Abstract: M+2 or M+3 Ion Peaks in the EI Mass Spectra of2─Isoxazoline DerivativesFu Guixiang; Li Chaozhong;Qi Weinian;Wu Yuanwei(Shanghai institute of Organic Chmistry,Chinese Academy ofSciences, Shanghai 200032, China )Received 1994-07-20Abstract:The EI mass spectra of 2-isoxazoline deravetives exhibit stong M+2 (or M+3) ionpeaks and do not show any molecular ion peaks. The relationship between the intensitiesof M+2 ion peaks and the evaporation temperature has been investigated. In order tounderstand the structure of M+2 inos and the other fragment ions,the high resolutionmass spectra of compound 1 and 3 have been examined.Keywords: 2-isoxazoline, EIMS, HRMS.