Amino Esters (amino + ester)

Distribution by Scientific Domains
Distribution within Chemistry


Selected Abstracts


Improved Synthesis of ,-Nitro-,-Amino Ester and Acid Derivatives.

CHEMINFORM, Issue 28 2005
Roberto Ballini
Abstract For Abstract see ChemInform Abstract in Full Text. [source]


Stereoselective Chemoenzymatic Preparation of ,-Amino Esters: Molecular Modelling Considerations in Lipase-Mediated Processes and Application to the Synthesis of (S)-Dapoxetine

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010
María Rodríguez-Mata
Abstract A wide range of optically active 3-amino-3-arylpropanoic acid derivatives have been prepared by means of a stereoselective chemoenzymatic route. The key step is the kinetic resolution of the corresponding ,-amino esters. Although the enzymatic acylations of the amino group with ethyl methoxyacetate showed synthetically useful enantioselectivities, the hydrolyses of the ester group catalyzed by lipase from Pseudomonas cepacia have been identified as the optimal processes concerning both activity and enantioselectivity. The enantiopreference of this lipase in these reactions has been explained, at the molecular level, by using a fragment-based approach in which the most favoured binding site for a phenyl ring and the most stable conformation of the 3-aminopropanoate core nicely match the (S)-configuration of the major products. The conversion and enantioselectivity values of the enzymatic reactions have been compared in order to understand the influence of the different substitution patterns present in the phenyl ring. This chemoenzymatic route has been successfully applied to the preparation of a valuable intermediate in the synthesis of (S)-dapoxetine, which has been chemically synthesised in excellent optical purity. [source]


ChemInform Abstract: Sustainable Synthetic Methods: Domino Construction of Dihydropyridin-4-ones and ,-Amino Esters in Aqueous Ethanol.

CHEMINFORM, Issue 15 2009
Peter J. Alaimo
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: Convenient Synthesis of trans-,-Amino Carboxylic Esters with an Azetidine Skeleton via Rearrangement of ,,,-Aziridino ,-Amino Esters.

CHEMINFORM, Issue 14 2008
Lorand Kiss
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]


A Vaulted Biaryl Phosphoric Acid-Catalyzed Reduction of ,-Imino Esters: The Highly Enantioselective Preparation of ,-Amino Esters.

CHEMINFORM, Issue 37 2007
Guilong 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]


Diastereoselective Reductive Amination of Aryl Trifluoromethyl Ketones and ,-Amino Esters.

CHEMINFORM, Issue 27 2007
Greg Hughes
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]


Nucleophilic Addition of Ethyl 3-Bromodifluoromethyl-3-benzyloxyacrylate to Imines: An Effective Entry to Novel gem-Difluorinated Amino Esters and Their Derivatives.

CHEMINFORM, Issue 24 2006
Weimin Peng
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]


Dynamic Kinetic Resolution of ,-Bromo Carboxylic Acid Derivatives in Asymmetric Nucleophilic Substitution with Chiral ,-Amino Esters.

CHEMINFORM, Issue 47 2005
Ji-yeon Chang
Abstract For Abstract see ChemInform Abstract in Full Text. [source]


Synthesis of the Quinolizidine Alkaloids (-)-Lasubine II (I) and (.+-.)-Myrtine (II) by Conjugate Addition and Intramolecular Acylation of Amino Esters with Acetylenic Sulfones.

CHEMINFORM, Issue 26 2005
Thomas G. Back
No abstract is available for this article. [source]


A New Protocol for the One-Pot Preparation of Highly Diastereomerically Enriched Secondary Amines and ,-Amino Esters Mediated by Lithium Perchlorate Solution in Diethyl Ether.

CHEMINFORM, Issue 15 2003
Mohammad R. Saidi
No abstract is available for this article. [source]


Selective Synthesis of ,-Amino Esters and ,-Lactams by Rhodium-Catalyzed Reformatsky-Type Reaction.

CHEMINFORM, Issue 11 2003
Kazuo Kanai
Abstract For Abstract see ChemInform Abstract in Full Text. [source]


Synthesis of Sugar Azido or Amino Esters and Their Use as Building Blocks for the Preparation of Saccharide Nucleosides.

CHEMINFORM, Issue 2 2003
Juan Xie
No abstract is available for this article. [source]


ChemInform Abstract: Synthesis of Enantiopure N-Protected 4,5-Disubstituted 3-Pyrrolidinones and N-Protected 2,5-Disubstituted 3-Pyrrolidinones via the Dieckmann Reaction of Dicarbonyl Compounds Derived from Enantiopure ,-Amino Esters.

CHEMINFORM, Issue 35 2001
Yue Wang
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]


Byproduct-Catalyzed Four-Component Reactions of Aldehydes with Hexamethyldisilazane, Chloroformates, and Nucleophiles in Acetonitrile Leading to Protected Primary Amines, ,-Amino Esters, and ,-Amino Ketones

CHEMISTRY - A EUROPEAN JOURNAL, Issue 2 2010
Bai-Ling Yang
Abstract Multicomponent reactions are a very powerful tool for the construction of complex organic molecules by using readily available starting materials. While most of the multicomponent reactions discovered so far consist of three components, the reactions with four or more components remain sparse. We have successfully developed several four-component reactions using a catalytic amount of water as a hydrolyzing agent to decompose byproduct chlorotrimethylsilane (TMSCl) to yield secondary byproduct HCl that serves as a catalyst. In the presence of 40,mol,% of water, the four-component reaction of aldehydes with hexamethyldisilazane (HMDS), chloroformates, and silylated nucleophiles proceeds smoothly at room temperature to give a range of protected primary amines in moderate to excellent yields. Importantly, a wide variety of protic carbon nucleophiles, such as ,-keto esters, ,-diketones, and ketones, have further been explored as suitable substrates for the synthesis of protected ,-amino esters and ,-amino ketones that are useful building blocks for various pharmaceuticals and natural products. These four-component reactions proceed through a pathway of tandem nitrogen protection/imine formation/imine addition, and the decomposition of byproduct TMSCl, generated in the first step of nitrogen protection, with water results in the formation of secondary byproduct HCl, a strong Brønsted acid that catalyzes the following imine formation/imine addition. Taking advantage of the fact that alcohols or phenols are also able to decompose byproduct TMSCl to yield secondary byproduct HCl, no catalyst is needed at all for the four-component reactions with aldehydes bearing hydroxy groups. [source]


Double Cyclization of Bis(,-hetarylmethyl)amino Esters to Optically Active Bridged N-Heterocycles of HIV-Inhibiting Activity

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2004
Heike Faltz
Abstract Anellated 1-azabicyclo[3.3.1]nonanes 6 were synthesized by several routes starting from natural ,-amino esters 2 and o -haloaryl- or o -bromohetarylmethyl bromides 1. N -Alkylation of the starting amino esters to 5 and 3 was followed by halogen/lithium exchange and double cyclization. The cyclization products 6 exhibit interesting inhibition of RNase H and DNA-polymerase activity of reverse transcriptase (RT) of HIV-1 at concentrations where human cellular DNA polymerases are not affected. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


ChemInform Abstract: Asymmetric Synthesis of ,-Substituted ,-Methyl-,-amino Esters by Mannich Reaction of (S,S)-(+)-Pseudoephedrine Acetamide Derived Enolate with Imines.

CHEMINFORM, Issue 27 2001
Jose L. Vicario
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]


A Concise Route to Racemic Anatoxin a from Cycloocta-1,5-diene

HELVETICA CHIMICA ACTA, Issue 1 2006
Tse-Lok Ho
Abstract The synthesis of racemic anatoxin a (1a) from cycloocta-1,5-diene via its 1,:,1 cycloadduct with N -chlorosulfonyl isocyanate is described. The N -unsubstituted , -lactam 2b was converted to a , -amino ester 3 which was then submitted to a Pd-catalyzed cyclization to afford the conjugated ester 4a. The N -tosyl derivative 4b was then elaborated into N -tosylanatoxin a (1b) via a Weinreb amide. [source]


Synthesis of N -Acetylglucosamine-Derived Nagstatin Analogues and Their Evaluation as Glycosidase Inhibitors

HELVETICA CHIMICA ACTA, Issue 1 2005
Miroslav Terinek
The gluco -configured analogue 15 of nagstatin (1) and the methyl ester 14 were synthesized via condensation of the thionolactams 17 or 18 with the , -amino ester 19. The silyl ethers 20 and 21 resulting from 17 were desilylated to 22 and 23; these alcohols were directly obtained by condensing 18 and 19. The attempted substitution of the C(8)OH group of 22 by azide under Mitsunobu conditions led unexpectedly to the deoxygenated , -azido esters 24. The desired azide 25 was obtained by treating the manno -configured alcohol 23 with diphenyl phosphorazidate. The azide was transformed to the debenzylated acetamido ester 14 that was hydrolyzed to the nagstatin analogue 15. The imidazole-2-acetates 14 and 15 are nanomolar inhibitors of the N -acetyl- , -glucosaminidases from Jack beans and from bovine kidney, submicromolar to micromolar inhibitors of the , -glucosidase from Caldocellum saccharolyticum, and rather weak inhibitors of the snail , -mannosidase. In all cases, the ester was a stronger inhibitor than the corresponding acid. As expected from their gluco -configuration, both imidazopyridines 14 and 15 are stronger inhibitors of the , - N -acetylglucosaminidase from bovine kidney than nagstatin. [source]


Combinatorial Modification of Degradable Polymers Enables Transfection of Human Cells Comparable to Adenovirus,

ADVANCED MATERIALS, Issue 19 2007
J. Green
End-modified poly(,-amino ester)s, easy-to-synthesize degradable polymers, are able to deliver DNA to primary human cells at levels comparable to adenovirus and two orders of magnitude better than the commonly used non-viral vector, polyethylenimine. Small structural changes are found to affect multiple steps of gene delivery including the DNA binding affinity, nanoparticle size, intracellular DNA uptake, and final protein expression. In vivo, these polymer modifications enhance DNA delivery to ovarian tumors. [source]


In vitro degradability and stability of hydrophobically modified pH-sensitive micelles using MPEG-grafted poly(,-amino ester) for efficient encapsulation of paclitaxel

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
Min Sang Kim
Abstract Methoxypoly(ethylene glycol)-grafted poly(,-amino ester) was synthesized for the fabrication of pH-sensitive micelles, and these micelles were modified with deoxycholic acid to facilitate the hydrophobic interaction between the micellar core and paclitaxel. The micelle properties were studied by dynamic light scattering and fluorescence spectrometry. An in vitro degradation study showed that the synthesized polymers degraded hydrolytically within 24 h under physiological conditions. The stability of paclitaxel-loaded pH-sensitive micelles was evaluated in vitro. The introduced deoxycholic acid more stabilized the micelles at pH 7.4 compared to the micelles without modification. But the pH-sensitive region of the micelles was lowered from pH 6.8 to pH 5.8. These results indicate that pH-sensitive micelles with improved stability have great potential as hydrophobic drug carriers for tumor targeting. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]


Copolymerization of amino acid and amino ester functionalized norbornenes via living ring-opening metathesis polymerization

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2008
Stefano C. G. Biagini
Abstract The block and random copolymerization of a series of amino acid and amino ester functionalized norbornenes by ring-opening metathesis polymerization (ROMP) induced by the well-defined molybdenum [Mo(N -2,6- iPrC6H3)(CHCMe2)Ph)(OCMe3)2] or ruthenium [Ru(PCy)2Cl2(CHPh)] based initiators is described. The monomers are derived from the amino acids glycine, alanine, and isoleucine or the methyl esters of these amino acids and either endo- or exo- norborn-5-ene-2,3-dicarboxylic anhydride. Enantiomerically pure monomers afforded optically active polymers, and the mechanism and kinetics of the copolymerizations are investigated. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7985,7995, 2008 [source]


Lewis Base Catalyzed Mannich-Type Reactions between Trimethylsilyl Enol Ethers and Aldimines

CHEMISTRY - A EUROPEAN JOURNAL, Issue 19 2006
Hidehiko Fujisawa
Abstract Lewis base catalyzed Mannich-type reaction between trimethylsilyl enol ethers and N -tosylaldimines is described. Nitrogen anions generated from amides or imides such as lithium benzamide or potassium phthalimide are found to be effective Lewis base catalysts in DMF at room temperature to afford the corresponding ,-amino carbonyl compounds in good to high yields; the oxygen anion generated from carboxylic acids such as lithium acetate was also found to be effective in dry DMF. The above-mentioned lithium acetate-catalyzed Mannich-type reaction between aldimines and various trimethylsilyl (TMS) enol ethers such as silyl ketene acetal proceeded smoothly even in water-containing DMF. Then, Lewis base catalyzed three-component Mannich-type reactions of TMS enol ether, tosylamide, and aromatic aldehyde having electron-withdrawing group such as p -nitrobenzaldehyde were investigated. The reaction proceeded smoothly to afford the corresponding ,-amino ester in good yield. Further, ammonium carboxylates such as tetrabutyl ammonium acetate or tetrabutyl ammonium benzoate were found to be more effective Lewis base catalysts in the above-mentioned Mannich-type reaction. The synthesis proceeded in various solvents at lower temperatures. The reaction between aldimines and TMS enol ethers generated from thioester and various ketones such as propiophenone or cyclohexanone also proceeded smoothly to afford the corresponding ,-amino carbonyl compounds in high yields with good to high anti -selectivities. [source]


Addition of Azomethine Ylides to Aldehydes: Mechanistic Dichotomy of Differentially Substituted ,-Imino Esters

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2010
Brinton Seashore-Ludlow
Abstract The formal 1,3-dipolar cycloaddition of azomethine ylides and aldehydes is explored, as hydrolysis of the resulting oxazolidine product gives facile access to valuable syn -,-aryl-,-hydroxy-,-amino esters. The use of using benzaldehyde-derived imines as the ylide precursor results in 1,3-dipolar cycloaddition with high conversions but low diastereoselectivity. In contrast, the employment of benzophenone-derived imines as the ylide precursor results in an aldol reaction, which gives the intermediate oxazolidine in high diastereoselectivity and requires a weak acid catalyst to achieve higher conversions. [source]


One-Pot Synthesis of 3-Aryltetramic Acids

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2010
Aurélie Mallinger
Abstract Tetramic acids substituted in the 3-position by various aryl groups were prepared in one-pot from amino esters and methyl arylacetates, by treatment with potassium tert -butoxide. A tandem process, involving the formation of an amide and a condensation reaction, is likely to occur. N -Unsubstituted tetramic acids were obtained from adducts containing a N -(2,4-dimethoxybenzyl) group. [source]


A Microwave-Assisted Heck Reaction in Poly(ethylene glycol) for the Synthesis of Benzazepines

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 1 2007
Valérie Declerck
Abstract The Heck reaction of alkylated 2-(trimethylsilyl)ethanesulfonyl (SES)-protected ,-amino esters provides benzazepines in good yields. Good selectivity towards cyclisation was obtained when the reaction was performed in PEG 3400 as the solvent under microwave activation. Cleavage of the SES group with HF provides the corresponding free benzazepine. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]


Double Cyclization of Bis(,-hetarylmethyl)amino Esters to Optically Active Bridged N-Heterocycles of HIV-Inhibiting Activity

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2004
Heike Faltz
Abstract Anellated 1-azabicyclo[3.3.1]nonanes 6 were synthesized by several routes starting from natural ,-amino esters 2 and o -haloaryl- or o -bromohetarylmethyl bromides 1. N -Alkylation of the starting amino esters to 5 and 3 was followed by halogen/lithium exchange and double cyclization. The cyclization products 6 exhibit interesting inhibition of RNase H and DNA-polymerase activity of reverse transcriptase (RT) of HIV-1 at concentrations where human cellular DNA polymerases are not affected. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


Enantioselective Organocatalytic Transfer Hydrogenation of ,-Imino Esters by Utilization of Benzothiazoline as Highly Efficient Reducing Agent

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010
Chen Zhu
Abstract Benzothiazoline was employed as an efficient and versatile reducing agent for the chiral phosphoric acid-catalyzed transfer hydrogenation of ,-imino esters. The corresponding ,-amino esters were furnished with excellent enantioselectivities. Novel and readily removable benzothiazolines bearing a hydroxy group were also investigated. [source]


Stereoselective Chemoenzymatic Preparation of ,-Amino Esters: Molecular Modelling Considerations in Lipase-Mediated Processes and Application to the Synthesis of (S)-Dapoxetine

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010
María Rodríguez-Mata
Abstract A wide range of optically active 3-amino-3-arylpropanoic acid derivatives have been prepared by means of a stereoselective chemoenzymatic route. The key step is the kinetic resolution of the corresponding ,-amino esters. Although the enzymatic acylations of the amino group with ethyl methoxyacetate showed synthetically useful enantioselectivities, the hydrolyses of the ester group catalyzed by lipase from Pseudomonas cepacia have been identified as the optimal processes concerning both activity and enantioselectivity. The enantiopreference of this lipase in these reactions has been explained, at the molecular level, by using a fragment-based approach in which the most favoured binding site for a phenyl ring and the most stable conformation of the 3-aminopropanoate core nicely match the (S)-configuration of the major products. The conversion and enantioselectivity values of the enzymatic reactions have been compared in order to understand the influence of the different substitution patterns present in the phenyl ring. This chemoenzymatic route has been successfully applied to the preparation of a valuable intermediate in the synthesis of (S)-dapoxetine, which has been chemically synthesised in excellent optical purity. [source]


Copper(I)-Catalyzed Asymmetric Addition of Terminal Alkynes to ,-Imino Esters: An Efficient and Direct Method in the Synthesis of Chiral ,3 -Alkynyl ,2,2 -Dimethyl Amino Acid Derivatives

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009
Jun Wang
Abstract The first catalytic asymmetric addition of terminal alkynes to ,-imino esters was carried out using chiral copper(I) complexes as catalysts under mild reaction conditions, providing an efficient and direct synthetic approach to ,3 -alkynyl ,2,2 -dimethyl amino esters with yields of 73,97% and 48,90% ee. The rich chemistry of the alkynyl functionality makes the present method a powerful and versatile approach to a wide range of optically active ,2,2 -dimethyl amino acid derivatives. [source]


Highly Enantioselective Transfer Hydrogenation of ,-Imino Esters by a Phosphoric Acid

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2007
Qiang Kang
Abstract Chiral phosphoric acids have been identified as highly efficient organocatalysts for the asymmetric transfer hydrogenation of ,-imino esters and amide. Utilizing Hantzsch esters as the hydrogen donor, versatile highly enantioenriched ,-amino esters and their derivatives were obtained with up to 98,% ee. [source]