Inotropic 2-arylimidazol[1,2-a]pyrimidines

Abstract A series of 2-arylimidazo[1,2- a ]pyrimidines has been prepared and evaluated for inotropic activity. Three of these heterocycles, ether 19 , sulphide 21 and mesylate 24 displayed more potent inotropic effects in vitro than isomazole. The in vivo inotropic potencies of 4′-mesylate 24 and 4′-carboxamido analogue 23 were similar to those of isomazole and sulmazole respectively. The effects of some ‘A’ and ‘C’ ring substituents on the inotropic activities of the imidazo[1,2- a ]pyrimidines were different from those on the imidazopyridines. Nevertheless the inotropic potencies of several imidazo[1,2- a ]pyrimidines were closer to those of their 1 H -imidazo[4,5- b ]pyridine isomers than to those of the corresponding isomazole analogues. Structure-activity relationships are discussed in detail.