Thiourea is an inexpensive, efficient and mild catalyst for the synthesis of Knoevenagelcondensation of pyrozoles derivate. In the presence of 10 mol% of thiourea, pyrazole aldehyde react with active methylene compound under microwave‐assisted solvent‐free conditions at 300 W for 2‐5 min to give corresponding products in good yields.
A green and efficient methodology has been developed for the construction of 2-[(1,3-diaryl-4-pyrazolyl)methylene]malononitriles, potent antioxidant molecules, in good to excellent yields in five minutes from 1,3-diarylpyrazole-4-carbaldehydes and malononitrile using PEG-400 and water at ambient temperature under catalyst-free conditions. The PEG-400 could be reused without appreciable loss in the yield. The methodology has been extended to the synthesis of a diverse range of homo/heteroaryl-based nitriles and acrylates, reflecting its versatility.