Oxazepam → 3,7-Dichloro-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one

Participants

Reaction Steps

Oxazepam (1.0 g) was added in portions to 1.0 ml of freshly distilled thionyl chloride that contained ~50μl of DMF with stirring under N2 atmosphere at ice-bath temperature. As soon as the oxazepam was added to the thionyl chloride, the color turned bright yellow and remained unchanged. After complete addition, the heterogeneous reaction mixture was stirred at 0° for 1 hour and then left in the cold room at ~4° for 24 hours. Excess thionyl chloride was removed on a rotary evaporator. The resulting bright yellow solid was thoroughly mixed with a small amount of anhydrous benzene and then benzene was removed on a rotary evaporator, this was repeated several times to remove thionyl chloride. The residue was then triturated with 3 ml of anhydrous benzene and filtered with suction. The product was dried under vacuum to give 1.1 g of bright yellow solid, m.p. 139°-140° C. decomposition (lit. m.p. 151°-153° dec. and 120°-122° C.).

Provenance & Evidence