CONFORMATIONALLY RESTRICTED THIAZOLE DERIVATIVES AS NOVEL CLASS OF 5-HT3 RECEPTOR LIGANDS

A new series of tricyclic derivatives of 2-methyl-naphtho[1,2-d] thiaz ole were synthesized in order to investigate the effects of the confor mational restriction of bicyclic thiazole derivatives previously repor ted on the 5-HT3 receptor affinity. The basic moiety in these compound s is represented by the terminal nitrogen of N-methyl-piperazine or N- methyl-piperidine ring linked at 2-methyl. All the tricyclic derivativ es have a significant 5-HT3 receptor binding affinity and the terminal piperazine ring is more suitable than piperidine one.