Functionalization of the Ring A in Some Benzo[g]pyridazino[1,2-b]- phthalazine-6,13-dione Derivatives Related to Anthracyclinones

A synthesis of benzo[g]pyridazino[1,2-b]phthalazine-6,13-dione derivatives (2) and (3), respectively related to the feudomicinone B and daunomicinone skeletons, has been accomplished by [4+2] cycloaddition of benzo[g]phthalazine-1,4-dione with the adequate 1,3-diene.Functionalization of ring A with hydroxy substituents has been performed by reaction with Nbromosuccinimide in acid aqueous medium, sodium hydroxide, or hydrobromic