a novel nano alumina based co (ii) complex catalyst for synthesis of 5-substituted-1h-tetrazoles

The use of heterogeneous catalysts for organic synthesis is rapidly growing over homogeneous catalytic systems because of their several advantages such as high stability and tolerant to harsh reaction conditions, environmental friendliness, reusability of the catalyst, and easy to purify the products [1]. numerous methods have been reported in the literature for synthesis of 5-substituted-1h-tetrazoles, but much of them have some drawbacks including the use of strong lewis acids or expensive and toxic metals and employment of acidic media [2]. many methods for the synthesis of tetrazoles used high polar solvents such as dmf requires harsh reaction conditions [3].tetrazoles as one of the most important synthetic heterocyclic compounds have so many applications in organic chemistry, the photographic industry, coordination chemistry, explosives, and in particular, medicinal chemistry [4].in this research, we synthesized a new heterogeneous catalyst using alumina nanoparticles. this catalyst was synthesized after formation a chain on alumina containing ester groups and then converting to amide groups by using of 1,2- diaminoethane, for having better functional group as ligand. complexation of co (ii) with this functional group yielded a novel heterogeneous nano catalyst. then, a small amount of the catalyst was used to one pot reactions between aldehyde derivatives (1 mmol), hydroxylamine hydrochloride (0.10 mg, 1.5 mmol), sodium azide (0.10 g, 1.5 mmol), distilled water (5 ml) as green solvent and in room temperature to produce 5-substituted-1h-tetrazoles derivatives (scheme 1), the products were obtained with high efficiency in a short time.