- ANTI-ODOR COMPOSITIONS AND THERAPEUTIC USE
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This application discloses a composition comprising a malodor compound and an anti-odor ingredient effective for reducing the presence or production of malodor. The composition may be topically applied to a subject and is useful for cosmetic conditions, pharmaceutical indications, or other objectives.
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- A substrate-based methodology that allows the regioselective control of the catalytic aminohydroxylation reaction
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Analogous to the Sharpless osmium-catalyzed asymmetric dihydroxylation (AD) reaction, structure I is proposed as the catalytically active species for the asymmetric aminohydroxylation (AA) reaction. Based on this model, the regiochemistry of the reaction
- Han, Hyunsoo,Cho, Chang-Woo,Janda, Kim D.
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p. 1565 - 1569
(2007/10/03)
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- Biotransformations with baker's yeast: pH effects on diastereoselectivity during α-hydroxy-β-ketoester reductions and carbon-carbon bond cleavages
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Baker's yeast mediated reduction of α-substituted-β-ketoesters lead to reduction of the carbonyl group with high enantiospecificity and diastereoselectivity at low pH (4.0-5.0, e.e. >99%, d.e. >90%) but cleavage of the C-C bond is observed at higher pH >8.0). Similar carbon-carbon bond cleavages are observed in the reactions of α-acetamido-β-ketoesters and acetamidocinnamic acid.
- Fadnavis,Kumara Vadivel,Bhalerao
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p. 2355 - 2359
(2007/10/03)
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- Purification and Properties of Aldehyde Reductases from Yeasts That Convert Ethyl 2-Acetamido-3-oxobutyrate to Optically Active Ethyl 2-Acetamido-3-hydroxybutyrate
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Yeasts were screened for strains that converted ethyl 2-acetamido-3-oxobutyrate (AAOB) to optically active ethyl 2-acetamido-3-hydroxybutyrate (AAHB).Sporobolomyces sp.AKU4430 was found to accumulate the D-threo isomer of AAHB by a whole-cell reaction.Candida albicans AKU4596 accumulated mainly the D-threo and L-threo isomers.The enzymes that reduced AAOB were purified from these two yeasts, and characterized.To judge from their substrate specifity, inhibition pattern, molecular structure, and reaction mechanisms, the enzymes were of the NADPH-dependent aldo-keto reductase family (probably aldehyde reductase, EC 1.1.1.2).The enzyme of Sporobolomyces sp. reduced AAOB more strongly than that of C. albicans.The stereoselectivity of the enzymes was low; three isomers of AAHB (L-threo, L-allo, and D-threo) were produced by each purified enzyme.The selective accumulation of an isomer(s) of AAHB by reaction in yeast cells probably occurred because of differences in isomer degradation.
- Kato, Nobuo,Fujie, Masayoshi,Hasegawa, Masayasu,Shimao, Masayuki,Kita, Keiko,Yanase, Hideshi
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p. 303 - 307
(2007/10/02)
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- ASYMMETRIC SYNTHESIS. PRACTICAL PRODUCTION OF D AND L THREONINE. DYNAMIC KINETIC RESOLUTION IN RHODIUM AND RUTHENIUM CATALYZED HYDROGENATION OF 2-ACYLAMINO-3-OXOBUTYRATES.
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Enantioselective syntheses of D and L threonine are described.Racemic methyl and ethyl 2-acylamino-3-oxobutyrate 1 were synthesized from the corresponding acetoacetates 6 and then hydrogenated stereoselectively via dynamic kinetic resolution with various chiral P * P Rh(I) 8 and Ru(II) 10 catalysts to give syn optically active alcohols which could be converted by hydrolysis and treatment with propylene oxide into threonine.The best results were obtained using (-) CHIRAPHOS Ru and (+) BINAP Ru as catalysts, in the hydrogenation step leading respectively to D threonine (ee : 99percent) and L threonine (ee : 94percent) in 26-34percent overall yields.
- Genet, J.P.,Pinel, C.,Mallart, S.,Juge, S.,Thorimbert, S.,Laffitte, J.A.
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p. 555 - 567
(2007/10/02)
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- Process for preparing optically active threonine
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A process for preparing optically active threonine is disclosed, which comprises asymmetrically hydrogenating a 2-N-acylaminoacetoacetic ester represented by formula (I): STR1 wherein R1 represents a lower alkyl group, a phenyl group, a phenyl group substituted with a lower alkyl group or a lower alkoxy group, a benzyl group, or a benzyl group substituted with a lower alkyl group or a lower alkoxy group; R2 represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a phenyl group, a phenyl group substituted with a lower alkyl group or a lower alkoxy group, a benzyloxy group, or a benzyloxy group substituted with a lower alkyl group or a lower alkoxy group, in the presence of a ruthenium-optically active phosphine complex as a catalyst to obtain an optically active threonine derivative represented by formula (II): STR2 wherein R1 and R2 are as defined above, and then hydrolyzing the compound of formula (II). The 2-N-acylaminoacetoacetic ester intermediate can be selectively prepared in a high yield. Either natural type threonine or non-natural type threonine can be prepared selectively by selecting the absolute configuration of the ligand of the ruthenium-optically active phosphine complex.
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- An Enantioselective Synthesis of L-Threonine
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An enantioselective synthesis of L-threonine (1) is described.Racemic ethyl 2-acetamido-3-oxobutyrate (6) was synthesized from ethyl acetoacetate (2) (4) (5) and then transformed to the epimeric optically active alcohols 7a and 7b by microbiological reduction with Saccharomyces rouxii.The mixture 7a/7b could be converted to 1 by slightly modified, known methods in a yield of ca. 52percent with respect to 7a/7b.
- Soukup, Milan,Wipf, Beat,Hochuli, Erich,Leuenberger, Hans G. W.
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p. 232 - 236
(2007/10/02)
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