13C- and 1H-NMR substituent-induced chemical shifts in N(1)-(4-substituted phenyl)-3-cyano-4,6-dimethyl-2-pyridones

Abstract

The 13C- and 1H-NMR chemical shifts of thirteen N(1)-(4-substituted phenyl)-3-cyano-4,6-dimethyl-2-pyridones were measured in deuterated dimethyl sulfoxide (DMSO-d6). The correlation analysis for the substituent-induced chemical shifts (SCS) with sigmap, inductive (sigmaI) and different scale of resonance (sigmaR) parameters were performed using the SSP (single substituent parameter), DSP (dual substituent parameter) and DSP–NLR (dual substituent parameter–non-linear resonance) methods. The results of the calculations concerning the polar and resonance effects satisfactorily describe the substituent effects at the carbon atoms of interest. The mode of transmission of the substituent effects, both inductive and resonance, in relation to the geometry of the investigated pyridones is discussed.

Keywords

• 13C-NMR substituent chemical shifts
• linear free energy relationships
• N(1)-(4-substituted phenyl)-3-cyano-4
• 6-dimethyl-2-pyridones