Highly enantioselective bioreduction of 1-(3,4-difluorophenyl)-3-nitropropan-1-one: key intermediate of ticagrelor

A simple, highly effective and economical whole-cell mediated process was developed for the biocatalytic reduction of a ketone, intermediate in the synthesis of platelet inhibiting drug ticagrelor. Sixteen different microorganisms were screened for the bioreduction of 1-(3,4-difluorophenyl)-3-nitropropan-1-one ( 1 ) to ( S )-1-(3,4-difluorophenyl)-3-nitropropan-1-ol ( 2 ). Growing as well as resting cells of Candida parapsilosis 104659 exhibited high conversion (>99.0%) and enantioselectivity (98.0%) for the S -enantiomer.