Ethanol → 8-Chloro-2-methyl-5,6-dihydro-4-oxo-6-phenyl-4H-pyrazolo[1,5-a][1,4]benzodiazepine

Participants

Reaction Steps

To a solution of 3.43 g. (10.15 mmol) of the end product of Example 15 in 60 ml. of absolute EtOH, was added 12 ml. of hydrazine-hydrate. The reaction was heated to reflux for 17 hours, then cooled and concentrated in vacuo. The residue was taken up in 60 ml. toluene; 1.0 g. potassium t-butoxide added and the mixture heated to reflux for 8 hours, then cooled to room temperature and stirred for 9 hours. The reaction was poured over ice and brine and toluene added. The toluene phase was separated and dried over Na2SO4. The aqueous phase was extracted well with CH2Cl2 and the combined extracts dried over Na2SO4. The dried solutions were combined and concentrated and the crude product recrystallized from THF/hexane to give the desired end product, mp 258°-261°. An analytical sample was prepared by an additional recrystallization from THF/hexane and was obtained as colorless crystals: mp 259°-261°.

Provenance & Evidence