Studies on dihydropyridines. II. Synthesis of 4,7-dihydropyrazolo(3,4-b)pyridines with vasodilating and antihypertensive activities.

Abstract

A series of 4-aryl-4, 7-dihydropyrazolo [3, 4-b] pyridine-5-carboxylate derivatives (72-149) was prepared and the compounds were tested for Ca-blocking activity in isolated guinea pig portal vein, antihypertensive activity in spontaneously hypertensive rats, and coronary vasodilating effect in isolated guinea pig heart. A number of derivatives had potent antihypertensive and coronary vasodilating activities. The structure-activity relationships of the series indicated that a 3-cyclopentyl or 3-cyclohexyl substituent and a hydrophobic 5-ester moiety with moderate bulkiness were effective for increasing the pharmacological potencies.