Chemical ionization and high resolution electron impact mass spectra of 1,6‐anhydro‐3,4‐ O ‐isopropylidene‐β‐ D ‐talopyranose

The high resolution, electron impact mass spectrum of 1,6‐anhydro‐3,4‐ O ‐isopropylidene‐β‐ D ‐talopyranose, together with those of its derivatives having specific deuterium substitution at C‐2, at C‐3, at C‐2 and C‐3, and in the isopropylidene group, is considered in detail and compared with the ammonia and isobutane mediated chemical ionization spectra of these five compounds. From the elemental compositions of the fragment ions and mass number shifts upon deuterium incorporation, the origin of the hydrogen atoms in each of the fragments is traced, and a detailed scheme of the main fragmentation. pathways is presented.