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Preparation of enantiopure ( R )‐hydroxy metabolite of denbufylline using immobilized Lactobacillus kefiri DSM 20587 as a catalyst
Author(s) -
Pȩkala Elżbieta,
Burbiel Joachim C.,
Müller Christa E.
Publication year - 2009
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20665
Subject(s) - enantiopure drug , chemistry , biotransformation , metabolite , calcium alginate , yield (engineering) , enantiomeric excess , chromatography , biocatalysis , ketone , enantioselective synthesis , catalysis , organic chemistry , stereochemistry , calcium , reaction mechanism , enzyme , biochemistry , materials science , metallurgy
Lactobacillus kefiri DSM 20587 cells were immobilized in calcium alginate and carrageenan. The immobilized cells were used as biocatalysts for the enantioselective reduction of the methyl ketone group of denbufylline to synthesize the enantiopure ( R )‐hydroxy metabolite: (−)‐1,3‐dibutyl‐7‐((2′ R )‐hydroxypropyl)‐1 H ‐purine‐2,6(3 H ,7 H )‐dione ( 1 ). The experimental conditions for the biotransformation were optimized. As denbufylline is insoluble in aqueous media, the influence of cosolvents (dimethylsulfoxide (DMSO), acetonitrile) and different concentrations of each solvent in the reaction mixture on the yield and enantiomeric excess of the final biotransformation product was studied. The maximum biotransformation yield (96–98%) and highest enantioselectivity (96% ee ) for the obtained metabolite were reached using DMSO as a cosolvent at a concentration of 7.5% (v/v) in the presence of L. kefiri immobilized either in calcium alginate or in carrageenan. The absolute configuration of the stereogenic center of 1 was determined by applying Mosher's method. Chirality 2009. © 2008 Wiley‐Liss, Inc.