Sulfuric Acid → Estazolam

Participants

Reaction Steps

To a solution of 2.0 parts of 7-chloro-2-hydrazino-5-phenyl-3H-1,4-benzodiazepine and 7.4 parts of ethyl orthoformate in 80 parts by volume of chloroform is added 2 parts of concentrated sulfuric acid with stirring. The mixture is stirred at room temperature for further 30 minutes, and neutralized with a saturated aqueous sodium bicarbonate solution. Chloroform layer is washed with water and dried over sodium sulfate, followed by distillation of the solvent. Recrystallization of the residue from acetone-n-hexane yields 8-chloro-6-phenyl-4H-s-triazolo-[4,3-a][1,4]benzodiazepine as colorless flakes melting at 226°-227° C.

Provenance & Evidence