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

O‐Isopropylidene and O‐benzylidene acetals of common 2,6‐anhydro‐1‐deoxy‐1‐nitroalditols (β‐D‐glycopyranosylnitromethanes) derived from D‐glucose, D‐galactose and D‐mannose were studied by chemical ionization mass spectrometry (CIMS) using methane, isobutane, ammonia or pyridine as reaction gas. Production of [M+H]+ adduct ions dominates in the case of methane or isobutane possessing proton affinity values PA = 552 or 683 kJ mol−1, respectively. The collision‐induced dissociation time‐of‐flight product ion spectra of [M+H]+ ions differ characteristically according the stereochemical arrangement of the pyranoid ring. These differences can be helpful when assigning stereochemical arrangements for the pyranoid ring. The dominant process in ammonia (PA = 853 kJ mol−1) CIMS for most of the compounds studied is the production of the cluster ions [M+NH4]+. The cluster [M+pyridineH]+ ions are observable only for substances possessing the O‐benzylidene group (PA of pyridine = 924 kJ mol−1). Copyright © 2000 John Wiley & Sons, Ltd.