Synthesis of fused 1,4-dihydropyridines as potential calcium channel blockers

Objective: The aim of this study was to synthesize ten 1,4-dihydropyridine (DHP) derivatives in which substituted cyclohexane rings were fused to the DHP ring and to determine how different ester groups and the benzoyl substituent introduced in 4-phenyl ring affected their calcium channel blocking activity. Methods: A microwave-assisted one-pot method was applied for the synthesis of compound 1-5 according to a modified Hantzsch reaction. The benzoyl moiety was introduced in the 4-phenyl ring of these dihydropyridines by refluxing with benzoyl chloride in acetone in the presence of anhydrous potassium carbonate. Synthesized products were characterized by elemental analysis, IR, H-1-NMR and C-13-NMR spectroscopy. The inhibitory actions of compounds 1-10 on calcium channel blocking activity were tested on isolated rat aorta preparations. Results: The obtained pharmacological results showed that although all compounds are potent relaxing agents on isolated rat aorta smooth muscle, introduction of a benzoyloxy substitiuent on the phenyl ring (compound 6-10) decreased the relaxant effect of these compunds. Conclusion: The reported 1,4-DHP derivatives have calcium channel blocking activity on rat aorta smooth muscle.