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Synthetic Potential (synthetic + potential)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Towards a Large-Scale Asymmetric Reduction Process with Isolated Enzymes: Expression of an (S)-Alcohol Dehydrogenase in E.,coli and Studies on the Synthetic Potential of this Biocatalyst

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2003
Werner Hummel
No abstract is available for this article. [source]

ChemInform Abstract: Gold-Catalyzed [4C + 3C] Intramolecular Cycloaddition of Allenedienes: Synthetic Potential and Mechanistic Implications.

CHEMINFORM, Issue 29 2009
Beatriz Trillo
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]

Synthetic Potentials of Heptamethine Merocyanine Dyes Containing an Active Chlorine Atom: Reactivity towards Nucleophiles

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2009
Tzveta Gospodova
Abstract The reactivity of heptamethine merocyanine dyes that contain an active chlorine atom at a meso position of the polymethine chain towards nucleophiles is investigated for the first time. The reactivity differs completely from that of cationic cyanine dyes and is consistent with a concerted SNAr addition,elimination mechanism. This mechanism is additionally supported by the performed DFT calculations in the gas phase and in solution. The observed dependence of the reaction on the type of the nucleophilic agents is discussed in terms of Pearson's theory. Additional diversification of and improvement in the stability of the ramified merocyanines is achieved in reactions with methyl-substituted quaternary salts of nitrogen-containing heterocycles. The photophysical characteristics of the novel dyes are reported and compared with those of the parent merocyanine.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Ruthenium-Catalyzed Allenyl Carbamate Formation from Propargyl Alcohols and Isocyanates

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2008
Edgar Haak
Abstract Ruthenium complexes of redox-coupled cyclopentadienone ligands catalyze the formation of allenyl carbamates from propargyl alcohols and isocyanates. This efficient and atom-economical process represents the first catalytic access to allenyl carbamates, compounds of high synthetic potential. The reaction needs an acidic co-catalyst and can be performed at room temperature. In addition, new (cyclopentadienone)iron and -ruthenium complexes were synthesized, and mechanistic aspects regarding catalytic transformations of propargyl systems with ruthenium catalysts are obtained. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Copper(II) Bromide/Boron Trifluoride Etherate-Cocatalyzed Cyclization of Ketene Dithioacetals and p -Quinones: a Mild and General Approach to Polyfunctionalized Benzofurans

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010
Yingjie Liu
Abstract A new application of copper(II) bromide-activated ketene dithioacetals as nucleophiles in organic chemistry has been developed. Under the cocatalysis of copper(II) bromide (2.0,mol%) and boron trifluoride etherate (10,mol%), the conjugate addition and sequential cyclization of ,-electron-withdrawing group-substituted ketene dithioacetals with p -quinones in acetonitrile at room temperature gave a variety of benzofurans. This formal [3+2],cycloaddition provides a general method for catalytic synthesis of polyfunctionalized benzofurans with the advantages of readily available starting materials, cheap catalysts, mild reaction conditions, good yields and wide range of synthetic potential for the benzofuran products. Further transformations of the resulting benzofurans to 2-aminobenzofurans and benzofuro[2,3- d]pyrimidine derivatives are also investigated. [source]

An enigmatic peptide ligation reaction: Protease-catalyzed oligomerization of a native protein segment in neat aqueous solution

PROTEIN SCIENCE, Issue 4 2000
Sangaralingam Kumaran
Abstract We report an enigmatic peptide ligation reaction catalyzed by Glu-specific Staphylococcus aureus V8 protease that occurs in neat aqueous solution around neutral pH utilizing a totally unprotected peptide substrate containing free ,-carboxyl and ,-amino groups. V8 protease catalyzed a chain of ligation steps between pH 6 and 8 at 4 °C, producing a gamut of covalent oligomers (dimer through octamer or higher) of a native protein segment TAAAKFE (S39) derived from ribonuclease A (RNAse A). Size-exclusion chromatography suggested the absence of strong interaction between the reacting peptides. The circular dichroism spectra of monomer through pentamer showed length-dependent enhancement of secondary structure in the oligomers, suggesting that protease-catalyzed ligation of a monomer to an oligomer resulted in a product that was more structured than its precursor. The relative conformational stability of the oligomers was reflected in their ability to resist proteolysis, indicating that the oligomerization reaction was facilitated as a consequence of the "conformational trapping" of the product. The ligation reaction proceeded in two phases,slow formation and accumulation of the dimer followed by a fast phase of oligomerization, implying that the conformational trap encountered in the oligomerization reaction was a two-step process. The Gly substitution at any position of the TAAAKFE sequence was deleterious, suggesting that the first step of the conformational trap, namely the dimerization reaction, that proceeded very slowly even with the parent peptide, was quite sensitive to amino acid sequence. In contrast, the oligomerization reaction of an Ala analog, AAAAKFE, occurred in much the same way as S39, albeit with faster rate, suggesting that Ala substitution stabilized the overall conformational trapping process. The results suggest the viability of the product-directed "conformational trap" as a mechanism to achieve peptide ligation of totally unprotected peptide fragments in neat aqueous solution. Further, the study projects the presence of considerable innate synthetic potential in V8 protease, baring rich possibilities of protein engineering of this enzyme to generate a "V8 peptide ligase." [source]

Perrhenate Esters in New Catalytic Reactions

CHEMCATCHEM, Issue 3 2009
Stéphane Bellemin-Laponnaz
Abstract There has been tremendous interest in the use of alkyltrioxorhenium complexes as catalysts for various organic transformations. Although such applications are now well known and, indeed, have been widely studied, other organorhenium oxide families, namely the perrhenate esters O3ReOR, have received much less attention. In this review, such ReVII species are shown to be very promising catalysts and several recent examples are presented, with the aim of shedding light on their synthetic potential as a new tool for organic chemists. [source]