AN IMPROVED PROCESS FOR THE PREPARATION OF BEPOTASTINE BESILATE AND INTERMEDIATE THEREOF

摘要

The invention provides a process for the preparation of benzene sulfonic acid salt of (S)-4-[4-[(4-chlorophenyl) (2-pyridyl)- methoxy]piperidino]butanoic acid of formula I comprising the steps of: (i) reacting compound (S) 2-[(4-chloro-phenyl) (4- piperidinyloxy)methyl]pyridine of formula IV with alkyl 4-halo butanoate of formula (V) in biphasic solvent system in presence or absence of phase transfer catalyst to obtain the compound alkyl (S)-4-[4-[(4-chlorophenyl)(2-pyridyl)methoxy]piperidino] butanoate of formula III; (ii) treating compound of formula III with polar solvent and water in presence of suitable base to obtain the compound (S)-4-[4-[(4-chlorophenyl)(2-pyridyl)-methoxy] piperidino]butanoic acid of formula II; (iii) contacting compound of formula II with benzene sulphonic acid in suitable solvent to obtain the benzene sulphonate salt of formula I; (iv) optionally, the steps (i) and (ii) are performed without the isolation of intermediate compound formed; and (v) optionally purifying the compound of formula I with suitable solvent.