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Electron and chemical ionization mass spectrometry in stereochemical differentiation of some 1,3‐amino alcohols
Author(s) -
Partanen Tuula,
Vainiotalo Pirjo,
Stájer Géza,
Bernáth Gábor,
Pihlaja Kalevi
Publication year - 1994
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210290303
Subject(s) - chemistry , chemical ionization , mass spectrum , electron ionization , isobutane , mass spectrometry , fragmentation (computing) , medicinal chemistry , analytical chemistry (journal) , organic chemistry , ion , ionization , chromatography , operating system , computer science , catalysis
Mass spectral fragmentations of two cyclopentane, eight cyclohexane and four norbornane/one 1,3‐amino alcohols were studied under electron ionization (EI) by low‐resolution, high‐resolution, metastable ion analysis and collision‐induced dissociation (CID) techniques. All stereoisomeric compounds gave rise to identical 70 eV EI mass spectra. However, the spectra of positional isomers clearly differed. The main fragmentation pathway for the saturated compounds began as an α‐cleavage reaction with respect to the nitrogen atom. For the norbornene compounds a retro‐Diels—Alder reaction was favoured. Relative to the aminomethyl‐substituted compounds the fragmentation patterns for the compounds having the amino group connected directly to the ring were more complicated. The chemical ionization (CI) mass spectra were recorded using ammonia, isobutane, methane, dichloromethane and acetone as reagent gas. From the norbornane/One compounds the di‐ exo isomers decomposed more easily than the di‐ endo isomers with most of the reagent gases used. Differences between stereoisomers were observed directly only under methane CI. The decomposition products of the [M + H] + ions generated under ammonia and isobutane CI were studies by recording their CID mass spectra. These spectra allowed the differentiation of the stereoisomers, at least to some extent.