Gas Phase Reactions OF 1,2:5,6-DI-O-Isopropylidene-α-D-Gluco- and Allofuranose with Electrophiles Derived From Acetone

ABSTRACT

In a quadrupole mass spectrometer, under chemical ionization conditions with acetone as the reagent gas, 1,2:5,6-di-O-isopropylidene-β-D-glucofuranose and 1,2:5,6-di-O-isopropylidene-β-D-allofuranose form M+1, M+43, and M+59 ions in the gas phase. In addition, the allo isomer produces M+41 ions. These ions and the corresponding ions derived from isotopomers in which the isopropylidene groups were differentiated by deuterium substitution were separately subjected to collisionally activated dissociation conditions. The different reactivities of these ions were attributed to the ability of the allo structure to hydrogen bond internally and the different sizes of the electrophilic groups which formed adducts with the neutral protected sugar molecules.