Phosphomolybdic Acid (H₃Mo₁₂O₄₀P) as a Reusable Heterogeneous Catalyst for the Synthesis of 5-Substituted 1H-Tetrazoles via [2 + 3] Cycloaddition of Nitriles and Sodium Azide

Abstract

An efficient and practical protocol for the preparation of 5-substituted 1H-tetrazole derivatives is reported using phosphomolybdic acid as an effective heterogeneous catalyst. Good yields, simple methodology, and easy workup make this protocol more attractive for the diversity-oriented synthesis of these heterocycle libraries. The catalyst can be recycled three times with good yields.

GRAPHICAL ABSTRACT

Keywords:

• [2 + 3] Cycloaddition
• heteropoly acid
• nitriles
• sodium azide
• tetrazoles

ACKNOWLEDGMENTS

We appreciate the supportive environment at C. K. Thakur College. We are thankful to Dr. S. T. Gadade, principal, C. K. Thakur College, for his generous support. The authors are grateful to the University Grant Commission, New Delhi, and to the University of Mumbai for financial support. We are extremely grateful to Dr. Lucio Melone of Politecnico di Milano for helpful discussions.

Notes

^a Reaction conditions: benzonitrile (1 mol), sodium azide (1.5 mol), catalyst (2 mol %).

^b Isolated yield.

^a Reaction conditions: benzonitrile (1 mol), sodium azide (1.5 mol), catalyst (2 mol %).

^b Isolated yield.

^a Reaction conditions: nitriles (1 mol), sodium azide (1.5 mol), catalyst (2 mol %). Solvent: DMF. Temperature: 80 °C.

^b Isolated yield.

^a Isolated yield.