Mini-Review of the Importance of Hydrazides and Their Derivatives—Synthesis and Biological Activity

Organic acid hydrazides include a vast group of organic derivatives of hydrazines containing the active functional group (-C(=O)NHNH2). Acid hydrazones were important bidentate ligands and show keto-enol (amido-iminol) tautomerism. They usually exist in keto form in the solid-state while in equilibrium between keto and enol forms in solution state. Such hydrazones were synthesized in the laboratory by heating substituted hydrazides or hydrazines with corresponding aldehydes or ketones in different organic solvents such as ethanol, methanol, butanol, tetrahydrofuran, etc., and some cases with the ethanol-glacial acetic acid or acetic acid alone. Hydrozones are very important intermediates for the synthesis of heterocyclic compounds and also have different biological activities. The organic chemist would have more interest in the synthesis of acid hydrazides and their derivatives because of their properties. These derivatives having wide applications as chemical preservers for plants, drugs, for manufacturing polymers, glues, etc., in industry and many other purposes. These acid hydrazides and their derivatives were found to be useful synthons for various heterocyclic five, six or seven-membered rings with one or more heteroatoms that were exhibited great biological, pharmacological and industrial applications. This paper will present a review of the chemistry and pharmacological potentials of hydrazide-hydrazones. The various synthetic routes for hydrazone, as well as antibacterial, antifungal and antiviral potentials, have been elaborated in brief.