Patent ID: 6187956
Filing Date: 2001-02-13
Classification: A61P,C07C

Abstract:
A process for preparing L-phenylephrine hydrochloride from prochiral N-benzyl-N-methyl-2-amino-m-hydroxyacetophenone hydrochloride, the process comprising:(a) asymmetrically hydrogenating prochiral N-benzyl-N-methyl-2-amino-m-hydroxyacetophenone hydrochloride using a catalyst system comprising [Rh(COD)Cl].sub.2 and a chiral, bidentate phosphine ligand, to obtain N-benzyl-L-phenylephrine; and(b) reductively debenzylating the N-benzyl-L-phenylephrine obtained from step (a) using palladium and hydrogen, to obtain L-phenylephrine hydrochloride,wherein the molar ration of N-benzyl-N-methyl-2-amino-m-hydroxyacetophenone hydrochloride to [Rh(COD)Cl].sub.2 is between 5000:1 and 100,000:1.