Cathodic Reduction of Phenacyl Azides

Abstract

The electrochemical reduction of phenacyl azides (1a−e) leads to the formation of 2-aroyl-4-arylimidazoles (2a−e) (70−80% yield). 1a−e were prepared from phenacyl bromides and sodium azide and were reduced in aprotic DMF-LiClO4 medium at the mercury cathode in a divided cell and under controlled potential.

An Efficient Combined Electrochemical and Ultrasound Assisted Synthesis of Imidazole‐2‐Thiones

“…NSubstituted imidazole-2-thiones have been also synthesized by the electrochemically induced cyclization of phenacyl azide thiosemicarbazones, on a mercury cathode. [8] The alternative way for the synthesis of these compounds is the one patented by Arduengo, [9] that is, the reaction of sulfur with an N-heterocyclic carbene, obtained by reaction of a strong base with an imidazolium salt, either in methanol over a period of 24 h, or in solventless conditions in 20 h, obtaining imidazole-2-thiones in high yields. The same reaction has been carried out by O. Yang and co-workers, [10] with BuLi in THF at À78 8C or with EtMgBr, in THF at room temperature; in this case the yields in thiones are 40- COMMUNICATIONS 84%.…”

Cyclization Reaction of 2‐Azido‐1‐(2‐hydroxyphenyl)ethanones with Terminal Alkynoates Catalyzed by 4‐Dimethylaminopyridine (DMAP): Synthesis of 2‐Aminobenzofuran‐3(2H)‐one Derivatives

“…Enolate 7 then undergoes Michael addition to 5 to give 8 with subsequent generation of 9 through another proton-transfer step. Intermediate 9 loses N 2 to be transformed into 10, [10] which then affords 11 through yet another proton-transfer step. Intermediate 11 might then undergo intramolecular nucleophilic addition to form intermediate 12, followed by proton transfer and elimination of DMAP to produce desired product 3a.…”

Electrochemical dimerization of phenacyl bromides N-acylhydrazones—a new way to 1-N-acylamino-2,5-diaryl-pyrroles

“…17 Electroreduction of 2a-f was accomplished in a divided cell on the mercury cathode. The first step in this process apparently involves two-electron cleavage of the carbon-bromine bond with the formation of anion A and bromide anion (Scheme 2).…”