Triethylamine → (+)-5-(o-fluorophenyl)-1,3-dihydro-3-methyl-7-nitro-2H-1,4-benzodiazepin-2-thione

Participants

Reaction Steps

32 g of (+)-5-(o-fluorophenyl)-1,3-dihydro-3-methyl-7-nitro-2H-1,4-benzodiazepin-2-one are dissolved in 450 ml of absolute dioxane and treated with 21 g of phosphorus pentasulfide and 15 ml of triethylamine. The mixture is heated to reflux for 20 minutes, cooled with ice and concentrated on a rotary evaporator. The residue is treated with 10% bicarbonate solution and ethyl acetate and the ethyl acetate phase is washed twice with 10% bicarbonate solution, dried with sodium sulfate, filtered and concentrated. Crystallisation of the residue from ethanol yields racemate. By concentration of the mother liquor, there is obtained crude (+)-5-(o-fluorophenyl)-1,3-dihydro-3-methyl-7-nitro-2H-1,4-benzodiazepin-2-thione which exhibits a rotation of [α]25D =+319.1° (in methylene chloride, 1%).

Provenance & Evidence