Asymmetric reduction of α,β-unsaturated iminium salts with 1,4-dihydronicotinamide sugar pyranosides

1980 ◽  
Vol 58 (4) ◽  
pp. 387-392 ◽  
Author(s):  
Naomichi Baba ◽  
Taketoshi Makino ◽  
Jun'ichi Oda ◽  
Yuzo Inouye
Keyword(s):  
Functional Groups ◽  
Structural Variation ◽  
Asymmetric Reduction ◽  
Enantiomeric Excess ◽  
Optically Active ◽  
Iminium Salts ◽  
Sugar Moiety

3,3,5-Trimethyl-2-cyclohexylidene iminium salts were reduced with 1,4-dihydronicotinamide sugar pyranosides to give optically active 3,3,5-trimethylcyclohexanone in enantiomeric excess ranging over 3–31%. The product stereochemistry changed sensitively with structural variation (including anomers, epimers, and deacetylation) of sugar residues. The reduction by more simplified chiral models, N1-(1′S,2′S)-2′-hydroxy- or acetoxycyclohexyl-1,4-dihydronicotinamide revealed that operation of the functional groups on the sugar moiety is not merely steric in nature for induction of chirality in the product.

A Novel Asymmetric reduction of Nitroolefin 2-Nitro-1-Phenyl-1-Propene by Using BINAP-Ruthenium(II) Complexes

2003 ◽  
Vol 2003 (3) ◽  
pp. 128-129 ◽  
Author(s):  
Yanjun Li ◽  
Taeko Izumi
Keyword(s):  
Asymmetric Reduction ◽  
Enantiomeric Excess ◽  
Optically Active

The ruthenium BINAP complex, [Ru(OAc)2{(S)-BINAP}], can catalyse the hydrogenation of 2-nitro-1-phenyl-1-propene (1) to give optically active 2-nitro-1-phenylpropane (2) in moderate enantiomeric excess.

scholarly journals Chemoenzymatic Synthesis of Synthes as Precursors for Enantiopure Clenbuterol and Other β2 Agonists

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 516
Author(s):  
Fredrik Blindheim ◽  
Mari Hansen ◽  
Sigvart Evjen ◽  
Wei Zhu ◽  
Elisabeth Jacobsen
Keyword(s):  
Protein Synthesis ◽  
Nicotinamide Adenine Dinucleotide ◽  
Asymmetric Reduction ◽  
Enantiomeric Excess ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
The Body ◽  
Chemoenzymatic Synthesis ◽  
The World ◽  
Β2 Agonist ◽  
Β2 Agonists

Clenbuterol is a β2-agonist used in the veterinary treatment of asthma in several countries. The drug is listed on the World Antidoping Agency’s prohibited list due to its effect on increased protein synthesis in the body. However, racemic clenbuterol has recently been shown to reduce the risk of Parkinson’s disease. In order to reveal which one (or both) of the enantiomers that cause this effect, pure enantiomers need to be separately studied. (R)-1-(4-Amino-3,5-dichlorophenyl)-2-bromoethan-1-ol has been synthesised in 93% enantiomeric excess (ee) by asymmetric reduction of the corresponding ketone catalysed by a ketoreductase and nicotinamide adenine dinucleotide phosphate (NADPH) as the cofactor in dimethyl sulfoxide (DMSO). (S)-N-(2,6-Dichloro-4-(1-hydroxyethyl)phenyl)acetamide has been synthesised in >98% ee by the same system. Both synthons are potential precursors for clenbuterol enantiomers.

scholarly journals Efficient Biocatalytic Preparation of Optically Pure (R)-1-[4-(Trifluoromethyl)phenyl]ethanol by Recombinant Whole-Cell-Mediated Reduction

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 391 ◽  
Author(s):  
Ying Chen ◽  
Nana Xia ◽  
Yuewang Liu ◽  
Pu Wang
Keyword(s):  
Organic Solvent ◽  
Asymmetric Reduction ◽  
Enantiomeric Excess ◽  
Aqueous System ◽  
Cell Membrane Permeability ◽  
Buffer Solution ◽  
Preparative Scale ◽  
Buffer Medium ◽  
Polar Organic Solvent ◽  
Optically Pure

(R)-1-[4-(Trifluoromethyl)phenyl]ethanol is an important pharmaceutical intermediate of a chemokine CCR5 antagonist. In the present study, a bioprocess for the asymmetric reduction of 4-(trifluoromethyl)acetophenone to (R)-1-[4-(trifluoromethyl)phenyl]ethanol was developed by recombinant Escherichia coli cells with excellent enantioselectivity. In order to overcome the conversion limitation performed in the conventional buffer medium resulting from poor solubility of non-natural substrate, we subsequently established a polar organic solvent-aqueous medium to improve the efficacy. Isopropanol was selected as the most suitable cosolvent candidate, based on the investigation on a substrate solubility test and cell membrane permeability assay in different organic solvent-buffer media. Under the optimum conditions, the preparative-scale asymmetric reduction generated a 99.1% yield with >99.9% product enantiomeric excess (ee) in a 15% (v/v) isopropanol proportion, at 100 mM of 4-(trifluoromethyl)acetophenone within 3 h. Compared to bioconversion in the buffer medium, the developed isopropanol-aqueous system enhanced the substrate concentration by 2-fold with a remarkably improved yield (from 62.5% to 99.1%), and shortened the reaction time by 21 h. Our study gave the first example for a highly enantioselective production of (R)-1-[4-(trifluoromethyl)phenyl]ethanol by a biological method, and the bioreduction of 4-(trifluoromethyl)acetophenone in a polar organic solvent-aqueous system was more efficient than that in the buffer solution only. This process is also scalable and has potential in application.

Bioreduction of Some Common Carbonylic Compounds Mediated by Yeasts

2010 ◽  
Vol 65 (1-2) ◽  
pp. 1-9 ◽  
Author(s):  
Javier Silva ◽  
Julio Alarcón ◽  
Sergio A. Aguila ◽  
Joel B. Alderete
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Pichia Pastoris ◽  
Aqueous Medium ◽  
Ethyl Acetoacetate ◽  
Enantiomeric Excess ◽  
Optically Active ◽  
Environmentally Benign ◽  
Wild Type ◽  
Regeneration System ◽  
Type Strains

Bioreduction of several prochiral carbonylic compounds such as acetophenone (1), ethyl acetoacetate (2) and ethyl phenylpropionate (3) to the corresponding optically active secalcohols 1a - 3a was performed using wild-type strains of Pichia pastoris UBB 1500, Rhodotorula sp., and Saccharomyces cerevisiae. The reductions showed moderate to excellent conversion and high enantiomeric excess, in an extremely mild and environmentally benign manner in aqueous medium, using glucose as cofactor regeneration system. The obtained alcohols follow Prelog’s rule, but in the reduction of 1 with P. pastoris UBB 1500 the anti- Prelog enantiopreference was observed

scholarly journals Direct asymmetric reduction of levulinic acid to gamma-valerolactone: synthesis of a chiral platform molecule

2015 ◽  
Vol 17 (12) ◽  
pp. 5189-5195 ◽  
Author(s):  
József M. Tukacs ◽  
Bálint Fridrich ◽  
Gábor Dibó ◽  
Edit Székely ◽  
László T. Mika
Keyword(s):  
Levulinic Acid ◽  
Asymmetric Reduction ◽  
Optically Active

Biomass-originated levulinic acid was directly converted to optically active (S)-gamma-valerolactone, a proposed biomass-based chiral platform molecule.

scholarly journals Development of Quality Assessment Method for Optically Active Food Flavor Chemicals

2011 ◽  
Vol 94 (3) ◽  
pp. 923-930 ◽  
Author(s):  
Koichi Saito ◽  
Kouhei Hosono ◽  
Nariko Kitazawa ◽  
Yusuke Iwasaki ◽  
Rie Ito ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Enantiomeric Excess ◽  
Optical Purity ◽  
Assessment Method ◽  
Optically Active ◽  
Standard Samples ◽  
Flavor Compound ◽  
Purity Test ◽  
Quality Assessment Method ◽  
Chemical Purity

Abstract A quality assessment method for commercially available, optically active flavor compounds, namely, menthol, menthyl acetate, borneol, perillaldehyde, and 1,8-cineol, was developed. A gas chromatograph equipped with a flame ionization detector and a DB-5ms capillary column was used for the chemical purity test. A GC/MS with a β-DEX cyclodextrin column was used for the optical purity test, by which the enantiomeric separation of each flavor compound was achieved. Enantiomeric excess was calculated as an expression of optical purity. Of the 25 standard samples subjected to the chemical purity test, six were found to have lower purity than the data provided by the manufacturers. When the same samples were subjected to the optical purity test, 11 were found to have lower purity than that indicated on the reagent labels. These results suggest that there is a need to conduct an optical purity test, in addition to a chemical purity test, for the quality assessment of flavor standards.

Sign in / Sign up

Export Citation Format

Share Document