Author's Organization：/ Faculty of Pharmaceutical Sciences, University of Chiba Department of Pharmaceutical Sciences, National Institute of Radiological Sciences Faculty of Pharmaceutical Sciences, University of Chiba Department of Pharmaceutical Sciences, National Institute of Radiological Sciences
Fragmentation of methyl substituted oxindoles (I-V) and 2-indolinethiones (VI-X) induced by electron impact were investigated. Main fragments of the oxindoles are M-Me, M-CO, and M-HCO. M-1, M-S and M-SH are main fragments in the indolinethiones and M-CS is observed as a minor fragment. Fragmentation of 1, 1'-dimethyl-3, 3'-bioxindole and its thione derivative are also discussed.
