Regioselective alkylation of 1,3,4,5-tetrahydrobenzo[d]azepin-2-one and biological evaluation of the resulting alkylated products as potentially selective $$\hbox {5-HT}_{\mathrm{2C}}$$ 5-HT 2 C agonists

The benzazepine ring system has offered interesting CNS-active medicinal agents. Taking this privileged structure as the basic scaffold, $$\hbox {C}_{1}$$ and/or $$\hbox {N}_{3}$$ -alkylated benzazepin-2-one derivatives and their reduced analogs have been prepared as potential $$\hbox {5-HT}_{\mathrm{2C}}$$ receptor agonists. The selective alkylation at the $$\hbox {C}_{1}$$ and/or $$\hbox {N}_{3}$$ positions of this seven-membered lactam ring is here reported for the first time under different reaction conditions. The synthesized compounds were evaluated for their biological profile as potential $$\hbox {5-HT}_{\mathrm{2C}}$$ agonists using a classic pharmacological approach. Three derivatives (15, 17, and 20) have shown promising $$\hbox {5-HT}_{\mathrm{2C}}$$ agonistic activity which can be further optimized as anti-obesity agents for the treatment of male sexual dysfunction. Further, a homology model for $$\hbox {5-HT}_{\mathrm{2C}}$$ receptor was generated using MODELLER, and ligand–receptor interactions for these potential molecules were studied.