A straightforward TBHP-mediated synthesis of 2-amidobenzoic acids from 2-arylindoles and their antimicrobial activity

Abstract

Synthesis of 2-amidobenzoic acids has been achieved through TBHP-mediated oxidative ring opening of 2-arylindoles. The synthesized compounds have been evaluated for their antimicrobial activity.

Selective Oxidative Cleavage of 3-Methylindoles with Primary Amines Affording Quinazolinones

“…Based on the above results and literature reports, ,− a plausible mechanistic pathway is illustrated in Scheme . First, tert -butoxyl and tert -butylperoxy radicals are easily formed by the exposure of TBHP to n -Bu 4 NI, , which initiates hydrogen abstraction of 1 to afford indolyl radical A and its resonance species B .…”

“…These results suggested that a free radical process was involved in the reaction. It was initiated by hydrogen abstraction of N–H bonds of indoles with tert -butoxyl or tert -butylperoxy radicals (vide infra) . The addition of 15 equiv of H 2 18 O to the reaction produced 3a in 68% yield without observation of 18 O-labeled product (Scheme , eq 2), which suggested that the carbonyl oxygen atom of the product came from TBHP .…”

“…First, tert -butoxyl and tert -butylperoxy radicals are easily formed by the exposure of TBHP to n -Bu 4 NI, , which initiates hydrogen abstraction of 1 to afford indolyl radical A and its resonance species B . According to the persistent radical effect, the adduction of longer-lived tert -butylperoxy radical to radical B affords intermediate C . Subsequently, the nucleophilic addition of amine to C forms D . , An intramolecular C–C bond cleavage of D with elimination of tert -butyl alcohol then produces intermediate E , , which can isomerize to intermediate F by intramolecular nucleophilic addition.…”

TBHP: A Sustainable Alternative For Carbon‐Oxygen Bond Formation

“…TBHP-catalysed synthesis of 2-amidobenzoic acids was reported by Patel and co-workers in 2019. [28] The oxidative ring opening reaction condition was adjusted by employing 2phenylindole (71) as model substrate. The model reaction attempted in presence of TBHP (3 equiv.)…”

Electrochemical Synthesis of 2-Aryl-3-(2-aminoaryl)quinoxalines via Oxidative Dearomatization/Ring-Opening/Cyclization Cascade Sequence of 2-Arylindoles with 1,2-Diaminoarenes

“…2-Arylindoles are central structural motifs in many pharmaceutically active compounds . Due to the inherent electron-richness of 2-arylindoles, oxidative-dearomative ring-opening transformations with different nucleophiles have recently been studied to access several heteroaromatic compounds. − Yan et al recently developed an interesting approach for synthesizing 2,3-diarylquinoxalines through NIS-mediated ring opening of 2-arylindoles with 1,2-diamino benzenes (Scheme b) . Besides, electrochemical organic transformations that use electrons as reagents for oxidative/reductive conversion and an excellent functional group tolerance under benign conditions have recently been influential in expanding modern organic synthesis. − Developing an environmentally benign organic-electrosynthesis approach for constructing privileged heterocycles has become a fascinating goal for synthetic chemists.…”