Patent ID: 9487487
Filing Date: 2016-11-08
CPC Classification: A61P,C07D

Claim Text:
1. A process for preparing montelukast sodium of Formula I, comprising the steps of: a) reacting 2-(2-(3(S)-(3-(2-(7-chloro-2-quinolinyl)-ethenyl)phenyl)-3-hydroxy propyl)phenyl)-2-propanol (diol compound) of formula with methane sulfonyl chloride in an organic solvent in the presence of a base to obtain a solution of 2-(2-(3(S)-(3-(2-(7-chloro-2-quinolinyl)-ethenyl) phenyl)-3-methanesulfonyloxypropyl)phenyl)-2-propanol (mesylate compound) b) reacting 1-(mercaptomethyl)cyclopropane acetic acid with a base and an additional alkali source in a polar aprotic solvent to obtain a solution of dibase salt of 1-(mercaptomethyl)cyclopropane acetic acid; c) reacting the mesylate compound of step a) with the dibase salt of 1-(mercaptomethyl)cyclopropane acetic acid of step b) at a temperature of about −20° C. to about 10° C. to obtain an montelukast intermediate; d) converting the montelukast intermediate from step c) with an organic amine to obtain a montelukast amine salt; and e) converting the montelukast amine salt from step d to montelukast sodium.