Chemical ionization mass spectra of acetals of beta-D-glycopyranosylnitromethanes

O-Isopropylidene and O-benzylidene acetals of common 2,6-anhydro-1-deoxy-1- nitroalditols (beta-D-glycopyranosylnitromethanes) derived from D-glucose, D-galactose and D-mannose were studied by chemical ionization mass spectrom etry (CIMS) using methane, isobutane, ammonia or pyridine as reaction gas. Production of [M + H](+) adduct ions dominates in the case of methane or is obutane possessing proton affinity values PA = 552 or 683 kJ mol(-1), respe ctively. The collision-induced dissociation time-of-flight product ion spec tra of [M + H]+ ions differ characteristically according the stereochemical arrangement of the pyranoid ring. These differences can be helpful when as signing stereochemical arrangements for the pyranoid ring, The dominant pro cess in ammonia (PA = 853 kJ mol(-1)) CIMS for most of the compounds studie d is the production of the cluster ions [M + NH4](+). The cluster [M + pyri dineH](+) ions are observable only for substances possessing the O-benzylid ene group (PA of pyridine = 924 kJ mol(-1)). Copyright (C) 2000 John Wiley & Sons, Ltd.