Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
The 15N chemical shifts of various m- and p-substituted anilides and related derivatives, ZNHC6H4Y [Z = C6H5CO, CH3CO, CF3CO, CH3SO2, (C6H5O)2PO and H], were correlated with σ- constants. With all series of anilides investigated, the plotted points for the m- and p-substituted derivatives tend to be separated from each other and to lie on two different regression lines. Reinvestigation from this point of view revealed that similar separations occur generally with substituted aniline derivatives. The anomalous polar substituent effect was ascribed to the very large contribution of a resonance effect. In addition, the local π-polarization effect causes a negative slope for the m-substituted series in the case of carboxylic anilides.
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