Cardiotonic activity of 2,5-dimethoxyphenylimidazo[2,1-b]thiazoles

We report about the synthesis and the activities of imidazo[2,1-b]thiazoles and -thiazolines bearing a 2,5-dimethoxyphenylgroup at position 6. The inotropic activity was investigated in isolated guinea pig atria. Compound 10 shows a strong positive inotropic activity: it increases the myocardial contractility in normal and hypodynamic heart muscle.