Substituent electrophilicities in the NMR spectra of barbituric derivatives

Comparison of the 1H and 13 C NMR spectra of a series of substituted 5‐benzylidene‐N,N′‐dimethylbarbituric acids (1) revealed chemical‐shift variations of different centers that correlated with the theoretical electrophilicities or with the substituent electrophilic constant σω , in an example of the usefulness of these DFT‐based indices. Copyright © 2012 John Wiley & Sons, Ltd. NMR spectra are described for a series of substituted 5‐benzylidene‐N,N′‐dimethylbarbituric acids. Data correlate with global electrophilicities and with electrophilic substituent constants σω. The results validate a general Hammett‐like approach based on DFT‐based electrophilicities.