relation: http://publicatio.bibl.u-szeged.hu/32180/ title: Electronic effects in the electron ionization fragmentations of 2‐aryl substituted octahydro‐1,3‐ and ‐3,1‐benzoxazines creator: Vainiotalo Pirjo creator: Lehtela Pirjo-Liisa creator: Fülöp Ferenc creator: Bernáth Gábor creator: Vuorilehto Lauri creator: Pihlaja Kalevi subject: 03.02. Klinikai orvostan description: The 70 eV electron ionization mass spectra of 27 2-aryl substituted octahydro-1,3- and -3,1-benzoxazines have been recorded in order to find out how the site and stereochemistry of the ring fusion and especially the nature of the substitutent X on the 2-phenyl group affect their fragmentation patterns. The structural isomers showed clearly different spectra; however, stereoisomeric differentiation was possible only with 1,3-derivatives. The fragment-ion peaks connected with the ionized ring and open chain forms of the compounds studied were clearly present in all the spectra. Analogously to the results obtained in solution, the electron-withdrawing ability of X increased the abundance of the fragments originating from the ring form. Also, the relative importance of different fragmentation channels varied according to the electron donating or withdrawing ability of the substituent X. date: 1993 type: Folyóiratcikk type: PeerReviewed format: text identifier: http://publicatio.bibl.u-szeged.hu/32180/1/aok_klny_808_93.pdf identifier: Vainiotalo Pirjo; Lehtela Pirjo-Liisa; Fülöp Ferenc; Bernáth Gábor; Vuorilehto Lauri; Pihlaja Kalevi: Electronic effects in the electron ionization fragmentations of 2‐aryl substituted octahydro‐1,3‐ and ‐3,1‐benzoxazines. RAPID COMMUNICATIONS IN MASS SPECTROMETRY, 7 (6). pp. 465-469. ISSN 0951-4198 (1993) identifier: doi:10.1002/rcm.1290070613 relation: https://doi.org/10.1002/rcm.1290070613 relation: 28005 language: eng