Copper-catalysed N-arylation of 5-aminopyrazoles: a simple route to pyrazolo[3,4- b]indoles

Org Biomol Chem. 2020 Aug 26;18(33):6571-6581. doi: 10.1039/d0ob00812e.

Abstract

A copper-catalysed intramolecular N-arylation of 5-aminopyrazoles is demonstrated for the first time. Highly substituted pyrazolo[3,4-b]indoles are synthesized. In particular, the indole core is decorated with halogens and alkyl and methoxy groups. Furthermore, a selective N-arylation of unsymmetrical diaryl bromide containing pyrazoles is exemplified, resulting in valuable pyrazolo[1,5-a]benzimidazoles.