Effects of the Nitrone Group in NMR Spectra of α,N-Diphenylnitrones

The NMR and UV spectra of α,N-diphenylnitrone and its derivatives which have a substituent at the para position of the α-phenyl group and some of which have in addition a methyl substituent at the ortho position of the α-phenyl group were measured. Examination led to the following conclusions. The NMR signal of the ortho protons of the α-phenyl group appears at a very low field. This is mainly attributed to the direct effect of the negatively charged oxygen atom of the nitrone group. Increase in the electron-donating power of the para substituent enhances this effect.