Anti-hypertensive activity of ergolinyl-ureido and thioureido derivatives

Structural modifications of 6-methyl-ergolinyl-8β-methanamine afforded a series of thioureas and ureas with interesting cardiovascular activities. Studies of their anti-hypertensive effects in spontaneously hypertensive rats and anesthetized dogs indicated that the thio-group could be effectively replaced with a carbonyl function. Replacement of the acylurea residue with a rigid structure, such as dihydrouracyl, yielded a compound with a longer-lasting anti-hypertensive effect.