Electron ionization mass spectra of naphthoxazine, naphthpyrrolooxazinone and naphthoxazinobenzoxazine derivatives

Abstract

Some naphthoxazinobenzoxazines (1a, 1b, 2a-2d, 3a, 3b), naphthoxazines (4a, 4b, 5, 6a, 6b) and naphthpyrrolo-oxazinones (7, 8a, 8b) were studied using mass spectrometry to find out regioisomeric effects and the effects of substituents. As expected the spectra of regioisomeric pairs la-3a vs lb-3b were very different. For example the relative abundances of molecular ions were higher for la-3a and the [M - OH]+ ions were observed only for them. Compounds derived from (1-α-aminobenzyl)-2-naphthol were usually characterized by abundant m/z 231 ions and l-aminomethyl-2-naphthol derivatives by m/z 156 ions. Ions related or similar to their complementary ions were also observed. Many of the studied compounds exhibited fairly abundant ions [M - C17H 11O2]+ (1a, 2a, 3a: [M - 247]+), [M - C17H11O2]+· (2b-2d: [M - 232]+·) or ion [M - C17H11O 2]+· (1b, 5, 6a, 7: [M - 156]+). The results may be useful when making regiochemical conclusions. © ARKAT USA, Inc.