profile of AMIO and MDEA, particularly their accumulation in plasma and liver after a long-term treatment. The clinical AMIO DDIs were predicted using the verified PBPK model with incorporation of cytochrome P450 inhibition from both AMIO and MDEA. The closest prediction was obtained for CYP3A (simvastatin) DDI when the competitive inhibition from both AMIO and MDEA was considered, for CYP2D6 (dextromethorphan) DDI when the competitive inhibition from AMIO and the competitive plus time-dependent inhibition from MDEA were incorporated, and for CYP2C9 (warfarin) DDI when the competitive plus time-dependent inhibition from AMIO and the competitive inhibition from MDEA were considered. The PBPK model with the ability to simulate DDI by considering dynamic change and accumulation of inhibitor (parent and metabolite) concentration in plasma and liver provides advantages in understanding the possible mechanism of clinical DDIs involving inhibitory metabolites. PMID:25324279

Chen, Yuan; Mao, Jialin; Hop, Cornelis E C A

2015-02-01

402

Comparison of five derivatizing agents for the determination of amphetamine-type stimulants in human urine by extractive acylation and gas chromatography-mass spectrometry.  

PubMed

Five acylation reagents have been compared for use as derivatizing agents for the analysis of amphetamine-type stimulants (ATS) in urine by gas chromatography-mass spectrometry (GC-MS). The evaluated reagents were heptafluorobutyric anhydride, pentafluoropropionic anhydride, trifluoroacetic anhydride, acetic anhydride (AA) and N-methyl-bis(trifluoroacetamide). The ATS included amphetamine, methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA). A mixture of the ATS was added to urine (1 mL) followed by KOH solution and saturated NaHCO(3) solution. The sample was then extracted with dichloromethane and the derivatizing agent and 2 L were injected into the GC-MS instrument. The derivatizing agents were compared with reference to the signal-to-noise (S/N) ratios, peak area values, relative standard deviations (RSDs), linearities, limits of detection (LODs) and selectivities. The acetic anhydride proved to be the best according to the S/N ratio and peak area results for amphetamine, MA, MDMA and MDEA. The best RSD values of peak areas and of S/N ratios at 3 g/mL were also given by AA in cases of MDA, MDMA and MDEA. At 20 g/mL, the lowest RSD values of peak areas for MDA and the lowest RSD values of S/N ratios for MA, MDA, MDMA and MDEA were again given by AA. Additionally, the highest correlation coefficients for MA, MDA, MDMA and MDEA and the lowest LOD results for MA, MDMA and MDEA were produced by AA. PMID:22582269

Dobos, Adrienn; Hidvgi, Elod; Somogyi, Gbor Pl

2012-06-01

403

Evaluation of the OSHA 42 and NIOSH 5521 methods in determining the free isocyanate concentration in aerosols and vapor phases during application of two component 1,6-hexamethylene diisocyanate paints  

E-print Network

-Ray Defraction Analysis iX 7 X-Ray Defraction Analyzer Spectrograph. . . 38 8 Baseline Polyethylene FTIR Scan. 42 9 FTIR Scan of 100-: HDI 43 10 FTIR Scan of Polyurethane Paint Hardener. 44 11 FTIR Baseline Scan of 100'-. 1-(2-pyridyl) -piperazine. . . 45... 12 FTIR Scan of Polyurethane Paint and 1- (2-pyridyl) -piperazine . . . . . . . . , . . . 47 13 FTIR Scan of Polyurethane Paint Polymerizing over a 12 Day Period. 48 14 FTIR Scan of Polyurethane Paint and 1-(2 -pyridyl) -piperazine (driven...

Bell, John Lee

1994-01-01

404

Acidic gas capture by diamines  

DOEpatents

Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

Rochelle, Gary (Austin, TX); Hilliard, Marcus (Missouri City, TX)

2011-05-10

405

Effets compars du Piribdil et de trois de ses mtabolites sur le systme extrapyramidal du rat  

Microsoft Academic Search

Summary The effects of Piribedil on central dopaminergic receptors were compared with the effects elicited by 3 metabolites of this drug. One of them S-584=[1-(2-pyrimidyl)-4 (34 dihydroxyphenyl) piperazine] showed dopaminergic stimulant properties when administered by the i.p. route, in unilateral nigro-neostriatal lesioned rats. Other metabolites: S 3284=[1-(2-pyrimidyl)1N-oxydo-4 piperonyl piperazine] and S 3473=[1-(5 hydroxy 2 pyrimidyl)-4 piperonyl piperazine] were ineffective.

J.-C. Poignant; F. Lejeune; E. Malecot; M. Petitjean; G. Regnier; R. Canevari

1974-01-01

406

Cationic Mn4 single-molecule magnet with a sterically isolated core.  

PubMed

The synthesis, structure, and magnetic properties of a ligand-modified Mn(4) dicubane single-molecule magnet (SMM), [Mn(4)(Bet)(4)(mdea)(2)(mdeaH)(2)](BPh(4))(4), are presented, where the cationic SMM units are significantly separated from neighboring molecules in the crystal lattice. There are no cocrystallized solvate molecules, making it an ideal candidate for single-crystal magnetization hysteresis and high-frequency electron paramagnetic resonance studies. Increased control over intermolecular interactions in such materials is a crucial factor in the future application of SMMs. PMID:21751785

Heroux, Katie J; Quddusi, Hajrah M; Liu, Junjie; O'Brien, James R; Nakano, Motohiro; del Barco, Enrique; Hill, Stephen; Hendrickson, David N

2011-08-15

407

76 FR 55616 - Schedules of Controlled Substances: Temporary Placement of Three Synthetic Cathinones Into...  

Federal Register 2010, 2011, 2012, 2013, 2014

...benzocaine, etc.), or other recreational substances (e.g., amphetamine, MDMA, cocaine, gamma-butyrolactone (GBL), kratom, N,N-benzylpiperazine (BZP), and 1-(3-trifluoromethylphenyl)-piperazine (TFMPP)). Chemical analyses of...

2011-09-08

408

Effect of selected anthelmintics on three common helminths in the brown pelican (Pelecanus occidentalis).  

PubMed

The effect of selected anthelmintics (albendazole, fenbendazole, piperazine dihydrochloride and clorsulon) against three major helminths (Contracaecum multipapillatum, Mesostephanus appendiculatoides, and Phagicola longus) were studied in 29 brown pelicans (Pelecanus occidentalis). Albendazole and fenbendazole were highly effective against all three parasites. Clorsulon had moderate effect against M. appendiculatoides and poor effect against C. multipapillatum and P. longus. Piperazine dihydrochloride had no effect against these helminths. PMID:2915399

Grimes, J; Suto, B; Greve, J H; Albers, H F

1989-01-01

409

Rapid analysis of illicit drugs by mass spectrometry: Results from seizures in Ireland  

Microsoft Academic Search

A gas chromatographic procedure with mass spectrometric detection (GC-MS) was established to determine the principal amphetamines, methylenedioxymethylamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA) and methylenedioxyamphetamine (MDA), cocaine and pharmacologically active impurities in 'ecstasy' tablets. The procedure was developed and optimised by combining the individual methods for the various drugs of abuse available in the literature into a single GC-MS run. New variants of

Donnacha OConnell; James J. A. Heffron

2000-01-01

410

Efficiency of an Integrated Gasification Combined Cycle (IGCC) power plant including CO 2 removal  

Microsoft Academic Search

This study is devoted to technical evaluation of a carbon dioxide removal in an existing Integrated Gasification Combined Cycle (IGCC) plant. This IGCC case is based on an oxygen blown entrained flow gasifier operating at 27bar, the removal of acid gas (H2S) is performed with MDEA unit, the efficiency of this IGCC is 43% based on the low heating value

C. Descamps; C. Bouallou; M. Kanniche

2008-01-01

411

Photoluminescent Mn4 single-molecule magnet.  

PubMed

The synthesis of [Mn(4)(anca)(4)(Hmdea)(2)(mdea)(2)].2CHCl(3) (1) is reported along with room temperature fluorescence, UV-vis, and NMR spectra. Direct current magnetization versus field data reveal a S = 8 ground state. Quantized steps in temperature- and field-dependent magnetization versus field hysteresis loops confirm single-molecule magnet behavior. PMID:18947226

Beedle, Christopher C; Stephenson, Casey J; Heroux, Katie J; Wernsdorfer, Wolfgang; Hendrickson, David N

2008-12-01

412

From: Mullins, Therese A Sent: Monday, January 13, 2014 8:36 AM  

E-print Network

1 From: Mullins, Therese A Sent: Monday, January 13, 2014 8:36 AM To: Staff Subject: Reminder About Debit Cards Please see the following message from MMBSEGIP. Important Reminder: New Debit Cards for Medical/Dental Expense Account (MDEA) & Healthcare Reimbursement Arrangement (HRA

Bates, Rebecca A.

413

49 CFR 40.87 - What are the cutoff concentrations for drug tests?  

Code of Federal Regulations, 2010 CFR

...Methamphetamine5 250 ng/mL. MDMA 6 500 ng/mL MDMA 250 ng/mL. MDA7 250 ng/mL. MDEA8 250 ng/mL 1 Delta-9-tetrahydrocannabinol-9-carboxylic acid (THCA). 2 Morphine is the target analyte for codeine/morphine...

2010-10-01

414

49 CFR 40.87 - What are the cutoff concentrations for drug tests?  

Code of Federal Regulations, 2011 CFR

...Methamphetamine5 250 ng/mL. MDMA 6 500 ng/mL MDMA 250 ng/mL. MDA7 250 ng/mL. MDEA8 250 ng/mL 1 Delta-9-tetrahydrocannabinol-9-carboxylic acid (THCA). 2 Morphine is the target analyte for codeine/morphine...

2011-10-01

415

Dipartimento di COMUNICAZIONE e RICERCA SOCIALE Universit degli Studi di Roma "La Sapienza"  

E-print Network

scientifico disciplinare M-DEA 01 Discipline Demoetnoantroplogiche, titolo della ricerca "Le applicazioni dell'Antropologia scientifico Prof. Paolo Palmeri. Il colloquio verter sui seguenti temi: a) Le basi teoriche dell'antropologia urbana; b) L'antropologia applicata ai Contratti di Quartiere; c) I metodi di ricerca partecipativi

Guidoni, Leonardo

416

Research paper Engineering of recombinant antibody fragments to methamphetamine  

E-print Network

of abuse 3,4- methylenedioxymethamphetamine (MDMA) and 3,4- methylenedioxy-N-ethylamphetamine (MDEA) respec over-the-counter (OTC) and prescription medication 0022-1759/$ - see front matter D 2005 Elsevier B unambiguous determination of the absence or presence of drug of abuse for legal purposes. However, GC

Georgiou, George

417

Universit degli Studi di Roma "La Sapienza" D.I.C.E.A. Dipartimento Ingegneria Civile, Edile e Ambientale  

E-print Network

RICERCA Cat. B tipologia II SSD ICAR/20 + M-DEA/01 Codice Bando 21/2013, PUBBLICATO IN DATA 29 essere posseduti alla data di scadenza del termine stabilito per la presentazione delle domande di indirizzo di posta elettronica personale al quale inviare ogni comunicazione, ivi comprese le convocazioni

Guidoni, Leonardo

418

Structural Modifications of Neuroprotective Anti-Parkinsonian (?)-N6-(2-(4-(Biphenyl-4-yl)piperazin-1-yl)-ethyl)-N6-propyl-4,5,6,7-tetrahydrobenzo[d]thiazole-2,6-diamine (D-264): An Effort toward the Improvement of in Vivo Efficacy of the Parent Molecule  

PubMed Central

In our overall goal to develop multifunctional dopamine D2/D3 agonist drugs for the treatment of Parkinsons disease (PD), we previously synthesized potent D3 preferring agonist D-264 (1a), which exhibited neuroprotective properties in two animal models of PD. To enhance the in vivo efficacy of 1a, a structureactivity relationship study was carried out. Competitive binding and [35S]GTP?S functional assays identified compound (?)-9b as one of the lead molecules with preferential D3 agonist activity (EC50(GTP?S); D3 = 0.10 nM; D2/D3 (EC50): 159). Compounds (?)-9b and (?)-8b exhibited high in vivo activity in two PD animal models, reserpinized and 6-hydroxydopamine (OHDA)-induced unilateral lesioned rats. On the other hand, 1a failed to show any in vivo activity in these models unless the compound was dissolved in 510% beta-hydroxy propyl cyclodextrin solution. Lead compounds exhibited appreciable radical scavenging activity. In vitro experiments with dopaminergic MN9D cells indicated neuroprotection by both 1a and (?)-9b from toxicity of MPP+. PMID:24471976

2015-01-01

419

Synthesis and spectroscopic characterization of dicyanamido-Cu(II) complexes. Part 2 : Crystal structure of the complexes of tris[2-(2-pyridylethyl)]amine, tris(2-pyridylmethyl)amine and 1,4-bis[2-(2-pyridylethyl)]piperazine  

NASA Astrophysics Data System (ADS)

Two classes of novel dicyanamido (dca)-Cu(II) complexes were synthesized with a variety of tetradentate tripod amines, tridentate amines and diazacycloalkanes with pyridyl arms of different alkyl lengths and with tetra-aza macrocycles with different cavity sizes; the mononuclear, Cu(L)(dca)]ClO 4 (L = tepa ( 1), TPA ( 2), pzdepy ( 4), hpzpy 2 ( 5), cyclen ( 7), cyclam ( 8), tacp ( 9)) or Cu(L)(dca)ClO 4 (L = MeDPA ( 10), Mepea ( 11)) and the dinuclear, [Cu 2(L') 2(dca)](ClO 4) 3 (L' = pmap ( 3), pzpy 2 ( 6)). The isolated complexes were structurally characterized by electronic and IR spectroscopy as well as by X-ray. Single crystal X-ray diffraction analysis of the complexes [Cu(tepa)(dca)]ClO 4 ( 1), [Cu(TPA)(dca)]ClO 4 ( 2) and [Cu(pzdepy)(dca)]ClO 4 ( 4) reveal their monomeric penta-coordinate nature with the isolated [Cu(L)(dca)] + cations and ClO4- counter ions. All the complexes with the exception of 2 adapt distorted square pyramidal geometry while the coordination polyhedron around the copper center in 2 may be described as a distorted trigonal bipyramidal stereochemistry. The visible spectra of the complexes in aqueous solutions or in methanol are in complete agreement with the assigned X-ray geometry around the Cu(II) centers.

Mautner, Franz A.; Soileau, Jesse B.; Bankole, Paul K.; Gallo, August A.; Massoud, Salah S.

2008-10-01

420

Design and synthesis of a novel family of triazine-based inhibitors of sorbitol dehydrogenase with oral activity: 1-{4-[3 R,5 S-dimethyl-4-(4-methyl-[1,3,5]triazin-2-yl)-piperazin-1-yl]-[1,3,5]triazin-2-yl}-( R) ethanol  

Microsoft Academic Search

Two new templates, (R) 2-hydroxyethyl-pyridine and (R) 2-hydroxyethyl-triazine, were used to design novel sorbitol dehydrogenase inhibitors (SDIs). The design concept included spawning of these templates to function as effective ligands to the catalytic zinc within the enzyme through incorporation of optimally substituted piperazino-triazine side chains so as to accommodate the active site in the enzyme for efficient binding. This strategy

Banavara L. Mylari; Gregory J. Withbroe; David A. Beebe; Nathaniel S. Brackett; Edward L. Conn; James B. Coutcher; Peter J. Oates; William J. Zembrowski

2003-01-01

421

3-(Adamantan-1-yl)-4-[(E)-(2,6-difluorobenzylidene)amino]-1-[(4-ethylpiperazin-1-yl)methyl]-4,5-dihydro-1H-1,2,4-triazole-5-thione  

PubMed Central

In the title compound, C26H34F2N6S, the triazole ring is linked to a benzene ring via an imine bond [N=C = 1.255?(2)?; conformation: E], with a dihedral angle of 25.21?(11) between the rings. The 4-ethylpiperazinyl residue is folded away from the thione-S atom. In the crystal, helical supramolecular chains propagating along [010] and sustained by weak CS??(triazole) interactions occur [S?centroid distance = 3.2872?(10)?]. Links between these chains are of the type benzene-CH?N(imine) and ?? [between centrosymmetrically related benzene rings with an inter-centroid distance of 3.9241?(15)?] and result in a three-dimensional architecture. PMID:23723845

Al-Tamimi, Abdul-Malek S.; Al-Abdullah, Ebtehal S.; El-Emam, Ali A.; Ng, Seik Weng; Tiekink, Edward R. T.

2013-01-01

422

Structure-activity-relationship study of N6-(2(4-(1H-indol-5-yl)piperazin-1-yl)ethyl)-N6-propyl-4,5,6,7-tetrahydrobenzo[d]thiazole-2,6-diamine analogues: Development of highly selective D3 dopamine receptor agonists along with a highly potent D2/D3 agonist and their pharmacological characterization  

PubMed Central

In our effort to develop multifunctional drugs against Parkinsons disease, a structure-activity-relationship study was carried out based on our hybrid molecular template targeting D2/D3 receptors. Competitive binding with [3H]spiroperidol was used to evaluate affinity (Ki) of test compounds. Functional activity of selected compounds in stimulating [35S]GTP?S binding was assessed in CHO-cells expressing either human D2 or D3 receptors. Our results demonstrated development of highly selective compounds for D3 receptor ((?)-40; Ki D3 = 1.84 nM, D2/D3 = 583.2, (?)-45; Ki D3 = 1.09 nM, D2/D3 = 827.5). Functional data identified (?)-40 (EC50 D2 = 114 nM and D3 = 0.26 nM, D2/D3 = 438) as one of the highest D3 selective agonists known to date. In addition, high affinity, non-selective, D3 agonist, (?)-19 (EC50 D2 = 2.96 nM and D3 = 1.26 nM), was also developed. Lead compounds with antioxidant activity were evaluated using an in vivo PD animal model. PMID:22642365

Johnson, Mark; Antonio, Tamara; Reith, Maarten E. A.; Dutta, Aloke K.

2012-01-01

423

Discovery of 4-(4-(2-((5-hydroxy-1,2,3,4-tetrahydronaphthalen-2-yl)(propyl)amino)-ethyl)piperazin-1-yl)quinolin-8-ol and its analogues as highly potent dopamine D2/D3 agonists and as iron chelator: In vivo activity indicates potential application in symptomatic and neuroprotective therapy for Parkinsons Disease  

PubMed Central

The role of iron in the pathogenesis of Parkinsons disease (PD) has been implicated strongly due to generation of oxidative stress leading to dopamine cell death. In our overall goal to develop bifunctional/multifunctional drugs, we designed dopamine D2/D3 agonist molecules with a capacity to bind to iron. Binding assays were carried out with HEK-293 cells expressing either D2 or D3 receptors with tritiated spiperone to evaluate inhibition constants (Ki). Functional activity of selected compounds was carried out with GTP?S binding assay. SAR results identified compounds (+)-19a and (?)-19b as two potent agonists for both D2 and D3 receptors (EC50 (GTP?S); D2 = 4.51 and 1.69 nM and D3 = 1.58 and 0.74 nM for (?)-19b and (+)-19a, respectively). In vitro complexation studies with 19b demonstrated efficient chelation with iron. Furthermore, the deoxyribose assay with 19b demonstrated potent antioxidant activity. In PD animal model study, (?)-19b exhibited potent in vivo activity in reversing locomotor activity in reserpinized rats and also in producing potent rotational activity in 6-OHDA lesioned rats. This reports initial development of unique lead molecules which might find potential use in symptomatic and neuroprotective treatment of PD. PMID:20146482

Ghosh, Balaram; Antonio, Tamara; Reith, Maarten E. A.; Dutta, Aloke K.

2010-01-01

424

Structure-activity relationship study of N?-(2-(4-(1H-Indol-5-yl)piperazin-1-yl)ethyl)-N?-propyl-4,5,6,7-tetrahydrobenzo[d]thiazole-2,6-diamine analogues: development of highly selective D3 dopamine receptor agonists along with a highly potent D2/D3 agonist and their pharmacological characterization.  

PubMed

In our effort to develop multifunctional drugs against Parkinson's disease, a structure-activity-relationship study was carried out based on our hybrid molecular template targeting D2/D3 receptors. Competitive binding with [(3)H]spiroperidol was used to evaluate affinity (K(i)) of test compounds. Functional activity of selected compounds in stimulating [(35)S]GTP?S binding was assessed in CHO cells expressing either human D2 or D3 receptors. Our results demonstrated development of highly selective compounds for D3 receptor (for (-)-40K(i), D3 = 1.84 nM, D2/D3 = 583.2; for (-)-45K(i), D3 = 1.09 nM, D2/D3 = 827.5). Functional data identified (-)-40 (EC(50), D2 = 114 nM, D3 = 0.26 nM, D2/D3 = 438) as one of the highest D3 selective agonists known to date. In addition, high affinity, nonselective D3 agonist (-)-19 (EC(50), D2 = 2.96 nM and D3 = 1.26 nM) was also developed. Lead compounds with antioxidant activity were evaluated using an in vivo PD animal model. PMID:22642365

Johnson, Mark; Antonio, Tamara; Reith, Maarten E A; Dutta, Aloke K

2012-06-28

425

CO2 Capture by Absorption with Potassium Carbonate  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. Ethylenediamine was detected in a degraded solution of MEA/PZ solution, suggesting that piperazine is subject to oxidation. Stripper modeling has demonstrated that vacuum strippers will be more energy efficient if constructed short and fat rather than tall and skinny. The matrix stripper has been identified as a configuration that will significantly reduce energy use. Extensive measurements of CO{sub 2} solubility in 7 m MEA at 40 and 60 C have confirmed the work by Jou and Mather. Corrosion of carbon steel without inhibitors increases from 19 to 181 mpy in lean solutions of 6.2 m MEA/PZ as piperazine increases from 0 to 3.1 m.

Gary T. Rochelle; Eric Chen; Babatunde Oyenekan; Andrew Sexton; Jason Davis; Marcus Hilliard; Amornvadee Veawab

2006-09-30

426

Synthesis and Biological Evaluation of New Imidazolium and Piperazinium Salts of Pyropheophorbide-a for Photodynamic Cancer Therapy  

PubMed Central

We have designed imidazolium and piperazinium salts of pyropheophorbide-a in order to develop effective photosensitizers which have good solubility in polar and non polar media and to reveal the possible influences of the piperazine and imidazole moieties on the biological activities of pyropheophorbide-a. The phototoxicity of those pyropheophorbide-a salts against A549 cells was studied in vitro and compared with that of pyropheophorbide-a. The result showed that complexing piperazine and imidazole into pyropheophorbide-a decreases its dark toxicity without greatly decreasing phototoxicity and, enhances its phototoxicity without greatly increasing dark toxicity, respectively. This work not only describes novel amphiphilic salt complexes of pyropheophobide-a which retain the biological activities of the parent compound pyropheophorbide-a and could be effective candidate for PDT, but also reveals the possibility of developing effective photosensitizers by complexing imidazole and piperazine into other hydrophobic photosensitizers. PMID:19325811

Sengee, Gerelt-Ireedui; Badraa, Narangerel; Shim, Young Key

2008-01-01

427

Synthesis and biological evaluation of new imidazolium and piperazinium salts of pyropheophorbide-a for photodynamic cancer therapy.  

PubMed

We have designed imidazolium and piperazinium salts of pyropheophorbide-a in order to develop effective photosensitizers which have good solubility in polar and non polar media and to reveal the possible influences of the piperazine and imidazole moieties on the biological activities of pyropheophorbide-a. The phototoxicity of those pyropheophorbide-a salts against A549 cells was studied in vitro and compared with that of pyropheophorbide-a. The result showed that complexing piperazine and imidazole into pyropheophorbide-a decreases its dark toxicity without greatly decreasing phototoxicity and, enhances its phototoxicity without greatly increasing dark toxicity, respectively. This work not only describes novel amphiphilic salt complexes of pyropheophobide-a which retain the biological activities of the parent compound pyropheophorbide-a and could be effective candidate for PDT, but also reveals the possibility of developing effective photosensitizers by complexing imidazole and piperazine into other hydrophobic photosensitizers. PMID:19325811

Sengee, Gerelt-Ireedui; Badraa, Narangerel; Shim, Young K

2008-08-01

428

1-Piperonylpiperazinium 4-chlorobenzoate  

PubMed Central

In the title salt {systematic name: 1-[(1,3-benzodioxol-5-yl)methyl]piperazin-1-ium 4-chlorobenzoate}, C12H17N2O2 +C7H4ClO2 ?, the piperazine ring adopts a slightly disordered chair conformation. The dioxole ring is in a flattened envelope conformation with the methylene C atom forming the flap. The relative orientation of the piperonyl ring system and the piperazine rings is reflected in the NCCC torsion angle of 132.3?(1). In the anion, the mean plane of the carboxylate group is twisted from that of the benzene ring by 14.8?(9). In the crystal, the components are linked by NH?O and weak CH?O hydrogen bonds, forming chains along [010]. PMID:24764993

Kavitha, Channappa N.; Kaur, Manpreet; Anderson, Brian J.; Jasinski, Jerry P.; Yathirajan, H. S.

2014-01-01

429

A study to investigate the performance of the Benfield-HiPure process of natural gas sweetening using computer simulations  

NASA Astrophysics Data System (ADS)

The removal of CO2 and H2S from natural gas is currently a global issue. Apart from meeting the customer's contract, pipeline, and LNG specifications; it is also a measure for reducing the global environmental emissions. The aim of this study is to investigate the performance of ADGAS' Train#3 plant through process simulations. ADGAS' Train#3 plant uses the Benfield HiPure design commissioned by Universal Oil Product (UOP Honeywell) in 1993. The Benfield HiPure process uses two independent but compatible circulating solutions in series to achieve high product purity in terms of acid gas concentrations that meet the LNG industry specifications. The ability to remove contaminants up to very low levels (1ppm H2S, 50ppm CO2 and 2ppm COS) makes the HiPure process an excellent choice for purifying natural gas for LNG requirement. At Das Island, ADGAS' Train#3 facility receives sour gas containing about 6-7 mole % acid gas content. This gas is first contacted with hot potassium carbonate (30wt% K2CO3) promoted with diethanolamine solution (3wt% DEA) followed by a contact with aqueous amine solution (20wt% DEA) alone as the second solvent. In this thesis, ADGAS Train#3 model was developed using the simulator tool ProMax. Simulation outputs were found to match reasonably well the design and plant operating data. Based on the model predictions, the carbonate absorber seemed to be over designed with much of the acid gases being absorbed at the bottom of the packing. With the confidence that the model is a reliable replicate of the real plant facility, a parametric sensitivity analysis was carried out to develop a strategy of controlling operational uncertainties and enable plant optimization. The parametric sensitivity analysis showed that the liquid circulation rates, solvent concentrations, trim cooler temperatures, feed gas flow rate, and feed gas H2S/CO2 ratio have a considerable effect on the performance of the plant with respect to acid gas removal, gas production capacity and plant energy efficiency. Due to the complexity and high investment cost of the Benfield HiPure process, potential alternatives are evaluated. The alternatives are basically MDEA based solvents with promoters to enable the simultaneous removal of H 2S and CO2. BASF's MDEA, MDEA/DEA or MDEA/DGA processes seem to be the best alternatives to the Benfield HiPure process. Using MDEA/DEA or MDEA/DGA process will reduce the capital costs of ADGAS by 50% , and up to 48% will be saved on the annual power consumption (0.33 million dollars per years) . BASF's MDEA has slightly higher capital costs due to the additional units required on the high pressure flash and the quenching units used to generate the semi-lean solution. However, BASF's MDEA process still stands as one of the best alternatives with a savings of about 102 million dollars (48%) on the capital costs and up to 36% (3.96 USD per ton of acid gas removed) on the cost stripping.

Ochieng, Richard

430

Drug Testing in Blood: Validated Negative-Ion Chemical Ionization Gas Chromatographic-Mass Spectrometric Assay for Enantioselective Measurement of the Designer Drugs 3,4-Methylenedioxyamphetamine, 3,4-Methylenedioxymethamphetamine (MDMA), and 3,4-Methylenedioxyethylamphetamine and Its Application to Samples from a Controlled Study with MDMA  

Microsoft Academic Search

Background: The enantiomers of the designer drugs 3,4-methylenedioxyamphetamine (MDA), 3,4-methyl- enedioxymethamphetamine (MDMA), and 3,4-methyl- enedioxyethylamphetamine (MDEA) differ in their pharmacologic and toxicologic potency. The aim of this study was to develop an assay for measuring these enantiomers in small plasma volumes and to analyze samples from a controlled study with MDMA. Methods: The analytes were extracted from <0.2 mL of

Frank T. Peters; Nele Samyn; Caroline T. J. Lamers; Wim J. Riedel; Thomas Kraemer; Gert de Boeck; Hans H. Maurer

431

Quantitative determination of amphetamines, cocaine, and opiates in human hair by gas chromatography\\/mass spectrometry  

Microsoft Academic Search

Hair of young subjects (N=36) suspected for drug abuse was analysed for morphine, codeine, heroin, 6-acetylmorphine, cocaine, methadone, amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA). The analysis of morphine, codeine, heroin, 6-acetylmorphine, cocaine, and methadone in hair included incubation in methanol, solid-phase extraction, derivatisation by the mixture of propionic acid anhydride and pyridine, and gas chromatography\\/mass spectrometry (GC\\/MS).

L Skender; V Kara?i?; I Br?i?; A Bagari?

2002-01-01

432

Automated solid-phase extraction and two-step derivatisation for simultaneous analysis of basic illicit drugs in serum by GC\\/MS  

Microsoft Academic Search

A combination of automated solid-phase extraction (SPE) and subsequent two-step derivatisation has been developed for the\\u000a simultaneous analysis of basic drugs of abuse and cocaine metabolites in serum samples. Substances included in this procedure\\u000a are morphine, codeine, methadone, cocaine, benzoylecgonine, methylecgonine, amphetamine, methamphetamine, MDMA, MDEA and MDA.\\u000a SPE with mixed-mode cartridges (RP-C8 and cation-exchange) was fully automated with a Zymark

W. Weinmann; M. Renz; S. Vogt; S. Pollak

2000-01-01

433

Octanuclear Mn(III)6Mn(II)Ln (Ln = Gd, Dy and Er) clusters with a novel core topology: syntheses, structures, and magnetic properties.  

PubMed

Reactions of [Mn6O2(piv)10(py)2.5(piv)1.5], Ln(NO3)36H2O and N-mdeaH2 in MeCN in the presence of Me3SiCl generated a family of octanuclear Mn/Ln complexes [Mn6(III)Mn(II)Ln(N-mdea)3(N-mdeaH)(piv)8O2(OH)3(NO3)(H2O)]xCH3CNxH2O [Ln = Gd (1), Dy (2), Er (3), pivH = pivalic acid, N-mdeaH2 = N-methyl diethanolamine]. Each complex possesses a [Mn6(III)Mn(II)Ln(?3-O)2(?3-OH)3](16+) core containing two butterfly-like subunits of [Mn3Ln(?3-OH)2] and [Mn4(?3-O)2] sharing a common vertex, and an outer Mn atom ligated to one of the subunits through a ?3-OH(-) ligand. The core topology represents a new Mn/Ln core type. The magnetic susceptibility study of 1-3 indicates the presence of dominant antiferromagnetic interactions within the complexes. For complex 1, which contains an isotropic Gd(III) atom, fitting of the obtained M/(N?B) vs. H/T data gave S = 4, g = 1.90, and D = -0.31 cm(-1). The results were further supported by ac data. Complex exhibits out-of-phase ac susceptibility signals, indicating it may be a SMM. PMID:23377042

Chen, Hui; Ma, Cheng-Bing; Hu, Ming-Qiang; Wen, Hui-Min; Cui, Hong-Hua; Liu, Jin-Ying; Song, Xiao-Wei; Chen, Chang-Neng

2013-04-14

434

The first 4d/4f single-molecule magnet containing a {Ru(III)2Dy(III)2} core.  

PubMed

We report the synthesis, structure and magnetic properties of the first 4d-4f single-molecule magnet. The complex [Ru(III)2Dy(III)2(OMe)2(O2CPh)4(mdea)2(NO3)2] displays a butterfly type core, with an anisotropy barrier of 10.7 cm(-1). Ab initio and DFT calculations provide insight into the observed magnetic behaviour. PMID:25536910

Langley, Stuart K; Wielechowski, Daniel P; Vieru, Veacheslav; Chilton, Nicholas F; Moubaraki, Boujemaa; Chibotaru, Liviu F; Murray, Keith S

2015-02-01

435

An integration of the multi-component DEA and GAR models to the measurement of hotel performance  

Microsoft Academic Search

The aim of this paper is to identify how well each hotel performs in each of its room and food and beverage divisions. To this end, this paper develops a multi-component data envelopment analysis\\/global assurance region (MDEA\\/GAR) model to fully gauge hotel performance where each hotel has its specific inputs and outputs for both divisions as well as shared inputs

Ming-Miin Yu

2012-01-01

436

An integration of the multi-component DEA and GAR models to the measurement of hotel performance  

Microsoft Academic Search

The aim of this paper is to identify how well each hotel performs in each of its room and food and beverage divisions. To this end, this paper develops a multi-component data envelopment analysis\\/global assurance region (MDEA\\/GAR) model to fully gauge hotel performance where each hotel has its specific inputs and outputs for both divisions as well as shared inputs

Ming-Miin Yu

2011-01-01

437

The effect of chitosan and other polycations on tight junction permeability in the human intestinal Caco-2 cell line 1 1 Abbreviations: AP = apical; BL = basolateral; 2DOG = 2-deoxyglucose; HBSS = Hanks balanced salt solution; FITC = fluorescein isothiocyanate; HEPES = N-2-hydroxyethyl piperazine-N-4-butanesulfonic acid; HMW = high molecular weight; LMW = low molecular weight; MES = morpholinoethane sulfonic acid; PBS + = phosphate buffered saline; PEI = polyethylenimine; TEER = trans-epithelial electrical resistance; TRITC = tetramethylrodamine isothiocyanate  

Microsoft Academic Search

Chitosan is a polycationic compound widely employed as dietary supplement and also present in pharmaceutical preparations. Although it has been approved for human consumption, its possible side effects have not been widely investigated and the available data in the literature are still controversial. Several polycationic substances have been shown to affect tight junction permeability in epithelial cell models in vitro.

Giulia Ranaldi; Iolanda Marigliano; Isabella Vespignani; Giuditta Perozzi; Yula Sambuy

2002-01-01

438

Interaction of arylpiperazines with 5HT1A, 5HT1B, 5HT1C and 5HT1D receptors: do discriminatory 5HT1B receptor ligands exist?  

Microsoft Academic Search

The effects of several putative 5-HT1 receptorsubtype selective ligands were investigated in biochemical models for 5-HT1A, 5-HT1B, and 5-HT1D receptors (inhibition of forskolin-stimulated adenylate cyclase activity in calf hippocampus, rat and calf substantia nigra, respectively) and 5-HT1C receptors (stimulation of inositol phosphates production in pig choroid plexus). Following compounds were studied: 5-HT (5-hydroxytryptamine), TFMPP (1-(mtrifluoromethylphenyl)piperazine), mCPP (1-m-chlorophe-nyl)piperazine, 1 CGS 12066

Philippe Schoeffter; Daniel Hoyer

1989-01-01

439

Synthesis and functional survey of new Tacrine analogs modified with nitroxides or their precursors.  

PubMed

A series of new Tacrine analogs modified with nitroxides or pre-nitroxides on 9-amino group via methylene or piperazine spacers were synthesized; the nitroxide or its precursors were incorporated into the Tacrine scaffold. The new compounds were tested for their hydroxyl radical and peroxyl radical scavenging ability, acetylcholinesterase inhibitor activity and protection against A?-induced cytotoxicity. Based on these assays, we conclude that Tacrine analogs connected to five and six-membered nitroxides via piperazine spacers (9b, 9b/HCl and 12) exhibited the best activity, providing direction for further development of additional candidates with dual functionality (anti Alzheimer's and antioxidant). PMID:24657571

Klai, Tams; Altman, Robin; Maezawa, Izumi; Balog, Mria; Morisseau, Christophe; Petrlova, Jitka; Hammock, Bruce D; Jin, Lee-Way; Trudell, James R; Voss, John C; Hideg, Klmn

2014-04-22

440

CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. A rigorous thermodynamic model has been further developed with a standalone FORTRAN code to represent the CO{sub 2} vapor pressure and speciation of the new solvent. Gas chromatography has been used to measure the oxidative degradation of piperazine. The heat exchangers for the pilot plant have been received. The modifications are on schedule for start-up in November 2003.

Gary T. Rochelle; Eric Chen; J. Tim Cullinane; Marcus Hilliard; Babatunde Oyenekan; Terraun Jones

2003-07-28

441

CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE  

SciTech Connect

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. Progress has been made in this reporting period on three subtasks. The rigorous Electrolyte Non-Random Two-Liquid (electrolyte-NRTL) model has been regressed to represent CO{sub 2} solubility in potassium carbonate/bicarbonate solutions. An analytical method for piperazine has been developed using a gas chromatograph. Funding has been obtained and equipment has been donated to provide for modifications of the existing pilot plant system with stainless steel materials.

Gary T. Rochelle; A. Frank Seibert; J. Tim Cullinane; Terraun Jones

2003-01-01

442

Synthesis of Chiral 2,3-Disubstituted 1,4-Diazabicyclo[2.2.2]octane Derivatives.  

PubMed

Racemic 2,3-diaryl-1,4-diazabicyclo[2.2.2]octane (DABCO) derivatives are synthesized from the readily accessible piperazines in 50-64% yield by cyclization using ethylene bromide, triethylamine, and KI at 80 C. The enantiomerically enriched 2,3-diphenylpiperazine and the 2,3-bis(1-naphthyl)piperazine derivatives are prepared by a resolution method using commercially available optically active acids, yielding the corresponding DABCO derivatives in 51-64% yield with up to 99% ee. This mild cyclization can also be applied to enantiopure camphanyldiamine derivatives, and the products are obtained in 72-86% yields. PMID:25756201

Periasamy, Mariappan; Edukondalu, Athukuri; Reddy, Polimera Obula

2015-04-01

443

Possible pharmacokinetic and pharmacodynamic factors affecting parkinsonism inducement by cinnarizine and flunarizine  

Microsoft Academic Search

Potentialities of cinnarizine [1-(diphenylmethyl)-4-(3-phenyl-2-propenyl)piperazine, CZ] and its fluorine derivative flunarizine [1-[bis(4-fluorophenyl)-methyl]-4-(3-phenyl-2-propenyl)piperazine, FZ] to induce parkinsonism as an adverse effect were evaluated pharmacokinetically and pharmacodynamically in rats. In multiple-dose experiments, CZ or FZ was given to rats at a daily dose of 20 ?mol\\/kg for 1, 5, 10, 15, and 30 days, and CZ, FZ, and the ring-hydroxylated metabolites of their

Satoru Kariya; Sadao Isozaki; Yasuhiro Masubuchi; Tokuji Suzuki; Shizuo Narimatsu

1995-01-01

444

Effect of piribedil and its metabolite, S584, on brain lipid peroxidation in vitro and in vivo  

Microsoft Academic Search

We studied the effect of piribedil (1-3,4-methylendioxybenzyl-4-(2-pyrimidyl) piperazine) and its catechol metabolite, S584 (1-(3,4-dihydroxybenzyl-4-(2-pyrimidinyl)-piperazine), on rat brain lipid peroxidation (a) in vitro in rat synaptosomes and cortical slices after induction of an oxidative stress and (b) in vivo in mouse brain after short-term exposure (two and three 4-h cycles) to O2\\/CO2 (95%:5%). The metabolite (10?410?5 M), but not piribedil, prevented

Federico Calzi; Raffaele Bellasio; Giovanna Guiso; Silvio Caccia; Maria Teresa Tacconi

1997-01-01

445

New analytical technique for carbon dioxide absorption solvents  

SciTech Connect

The densities and refractive indices of two binary systems (water + MEA and water + MDEA) and three ternary systems (water + MEA + CO{sub 2}, water + MDEA + CO{sub 2}, and water + MEA + MDEA) used for carbon dioxide (CO{sub 2}) capture were measured over the range of compositions of the aqueous alkanolamine(s) used for CO{sub 2} absorption at temperatures from 295 to 338 K. Experimental densities were modeled empirically, while the experimental refractive indices were modeled using well-established models from the known values of their pure-component densities and refractive indices. The density and Gladstone-Dale refractive index models were then used to obtain the compositions of unknown samples of the binary and ternary systems by simultaneous solution of the density and refractive index equations. The results from this technique have been compared with HPLC (high-performance liquid chromatography) results, while a third independent technique (acid-base titration) was used to verify the results. The results show that the systems' compositions obtained from the simple and easy-to-use refractive index/density technique were very comparable to the expensive and laborious HPLC/titration techniques, suggesting that the refractive index/density technique can be used to replace existing methods for analysis of fresh or nondegraded, CO{sub 2}-loaded, single and mixed alkanolamine solutions.

Pouryousefi, F.; Idem, R.O. [University of Regina, Regina, SK (Canada). Faculty of Engineering

2008-02-15

446

Hair analysis for drug abuse. XV. Disposition of 3, 4-methylenedioxymethamphetamine (MDMA) and its related compounds into rat hair and application to hair analysis for MDMA abuse.  

PubMed

In order to clarify the mechanism of drug incorporation into hair, disposition of 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), 3-methoxy-4,5-methylenedioxyamphetamine (MMDA) and metabolites of MDMA, 4-hydroxy-3-methoxyamphetamine (HMAP) and 4-hydroxy-3-methoxymethamphetamine (HMMA), into hair was investigated with an animal model. After the intraperitoneal administration of those six drugs to pigmented hairy rats (5 mg/kg/day, 10 days, n = 3), the parent compounds and their metabolites in the rat plasma (5, 15, 30, 60, 120, 360 min after administration) and in the newly grown rat hair for 4 weeks were determined by GC/MS-SIM. When the ratio of hair concentration to area under the concentration versus time curves (AUCs) in plasma was represented as an index of incorporation rate (ICR) of drugs into hair, the order of ICRs was HMAP < MDA < HMMA < MDMA < MDEA < MMDA. In the comparison between MDA, MDMA and MDEA, their ICRs increased according to the length of carbon branches from proton to ethyl at the N position. From the point of view that the ICRs of MMDA was 2.3 times as much as that of MDA, the methoxy group on the benzene ring seemed to serve as a positive factor for the ICR. However, the ICRs of 4-hydroxy-3-methoxy compounds, HMAP and HMMA, were lower in comparison with those of MDA and MDMA, respectively. On the other hand, the ICRs of MDA, MDMA and MDEA were 5.5-6.1 times larger than those of amphetamine, methamphetamine and ethylamphetamine, suggesting that the methylenedioxy group on the benzene ring raises their ICRs very positively. Moreover, in order to apply the results from the animal experiments to human cases, the scalp hair samples of seven MDMA abusers were analyzed. MDMA and its metabolites, MDA; were simultaneously detected in all the samples by GC/MS. In the two samples, MDEA was found in addition to MDMA and MDA. It was shown that a hair sample is a good specimen for the confirmation of retrospective use of methylenedioxyamphetamines. PMID:9042722

Kikura, R; Nakahara, Y; Mieczkowski, T; Tagliaro, F

1997-01-17

447

Synthesis of a 1-benzylpiperazin-2-one nitrone and its reaction with alkynes and alkenes  

Microsoft Academic Search

A novel 1-benzylpiperazin-2-one nitrone has been synthesized. It readily undergoes [3+2] cycloadditions with alkynes and alkenes to give ?4-isoxazolines and isoxazolidines, respectively, which can be reductively opened to 3-substituted piperazin-2-ones and 1,3-amino alcohols.

Ronald C. Bernotas; Ginette Adams

1996-01-01

448

The Effect of the Adsorption of Multicharge Cations on the Selectivity of a Nanofiltration Membrane  

Microsoft Academic Search

The selective and electrokinetic properties of an OPMN-KMZ nanofiltration membrane with a selective layer of piperazine and trimesoyl chloride copolymer with respect to aqueous solutions of barium, yttrium, and thorium nitrates are investigated in a wide range of their concentrations. It is disclosed that, after the charge reversal of the initially negatively charged surface of this membrane by thorium cations,

K. G. Sabbatovskii

2003-01-01

449

Preparation and characterization of polypiperazine amide\\/PPESK hollow fiber composite nanofiltration membrane  

Microsoft Academic Search

A modified interfacial polymerization procedure suitable for preparing hollow fiber composite membrane was developed. By this modified procedure, a new hollow fiber composite nanofiltration membrane with high permeability was prepared by interfacial polymerization of piperazine (PIP) aqueous solution and trimesoyl chloride (TMC) hexane solution. The selective layer was synthesized on the inner surface of poly(phthalazinone ether sulfone ketone) (PPESK) hollow

Fajie Yang; Shouhai Zhang; Daling Yang; Xigao Jian

2007-01-01

450

Synthesis and properties of a novel hyperbranched polyphosphate acrylate applied to UV curable flame retardant coatings  

Microsoft Academic Search

A series of hyperbranched polyphosphate acrylates (HPPAs) being used for UV curable flame retardant coatings were prepared by the reaction of tri(acryloyloxyethyl) phosphate (TAEP) with piperazine at given ratios, and characterized using FTIR, 1H NMR and GPC measurements. HPPA was blended with TAEP in different ratios to obtain a series of UV curable resins. Their maximum photopolymerization rates (RPmax) and

Zhanguang Huang; Wenfang Shi

2007-01-01

451

Structural studies of terpenoid biosynthesis and bacterial cell division  

E-print Network

Guanosine 5'-(?, ?-methylene)-diphosphonate GMPPNP Guanosine 5?-(?, ?-imido)-triphosphate GPP Geranyl Pyrophosphate GTP Guanosine 5?-triphosphate GTP...?S Guanosine 5'-(3-O-thio)triphosphate HEPES N-(2-hydroxyethyl)-piperazine-N'-2-ethanesulfonic Acid HIDS Hyperimmunoglobulinemia D Syndrome HMB-PP (E)-4-hydroxy-3-methyl...

Yang, Dong

2009-06-02

452

Dipeptidyl peptidase-4 inhibitor with ?-amino amide scaffold: synthesis, SAR and biological evaluation.  

PubMed

Inhibitors of dipeptidyl peptidase-4 (DPP4) have been shown to be effective treatments for type 2 diabetes. Several series of ?-amino amide containing piperazine derivatives have been prepared and evaluated as a inhibitor of DPP4. Finally compound 5m was selected for further evaluation. PMID:22850208

Kim, Heung Jae; Kwak, Woo Young; Min, Jong Pil; Sung, Si Young; Kim, Ha Dong; Kim, Mi Kyung; Kim, Hae Sun; Park, Kyung Jin; Son, Moon Ho; Kim, Soon Hoe; Lee, Bong Jin

2012-09-01

453

Adsorption and desorption of atrazine on a melamine-based soil amendment  

E-print Network

Adsorption kinetics and adsorption-desorption of atrazine on organoclay composites prepared with the surfactant 6-piperazin-1-yl-N,N'-bis-(1,1,3,3-tetramethyl-butyl)-(1,3,5)triazine-2,4-diamine and Houston Black clay were studied using the indirect...

Neitsch, Susan Lynn

2004-09-30

454

Zeolite based catalysts for hydrodenitrogenation of quinoline  

E-print Network

-linear----------- Table 5 Continued: Initial Concentration K, 95 I Confidence 2, 4, 6-collidine 3-ethyl-4-methyl pyridine 0. 307 0. 3655 0. 512 0. 114 None +0. 076& Piperazine Piperidine 2-methyl piperidine 0. 307 0. 307 0. 302 Quinoline Acridine 0. 288...

Sanghvi, Bhavyen Suman

1982-01-01

455

CO2 Capture by Absorption with Potassium Carbonate  

E-print Network

CO2 Capture by Absorption with Potassium Carbonate Third Quarterly Report 2005 Quarterly Progress absorption/stripping by developing an alternative solvent, aqueous K2CO3 promoted by piperazine. Modeling.................................................................................................................................. 11 Task 1 ­ Modeling Performance of Absorption/Stripping of CO2 with Aqueous K2CO3 Promoted

Rochelle, Gary T.

456

CO2 Capture by Absorption with Potassium Carbonate  

E-print Network

CO2 Capture by Absorption with Potassium Carbonate Fourth Quarterly Report 2005 Quarterly Progress absorption/stripping by developing an alternative solvent, aqueous K2CO3 promoted by piperazine. In Campaign.................................................................................................................................... 9 Task 1 ­ Modeling Performance of Absorption/Stripping of CO2 with Aqueous K2CO3 Promoted

Rochelle, Gary T.

457

PREHIBERNATION AND HIBERNATION EFFECTS ON THE D-3-HYDROXYBUTYRATE DEHYDROGENASE OF THE HEAVY AND LIGHT MITOCHONDRIA FROM LIVER JERBOA  

E-print Network

acid ; ELISA, Enzyme-Linked Immunosorbent Assay; GOT, Glutamate Oxalate Transaminase; GPT, Glutamate Pyruvate Transaminase; HDL, High Density Lipoprotein; Hepes, 4-(2-hydroxyethyl)-1-piperazine ethane sulfonic acid ; LDL, Low Density Lipoprotein; Mes, 4-N-morpholinoethanesulfonic acid ; NAD(H), Nicotinamide

Paris-Sud XI, Universit de

458

Quantitative Determination of Some Pharmaceutical Veterinary Formulations Using Bromocresol Purple and Bromocresol Green  

Microsoft Academic Search

A simple, sensitive, accurate and rapid spectrophotometric method for the determination of some anthelmintics that are used in veterinary medication is described, based on the formation of an ion pair complex with bromocresol purple (BCP) and bromocresol green (BCG). Drugs analyzed are piperazine hexahydrate, tetramisole hydrochloride and metronidazole. The drugs were determined either in pure powdered forms or in pharmaceutical

Alaa S. Amin

1997-01-01

459

Functional selectivity of dopamine D1 receptor agonists in regulating the fate of internalized receptors  

E-print Network

(adenosine 30 ,50 -cyclic monophosphate); A-77636, (1R,3S )-3-(10 adamantyl)-1-aminomethyl-3,4-dihydro-5,2,3-de]isoquinoline); GRK, G protein-coupled receptor kinase; HEPES, 4-(2-hydroxyethyl)-1-piperazine

Goddard III, William A.

460

CO2 Capture Using Activated Amino Acid Salt Solutions in a Membrane Contactor  

Microsoft Academic Search

An activated solution based on amino acid salt was proposed as a CO2 absorbent. Piperazine (PZ) was selected as an activating agent and added into the aqueous glycine salt to form the activated solution. A coupling process, which associated the activated solution with a PP hollow fiber membrane contactor, was set up. An experimental and theoretical analysis for CO2 capture

Jian-Gang Lu; Yan Ji; Hui Zhang; Min-Dong Chen

2010-01-01

461

Efficacy and Safety of a Metabolic Modulator Drug in Chronic Stable Angina: Review of Evidence from Clinical Trials  

Microsoft Academic Search

A number of newer antianginal agents, including nicorandil, trimetazidine, and ivabradine, have been synthesized in recent years, but ranolazine, a piperazine derivative that partially inhibits fatty acid oxidation and the late INa current in animal models, is of particular interest mechanistically. Earlier clinical trials with immediate-release ranolazine led to the current sustained-release version tested in the Monotherapy Assessment of Ranolazine

Bernard R. Chaitman

2004-01-01

462

Studies of flammability and thermal degradation for flame retardant cotton fabric with P-N containing derivatives  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effectiveness of a phosphoramidate Tetraethyl piperazine-1,4- diyldiphosphoramidate (TEPP) as a flame retardant (FR) on cotton twill fabrics was compared with that of a previously studied Diethyl 4- methylpiperazin-1-ylphosphoramidate (DEPP). TEPP was formed in a reaction between two phosphonat...

463

* Corresponding author. Tel.: #1-512-471-7230; fax: #1-512-471-E-mail addresses: sbishnoi@che.utexas.edu (S. Bishnoi), rochelle@  

E-print Network

rate of reaction of the primary or secondary amine with carbon dioxide combined with the low heat was studied from 298 to 333 K in solutions of 0.6 and 0.2 M aqueous piperazine. The apparent reaction rate of reaction of the tertiary amine. By adding small amounts of the pri- mary or secondary amine, a high rate

Rochelle, Gary T.

464

Rat epidermal keratinocyte organotypic culture (ROC) compared to human cadaver skin: The effect of skin permeation enhancers  

Microsoft Academic Search

The objective of this study was to evaluate the response of the rat epidermal keratinocyte organotypic culture (ROC) to permeation enhancers, and to compare these responses to those in human cadaver skin. Different concentrations of two mixtures for enhancing permeation were investigated, sodium dodecyl sulfate:phenyl piperazine and methyl pyrrolidone:dodecyl pyridinium chloride, using skin impedance spectroscopy and two experimental compounds, the

Sari Pappinen; Sanna Tikkinen; Sanna Pasonen-Seppnen; Lasse Murtomki; Marjukka Suhonen; Arto Urtti

2007-01-01

465

Buclizine  

Microsoft Academic Search

A comprehensive profile on buclizine hydrochloride, the piperazine derivative which is a sedating antihistamine with antimuscarinic and moderate sedative action and used mainly for its antiemetic effect in the prevention of motion sickness and migraine, is prepared. This profile contains the following sections: description, uses and applications, methods of preparation, physical characteristics, methods of analysis and stability. The physical characteristics

Gamal A. E. Mostafa; Abdullah A. Al-Badr

2011-01-01

466

WHO expert committee on drug dependence.  

PubMed

This report presents the recommendations of a WHO Expert Committee responsible for reviewing information on psychoactive substances to assess the need for their international control. The report contains a summary of the Committee's evaluations of gamma-hydroxybutyric acid (GHB) and ketamine. GHB was recommended to be rescheduled from Schedule IV to Schedule II of the Convention on Psychotropic Substances. The report also discusses the nine substances that were pre-reviewed: dextromethorphan, tapentadol, N-benzylpiperazine (BZP), 1-(3-trifluoromethylphenyl) piperazine (TFMPP), 1-(3-chlorophenyl)piperazine (mCPP), 1-(4-methoxyphenyl)piperazine (MeOPP), 1-(3,4-methylenedioxybenzyl)piperazine (MDBP), gamma-butyrolactone (GBL), and 1,4-butanediol (1,4-BD). Of these, tapentadol, BZP, GBL and 1,4-BD were recommended for critical review. Issues identified for consideration at future Expert Committee meetings are also listed. Furthermore, the report discusses the use of terms, the use of pharmacovigilance data for the assessment of abuse and dependence potential, balancing medical availability and prevention of abuse of medicines manufactured from controlled substances, and improving the process for substance evaluation. PMID:24547667

2012-01-01

467

Axial coordination changes the morphology of porphyrin assemblies in an organogel system.  

PubMed

The gelation properties of a zinc porphyrin bearing peripheral urea groups (1 x Zn) were evaluated in the absence and the presence of several diamines. In aromatic solvents such as benzene, toluene and p-xylene, 1 x Zn only provided the precipitate. In contrast, 1 x Zn with 0.5 and 1.0 equiv. of piperazine formed gels, and the gel with 0.5 equiv. of piperazine showed a unique physical property called 'thixotropy'. On the other hand, upon addition of similar diamines such as DABCO, ethylenediamine and N,N'-dimethylethylenediamine, 1 x Zn did not gelate these solvents. When the critical gelation concentration was plotted against the ratio of piperazine versus 1 x Zn, it afforded a minimum breakpoint at 0.5 equiv. and the critical concentration increased with further increase in the fraction of piperazine, indicating that the stable gel is formed from the 1 x Zn + piperazine 2:1 complex and the subsequent transformation to the 1:1 complex rather destabilizes the gel. Very interestingly, it was clearly shown by SEM and TEM observations that such structural changes of the unit complex induced by the ratio of piperazine versus 1 x Zn can lead to gradual morphological transitions: that is, spherical structure at 0 equiv., 1-D fibrous structure at 0.5 equiv. and 2-D sheet-like structure at 1.0 equiv. In addition, UV-VIS spectra revealed that 1 x Zn itself adopts a J-aggregation mode, whereas 1 x Zn + piperazine 2:1 and 1:1 complexes adopt an H-like aggregation mode. On the other hand, upon addition of 0.5 equiv. of other diamines, 1 x Zn + diamine complexes result in different morphologies other than the 1-D fibrous structure. To explore a reasonable rationale for these results, we conducted computational studies. As a result, we found that the complex symmetry of the unit complex plays an important role in determining the final ordered structure. PMID:16688336

Kishida, Takanori; Fujita, Norifumi; Hirata, Osamu; Shinkai, Seiji

2006-05-21

468

Effects of the electrode size and modification protocol on a label-free electrochemical biosensor.  

PubMed

In the present work, the effect of a surface modification protocol along with the electrode size has been investigated for developing an efficient, label-free electrochemical biosensing method for diagnosis of traumatic brain injury (TBI) biomarkers. A microdisk electrode array (MDEA) and a macroelectrode with a comb structure (MECS) were modified with an anti-GFAP (GFAP = glial fibrillary acidic protein) antibody using two protocols for optimum and label-free detection of GFAP, a promising acute-phase TBI biomarker. For the MDEA, an array of six microdisks with a 100 ?m diameter and, for the MECS, a 3.2 mm 5.5 mm electrode 5 ?m wide with 10 ?m spaced comb fingers were modified using an optimized protocol for dithiobis(succinimidyl propionate) (DSP) self-assembled monolayer formation. Anti-GFAP was covalently bound, and the remaining free DSP groups were blocked using ethanolamine (Ea). Sensors were exposed to solutions with different GFAP concentrations, and a label-free electrochemical impedance spectroscopy (EIS) technique was used to determine the concentration. EIS results confirmed that both types of Ea/anti-GFAP/DSP/Au electrodes modified with an optimized DSP-based protocol can accurately detect GFAP in the range of 1 pg mL(-1) to 100 ng mL(-1) with a detection limit of 1 pg mL(-1). However, the cross-use of the MDEA protocol on the MECS and vice versa resulted in very low sensitivity or poor signal resolution, underscoring the importance of proper matching of the electrode size and type and the surface modification protocol. PMID:23651210

Arya, Sunil K; Pui, Tze Sian; Wong, Chee Chung; Kumar, Sai; Rahman, Abdur Rub Abdur

2013-06-01

469

A family of novel Mn?Ln? clusters displaying single-molecule magnet behavior.  

PubMed

Using 3-methyloxysalicylaldoxime (mosaoH2) and N-methyl diethanolamine (N-