Mass spectral characterization of 3,4,6-tri-O-benzyl-β-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-β-C-glucosides which had been modified at C(2) by the introduction of an XC6H4S fragment (where X = CH3 or CI) in an effort to understand better fragmentation processes for the structural characterization of this important class of compounds. The model compounds which were synthesized were glucoside derivatives of CH2CHO, C(CH3)2CHO, , C6H5 and CN. For all O-benzylated compounds, the benzyl moiety was the base ion; however, the molecule ion of each modified glucoside was significantly abundant. A characteristic feature of S-containing C-glucosides was an abundant CH3C6H5SCHCHCH2 ion at m/z 163. Fragmentation of these C-glucosides was interpreted in terms of positive charge localization on the molecule ion according to rules for normal carbohydrates. Knowledge of the fragmentation on the S-containing C-glucosides should be useful for the characterization of additional new analogues.