As described for Example 157, 0.47 g of 4,5-dihydro-5-(4-aminobenzoyl)pyrrolo[1,2-a]quinoxaline, 346 μl of triethylamine and 5 ml of dichloromethane are chilled (ice bath) and 0.415 g of 2,3-dichlorobenzoyl chloride in 2 ml of dichloromethane added. After stirring overnight, an additional 346 μl of triethylamine is added and an additional 0.415 g of 2,3-dichlorobenzoyl chloride added. The mixture is stirred for 2 hours, diluted with 50 ml of dichloromethane and the solution washed with 20 ml each of H2O, 2N citric acid, 1M NaHCO3 and brine. The organic layer is dried (Na2SO4) and filtered through a thin pad of hydrous magnesium silicate and the filtrate concentrated to dryness. The residue is chromatographed on thick layer silica gel plates with ethyl acetate-hexane (1:1) as solvent to give 0.100 g of white solid, m.p. 230°-240° C.
