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 ##STR1## wherein A, B, C and D are -- N, HN, R.sub.3 N, OC, HC.tbd., HO--C.tbd. or R.sub.3 SO. sub.2 --O--C.tbd.; andPPR.sub.1 and R.sub. 2 are substituents of various types.PPThe compounds are useful as hypotensives and cardiotonics.