1980 Volume 28 Issue 3 Pages 249-262
The mass spectra of anilides represented general formula o- or p-ClC6H4NHCOR (R=H,CH3~C3H7, i-C3H7) and substituted formanilides (R=H) and acetanilides (R=CH3) were measured to determine the effect of R and substituent on anilide fragmentation.
The mass spectra of anilides of R = CH3~C3H7, i-C3H7 independent of length of R indicated almost the same fragmentation, qualitatively and quantitatively except for the -CO-R bond simple cleavage in R=C2H5, C3H7, i-C3H7. But, those of formanilides were characterized by fairly strong M+·, strong fragments produced from [M-ketene]+·, prominent o-effect ([M-Cl]+) and weak fragments produced through the -NH-CO- bond cleavage involving ketene elimination, and little HC≡O+.
In investigations of mono substituted formanilides and acetanilides, it was found that o-isomeres (Cl, NO2, NH2, CH3, C2H5) produced specific fragment ions but almost all p- and m-isomeres didn't. This o-effect was stronger in formanilides than in acetanilides and [M-OH]+ ions from o-alkyl isomeres were recognized only in formanilides.
It was concluded that three isomeres (o-, m-, or p-) in nitroformanilide, methoxy-formanilide, aminoformanilide and aminoacetanilide could be identified.
