Phosphorus sulfide (P2S5) → 7-chloro 5-(2-chlorophenyl)-1,3-dihydro-2H-(1,4)-benzodiazepine-2-thione

Participants

Reaction Steps

A solution of (0.025 mole) of 1,3-dihydro-7-chloro-5-(2-chlorophenyl)-2H-1,4-benzodiazepin-2-one in about 500 ml. of pyridine is treated with 5.55 g. (0.025 mole) of phosphorus pentasulfide and heated under reflux in a nitrogen atmosphere for 2 hours. The pyridine is removed in vacuo and the thus-produced residue is poured onto crushed ice. The aqueous phase is extracted with methylene chloride and then discarded. The extract is washed successively with three 200-ml. portions of water and 100 ml. of brine, and dried over anhydrous sodium sulfate. Removal of the solvent gives a solid which is recrystallized from ethanol-water, to give crude material which, after recrystallization from ethanolwater, gives pure 1,3-dihydro-7-chloro-5-(2-chlorophenyl)-2H-1,4-benzodiazepine-2-thione, melting point 251°-253° C.

Provenance & Evidence