The steric course of some electrophilic additions to the tetrahydropyridazine ring moiety of benzo[g]phthalazino[1,2-b]pyridazine-6,13-dione derivatives. I.

Article abstract of DOI:10.1016/S0040-4020(01)80523-8

The functionalization of ring A in diazatetracyclic analogues of anthracyclinones via electrophilic addition of psotive halogen sources has been investigated. Bromine azide, iodine azide, NBS/H₂O/DMSO and NBS/EtOH were the reactions of choice. Dehydrohalogenation and further regiospecific addition products to the C-1/C-2 double bond have been found in most cases besides the expected addition compounds. Conformational homogeneity and trans-axial orientations are shown by all the isolated compounds. The influence of the attacking species over the nuycleophilic step and that of the carbonyl neighbouring group over the conformational features have been evaluated.