Synthesis and beta-adrenergic blocking action of a new thiazolylthiopropanolamine derivative

The synthesis of (+/-)-2-(3'-tert-butylamino-2'-hydroxypropylthio)-4-(5'-carbamoyl-2'-thienyl)thiazole hydrochloride is described. The new compound antagonized the cardiovascular effects, such as positive chronotropic, positive inotropic, or depressor arterial blood pressure responses, elicited by intravenous isoproterenol; it was 9--14 times as potent as propranolol in anesthetized open chest dogs. The oral administration of the compound reduced isoproterenol tachycardia in conscious dogs. It was about five times as potent as propranolol in this test, with maximal action after 1 hr, and its duration was significantly longer than that of propranolol.