Electron impact induced cyclization of ortho-cyclopropylphenylacetamides and benzamides. Prognosis for a similar reaction in solution

The electron impact and collision-induced dissociation spectra of N-(ortho-cyclopropylphenyl)acetamide (1), N-(ortho-cyclopropylphenyl)benzamide (2), N-(ortho-cyclopropylphenyl)bromoacetamide (3), N-[ortho-(1-methylcyclopropyl)phenyl]benzamide (4) and N-[ortho-(1-methylcyclopropyl)phenyl]acetamide (5) were studied. The molecular ions of these compounds were shown to undergo cyclization into the corresponding 3-substituted 1-ethyl-1H-2,4-benzoxazines (6-10). Following proposals made on the basis of mass spectrometry experiments, compound 7 was obtained by interaction of compound 2 with sulfuric acid. GC/MS experiments confirmed that the bromine-containing derivative 8 is the major product from the reaction of compound 3 with sulfuric acid.