The present invention relates to biocatalytic asymmetric reduction for the preparation of 2-amino-[5-(1-hydroxy-2-hydroxy or halogen-ethyl)]-pyrazine derivatives of the formula; ;wherein R is lower alkylcarbonyl or an amino protecting group and R1 is hydroxy or halogen. The compounds are key intermediates in the manufacture of a glucokinase activator.
展开▼