Electrochemically induced synthesis of quinazolinones via cathode hydration of o-aminobenzonitriles in aqueous solutions

Abstract

An efficient and practical electrochemically catalyzed transition metal-free process for the synthesis of substituted quinazolinones from simple and readily available o-aminobenzonitriles and aldehydes in water has been accomplished.

Complementary Reactivity in Selective Radical Processes: Electrochemistry of Oxadiazolines to Quinazolinones

“…Herein, we report a selective electrochemical N–O bond cleavage at a controlled oxidation potential, which could not be achieved by photocatalytic electron transfer; the result was the same iminyl radical intermediate as with energy transfer photocatalysis, though with a different final product, quinazolinone (Scheme ). Notably, quinazolinone was previously generated under thermal conditions with O 2 by the Chiba group . Several control experiments and density functional theory (DFT) studies supported the electrochemical pathway of A , involving iminyl radical generation by oxidative N–O bond cleavage, the ipso attack of the radical on the tethered aryl ring, and the 1,2-migration of the carbonyl group to afford quinazolinone.…”

Electrochemical Organic Synthesis in Aqueous Media

“…[47] In 2021, the Fang group reported the condensation reaction of 2-aminobenzonitrile 18-1 and benzaldehyde 18-2 in water, producing aminal 18-3 in 90 % yield (Figure 18-a). [48] In comparison, using DMSO or THF as the cosolvent, the yield dropped to 86 % and 79 %, respectively. The reaction underwent a general intermediate 18-4 that was oxidized at the anode to furnish N-heterocycles.…”

Non-metal-mediated N-oxyl radical (TEMPO)-induced acceptorless dehydrogenation of N-heterocycles via electrocatalysis

“…Furthermore, our previous reports on electrochemical synthesis show high reactivity for acceptorless dehydrogenation of primary alcohols to aldehydes. 13 Therefore, simultaneous electron transfer and TEMPO-induced chemical reaction is a powerful tool to realize highly selective and relatively environmentally friendly CAD. Herein, we report such a reaction catalyzed by TEMPO to selectively generate nitrogen heterocycles under neutral conditions, with the evolution of H 2 as the only byproduct.…”