Substituted phenyl 2-thiophenecarboxylates and benzoates: synthesis, NMR spectra, and aromaticity index

A series of m-, and p-substituted phenyl 2-thiophenecarboxylates and benzoates was prepared by the reaction of the corresponding acyl chlorides and phenols. Their 1H and 13C NMR chemical shifts were analyzed using single substituent parameter (SSP) and dual substituent parameter (DPS) methods. The relative aromaticity index of thiophene was estimated to be 0.92 from the plot of the chemical shift of the carbonyl carbons of the thienoyl esters against chemical shift of the carbonyl carbons of the benzoyl esters