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

Participants

Reaction Steps

A stirred mixture of 7-chloro-1,3-dihydro-3-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one (10 g, 0.035 mol) in pyridine (300 ml), treated with P2S5 (8.0 g, 0.036 mmol) was refluxed, under N2, for 2 hours then concentrated in vacuo. To remove the remaining pyridine the residue was combined with toluene twice with concentration after each addition. The remaining material was mixed with cold NaHCO3 and extracted twice with CH2Cl2. At this point a precipitate thought to be undissolved product formed between the two layers. This was filtered and washed with CH2Cl2 and H2O. The NaHCO3 layer was extracted with CH2Cl2 again. The combined CH2Cl2 extracts were washed with brine, dried over Na2SO4, and concentrated in vacuo. The residue was crystallized from EtOAc-Skelly B to give 3.0 g of the subtitled intermediate, mp 250°. The precipitate was also recrystallized from EtOAc-Skelly B to give 3.01 g of additional subtitled intermediate, mp 255°.

Provenance & Evidence