反应详情

The combination of yeast transformation of benzaldehyde to produce PAC and chemical conversion of the PAC to make 1-ephedrine is described in U.S. Pat. No. 1,956,950. The PAC can be converted by a chemical reductive amination with methylamine to optically pure L-ephedrine as follows: ##STR2## The 1-ephedrine can then converted in high yield to d-pseudoephedrine as follows: ##STR3## It is apparent from this reaction scheme that microbial transformation of benzaldehyde by yeast to form L-(-)phenyl acetyl carbinol in high yield and purity is of prime importance for successful commercial operation of the synthetic route.