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Ethyl Ester (ethyl + ester)
Kinds of Ethyl Ester Selected AbstractsPolyimide Orientation Layers Prepared from Lyotropic Aromatic Poly(Amic Ethyl Ester)s,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2003C. Neuber Abstract The synthesis and characterization of liquid-crystalline precursor polymer solutions[1] for polyimides permit for the first time the preparation of bulk- and surface-oriented polyimide thin films from the nematic lyotropic state by shear. A special shearing technique was developed and optimized to orient viscous solutions into thin films with thicknesses below 100 nm. The films produced were thermally imidized and characterized by polarized light microscopy, as well as polarized FTIR and UV-vis spectroscopy before and after imidization. The dichroic ratios (DRs) before imidization were determined as 5 by FTIR, and 4.5 by UV-vis spectroscopies. After imidization the DRs increased to 14 and 7, respectively. The shear-oriented layers possess a surface profile in the form of striations, which was characterized by mechanical surface scanning and atomic force microscopy (AFM). The profile height was determined in the nanometer range in contrast to the profile distance in the micrometer range, thus the latter is a magnitude larger than the film thickness. To quantify and compare the orientation potential of the obtained orientation layers, cells with a liquid-crystalline host and a dichroic azo dye as guest were prepared. Interesting for this class of rod-like polyimides is that layers, which were cast from low concentration isotropic solutions and rubbed, exhibited an almost doubled DR of 15 compared to analogously prepared alignment layers based on commercial flexible polyimide systems (DR,=,8). [source] Unexpected Isolation of 4-Isothiocyanatomethylene-4H-pyridine-1-carboxylic Acid Ethyl Ester as Potential Template in Organic Synthesis.CHEMINFORM, Issue 5 2006Aladdin E. Sarhan Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthesis and Pharmacological Evaluation of Amide Conjugates of NSAIDs with L-Cysteine Ethyl Ester, Combining Potent Antiinflammatory and Antioxidant Properties with Significantly Reduced Gastrointestinal Toxicity.CHEMINFORM, Issue 47 2004Dimitrios Galanakis Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Formation of Isoquinoline Derivatives by the Irradiation of N-Acetyl-,-dehydrophenylalanine Ethyl Ester and Its Derivatives.CHEMINFORM, Issue 6 2001Hideki Hoshina Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Fatty Acid Ethyl Esters in Meconium: Are They Biomarkers of Fetal Alcohol Exposure and Effect?ALCOHOLISM, Issue 7 2006Enrique M. Ostrea Jr. Background: Biomarkers of fetal exposure to alcohol are important to establish so that early detection and intervention can be made on these infants to prevent undesirable outcomes. The aim of this study was to analyze long-chain fatty acid ethyl esters (FAEEs) in meconium as potential biomarkers of fetal alcohol exposure and effect. Methods: Fatty acid ethyl esters were analyzed in the meconium of 124 singleton infants by positive chemical ionization gas chromatography/mass spectrometry (GC/MS) and correlated to maternal ethanol use. Results: A total of 124 mother/infant dyads were enrolled in the study: 31 were in the control group and 93 were in the alcohol-exposed group. The incidence (28% vs 9.7%, p=0.037) of ethyl linoleate detected in meconium was significantly higher in the alcohol-exposed groups than the control groups. Similarly, when the concentrations of ethyl linoleate in meconium were grouped (trichotomized), there was a significant linear by linear association between alcohol exposure and group concentrations of ethyl linoleate (p=0.013). Furthermore, only alcohol-exposed infants were found in the group with the highest ethyl linoleate concentration. The sensitivity of ethyl linoleate in detecting prenatal alcohol exposure was only 26.9%, and its specificity and positive predictive value were 96.8 and 96.2%, respectively. There was no significant correlation between the concentration of ethyl linoleate in meconium and absolute alcohol consumed (oz) per drinking day across pregnancy, although a trend toward a positive correlation is seen at lower amounts of alcohol consumed. Among the polyunsaturated, long-chain FAEEs, there was weak evidence that the incidence (21.5% vs 6.5%, p=0.057) and concentration (p=0.064) of ethyl arachidonate (AA) were significantly higher in the alcohol-exposed groups than the control groups. Ethyl linolenate and ethyl docosahexanoate (DHA) in meconium were found only in the alcohol group, although not at statistically significant levels. Highly significant correlations were found among the concentrations of ethyl linoleate, ethyl linolenate, ethyl AA, and ethyl DHA in meconium (correlations ranged between rs=0.203, p=0.024; and rs=0.594, p<0.001). Conclusion: We conclude that FAEEs in meconium, particularly ethyl linoleate and ethyl AA, are biomarkers of high specificity for prenatal exposure to alcohol in newborn infants. We also propose that ethyl AA and DHA could be potential biomarkers of fetal alcohol effects on the developing fetal brain and should be investigated further. [source] Detection of Recent Ethanol Intake With New Markers: Comparison of Fatty Acid Ethyl Esters in Serum and of Ethyl Glucuronide and the Ratio of 5-Hydroxytryptophol to 5-Hydroxyindole Acetic Acid in UrineALCOHOLISM, Issue 5 2005K Borucki Background: At present, recent ethanol consumption can be routinely detected with certainty only by direct measurement of ethanol concentration in blood or urine. Because ethanol is rapidly eliminated from the circulation, however, the time span for this detection is in the range of hours. Several new markers have been proposed to extend the detection interval, but their characteristics have not yet justified their use in routine clinical practice. We therefore investigated three new markers and compared their kinetics and sensitivities: (1) fatty acid ethyl esters (FAEEs) in serum, (2) ethyl glucuronide (EtG) in urine, and (3) the ratio of 5-hydroxytryptophol to 5-hydroxyindole acetic acid (5-HTOL/5-HIAA) in urine. Methods: Seventeen healthy men participated in a drinking experiment. Blood and urine samples were collected twice daily on three consecutive days and once daily on days 4 and 5. Ethanol concentration was determined by gas chromatography, FAEE levels, by gas chromatography with mass spectrometry, EtG concentration, by liquid chromatography-tandem mass spectrometry, and 5-HTOL/5-HIAA ratio, by high-performance liquid chromatography. Results: The peak serum ethanol concentrations of the subjects ranged from 5.4 to 44.7 mmol/liter (mean ± SD, 30.1 ± 9.1 mmol/liter). In the case of the serum ethanol determination, 100% sensitivity was reached only immediately after the end of the drinking experiment, and in the case of FAEE levels and 5-HTOL/5-HIAA ratio, it tested for 6.7 hr after the end of the ethanol intake. Thereafter, these latter parameters declined until 15.3 hr (FAEEs) and 29.4 hr (5-HTOL/5-HIAA), subsequently remaining in a stable range until 78.5 hr without further decrease. In contrast, EtG concentration showed 100% sensitivity until 39.3 hr and thereafter decreased, falling to below the limit of quantification of 0.1 mg/liter at 102.5 hr. Conclusion: After moderate drinking, EtG in the urine proved to be a superior marker of recent ethanol consumption in healthy subjects. This is because EtG is a direct ethanol metabolite, it occurs in the urine only when ethanol has been consumed, and its sensitivity remains at the level of 100% for 39.3 hr. [source] In Heavy Drinkers Fatty Acid Ethyl Esters in the Serum Are Increased for 44 hr After Ethanol ConsumptionALCOHOLISM, Issue 7 2004Katrin Borucki Background: Fatty acid ethyl esters (FAEEs) have been proposed as a marker of ethanol consumption because they can be detected for up to 24 hr after a moderate intake of ethanol, even though blood ethanol remains increased for only 8 hr. Therefore, this study investigated whether FAEEs can be found during a time period exceeding 24 hr in a group of patients who were hospitalized for ethanol detoxification. A second aim was to study the distribution of FAEEs between lipoproteins during that time. Methods: Serum samples of 12 patients with acute ethanol intoxication were assayed for FAEEs. Blood samples were drawn 8.2, 20.2, 32.2, and 44.2 hr after hospitalization. FAEEs were quantified by gas chromatography-mass spectrometry. Results: Ethanol was no longer detectable after 20.2 hr from hospitalization, whereas FAEEs were still found after 32.2 and 44.2 hr. These late FAEEs were significantly higher than the FAEEs in 15 different healthy men who had abstained from ethanol for 4.5 days (p < 0.001 and p= 0.001). FAEEs were associated mainly with lipid-free serum but tended to accumulate in very-low-density lipoprotein in patients with moderate hypertriglyceridemia. Conclusions: In heavy drinkers, the FAEEs were increased after ethanol consumption for at least 44 hr. It remains to be studied whether they originate from a single ethanol intake or, in addition, from a slow release out of body storage compartments. [source] Highly Diastereoselective Synthesis of ,-Carboxy-,-lactams and Their Ethyl Esters via Sc(OTf)3 -Catalyzed Imino Mukaiyama-Aldol Type Reaction of 2,5-Bis(trimethylsilyloxy)furan with Imines.CHEMINFORM, Issue 49 2007Manat Pohmakotr Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis of 3-Substituted Ethyl Esters of 6-Aryl-5-cyano-2,4-dioxo-3-azabicyclo[3.1.0]hexane-1-carboxylic Acid, Based on a Modified Reformatsky Reaction.CHEMINFORM, Issue 32 2006V. V. Shchepin Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] A Linchpin Approach to Unsaturated Fatty Acids: 11,12-Epoxyeicosatrienoic Acid and 11S,12S-Dihydroxyeicosatrienoic Acid Ethyl Esters.CHEMINFORM, Issue 52 2005Douglass F. Taber No abstract is available for this article. [source] Synthesis of Selenolo[2,3-b]quinoline-2-carboxylic Ethyl Esters (III): Cytogenetic Studies on Human Peripheral Blood Leucocyte Cultures, and Antibacterial Studies, and Antifungal Studies of Their Effects.CHEMINFORM, Issue 46 2005V. Nithyadevi No abstract is available for this article. [source] An Efficient Synthesis of Dihydro Selenolo (2,3-b)Quinoline-2-carboxylic Ethyl Esters and 2-Selenoxo-1, 2-Dihydro-3-carbethoxy Ethyl Quinolines , Their Antibacterial Studies.CHEMINFORM, Issue 13 2005V. Nithyadevi Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthesis and Antimicrobial Activity of {2-[2-(N,N-Disubstituted thiocarbamoyl-sulfanyl)acylamino]thiazol-4-yl}acetic Acid Ethyl Esters.CHEMINFORM, Issue 28 2003Oeznur Ates No abstract is available for this article. [source] ChemInform Abstract: Synthesis and Biological Data of 4-Amino-1-(2-chloro-2-phenylethyl)-1H-pyrazolo [3,4-b]pyridine-5-carboxylic Acid Ethyl Esters, a New Series of A1 -Adenosine Receptor (A1AR) Ligands.CHEMINFORM, Issue 5 2002Silvia Schenone Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Vinpocetine treatment in acute ischaemic stroke: a pilot single-blind randomized clinical trialEUROPEAN JOURNAL OF NEUROLOGY, Issue 1 2001V. L. Feigin The aim of the study was to assess the safety and feasibility of a clinical trial on the effect of vinpocetine, a synthetic ethyl ester of apovincamine, in acute ischaemic stroke. Thirty consecutive patients with computed tomography verified diagnosis of acute ischaemic stroke, who could receive drug treatment within 72 h of stroke onset, were enrolled. The patients were randomly allocated to receive either low-molecular weight dextran alone or in combination with vinpocetine. Poor outcome was defined as being dead or having a Barthel index of <,70 or a Rankin score of 3,5. Intention-to-treat analysis was applied. One-tenth of all hospitalized patients with acute ischaemic stroke were eligible for the trial. Thirty eligible patients were treated with either low-molecular weight dextran alone (mean age 57.9 ± 11.6 years, n = 15) or in combination with vinpocetine (mean age 60.8 ± 6.6 years, n = 15). The two treatment groups were comparable with respect to major prognostic variables. A relative risk (RR) reduction of poor outcome at 3 months follow-up was 30% (RR = 0.7; 95% confidence interval [CI] 0.1,3.4), as defined by the modified Barthel Index, and 60% as defined by the modified Ranking score (RR = 0.4, 95% CI: 0.1,1.7). The National Institute of Health (NIH,NINDS) Stroke Scale score was marginally significantly better in the vinpocetine treated group at 3 months of follow-up (P = 0.05, anova). No significant adverse effects were seen. This pilot study shows that a full-scale randomized double-blind, placebo-controlled trial of vinpocetine treatment in acute ischaemic stroke is feasible and warranted. [source] The New Metabolite (S)-Cinnamoylphosphoramide from Streptomyces sp. and Its Total SynthesisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 30 2008Melanie Quitschau Abstract The tunicate-associated strain Streptomyces sp. JP90 produces the unprecedented metabolite cinnamoylphosphoramide (1) among several other compounds. Structure elucidation was accomplished by NMR spectroscopic studies and efficient total synthesis. The absolute configuration at phosphorus was determined by synthesis of both enantiomers of 1 performing a resolution of the corresponding diastereomeric phosphoramides of L -phenylalanine ethyl ester. Unusual cinnamic acid derivative 1 represents the first bacterial organophosphoramide. As it matches the Schrader's formula for insecticidal organophosphates, its biological activity was investigated. A weak inhibition of acetylcholinesterase was observed in in vitro tests, and water-soluble analogues of 1 were prepared. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis of meso -Coumarin-Conjugated Porphyrins and Investigation of Their Luminescence PropertiesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 26 2007Weiying Lin Abstract A series of meso -coumarin-conjugated porphyrins 1a,e were designed and synthesized. Condensation of 4-chloroacetoacetate ethyl ester with m -cresol or resorcin afforded 4-chloromethylcoumarins, which were then hydrolyzed to give coumarin alcohols, followed by oxidation to provide coumarin aldehydes. The reaction of coumarin aldehydes with pyrrole under Adler or Lindsey conditions afforded the meso -coumarin-conjugated porphyrins 1a,e. Their UV/Vis absorption spectra and photoluminescent spectra were recorded both in dilute THF solution and as solid films. Analysis of the luminescence spectra indicate that the energy transfer from the coumarin substituents to the porphyrin core for 1a,e is more efficient in solid film than in solution, and the energy transfer from the coumarin substituent to the porphyrin core for 1d and 1e is more efficient than that of 1a, 1b and 1c in solid film. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Enantio- and Diastereomerically Pure Decalins by Deslongchamps-Type Annulation of Dienolates Containing a Chiral Lactone SubstituentEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2007Thomas Tricotet Abstract A conceptionally novel 1,3-asymmetric induction has been established. It controls the relative and absolute configuration of up to 5 stereocenters. They emerge from the anionic Diels,Alder reactions ("Deslongchamps annulations") between oxocyclohexenecarboxylates 25, 29 and dienolates 26, 30. The latter contain a ,-lactone. A Ph3Si,CH2 substituent therein controls the asymmetry of C,C bond formation with ds , 10:1. Strangely, the preferred sense of attack of the dienophile is contrasteric. Cycloadduct 31 was processed by an unprecedented fluoride-induced ambient-temperature tandem fragmentation. It turned the lactone moiety into an allyl group and the ,-oxo (trimethylsilyl)ethyl ester into a ketone. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Effects of the nature and concentration of substrates in aqueous solutions on the solubility of aroma compoundsFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2005Marco Covarrubias-Cervantes Abstract The solubility of nine aroma compounds (acetone, 2-butanone, 2-hexanone, 2-octanone, ethyl acetate, ethyl butanoate, ethyl hexanoate, n -hexanal, and n -hexanol) in both water and various aqueous solutions was measured at 25 °C using the mutual solubility method. The aqueous solutions consisted of sucrose, glucose, sorbitol, glycerol, polyethylene glycol 200, or maltodextrins at different concentrations. Aroma solubility in water decreased with increased hydrophobicity. For aroma molecules which have the same number of carbon atoms in their structure, aqueous solubility decreased as follows: aldehyde > methyl ketone > alcohol > ethyl ester. When using a group contribution method, the estimated solubility of ethyl esters and methyl ketones in water was, respectively, underestimated and overestimated. Compared to water, the solubility of the volatile molecules in aqueous solutions was higher in the aqueous polyols solutions than in the carbohydrate solutions, although solubility decreased as substrate concentration increased. Aqueous solutions properties, such as water activity, also in,uenced aroma compound solubility. Copyright © 2004 John Wiley & Sons, Ltd. [source] Water Stability and Luminescence of Lanthanide Complexes of Tripodal Ligands Derived from 1,4,7-Triazacyclononane: Pyridinecarboxamide versus Pyridinecarboxylate DonorsHELVETICA CHIMICA ACTA, Issue 11 2009Grégory Nocton Abstract A series of europium(III) and terbium(III) complexes of three 1,4,7-triazacyclononane-based pyridine containing ligands were synthesized. The three ligands differ from each other in the substitution of the pyridine pendant arm, namely they have a carboxylic acid, an ethylamide, or an ethyl ester substituent, i.e., these ligands are 6,6,,6,-[1,4,7-triazacyclononane-1,4,7-triyltris(methylene)]tris[pyridine-2-carboxylic acid] (H3tpatcn), -tris[pyridine-2-carboxamide] (tpatcnam), and -tris[pyridine-2-carboxylic acid] triethyl ester (tpatcnes) respectively. The quantum yields of both the europium(III) and terbium(III) emission, upon ligand excitation, were highly dependent upon ligand substitution, with a ca. 50-fold decrease for the carboxamide derivative in comparison to the picolinic acid (=pyridine-2-carboxylic acid) based ligand. Detailed analysis of the radiative rate constants and the energy of the triplet states for the three ligand systems revealed a less efficient energy transfer for the carboxamide-based systems. The stability of the three ligand systems in H2O was investigated. Although hydrolysis of the ethyl ester occurred in H2O for the [Ln(tpatcnes)](OTf)3 complexes, the tripositive [Ln(tpatcnam)](OTf)3 complexes and the neutral [Ln(tpatcn)] complexes showed high stability in H2O which makes them suitable for application in biological media. The [Tb(tpatcn)] complex formed easily in H2O and was thermodynamically stable at physiological pH (pTb 14.9), whereas the [Ln(tpatcnam)](OTf)3 complexes showed a very high kinetic stability in H2O, and once prepared in organic solvents, remained undissociated in H2O. [source] The mechanism of neutral amino acid decomposition in the gas phase.INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 8 2001N -dimethylglycine, N -dimethylglycine ethyl ester, The elimination kinetics of N, ethyl 1-piperidineacetate The gas-phase elimination kinetics of the ethyl ester of two ,-amino acid type of molecules have been determined over the temperature range of 360,430°C and pressure range of 26,86 Torr. The reactions, in a static reaction system, are homogeneous and unimolecular and obey a first-order rate law. The rate coefficients are given by the following equations. For N,N-dimethylglycine ethyl ester: log k1(s,1) = (13.01 ± 3.70) , (202.3 ± 0.3)kJ mol,1 (2.303 RT),1 For ethyl 1-piperidineacetate: log k1(s,1) = (12.91 ± 0.31) , (204.4 ± 0.1)kJ mol,1 (2.303 RT),1 The decompositon of these esters leads to the formation of the corresponding ,-amino acid type of compound and ethylene. However, the amino acid intermediate, under the condition of the experiments, undergoes an extremely rapid decarboxylation process. Attempts to pyrolyze pure N,N-dimethylglycine, which is the intermediate of dimethylglycine ethyl ester pyrolysis, was possible at only two temperatures, 300 and 310°C. The products are trimethylamine and CO2. Assuming log A = 13.0 for a five-centered cyclic transition-state type of mechanism in gas-phase reactions, it gives the following expression: log k1(s,1) = (13.0) , (176.6)kJ mol,1 (2.303 RT),1. The mechanism of these ,-amino acids differs from the decarbonylation elimination of 2-substituted halo, hydroxy, alkoxy, phenoxy, and acetoxy carboxylic acids in the gas phase. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33:465,471, 2001 [source] Injectable and thermosensitive poly(organophosphazene) hydrogels for a 5-fluorouracil deliveryJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009Sun Mi Lee Abstract The drug solubility and its release profiles of an anticancer drug from an injectable thermosensitive poly(organophosphazene) hydrogel bearing hydrophobic L -isoleucine ethyl ester and hydrophilic ,-amino-,-methoxy-poly(ethylene glycol) with and without hydrolysis-sensitive glycyl lactate ethyl ester or functional glycyl glycine have been investigated. 5-Fluorouracil (5-FU) was used as a model anticancer drug. The aqueous solutions of 5-FU incorporated poly(organophosphazenes) were an injectable fluid state at room temperature and formed a transparent gel at body temperature. The poly(organophosphazene) solution could enhance the solubility of 5-FU and its solubility (34.26 mg/mL) was increased up to 10-fold compared to that in phosphate-buffered saline (3.39 mg/mL, pH 7.4, 4°C). The in vitro drug release profiles from poly(organophosphazene) hydrogels were established in phosphate-buffered saline at pH 7.4 at 37°C and the release of 5-FU was significantly affected by the diffusion-controlled stage. The results suggest that the injectable and thermosensitive poly(organophosphazene) hydrogel is a potential carrier for 5-FU to increase its solubility, control a relatively sustained and localized release at target sites and thus decrease systemic side effects. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Analysis of Headspace Volatile and Oxidized Volatile Compounds in DHA-enriched Fish Oil on Accelerated Oxidative StorageJOURNAL OF FOOD SCIENCE, Issue 7 2003H. Lee ABSTRACT: Oxidative stability of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and volatile and oxidized volatile compounds in 2 types of DHA-enriched fish oil, triacylglycerol (TG) and ethyl ester (EE), were studied during storage at 80 °C with aeration. The rate of DHA autoxidation was higher than that of EPA. DHA in EE form was more susceptible to autoxidation than in TG form. Thirty-one volatile compounds were identified in EE and 23 volatile compounds in TG. (E)-2-pentenal, 2-(1-pentenyl) furan, and (E,E)-2,4-heptadienal were commonly detected as oxidized volatile compounds from TG and EE fish oil. These volatile oxidized compounds might be formed mainly from the oxidation of DHA and EPA, the main fatty acids of the oil. [source] Microwave-assisted synthesis of quinolone derivatives and related compoundsJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2010Suhas Pednekar The Gould-Jacob type of reaction for the synthesis of ethyl 5-ethyl-8-oxo-5,8-dihydro-[1,3]-dioxolo[4,5-g]quinoline-7-carboxylate 4 has been carried out conventionally by the condensation between N -ethyl-3,4-methylenedioxyaniline 1 and diethyl ethoxymethylenemalonate 2 gave the unsaturated ester 3 and thermal cyclization in refluxing diphenyl oxide gave quinolone ethyl ester 4 and the results obtained were compared with single step microwave irradiation under solvent free conditions for the synthesis of 4. The esters on basic hydrolysis formed free acid 5, which, upon treatment with thionyl chloride gave the acid chloride 6. Treatment of acid chloride with o -phenylenediamine, hydrazine hydrate, ammonia, urea, and thiourea gave the amides (7,11). CS2 treatment in presence of KOH on 8 gave 12. We prepared 7,12 derivatives by conventional as well as microwave irradiation. These compounds have been characterized on the basis of IR, 1H NMR, MS, and elemental analysis. All the compounds prepared herein were screened for their antibacterial activity. Compounds 4, 5 possess promising antibacterial activity and compound 8 showed significant antibacterial activity. J. Heterocyclic Chem., (2010). [source] Modeling of extraction behavior of docosahexaenoic acid ethyl ester by utilizing slug flow prepared by microreactorAICHE JOURNAL, Issue 8 2010Eiji Kamio Abstract The liquid,liquid extraction dynamics of an ethyl ester of docosahexaenoic acid (DHA-Et) with silver ion was investigated. The kinetic model was derived according to the following stepwise processes: Diffusion of DHA-Et across the organic film, complex-formation between DHA-Et and silver ion at the interface, and diffusion of extracted complex across the aqueous film. The kinetic parameters for the complex-formation reaction were determined from the investigation with the stirred transfer cell. With the proposed model and determined parameters, we predicted the uptakes of DHA-Et for the extraction system utilizing a slug flow prepared by a microchip. The calculated uptakes showed good correlation to the experimental data. The theoretical investigation suggested that the fast equilibration realized for the slug flow extraction system was due to the large specific interfacial area of the slug caused by the presence of wall film and the thin liquid film caused by the internal circulation. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Radiosynthesis of [11C]ximelagatran via palladium catalyzed [11C]cyanationJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 1 2008Anu J. Airaksinen Abstract N -hydroxyamidines (amidoximes) may be used in prodrug technology in improving oral bioavailability of drugs containing amidino functional groups. In the body, amidoximes are reduced quickly to amidines by enzymes that are present in several organs. Ximelagatran is a benzamidoxime and ethyl ester prodrug of melagatran, which is a thrombin inhibitor. Our aim was to develop a fast and efficient labeling route for the synthesis of [11C]ximelagatran ([11C]3) with a label in a metabolically stable position. [11C]3 was synthesized via a two-step synthesis sequence, starting from palladium catalyzed [11C]cyanation of its corresponding bromide precursor (2-[2-(4-bromo-benzylcarbamoyl)-azetidin-1-yl]-1-cyclohexyl-2-oxo-ethyl amino-acetic acid ethyl ester) (1), followed by a reaction with hydroxylamine. [11C]3 was synthesized with 27±17% total overall decay corrected yield (specific radioactivity of 2360±165,Ci/mmol at EOS), with a total synthesis time of 45,min. A fast and efficient labeling route for the synthesis of [11C]3 was developed. Copyright © 2008 John Wiley & Sons, Ltd. [source] Intracellular glutathione mediates the denitrosylation of protein nitrosothiols in the rat spinal cordJOURNAL OF NEUROSCIENCE RESEARCH, Issue 3 2009Jorge M. Romero Abstract Protein S-nitrosothiols (PrSNOs) have been implicated in the pathophysiology of neuroinflammatory and neurodegenerative disorders. Although the metabolically instability of PrSNOs is well known, there is little understanding of the factors involved in the cleavage of S-NO linkage in intact cells. To address this issue, we conducted chase experiments in spinal cord slices incubated with S-nitrosoglutathione (GSNO). The results show that removal of GSNO leads to a rapid disappearance of PrSNOs (t½ , 2 hr), which is greatly accelerated when glutathione (GSH) levels are raised with the permeable analogue GSH ethyl ester. Moreover, PrSNOs are stable in the presence of the GSH depletor diethyl maleate, indicating that GSH is critical for protein denitrosylation. Inhibition of GSH-dependent enzymes (glutathione S-transferase, glutathione peroxidase, and glutaredoxin) and enzymes that could mediate denitrosylation (alcohol dehydrogense-III, thioredoxin and protein disulfide isomerase) do not alter the rate of PrSNO decomposition. These findings and the lack of protein glutathionylation during the chase indicate that most proteins are denitrosylated via rapid transnitrosylation with GSH. The differences in the denitrosylation rate of individual proteins suggest the existence of additional structural factors in this process. This study is relevant to our recent discovery that PrSNOs accumulate in the central nervous system of patients with multiple sclerosis. © 2008 Wiley-Liss, Inc. [source] Nordihydroguaiaretic acid induces astroglial death via glutathione depletionJOURNAL OF NEUROSCIENCE RESEARCH, Issue 14 2007Joo-Young Im Abstract Nordihydroguaiaretic acid (NDGA) is known to cause cell death in certain cell types that is independent of its activity as a lipoxygenase inhibitor; however, the underlying mechanisms are not fully understood. In the present study, we examined the cellular responses of cultured primary astroglia to NDGA treatment. Continuous treatment of primary astroglia with 30 ,M NDGA caused >85% cell death within 24 hr. Cotreatment with the lipoxygenase products 5-HETE, 12-HETE, and 15-HETE did not override the cytotoxic effects of NDGA. In assays employing the mitochondrial membrane potential-sensitive dye JC-1, NDGA was found to induce a rapid and almost complete loss of mitochondrial membrane potential. However, the mitochondrial permeability transition pore inhibitors cyclosporin A and bongkrekic acid did not block NDGA-induced astroglial death. We found that treatment with N-acetyl cysteine (NAC), glutathione (GSH), and GSH ethyl ester (GSH-EE) did inhibit NDGA-induced astroglial death. Consistently, NDGA-induced astroglial death proceeded in parallel with intracellular GSH depletion. Pretreatment with GSH-EE and NAC did not block NDGA-induced mitochondrial membrane potential loss, and there was no evidence that reactive oxygen species (ROS) production was involved in NDGA-induced astroglial death. Together, these results suggest that NDGA-induced astroglial death occurs via a mechanism that involves GSH depletion independent of lipoxygenase activity inhibition and ROS stress. © 2007 Wiley-Liss, Inc. [source] Cadmium-induced astroglial death proceeds via glutathione depletionJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2006Joo-Young Im Abstract Cadmium is a heavy metal that accumulates in the body, and its accumulation in the brain damages both neurons and glial cells. In the current study, we explored the mechanism underlying cadmium toxicity in primary cortical astroglia cultures. Chronic treatment with 10 ,M cadmium was sufficient to cause 90% cell death in 18 hr. However, unlike that observed in neurons, cadmium-induced astroglial toxicity was not attenuated by the antioxidants trolox (100 ,M), caffeic acid (1 mM), and vitamin C (1 mM). In contrast, extracellular 100 ,M glutathione (GSH; ,-Glu-Cys-Gly) or 100 ,M cysteine almost completely blocked cadmium-induced astroglial death, whereas 300 ,M oxidized GSH (GSSG) or 300 ,M cystine, which do not have the free thiol group, were ineffective. In addition, cadmium toxicity was noticeably inhibited or enhanced when intracellular GSH was, respectively, increased by using the cell-permeable glutathione ethyl ester (GSH-EE) or depleted by using buthionine sulfoximine (BSO), an inhibitor of ,-glutamylcysteine synthetase. In agreement with these data, intracellular GSH levels were found to be depressed in cadmium-treated astrocytes. These results suggest that the toxic effect of cadmium on primary astroglial cells involves GSH depletion and, furthermore, that GSH administration can potentially be used to counteract cadmium-induced astroglial cell death therapeutically. © 2005 Wiley-Liss, Inc. [source] ,-glutamylcysteine ethyl ester-induced up-regulation of glutathione protects neurons against A,(1,42)-mediated oxidative stress and neurotoxicity: Implications for Alzheimer's diseaseJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2005Debra Boyd-Kimball Abstract Glutathione (GSH) is an important endogenous antioxidant found in millimolar concentrations in the brain. GSH levels have been shown to decrease with aging. Alzheimer's disease (AD) is a neurodegenerative disorder associated with aging and oxidative stress. A,(1,42) has been shown to induce oxidative stress and has been proposed to play a central role in the oxidative damage detected in AD brain. It has been shown that administration of ,-glutamylcysteine ethyl ester (GCEE) increases cellular levels of GSH, circumventing the regulation of GSH biosynthesis by providing the limiting substrate. In this study, we evaluated the protective role of up-regulation of GSH by GCEE against the oxidative and neurotoxic effects of A,(1,42) in primary neuronal culture. Addition of GCEE to neurons led to an elevated mean cellular GSH level compared with untreated control. Inhibition of ,-glutamylcysteine synthetase by buthionine sulfoximine (BSO) led to a 98% decrease in total cellular GSH compared with control, which was returned to control levels by addition of GCEE. Taken together, these results suggest that GCEE up-regulates cellular GSH levels which, in turn, protects neurons against protein oxidation, loss of mitochondrial function, and DNA fragmentation induced by A,(1,42). These results are consistent with the notion that up-regulation of GSH by GCEE may play a viable protective role in the oxidative and neurotoxicity induced by A,(1,42) in AD brain. © 2005 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||