Hydrazones as versatile scaffolds: Structural features, NMR insights, and emerging applications

Hydrazones, derived from hydrazine, possess distinctive structural features and are widely applied in medicinal chemistry, material science, and agrochemical research. This review discusses hydrazones with diverse substituents, synthesized through various strategies, during the period from 2018 to 2025. Their spectroscopic characteristics are analyzed in detail, with particular emphasis on duplicate signals resulting from geometric and conformational isomerism. The impact of elevated temperature on the NMR spectra of hydrazones is also examined. Emerging application of hydrazones in the field of medicine and materials are also discussed. Overall, this work provides a comprehensive and latest overview of the conformational and geometrical properties of aroyl and acyl hydrazones, highlighting key developments over the past seven years. The insights presented are expected to serve as a valuable resource for chemists and researchers in developing and designing novel compounds with enhanced properties for diverse applications in medicine and chemistry.