Chlorine → 9-chloro-5-(o-fluorophenyl)-1,3-dihydro-3,3-dimethyl-7-nitro-2H-1,4-benzodiazepin-2-one

Participants

Reaction Steps

A solution of 160 g (0.49 mol) of 5-(o-fluorophenyl)-1,3-dihydro-3,3-dimethyl-7-nitro-2H-1,4-benzodiazepin-2-one in 400 ml of concentrated hydrochloric acid and 400 ml of formic acid is treated while stirring with a solution of 46 g of chlorine gas in 400 ml of 1,2-dichloroethane. The reaction mixture, which consists of two phases, is stirred at room temperature, whereby after 3 days a further 25 g of chlorine gas in 200 ml of 1,2-dichloroethane are added and after 5 days a further 5 g of chlorine gas in 40 ml of 1,2-dichloroethane are added. After 7 days, the mixture is concentrated, treated with ice-water, made alkaline with aqueous ammonia and extracted four times with methylene chloride. The organic extract is concentrated and treated with 600 ml of isopropanol. Subsequently, the residual methylene chloride is removed on a steam-bath and the product is left to crystallise. There is obtained 9-chloro-5-(o-fluorophenyl)-1,3-dihydro-3,3-dimethyl-7-nitro-2H-1,4-benzodiazepin-2-one of melting point 174°-175°.

Provenance & Evidence