Bromazepam → 8-Bromo-6-(2-pyridyl)-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylic acid, ethyl ester

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Reaction Steps

A solution of 15.8 g (0.05 mol) of 7-bromo-1,3-dihydro-5-(2-pyridyl)-2H-1,4-benzodiazepin-2-one in 300 ml of dry tetrahydrofuran was cooled to 10° with stirring under argon. Potassium tert. butoxide 6.3 g (0.056 mol) was added and stirring was continued for 10 min. Following the addition of 14 ml of diethyl chlorophosphate the mixture was stirred for additional 20 min. A previously prepared mixture of 11.3 g ethyl isocyanoacetate, 11.3 g of potassium tert. butoxide and 300 ml of tetrahydrofuran was then poured into the reaction mixture.

Provenance & Evidence