THE SYNTHESIS OF 6,9-BIS[(AMINOALKYL)AMINO] SUBSTITUTED BENZO[G]QUINOXALINE-5,10-DIONES, BENZO[G]QUINAZOLINE-5,10-DIONES AND BENZO-[G]PHTHALAZINE-5,10-DIONES VIA REGIOSPECIFIC DISPLACEMENTS

The synthesis of 6,9-difluoro substituted benzo[g]quinoxaline-5,10-dio nes (3A), benzo[g]quinazoline-5,10-diones (3B) and benzo[g]phthalazine -5,10-diones (3C) have been accomplished. Treatment of 3A, 3B or 3C wi th diamines or N-(t-butoxycarbonyl)ethylenediamine led to the correspo nding 6,9-bis[(aminoalkyl)amino]-substituted analogues related to 2A, 2B and 2C, respectively. The mono-substituted derivatives 4h and 4i co uld be isolated from displacements commencing from 3A. A competitive r ing-opening of the pyrimidine ring of 2C occurred during the reaction with N,N-dimethylethylenediamine. Removal of the BOC-protecting group from 2Ac led to the hydrochloride salt 2Ab. A novel synthetic pathway to 6,9-dihydroxybenzo[g]phtalazine-5,10-dione (21a) was developed. Con version of 21a to the ditosylate 21b was readily accomplished. Treatme nt of 21b with N,N-dimethylethylenediamine or N-(t-butoxycarbonyl)ethy lenediamine led to 2Ca and 2Cc, respectively. Removal of the BOC-prote cting group from 2Cc with trifluoroacetic acid followed by ion-exchang e led to the hydrochloride salt 2Cb. Treatment of ditosylate 21b with N-(t-butoxycarbonyl)ethylenediamine also led to the mono-substituted a nalogue 25a along with a small amount of the O-S cleavage product 25b. Treatment of 25a with N,N-dimethylethylenediamine led to the unsymmet rically substituted derivative 25c which was converted into the triflu oroacetate salt 25d.