MASS-SPECTRAL CHARACTERIZATION OF 3,4,6-TRI-O-BENZYL-BETA-C-GLUCOPYRANOSIDES CONTAINING XC6H4S SUBSTITUENTS OF C(2)

Electron impact mass spectra (70 eV) were generated for tri-O-benzyl-D -glucal and six XC6H5S substituted 3,4,6-tri-O-benzyl-beta-C-glucoside s which had been modified at C(2) by the introduction of an XC6H4S fra gment (where X = CH3 or Cl) in an effort to understand better fragment ation processes for the structural characterization of this important class of compounds. The model compounds which were synthesized were gl ucoside derivatives of CH2CHO, C(CH3)2CHO, CHCH=CHCO , C6H, and CN. Fo r all O-benzylated compounds, the benzyl moiety was the base ion; howe ver, the molecule ion of each modified glucoside was significantly abu ndant. A characteristic feature of S-containing C-glucosides was an ab undant CH3C6H5S-CHCH-CH, ion at m/z 163. Fragmentation of these C-gluc osides was interpreted in terms of positive charge localization on the molecule ion according to rules for normal carbohydrates. Knowledge o f the fragmentation on the S-containing C-glucosides should be useful for the characterization of additional new analogues.