PROCESSES FOR THE PREPARATION OF ESCITALOPRAM AND ITS PRECURSOR

摘要

The present invention relates to an improved process for the preparation of escitalopram of the formula-I which consists of a sequential double Grignard reaction on 5-bromophthalide, isolation of di-magnesium salt, neutralization of di-magnesium salt, resolution of dihydroxy compound of the formula-IV and cyclization of resolved compound of the formula-IV, cyanation of compound of the formula-IV using DMF and copper(I)cyanide. The present process utilizes the insoluble property of di-magnesium salt of formula-XII in a mixture of THF and a non-polar organic solvent and separates it from impurities by simple filtration thereby making the isolation and purification process simple.