A convenient synthesis of 2(2-benzo[<i>b</i>]furo)indoles and benzofuropyrazoles

1419-1423A short synthesis of benzo[b]furo indolyls 3a-g from 2-acetylbenzofuran 1 in two steps and corresponding pyrazoles 4a-g is described. An interesting scale-up procedure for the synthesis of 2-acetylbenzofuran is also been reported. Similarly 2-acetylbenzofurohydrazones 2a-g is prepared from 2-acetyl benzofuran and with various phenylhydrazine hydrochlorides in presence of CH3COONa/EtOH at RT in excellent yield (90-95%). These 2-acetyl benzofurohydrazones 2a-g are subjected to Fischer indole cyclisation in presence of ZnCl2 in acetonitrile as solvent to get 2(2-benzo[b]furo)indoles 3a-g in good yield