Electrochemically driven reductive cyclization of o-nitroanilines: synthesis of 1,2-fused benzimidazoles and benzo[d]imidazoles

Saetan, Jutamart; Purahong, Nitchakan; La-Ongthong, Kannika; Hassa, Nattawoot; Chotsaeng, Nawasit; Kuhakarn, Chutima; Meesin, Jatuporn

doi:10.1039/d5ob00214a

Electrochemically driven reductive cyclization of o-nitroanilines: synthesis of 1,2-fused benzimidazoles and benzo[d]imidazoles

Author(s)

Saetan, Jutamart

Purahong, Nitchakan

La-Ongthong, Kannika

Hassa, Nattawoot

Chotsaeng, Nawasit

Kuhakarn, Chutima

Meesin, Jatuporn

Date Issued

March 31, 2025

Type

Article

DOI

10.1039/d5ob00214a

Abstract

The electrochemical synthesis of 1,2-fused benzimidazoles and benzo[d]imidazoles from o-nitroanilines in an undivided cell under constant current conditions was developed. The electrosynthesis proceeded through a tandem process involving nitro reduction/C(sp³)-H amination/condensation. The method can accommodate a broad range of o-nitroanilines and results in the desired products in yields of up to 99%. A plausible reaction mechanism was proposed on the basis of controlled experiments and cyclic voltammetry (CV) analysis. The benefits of the developed method include one-pot synthesis, open-air conditions, gram-scale synthesis and no requirement for a strong reductant.

Citation

Organic and Biomolecular Chemistry, 23(17), 4226-4231, 2025