A novel nano alumina based Co (II) complex catalyst for synthesis of 5-substituted-1Htetrazoles

The use of heterogeneous catalysts for organic synthesis is rapidly growing over homogeneous catalytic systems because of theirseveral advantages such as high stability and tolerant to harsh reaction conditions, environmental friendliness, reusability of thecatalyst, 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 andemployment of acidic media [2]. Many methods for the synthesis of tetrazoles used high polar solvents such as DMF requires harshreaction conditions [3].Tetrazoles as one of the most important synthetic heterocyclic compounds have so many applications inorganic 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 afterformation a chain on alumina containing ester groups and then converting to amide groups by using of 1,2- diaminoethane, forhaving better functional group as ligand. Complexation of Co (II) with this functional group yielded a novel heterogeneous nanocatalyst. Then, a small amount of the catalyst was used to one pot reactions between aldehyde derivatives (1 mmol), hydroxylaminehydrochloride (0.10 mg, 1.5 mmol), sodium azide (0.10 g, 1.5 mmol), distilled water (5 mL) as green solvent and in roomtemperature to produce 5-substituted-1H-tetrazoles derivatives (Scheme 1), the products were obtained with high efficiency in ashort time.

کلیدواژه ها:

tetrazoles ، nano alumina ، heterogeneous catalyst: Co(II) complex