Sulfuric Acid → 1H-1,4-Benzodiazepine

Participants

Reaction Steps

To a suspension of 2.84 parts of 7-chloro-2-hydrazino-5-phenyl-3H-1,4-benzodiazepine in 50 parts by volume of acetic anhydride is added 1 part by volume of concentrated sulfuric acid. The resulting solution is left standing at room temperature for 1 hour, poured in ice-water, neutralized with sodium bicarbonate and extracted with methylene chloride. The methylene chloride extract is washed with water and dried over anhydrous sodium sulfate, followed by evaporation of the solvent. The residue is recrystallized from a mixture of acetone and n-hexane to give 8-chloro-1-methyl-6-phenyl-4H-s-triazolo [4,3-a]][1,4] benzodiazepine as colorless needles. Melting point: 224° C to 225° C.

Provenance & Evidence