Synthesis and structure-activity relationships of new carbonyl guanidine derivatives as novel dual 5-HT2B and 5-HT7 receptor antagonists

A series of carbonyl guanidine derivatives have been discovered as potent dual 5-HT2B and 5-HT7 receptor antagonists. N-(9-Hydroxy-9H-fluorene-2-carbonyl)guanidine (10) had a good in vitro profile and showed a suppressing effect on 5-HT-induced dural protein extravasation in guinea pigs when orally administered.