To a solution of 314 mg of 2-fluorobenzoyl chloride in 5 ml of methylene chloride at 0° C. is added 346 μl of triethylamine. After stirring for 3 minutes, 500 mg of 10,11-dihydro-10-(4-aminobenzoyl)-5H-pyrrolo[2,1-c][1,4]benzodiazepine is added. The bath is removed and the reaction mixture stirred at room temperature for 18 hours. The volatiles are concentrated in vacuo to give a residue which is dissolved in methylene chloride, washed with water, 2N citric acid, 1M NaHCO3 and brine. The organic layer is dried with Na2SO4, filtered and concentrated in vacuo to give 620 mg of the desired product as a crystalline solid, m.p. 257°-260° C.
