Author/Authors :
Huang، نويسنده , , Sha and Wong، نويسنده , , Jesse C.S. and Leung، نويسنده , , Adam K.C. and Chan، نويسنده , , Yee Man and Wong، نويسنده , , Lili and Fernendez، نويسنده , , Myrien R. and Miller، نويسنده , , Amanda K. and Wu، نويسنده , , Weiming، نويسنده ,
Abstract :
Substituents on the pyridinium ring of N-methylpyridinium derivatives, especially those on the 2- or 4-position, have a large effect on the 1H and 13C NMR chemical shifts of the N-methyl group. Reasonable correlations between the chemical shift changes and the resonance substituent constants are observed. The dual substituent parameter approach provides an excellent correlation when a combination of polar and resonance substituent constants is employed.
