Facile and concise procedures for the construction of indole fused N-heterocyclic systems were described. A series of benzo-, pyrido-, thieno-, naphtho-fused azepinoindolones and indolo-azepinoquinolinones has been prepared starting from indol-2-acetic acids. The required starting carboxylic acids 3a–e were readily obtained by the N-arylations of indoleacetic acid 1 with various aromatic halides 2a–e. Subsequent carboxylic acids were esterified, followed by the addition of Grignard reagents to afford the corresponding indole-based alcohols 5a–e. The key step in this protocol is the Friedel–Crafts cyclisations of these precursors promoted by AlCl3/CH3NO2 or trifluoromethanesulfonic acid (TfOH) or polyphosphoric acid (PPA) catalysts to form the desired condensed indoles in moderate to good yields.
Research Abstract	
              Research Date	
              Research Department	
              
          Research Journal	
              Australian Journal of Chemistry
          Research Member	
          
      Research Publisher	
              CSIRO PUBLISHING
          Research Website	
              https://www.publish.csiro.au/CH/CH25003
          Research Year	
              2025
          Research Pages	
              1-15