The electron-ionization induced mass spectra of some N-monosubstituted fluoroacetamides of the general formula FCHAONH-R, in which the substituent R is ( C d , ) cycloalkyl, phenyl, 4-methylphenyl, 4-carbomethoxyphenyl, 4-nitrophenyl and 4-diethylaminophenyl, were recorded and their fragmentation patterns were studied by metastable-ion analyses.As part of an effort to correlate the toxicological properties of various fluorine-containing organic compounds with chemical several workers have investigated N-monosubstituted fluoroacetamide~.~,' Moreover, for example, various N-mono-and N,N-disubstituted fluoroacetamides6 and N-methylenefluoroacetamide derivatives7 have been tested as potential larvicides, contact insecticides and rodenticides.In order to characterize the structure/fragmentation characteristics of these compounds, the mass spectrometric fragmentation of ten N-monosubstituted fluoroacetamides are described. Depending on the nature of the substituents on the nitrogen atoms, the amides examined have been grouped into two different series: N-(C3-C,) cycloalkyl and N-Csubstituted phenyl. These compounds are listed in Table 1.Information concerning the fragmentation routes, the effects of overall and partial structure, as well as of the amide group substituents, on the fragmentation pattern, were obtained by the study of the reaction of metastable ions.
EXPERIMENTALThe syntheses of various N-monosubstituted fluoroacetamides of the general formula FCH,-CONH-R, in which the substituent group is (C3-C7) cycloalkyl, have been reported elsewhere.' The syntheses of the N-4-substituted phenyl fluoroacetamides were performed by the acylation of corresponding 4-substituted anilines with fluoroacetyl chloride. The reactions were carried out in the presence of a 70% aqueous solution of potassium hydroxide, while the temperature of the reaction mixture was maintained at 5-15 "C. The structures of the carefully purified synthetic N-monosubstituted fluoroacetamides were confirmed on the basis of infrared, nuclear magnetic resonance and mass spectrometric data. All the synthesized compounds had very high purity (GC) and satisfactory elemental C, H, N analyses. Mass spectra were taken on a type 311 A reversedgeometry mass spectrometer (Varian MAT, Bremen, FRG), using a direct probe and 70 eV ionizing energy with an emission current of 6OOpA. Samples were introduced through a direct-inlet system at a source temperature of 100-120 "C. Metastable peaks were studied by the usual DA and DAD1 techniques.
RESULTS AND DISCUSSIONThe mass spectra of the N-monosubstituted fluoroacetamides (1-10) are presented in Table 2. The principal
(9)Intensities expressed as % base peak.