Catalyst-free coupling of indole derivatives with 3,4-dihydroisoquinoline and related compounds

The direct aza-Friedel-Crafts reaction of indole with 3,4-dihydroisoquinolines, 4,6-dihydro-3H-benzo[c]azepine and 6,7-dihydrothieno[2,3-c]pyridine led to the formation of 3-substituted indole derivatives. The reaction was also successfully extended to the synthesis of 3-substituted indole-2-carboxylic acids as new indole 7-amino acid derivatives. All the reactions were optimized and were accelerated under microwave conditions. (C) 2013 Elsevier Ltd. All rights reserved.