Sodium Bicarbonate → 5-(o-fluorophenyl)-1,3-dihydro-1,3,3-trimethyl-7-nitro-2H-1,4-benzodiazepin-2-one

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Reaction Steps

A solution of 20 mg (0.04 mol) of benzyl [1-[[2-(o-fluorobenzoyl)-4-nitrophenyl]-methylcarbamoyl]-1-methylethyl]carbamate in 0.5 ml of hydrogen bromide/glacial acetic acid (30 percent) is left to stand for 15 minutes, subsequently treated with a 10 percent sodium bicarbonate solution and extracted several times with methylene chloride. The organic phase is dried over sodium sulphate and concentrated, whereupon the residue is chromatographed on a pressure column containing 2 g of silica gel (particle size 0.04-0.06 mm) under 0.2-0.4 atmospheres of nitrogen with methylene chloride as the elution agent. By crystallisation from ether/petroleum ether there is obtained 5-(o-fluorophenyl)-1,3-dihydro-1,3,3-trimethyl-7-nitro-2H-1,4-benzodiazepin-2-one of melting point 127°-129°.

Provenance & Evidence