Patent ID: 7417149
Filing Date: 2008-08-26
Classification: C07D

Abstract:
1. A process for the preparation of Montelukast or pharmaceutically acceptable salts thereof comprising the following steps: (a) reaction of a compound A with a compound A2 in which n varies between 1 and 2 and, when n is 1, R is methyl and, when n is 2, R is a C in which n and R have the above-stated meanings; (b) reaction of the compound A3 with an inorganic acid HY, in which Y is Cl, Br, I, and subsequent isolation of the resultant salt A4; (c) optional conversion of the salt A4 into the compound A3; (d) methylation of the salt A4 and/or of the compound A3 to yield Montelukast.