ASYMMETRIC PROCESS FOR PREPARING FLORENICOL, THIAMPHENICOL, CHLORAMPHENICOL AND OXAZOLINE INTERMEDIATES

摘要

The present invention comprises a process for the asymmetric synthesis of florfenicol, thiamphenicol or chloramphenicol. In an alternative embodiment, the present invention comprises a process for isomerizing of the S,S-isomer of florfenicol to the R,S-isomer (I) by sequentially treating with: (i) a lower alkylsulfonyl chloride and a tertiary amine base; (ii) sulfuric acid and water; (iii) an alkali metal hydroxide. The present invention further comprises a process for regioselectively opening an epoxide to form a threo-oxazoline.