Ethyl Acetate → 7-chloro-8-fluoro-5-methyl-6-oxo-5,6-dihydro-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carbonitrile

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Reaction Steps

A suspension of 14.4 g (0.0466 mol) of 7-chloro-8-fluoro-5-methyl-6-oxo-5,6-dihydro-4H-imidazo[1,5-a][1,4]benzodiazepin-3-carboxamide in a mixture of 60 ml of dioxan and 8 ml of pyridine was treated dropwise at 0° with 6.8 ml (0.049 mol) of trifluoroacetic anhydride. The dark solution was stirred at 50° for 3 hrs., cooled, poured on to 400 ml of ice-water, treated with ethyl acetate and extracted. The organic solution was filtered on 100 g of silica gel and rinsed with 200 ml of ethyl acetate. The product was recrystallized from hot ethyl acetate. There were obtained 12 g (89%) of 7-chloro-8-fluoro-5-methyl-6-oxo-5,6-dihydro-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carbonitrile as light yellowish crystals; m.p. 221-223°.

Provenance & Evidence