Engineered anion π complex with non-covalent π interaction system and its catalytic ability on the cyclocondensation reaction of 2-aminobenzimidazole, aryl aldehyde and ethyl acetoacetate

The specific-task engineered anion π complex namely N-sulfopyridin-1-ium monozinc (II) trichloride {[NSPy]ZnCl3} was used as a catalyst for the cyclocondensation reaction of 2-aminobenzimidazole, aryl aldehyde and ethyl acetoacetate with interesting mechanism to give 4H-pyrimido[2,1-b] benzimidazoles in high yields and short reaction times. The designed complex with non-covalent π interaction between [Pyridine–SO3H]Cl and zinc (II) can be acted as multipurpose and efficient catalyst for the preparation of the expected products.