Patent ID: 8084606

Claim:
A process for the preparation of substantially optically pure levorotatory and dextrorotatory enantiomers of 1-[(4-chlorophenyl)phenylmethyl]piperazine of formula I: which comprises: a) reacting substantially optically pure levorotatory and dextrorotatory enantiomers of (4-chlorophenyl)phenylmethylamine of formula II: with sulfonamide compound of formula III: wherein X is a leaving group selected from the group consisting of halogen, (4-methylphenyl)sulfonyloxy, and methylsulfonyloxy group; and R is alkyl, cycloalkyl, phenyl, halo-substituted phenyl, nitro-substituted phenyl, amino-substituted phenyl, or acetyl amino-substituted phenyl; in the presence of a base to give substantially optically pure levorotatory and dextrorotatory enantiomers of piperazine sulfonamide compound of formula IV: wherein R is as defined above; and b) deprotecting the piperazine sulfonamide compound of formula IV to give substantially optically pure levorotatory and dextrorotatory enantiomers of 1-[(4-chlorophenyl)phenylmethyl]piperazine of formula I.