Synthesis of Ferrocenylimidazo[1,2-a]pyridine-3-amines Using Catalyst ZrO(NO3)2.2H2O and their Theoretical Studies

In this study, synthesis of ferrocenylimidazo[1,2-a]pyridine-3-amines was reported from the condensation reaction of ferrocenecarboxaldehyde, 2-aminopyridine, and isocyanides using ZrO(NO3)(2).2H(2)O as an efficient, new, and reusable catalyst under reflux conditions in ethanol. The structures of the products were confirmed by IR, H-1 NMR, C-13 NMR, and elemental analysis. Quantum theoretical calculations for the structure of compounds (4a, 4b, and 4c) were done using the Def2 with the TZVPPD basis set. Geometric parameters were obtained from the optimized structures, and experimental results were analyzed with the calculated data. The structures of the products were proved by IR, H-1 NMR, C-13 NMR, and elemental analysis. Computations were carried out for the IR spectra data and H-1 NMR and C-13 NMR chemical shifts of the ferrocenylimidazo[1,2-a]pyridine-3-amine derivatives in the ground state. Ultimately, a great agreement was found between experimental and theoretical results.