Imidazo[4,5-c]pyridazine-3-ones, imidazo[4,5-d]pyridazine-4-ones, imidazo[4,5-b]pyrazin-5-ones, purin-2-ones, purin-6-ones, and purin-2,6-diones useful as hypotensive or cardiotonic agents

摘要

Compounds of the formula <IMAGE> wherein A, B, C and D are -N+50, HN=, R3N=, O=C=, HC 3BOND , HO-C 3BOND or R3SO2-O-C 3BOND ; and R1 and R2 are substituents of various types. The compounds are useful as hypotensives and cardiotonics.