Pivaloyl chloride → 3-(7-chloro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepin-3-yl)-1,1-dimethyl-2-propynyl pivalate

Participants

Reaction Steps

3.30 g (10 mmol) of 7-chloro-4,5-dihydro-3-(3-hydroxy -3-methyl-1-butynyl)-5-methyl-6H-imidazo[1,5-a][1,4]benzo diazepin-6-one were dissolved in 20 ml of pyridine and treated at room temperature with 1.57 g (13 mmol) of pivaloyl chloride. The reaction mixture was stirred at 65° for 24 hours and then evaporated. The residue was taken up in methylene chloride, the solution was washed once with lN hydrochloric acid and twice with water, dried over magnesium sulfate and evaporated. By chromatography on silica gel while eluting with ethyl acetate and subsequent crystallization from ethyl acetate and hexane, there was obtained 0.96 g (23%) of 3-(7-chloro-5,6-dihydro-5-methyl -6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepin-3-yl)-1,1-dimethyl-2-propynyl pivalate of melting point 132-133°.

Provenance & Evidence