Microwave‐assisted Vilsmeier‐Haack synthesis of Pyrazole‐4‐carbaldehydes

Abstract

Abstract The synthesis of 4‐formylpyrazoles using Vilsmeier‐Haack reagent is a common protocol in pyrazole chemistry. An efficient microwave‐assisted synthesis of 4‐formylpyrazoles by employing Vilsmeier‐Haack reagent (OPC‐VH) derived from phthaloyl dichloride/dimethylformamide has been described. This method offers the advantages of operational simplicity, avoiding the use of POCl 3 as toxic reagents and reuse of the by‐product in the preparation of phthaloyl dichloride.