An improved preparing process for rivastigmine / 中国药科大学学报

@#An improved manufacturing process for rivastigmine(1)was developed by performing the condensation reaction of m-hydroxyacetophenone(4)with N-ethyl-N-methyl carbamoyl chloride, then Corey-Bakshi-Shibata(CBS)chiral reduction to(R)-3-(1-hydroxyethyl)phenyl ethyl(methyl)carbamate(2)and then mesylation with methanesulfonyl chloride and nucleophilic substitution with dimethylamine, respectively. To be successful, a crucial reductive process in the conversion of ketone(3)to chiralalcohol(2)had to be correctly understood and optimized via orthogonal experiment. The whole improved process was convenient for operation and purification, with completion of the synthesis of rivastigmine and an overall yield of 88%.