Bromine → 7-amino-6-bromo-5-(o-chlorophenyl)-1,3-dihydro-1,3,3-trimethyl-2H-1,4-benzodiazepin-2-one

Participants

Reaction Steps

16 g (0.049 mol) of 7-amino-5-(o-chlorophenyl)-1,3-dihydro-1,3,3-trimethyl-2H-1,4-benzodiazepin-2-one in 160 ml of glacial acetic acid are treated slowly while stirring with 8.5 g of bromine in 10 ml of glacial acetic acid. After 60 minutes at room temperature, the reaction mixture is concentrated and the residue is partitioned between aqueous ammonia and methylene chloride. The aqueous phase is extracted several times more with methylene chloride. The combined organic extracts are dried and evaporated. The crude product is purified on 500 g of silica gel with methylene chloride/ethyl acetate (5:1) as the elution agent. From ethyl acetate/ether there is obtained 7-amino-6-bromo-5-(o-chlorophenyl)-1,3-dihydro-1,3,3-trimethyl-2H-1,4-benzodiazepin-2-one of melting point 188°-189°.

Provenance & Evidence