Electrochemical Cyclization of Hydrazones and Amidines To Access Trisubstituted 1,2,4-Triazoles

Abstract

KI-mediated electrochemical method for the synthesis of trisubstituted 1,2,4-triazoles from easily accessible hydrazones and amidines derivatives has been developed.The protocol provides various aryl and alkyl 1,2,4-triazoles in moderate to good yields, which achieves with good functional group tolerance and without the need for any chemical oxidants in an undivided cell.

Synthesis of 3,4,5-Trisubstituted 1,2,4-Triazoles via I2-Catalyzed Cycloaddition of Amidines with Hydrazones

“…Then, the nucleophilic addition of N -phenylbenzamidine 2a to species A generates species B , which is next transformed into species C via intramolecular electron transfer. Subsequently, species C undergoes an intramolecular nucleophilic attack to afford species D , followed by reductive elimination to form species E and deliver HI . Finally, the elimination of Ts-NH 2 ,,, from species E gives the product 3aa, and HI is oxidized to I 2 by air to finish the catalytic cycle.…”

Selected Electrosynthesis of 3-Aminopyrazoles from α,β-Alkynic Hydrazones and Secondary Amines

“…In the past decade, electrosynthesis has been exhibited as a powerful synthetic methodology and attracted extensive attention from organic chemists . The electrochemical strategies features with using electrons as redox reagents, which is in accord with the demand for green chemistry, and our group has a continuation interesting in the synthesis of valuable heterocyclic compound by electrochemical tools, especially in the iodine-mediated indirect electrosynthesis. According to the previous literature and our reported works, the electrochemical anodic oxidation of iodide leads to highly active iodine species, which can efficiently activate the N–H bonds, unsaturated bonds, and sulfur/selenium compounds .…”