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Carbamates
Kinds of Carbamates Terms modified by Carbamates Selected AbstractsSuppressing the Anionic Fries Rearrangement of Aryl Dialkylcarbamates; the Isolation of a Crystalline ortho -Deprotonated CarbamateEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2008Felipe García Abstract In the presence of organolithium bases phenyl dialkylcarbamates have previously been shown to undergo facile rearrangement to yield the corresponding salicylamides. However, heterometallic lithium diethyl(2,2,6,6-tetramethylpiperidido)zincate achieves the clean directed ortho -metallation (DoM) of phenyl dialkylcarbamates, with [C6H4{OC(O)NMe2}{Zn(-TMP)Et}Li]2 having been structurally characterized. DFT studies point to a stepwise deprotonative mechanism in which the zincate reagent exhibits kinetic amido basicity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Gold-Catalyzed Phosgene-Free Synthesis of Polyurethane Precursors,ANGEWANDTE CHEMIE, Issue 7 2010Raquel Juárez Gold statt Phosgen: Ein zweistufiger Eintopfprozess an Goldnanopartikeln auf CeO2 als Katalysator wandelt Nitroarene in aromatische Carbamate um. Das Verfahren stellt eine phosgenfreie Alternative für die Synthese aromatischer Polyurethane dar. [source] ChemInform Abstract: Asymmetric Synthesis of cis-1,3-Dialkenyl-Substituted Cyclopentanes via (-)-Sparteine-Mediated Lithiation and Cycloalkylation of a 9-Chloro-2,7-nonadienyl Carbamate.CHEMINFORM, Issue 36 2001Alexander Deiters 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] Benzene-di- N -substituted carbamates as conformationally constrained analogs of Pseudomonas lipase substratesEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 11 2007Ming-Cheng Lin Abstract Benzene-1,2-, -1,3-, and -1,4-di- N -substituted carbamates (1,15) are synthesized as the constrained analogs of gauche, eclipsed, and anti conformations of diesters of ethylene glycol, respectively. Carbamates 1,15 are characterized as the pseudo-substrate inhibitors of Pseudomonas species lipase. Long-chain carbamates are more potent inhibitors than short-chain ones. Different geometries of benzene-di-substituted carbamates, such as benzene-1,2-di- N -octylcarbamate (3) (ortho compound), benzene-1,3-di- N -octylcarbamate (8) (meta compound), and benzene-1,4-di- N -octylcarbamate (13) (para compound), show similar inhibitory potencies for the enzyme. In other words, kinetic data suggest that the enzyme does not discriminate ortho, meta, and para geometries of these constrained analogs. [source] Hydrosilanes Are Not Always Reducing Agents for Carbonyl Compounds, II: Ruthenium-Catalyzed Deprotection of tert -Butyl Groups in Carbamates, Carbonates, Esters, and EthersEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2010Shiori Hanada Abstract Hydrosilanes act as a reagent to cleave the C,O bond of OtBu groups in carbamates, carbonates, esters, and ethers by catalysis of a triruthenium cluster. The reaction offers a novel deprotection method for OtBu groups under neutral conditions, showing unique selectivities that have never been accomplished with conventional Brønsted or Lewis acidic promoters. Possible mechanisms for C,O cleavage are discussed on the basis of NMR spectroscopic analysis. [source] Cyclic Allyl Carbamates in Stereoselective syn SE, Processes: Synthetic Approach to Sarcodictyins and EleutherobinEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 31 2007Sylvie Dhulut Abstract Our synthetic approach of marine diterpenoids sarcodictyins A and B and eleutherobin relies on the one-step attachment of a C5,C9 side chain at the C10 position. The C1,C10 cis -disubstituted cyclohexene derivative is obtained in 86,% yield with total stereoselectivity. The reaction is based on a syn SE, process involving a cyclic (Z)-allyl diisopropylcarbamate. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Substrate activation of butyrylcholinesterase and substrate inhibition of acetylcholinesterase by 3,3-dimethylbutyl- N - n -butylcarbamate and 2-trimethylsilyl-ethyl- N - n -butylcarbamateJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 1 2007Shyh-Ying Chiou Abstract Carbamates are used to treat Alzheimer's disease. These compounds inhibit acetylcholinesterase and butyrylcholinesterase. The goal of this work is to use the substrate analogs of butyrylcholinesterase, 3,3-dimethylbutyl- N - n -butylcarbamate (1) and 2-trimethylsilyl-ethyl- N - n -butylcarbamate (2) to probe the substrate activation mechanism of butyrylcholinesterase. Compounds 1 and 2 are characterized as the pseudo substrate inhibitors of acetylcholinesterase; however, compounds 1 and 2 are characterized as the essential activators of butyrylcholinesterase. Therefore, compounds 1 and 2 mimic the substrate in the acetylcholinesterase-catalyzed reactions, but the behavior of compounds 1 and 2 mimics the substrate activation in the butyrylcholinesterase-catalyzed reactions. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:24,31, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20158 [source] Development of a Simple and Low-Cost Enzymatic Methodology for Quantitative Analysis of Carbamates in Meat Samples of Forensic InterestJOURNAL OF FORENSIC SCIENCES, Issue 3 2010Bruno Duarte Sabino Ph.D. Abstract:, Foods contaminated with a granulated material similar to Temik (a commercial pesticide formulation containing the carbamate insecticide aldicarb) are often involved in accidental ingestion, suicides, and homicides in Brazil. We developed a simple technique to detect aldicarb. This technique is based on the inhibition of a stable preparation of the enzyme acetylcholinesterase, and it is specially adapted for forensic purposes. It comprises an initial extraction step with the solvent methylene chloride followed by a colorimetric acetylcholinesterase assay. We propose that results of testing contaminated forensic samples be expressed in aldicarb equivalents because, even though all other carbamates are also potent enzyme inhibitors, aldicarb is the contaminant most frequently found in forensic samples. This method is rapid (several samples can be run in a period of 2 h) and low cost. This method also proved to be precise and accurate, detecting concentrations as low as 40 ,g/kg of aldicarb in meat samples. [source] Ortho Effects in Quantitative Structure Activity Relationships for Lipase Inhibition by Aryl CarbamatesMOLECULAR INFORMATICS, Issue 8 2003Gialih Lin Abstract Ortho -substituted phenyl- N -butyl carbamates (1,11) are synthesized and evaluated for their inhibition effects on Pseudomonas species lipase. Carbamates 1,11 are characterized as pseudo-substrate inhibitors of the enzyme. The logarithms of dissociation constant (Ki), carbamylation constant (k2), and bimolecular inhibition constant (ki) multiply linearly correlate with Hammett substituent constant (,), Taft-Kutter-Hansch ortho steric constant (ES), and Swan-Lupton field constant (F). For ,logKi -, logk2 -, and logki -correlations, values of ,, ,, f, ,XR are 0.2, ,0.06, ,1.7, 0.8; 0.0, 0.0, 1.0, ,0.07; and ,1.8, 7, 0.6, 5; respectively. The enzyme inhibition mechanism is composed of four steps: 1) the first step which is protonation of carbamates 1,11, 2) the second step (Ki1) which involves in the proton 1,3-shift of protonated carbamates 1,11 then the pseudo- trans to cis conformational change, 3) the third step (Ki2) which is formation of a negative charged enzyme-inhibitor tetrahedral intermediate, and 4) the fourth step (k2) which is the carbamylation step. The former three steps are likely composed of the Ki step. There is little ortho steric enhancement effect in the Ki step. From cross-interaction correlations, distance between carbamate and phenyl substituents in transition state for the Ki step is relatively short due to a large ,XR value of 7. The k2 step is insensitive to ortho steric effect. The k2 step involves in departure of leaving group, substituted phenol in which is protonated from the proton 1,3-shift but not from the active site histidine of the enzyme. From cross-interaction correlations, the distance between carbamate and phenyl substituents in transition state for the k2 step is relatively long due to a small ,XR value of 0.6. [source] Asymmetric Synthesis of Allylsilanes by the Borylation of Lithiated Carbamates: Formal Total Synthesis of (,)-Decarestrictine,D,ANGEWANDTE CHEMIE, Issue 25 2010Michael Binanzer Dipl.-Chem. Enantiokomplementäre Routen zu ,-Hydroxyallylsilanen stehen durch die Reaktion von lithiierten Carbamaten mit ,-Silylvinylboranen offen. Nach der Komplexierung mit (,)-Spartein reagieren die lithiierten Carbamate unter Inversion der Konfiguration, ohne das Diamin dagegen unter Retention (siehe Schema). Diese Methode wurde in einer kurzen formalen Totalsynthese von (,)-Decarestrictin,D angewendet. [source] ChemInform Abstract: Efficient Synthesis of ,-Oxoalkyl Carbamates from Carbon Dioxide, Internal Propargylic Alcohols, and Secondary Amines Catalyzed by Silver Salts and DBU.CHEMINFORM, Issue 35 2010Chaorong Qi Abstract The cooperation between AgOAc and DBU is a key factor in activating the transformation. [source] ChemInform Abstract: Nickel-Catalyzed Efficient and Practical Suzuki,Miyaura Coupling of Alkenyl and Aryl Carbamates with Aryl Boroxines.CHEMINFORM, Issue 27 2010Li Xu 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] ChemInform Abstract: Gold(I)-Catalyzed Tandem Reactions Initiated by Hydroamination of Alkynyl Carbamates: Application to the Synthesis of Nitidine.CHEMINFORM, Issue 17 2010Taro Enomoto 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] ChemInform Abstract: A Non-Acyl Azide Route to Isoquinolin-1(2H)-one Derivatives via ,-Styril Carbamates.CHEMINFORM, Issue 15 2010Chien-Chang Chen 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] ChemInform Abstract: Reduction of 1-Pyrrolyl and 1-Indolyl Carbamates to Hemiaminals.CHEMINFORM, Issue 14 2010He-Chu Hsu 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] ChemInform Abstract: Amidation Through Carbamates.CHEMINFORM, Issue 36 2009Antonio Latorre 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: N-Alkylation of Carbamates and Amides with Alcohols Catalyzed by a Cp*Ir Complex.CHEMINFORM, Issue 34 2009Ken-ichi Fujita 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Microwave-Assisted Synthesis of Novel (5-Nitropyridin-2-yl)alkyl and (5-Nitropyridin-3-yl)alkyl Carbamates.CHEMINFORM, Issue 30 2009Christophe Henry 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Facile One-Pot Synthesis of 3-Unsubstituted-2,4-oxazolidinediones via in situ Generation of Carbamates from ,-Hydroxyesters Using Trichloroacetyl Isocyanate.CHEMINFORM, Issue 22 2009Yue H. Li 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Complementary Reactions of Allylic Carbamates Using Palladium(II): Formation of Oxazolidinones or Allylic Amides from a Common Precursor.CHEMINFORM, Issue 18 2009Steven D. R. Christie 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: An Efficient Synthesis of Vinylogous Carbamates from Alkyl Azides.CHEMINFORM, Issue 12 2008Akundi Surya Prabhakar 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Syntheses and Anticholinesterase Activities of Novel 3-Aminocarbonylmethylene-3-methyl-2,3-dihydrobenzofuran-5-yl Carbamates.CHEMINFORM, Issue 11 2008Weiming Luo 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Gold(I)-Catalyzed Enantioselective Hydroamination of N-Allenyl Carbamates.CHEMINFORM, Issue 47 2007Zhibin Zhang 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] Electrochemically Promoted C,N Bond Formation from Amines and CO2 in Ionic Liquid BMIm,BF4: Synthesis of Carbamates.CHEMINFORM, Issue 19 2007M. Feroci 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] Bismuth-Catalyzed Direct Substitution of the Hydroxy Group in Alcohols with Sulfonamides, Carbamates, and Carboxamides.CHEMINFORM, Issue 17 2007Hongbo Qin 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] Bismuth- and Hafnium-Catalyzed Hydroamination of Vinyl Arenes with Sulfonamides, Carbamates, and Carboxamides.CHEMINFORM, Issue 17 2007Hongbo Qin 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] Aqueous Phosphoric Acid as a Mild Reagent for Deprotection of tert-Butyl Carbamates, Esters, and Ethers.CHEMINFORM, Issue 12 2007Bryan Li 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] Palladium-Catalyzed Silane/Siloxane Reductions in the One-Pot Conversion of Nitro Compounds into Their Amines, Hydroxylamines, Amides, Sulfonamides, and Carbamates.CHEMINFORM, Issue 5 2007Ronald J. Jr Rahaim 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] Palladium-Catalyzed Silane/Siloxane Reductions in the One-Pot Conversion of Nitro Compounds into Their Amines, Hydroxylamines, Amides, Sulfonamides, and Carbamates.CHEMINFORM, Issue 5 2007Ronald J. Jr. Rahaim 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] One-Pot Transformation of Trichloroacetamide into Readily Deprotectable Carbamates.CHEMINFORM, Issue 46 2006Toshio Nishikawa 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] | ||||||||||||||||||||||||||||||||||||||||