Electrosynthesis of Oxazol‐2(3H)‐Ones and Diaroylhydrazines from 1, 2‐Dicarbonyl Compounds and Arenediazonium Salts. Issue 16 (28th March 2019)

• Record Type: Journal Article
• Authors: Barba, Fructuoso; Quirós, Irene; Salgado, Antonio; Batanero, Belen
• Is Part Of: ChemElectroChem. Volume 6:Issue 16(2019)
• Page Start: 4246
• Page End: 4251
• Publication Date: 2019-03-28
• Subjects: 1, 2-diaroylhydrazines -- 3-methyl-oxazol-2(3H)-ones -- electrochemical reduction -- N-methylformamide -- radical coupling; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201900299
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: New five‐membered oxazol‐2(3 H )‐one heterocycles and 1, 2‐diaroylhydrazines are obtained in good yield when 1, 2‐dicarbonyl substrates are reduced at the cathode in N‐ methyl formamide/LiClO4 as solvent‐supporting‐electrolyte system, and in the presence of arenediazonium salts. Electrochemical pathways are presented to involve a) cascade reactions: hydrogen atom abstraction from a solvent molecule, radical coupling reaction with substrate intermediate, and intramolecular migration of a methylamino group, to provide oxazolones or b) surprising C−C bond cleavage in the substrate radical anion, assisted by a diazonium salt, that evolves to disubstituted arylhydrazides. Abstract : Electrochemical preparative‐scaled concomitant reduction of aromatic 1, 2‐dicarbonyl substrates and arenediazonium tetrafluoroborates in N‐ methylformamide/LiClO4 as solvent‐supporting‐electrolyte system is used to obtain new five‐membered oxazol‐2(3 H )‐one heterocycles and 1, 2‐diaroylhydrazines in good yield.