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

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Reaction Steps

A mixture of 23 g. (0.085 mole) of 1,3-dihydro-5-(o-chlorophenyl)-2H-1,4-benzodiazepin-2-one [Sternbach et al., J. Med. Chem. 6, 261 (1963)] and 21 g. of P2S5 in 1500 ml. of pyridine was heated rapidly to the reflux temperature and refluxed for 45 min. It was then concentrated to dryness in vacuo and the residue was treated with 150 ml. of saturated NaCl solution and extracted (thrice) with methylene chloride. The CH2Cl2 solution was washed (water), dried (MgSO4), filtered and evaporated to dryness. The residue was dissolved in 1 l. of abs EtOH treated with Darco and filtered hot. The solution was then concentrated to 200 ml. and allowed to cool giving 19 g. (78%) of yellow crystalline compound, m.p. 228-229° C. The ir and nmr support the structure.

Provenance & Evidence