Patent ID: 9145365
Filing Date: 2015-09-29
Classification: C07C,C07D

Abstract:
1. A process for the preparation of Roflumilast comprising the steps of: a) reacting 4-Difluoromethoxy-3-hydroxy benzaldehyde of Formula II with a cyclopropylmethyl compound of Formula III in the presence of an organic base to obtain 3-cyclopropylmethoxy-4-Difluoromethoxy benzaldehyde of Formula IV b) oxidising the obtained aldehyde compound of Formula IV into 3-cyclopropylmethoxy-4-Difluoromethoxy benzoic acid of Formula V, c) converting 3-cyclopropylmethoxy-4-Difluoromethoxy benzoic acid of Formula V to its acid halide and condensing with 4-amino 3,5-Dichloropyridine in the presence of base to obtain Roflumilast, and d) optionally purifying Roflumilast in an organic solvent to get pure Roflumilast.