Solvent-Free Synthesis of Pyrazole Derivatives Mediated by Cobalt-Doped Iron Tartarate

A novel, green, and economically viable method for the one-pot synthesis of 5-amino pyrazole 4-carbonitrile has been established. This approach features the solvent-free reaction between substituted benzaldehyde, malononitrile, and phenyl hydrazine catalyzed by CoFe₂(C₄H₄O₆)₃·6H₂O. The elimination of solvent renders this methodology highly attractive from both cost-effective and environmental perspective. Moreover, the optimized reaction conditions offer operational simplicity, utilize readily available and affordable starting materials, and deliver good to excellent yields (72–92%). The versatility of this protocol is demonstrated by the successful synthesis of ten distinct pyrazole derivatives.