Oxidative cyclization of 3‐cinnamoyltropolones with I₂/DMSO/H₂SO₄ system

Abstract

Abstract magnified image In this study, a facile and general method synthesizing flavone‐like 2‐aryl‐4,9‐dihydrocyclohepta[ b ]pyran‐4,9‐diones ( 2a , 2b , 2c , 2d , 2e , 2f , 2g , 2h , 2i , 2j , 2k , 2l , 2m , 2n , 2o , 2p , 2q , 2r , 2s , 2t , 2u , 2v , 2w , 2x , 2y ) from 3‐cinnamoyltropolones ( 1a , 1b , 1c , 1d , 1e , 1f , 1g , 1h , 1i , 1j , 1k , 1l , 1m , 1n , 1o , 1p , 1q , 1r , 1s , 1t , 1u , 1v , 1w , 1x , 1y ) via oxidative cyclization reaction by using I 2 /DMSO/H 2 SO 4 system is described. The method was found to be successfully applicable to a wide range of 3‐cinnamoyltropolone derivatives and characterized by generality, compatibility, and easy work‐up procedures. J. Heterocyclic Chem., (2009).