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Diaryl Ketones (diaryl + ketone)

Distribution by Scientific Domains
Chemistry66%

Selected Abstracts

Enantioselective Reduction of Diaryl Ketones Catalyzed by a Carbonyl Reductase from Sporobolomyces salmonicolor and its Mutant Enzymes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009
Hongmei Li
Abstract The carbonyl reductase from red yeast Sporobolomyces salmonicolor AKU4429 (SSCR) and its mutant enzymes effectively catalyzed the enantioselective reduction of diaryl ketones to give the corresponding chiral alcohols. Both conversion and enantioselectivity were dependent on the co-solvent in the reaction medium. Diaryl ketones with a para -substituent on one of the phenyl groups were reduced with high enantioselectivity (up to 99% ee), which is difficult to achieve using chemical methods such as chiral borane reduction, asymmetric hydrogenation or hydrosilylation. Mutation of SSCR at Q245 resulted in a higher amount of (S)-enantiomer in the products, and in the case of mutant Q245P with para -substituted diaryl ketones as substrate, this effect was so remarkable that the reduction enantiopreference was switched from (R) to (S). The present study provides valuable information about the catalytic properties of the carbonyl reductase SSCR toward the reduction of diaryl ketones, serving as basis for further engineering of this enzyme to develop efficient biocatalysts for highly enantiospecific reduction of diaryl ketones without high electronic dissymmetry or an ortho -substituent on one of the aryl groups. [source]

Synthesis and Cyclohexene Oxide/Carbon Dioxide Copolymerizations of Zinc Acetate Complexes Bearing Bidentate Pyridine-Alkoxide Ligands

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 8 2004
Il Kim
Abstract Summary: The reaction of 2-lithio-6-methylpyridine or 2-lithiopyridine and the appropriate diaryl ketone followed by hydrolysis yields 6-Me-pyCAr2OH pyridine alcohols or pyCAr2OH pyridine alcohols. The reactions of zinc acetate with 1 equiv. of the lithiated products of the ligands proceed rapidly to afford LiOAc salt and mono-ligand complexes (6-Me-pyCAr2O)Zn(OAc) and (pyCAr2O)Zn(OAc), respectively, in high yield. The copolymerizations of carbon dioxide with cyclohexene oxide were investigated. The (6-Me-pyCAr2O)Zn(OAc) showed moderate yield and CO2 incorporation. The [6-Me-pyC(4-Cl-C6H4)2O]Zn(OAc) complex gave large polymers with high proportions of carbonate linkage (>60%) and narrow polydispersity, indicating single active sites. The monoligated Zn complexes synthesized and used here as catalysts for the copolymerization of cyclohexene oxide and carbon dioxide. [source]

Enantioselective Reduction of Diaryl Ketones Catalyzed by a Carbonyl Reductase from Sporobolomyces salmonicolor and its Mutant Enzymes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009
Hongmei Li
Abstract The carbonyl reductase from red yeast Sporobolomyces salmonicolor AKU4429 (SSCR) and its mutant enzymes effectively catalyzed the enantioselective reduction of diaryl ketones to give the corresponding chiral alcohols. Both conversion and enantioselectivity were dependent on the co-solvent in the reaction medium. Diaryl ketones with a para -substituent on one of the phenyl groups were reduced with high enantioselectivity (up to 99% ee), which is difficult to achieve using chemical methods such as chiral borane reduction, asymmetric hydrogenation or hydrosilylation. Mutation of SSCR at Q245 resulted in a higher amount of (S)-enantiomer in the products, and in the case of mutant Q245P with para -substituted diaryl ketones as substrate, this effect was so remarkable that the reduction enantiopreference was switched from (R) to (S). The present study provides valuable information about the catalytic properties of the carbonyl reductase SSCR toward the reduction of diaryl ketones, serving as basis for further engineering of this enzyme to develop efficient biocatalysts for highly enantiospecific reduction of diaryl ketones without high electronic dissymmetry or an ortho -substituent on one of the aryl groups. [source]

Photoreaction Between Benzoylthiophenes and N -BOC-Tryptophan Methyl Ester,

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2006
Julia Pérez-Prieto
ABSTRACT Drug-induced photoallergy requires as the first step formation of covalent drug-protein photoadducts. One of the key amino acids involved in this process is tryptophan (Trp). In this context, several diaryl ketones, including 2-benzoylthiophene (BT), [2-(5-benzoyl-5-thienyl)]-2-methylpropanoic methyl ester (TPA methyl ester) and 4-(2-thienylcarbonyl)phenyl]-2-methylpropanoic methyl ester (SUP methyl ester) have been irradiated in the presence of N -BOC-(L)-tryptophan methyl ester. Laser flash photolysis has allowed to detect three neutral radicals (ketyl, indolyl and skatolyl radicals) resulting from formal hydrogen-atom abstraction. This correlates well with the isolation of homodimers, as well as with cross-coupling products, in the preparative irradiation. The main cross-coupling products were in all cases lactones arising from the reaction of the Trp-derived skatolyl radicals with the corresponding ketyl radicals. These lactones were obtained as the (4R) stereoisomers with remarkable diasteroselectivity. No coupling products through the phenyl p -position of BT or TPA methyl ester were found. By contrast, ketone homodimers and cross-coupling products arising from reaction through the thienyl 5-position were obtained when using BT and SUP methyl ester; this is very interesting, because stable LAT-derived products are difficult to isolate. [source]

Reduction and Coupling Reaction of Carbonyl Compounds by Aluminum Powder and a Small Amount of Oxalic Acid in Water

CHINESE JOURNAL OF CHEMISTRY, Issue 1 2006
Shi-Zhen Yuan
Abstract A convenient pinacol coupling of aromatic aldehydes and aryl methyl ketones has been achieved with high yields by aluminum powder in the presence of oxalic acid in water. However, the diastereoselectivities of pinacols were not satisfying, and most aliphatic aldehydes and diaryl ketones have been found to be unreactive under the same conditions. [source]