The present invention relates to a novel process for the preparation of an anaesthetic drug Midazolam of formula I which comprises reductive amination of l-{4-chloro-2-[2-(2-fluorophenyl)-l,3-dithiolan-2-yl]phenyl}-5-methyl-lH-imidazole-5-carboxaldehyde using a reducing agent and ammonia in an alcoholic solvent to obtain 1-(l-{4-chloro-2-[2-(2-fluorophenyl)-l,3-dithiolan-2-yl]phenyl}-2-methyl-lH-imidazol-5-yl)methanamine followed by deprotection and cyclization of the obtained l-(l-{4-chloro-2-[2-(2-fluorophenyl)-l,3-dithiolan-2-yl]phenyl}-2-methyl-lH-imidazol-5-yl)methanamine using a reagent in presence of a monochlorobenzene .
