1,4-Dihydropyridine-3-carboxylates having the general formula
and the pharmacologically acceptable salts thereof are found to exhibit marked coronary vasodilating, hypotensive and other vasodilating actions with very little toxicity, so that they can be widely applied as remedies for circulatory diseases.
A series of 1, 4-dihydropyridine-5-cyclic phosphonate derivatives, designed as analogues of 1, 4- dihydropyridine-3, 5-dicarboxylate calcium antagonists, was synthesized and examined for antihypertensive activity. Several compounds were proved to have activities superior or comparable to that of nifedipine in lowering blood pressure in normotensive and spontaneously hypertensive rats (SHR). Among these compounds, methyl 2, 6-dimethyl-5- (2-oxo-1, 3, 2-dioxaphosphorinan-2-yl) -4- (2-nitrophenyl) -1, 4-dihydropyridine-3-carboxylate (31, DHP-218) was approximately 7 times more active than nifedipine in SHR and was selected for further development and clinical evaluation. The structure-activity relationships are discussed.