Patent ID: 8350031
Filing Date: 2013-01-08
Classification: C07C,C07D

Abstract:
1. A process for the preparation of levocetirizine or a salt thereof, which comprises preparing a compound of formula (I) by reacting a compound of formula (IV) with a deprotecting agent to obtain the corresponding carbamate ester of (−)-1-[(4-chlorophenyl)-phenyl methyl] piperazine, and hydrolysing the carbamate ester to obtain the compound (I), converting the compound (I) to levocetirizine, wherein the compound of formula (IV) has the following structure: wherein R is Cl, Br, NO 2 , OH or OR′, and R′ is alkyl; and wherein the compound of formula (IV) is prepared by reacting a compound of formula (III) with (−)-(4-chlorophenyl) phenyl methyl amine in the presence of a base and a solvent wherein R is Cl, Br, NO 2 , OH or OR′. and R′ is alkyl. and wherein P is a protecting group.