PROCESS FOR THE PREPARATION OF ZALEPLON AND AN INTERMEDIATE THEREOF

摘要

A process for the preparation of N-[3-[3-(dimethylamino)-l-oxo-2-propenyl]phenyl]-N-ethyl acetamide of formula (II), comprising reacting a compound N-[3-[3-(dimethylamino)-l-oxo-2-propenyl]phenyl] acetamide of formula (III), with an ethylating agent in the presence of a strong alkali metal hydroxide and a phase transfer catalyst in a polar-aprotic solvent, and a process for preparation of Zaleplon, which is substantially free of impurities using the said compound of formula (II).