13C NMR Chemical Shifts Substituent Effects of (E)- and (Z)-N-ethyl-N-Methylamides

Carbon-13 NMR chemical shifts of a series of (E)- and (Z)-N-ethyl-N-methylamides [RC(O)NEtMe, R=H, Me, Et, i-Pr, t-Bu, CF 3 , ClCH 2 , Cl 2 CH, Cl 3 C, BrCH 2 , Br 2 CH, Br 3 C and ICH 2 ] are reported. The α-carbon and carbonyl carbon chemical shifts are correlated with the empirical α-substituent effect and Charton's electrical parameter ([sgrave] I ), respectively. The N-alkyl carbon resonances were attributed mainly to the γ- and δ-effects of R.