The electron ionization (EI) and collision-induced dissociation (CID) spectra of substituted N-(ortho-cyclopropylphenyl)benzamides 1-7 and N-[ortho-(1-methylcyclopropyl)phenyl]benzamides 8-12 were recorded. In addition to routine bond cleavages, the molecular ions (M+) of 1-12 undergo cyclization into the corresponding 3-aryl-1-alkyl-1-ethyl-1H-benzoxazines and isomeric 5-ethyl-2-oxodibenzoazepines. The presence of a methyl group in the cyclopropyl ring (compounds 8-12) makes the formation of 5-ethyl-2-oxodibenzoazepine less favorable. In accord with mass spectrometric predictions, compound 13 (3-p-tolyl-1-ethyl-1H-benzoxazine) was obtained as a major product of the reaction of N-(ortho-cyclopropylphenyl)-4-methylbenzamide 1 with sulfuric acid. Traces of 5-ethyl-2-oxodibenzoazepine were also detected in gas chromatography-mass spectrometry (GC-MS) analysis of the reaction mixture although the yield was too low to allow its isolation.

Tbe collision-induced dissociation mass-analysed ion kiwtic energy (CID MIKE) spectra (electron impact and chemical ionization) of five adia~arykulpbonylaminoalkan-2~nes and corresponding N-arylsulpboaylazetidin-3-0and N-arylsulpboaylpyrrolidio-3-uiws were studied. The IM -Nzl*' and IMH -NzI + ioas of two types of tbe diazo ketows provide CID MIKE spectra similar to those of the corresponding M" and MH' of tbe heterocyclic compounds, i.e a cyclization analogous to that in solution takes place. For the otber three types of diazo compoumls the Wolff rearrangement prevails in both the gas and liquid phases. The eftect of the substitwnts on the cyclization process was studied The data obtained permit the results of acid-catalysed cyclizptioa of similar diazo ketones to be predicted on the basis of tbeir CID MIKE spectra. Chemical ionization provides a closer similarity with reactioas in solution than electron impact ionization, which can be rationalized by tbe protonation of the diazo Letow molecule being the driving force of the cyclization reaction either in solution or in the ion source of a mass spectrometer.