A PROCESS FOR THE MANUFACTURING OF LORATADINE AND ITS INTERMEDIATES

摘要

The process comprises (i) subjecting substituted benzyl halide to cyanation in a biphasic system using water immiscible solvents by any known methods, (ii) condensing in situ the phenyl acetonitrile thus obtained with nicotinic ester in presence of alkali metal alkoxide and water immiscible organic solvent to produce ketonitrile, (iii) hydrolyzing followed by decarboxylating the said ketonitrile in situ to respective ketone in acid environment below 60° C, (iv) subjecting the ketone so obtained to reduction followed by N-oxidation, cyanation, and hydrolysis by any known methods to produce picolinic acid, (v) cyclising the said picolinic acid to tricyclic ketone by conventional methods, (vi) treating the said tricyclic ketone with organometallic compound containing Mg to produce carbinol, (viii) purifying the said carbinol with purifying agent selected from polar water miscible organic solvent followed by dehydrating with neat sulphuric acid at the temperature below 50° C, to get N-methyl product (olefin), and subjecting the said olefin to N-carbethoxylation to produce loratadine. Loratadine can also be prepared by treating cayano compound with organometallic compound containing Mg to produce a ketone by the methods known in the art followed by cyclising in presence of a mixture of sulfuric acid and a source of boric acid to get N-methyl product and converting to loratadine by N-carbethoxylation.