Studies on positive inotropic agents. IV. Synthesis of 5-(3-amino-2-hydroxypropoxy)-3,4-dihydro-8-hydroxy-2(1H)-quinolinone derivatives

Many 5- (3-amino-2-hydroxypropoxy) -3, 4-dihydro-8-hydroxy-2 (1H) -quinolinone derivatives were synthesized and examined for positive inotropic activity on the canine heart. These compounds were prepared by the reaction of 8-alkoxy-5- (2, 3-epoxypropoxy) -2 (1H) -quinolinone derivatives and various amines. Among them, 3, 4-dihydro-8-hydroxy-5-[3- (1, 1, 3, 3-tetramethylbutylamino) propoxy] -2 (1H) -quinolinone hydrochloride (IIIf) was found to have potent positive inotropic activity with a relatively minor increase in heart rate.