Studies of substituent effects by carbon‐13 NMR spectroscopy. Thiophene and furan chalcone analogues

Abstract
13C NMR spectra of 39 thiophene and furan chalcone analogues in CDCl3 solutions are reported. The effect of substituents on the 13C chemical shifts in the phenyl and in the 5‐membered rings is discussed. 13C NMR shifts are correlated with Hammett parameters and with experimental shifts in the chalcone series.