Patent ID: 8350045

Claim:
A process for preparation of E-isomer of 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinoprop-1-ene of Formula I or its acid addition salts thereof, which are substantially free from corresponding Z-isomer said process comprising: a. adding 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinopropan-1-ol to a solution of at least 90% concentrated sulphuric acid, at a temperature in the range of 25 to 110° C. for a period of 1 to 6 hours to obtain a solution of 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinoprop-1-ene sulphate, b. adding a base solution to said solution of 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinoprop-1-ene sulphate to obtain a mixture of E and Z isomers of 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinoprop-1-ene, and c. washing said mixture of E and Z isomers of 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinoprop-1-ene with water to dissolve Z isomer and to obtain E-isomer of 1-(4-methylphenyl)-1-(2-pyridyl)-3-pyrrolidinoprop-1-ene of Formula I, which is substantially free from Z isomer.