Cross-conjugated and pseudo-cross-conjugated mesomeric betaines, XVIII: Bicyclic mesoionic pyrimidines with cardiovascular activity.

Reaction of alpha-Anilino-azines 1a-i with activated malonates (magic malonates) 2a-e leads to bicyclic mesoionic systems 3-7. Out of these, pyrimido[1,2-alpha]pyrimidines 3b,d are active as cardiotonics, whereas pyrimido[1,2-alpha]pyrimidines 4a-g show significant anti-anginal and anti-hypertensive activity.