Synthesis of Indazoles via N-N Bond-Forming Oxidative Cyclization from 2-Aminomethyl-phenylamines

Org Lett. 2024 Feb 16;26(6):1229-1232. doi: 10.1021/acs.orglett.4c00036. Epub 2024 Feb 5.

Abstract

Herein we report a method for the synthesis of indazoles from readily available 2-aminomethyl-phenylamines via N-N bond-forming oxidative cyclization. Inspired by indazole formation initially observed as a side product by N. Coskun et al. we developed a robust protocol to access indazoles in all three tautomeric forms. The method selectively gives access to various 2-substituted 2H-indazoles which are frequently used in drug design, and we also demonstrated its applicability to less studied 3H-indazoles.