Patent ID: 8207343
Filing Date: 2012-06-26
Classification: C07D

Abstract:
1. A process for preparation of Montelukast or a salt thereof, said process comprising the steps of: reacting (S)-1-(3-(E)-2-(7-chloroquinolin-2-yl)vinyl)phenyl)-3-(2-isopropenyl phenyl]propan-1-ol with methane sulfonyl chloride or toluene sulfonyl chloride to obtain a hydroxy styrene mesylate salt or tosylate salt; condensing the hydroxy styrene mesylate salt or tosylate salt with 1-(mercapto methyl)cyclopropane acetic acid followed by salification with an amine to obtain (1-[(R)-1-(3-[(E)-2-(7-chloroquinolin-2-yl)vinyl]-phenyl)-3-(2-isopropenylphenyl)propylsulfanyl methyl]cyclopropyl]acetic acid styrene amine salt; converting the styrene amine salt to Montelukast amine salt; and converting the Montelukast amine salt to Montelukast free acid or an alkali or alkaline salt of Montelukast.