Synthesis of 6-substituted 2-pyrrolyl and indolyl benzoxazoles by intramolecular O-arylation in photostimulated reactions

J Org Chem. 2012 Feb 3;77(3):1507-19. doi: 10.1021/jo202386b. Epub 2012 Jan 19.

Abstract

The synthesis of a series of 6-substituted 2-pyrrolyl and 2-indolyl benzoxazoles by photostimulated C-O cyclization of anions from 2-pyrrole carboxamides, 2-indole carboxamides, or 3-indole carboxamides has been found to proceed in good to excellent yields (41-100%) in DMSO and liquid ammonia. The pyrrole and indole carboxamides are obtained in good to very good isolated yields by an amidation reaction of different 2-haloanilines with 2-carboxylic acid of pyrrole and 2- or 3-carboxylic acid of indole. To explain the regiochemical outcome of these reactions (C-O arylation vs C-N or C-C arylation), a theoretical analysis was performed using DFT methods and the B3LYP functional.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzoxazoles / chemical synthesis*
  • Benzoxazoles / chemistry*
  • Chemistry Techniques, Synthetic / methods*
  • Electron Transport
  • Indoles / chemistry*
  • Photochemical Processes*
  • Pyrroles / chemistry*

Substances

  • Benzoxazoles
  • Indoles
  • Pyrroles