%0 Journal Article
%T Mass Spectrometry of Bis-Quinolizidine Alkaloids: FAB-MS of Oxo-Substituted Sparteines
%A Beata Jasiewicz
%A El£¿bieta Wyrzykiewicz
%J International Journal of Analytical Chemistry
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/652589
%X The unpublished in the literature FAB mass spectral fragmentation of seven oxosparteines (i.e., 2-oxosparteine, 15-oxosparteine, 17-oxosparteine, 2,17-dioxosparteine, 2,13-dioxosparteine, 2-oxo-13-hydroxysparteine, and 2-oxo-17-hydroxysparteine) is investigated. Fragmentation pathways, elucidation of which was assisted by FAB/collision-induced dissociation (CID) mass spectra measurements, are discussed. The data obtained create the basis for distinguishing positional isomers. 1. Introduction Bis-quinolizidine alkaloids produced by Lupine species have generated much interest because of their valuable pharmacological properties. Both pharmacological and toxicological properties of these alkaloids are well known [1, 2]. Sparteine appears to offer protection to plants from Leguminosae family against insects and grazing mammals [3, 4]. Several bis-quinolizidine alkaloids (sparteine, lupanine, 17-oxosparteine, 13-hydroxylupanine, angustifoline, etc.) show antihypertensive, antipyretic, anti-inflammatory, antiarrhythmic, diuretic, hypoglicemic, hypotensive, antidiabetic, respiratory depressant and stimulant, and uterotonic properties [5, 6]. The mass spectrometry study of bis-quinolizidine alkaloids has been stimulated by the evidence of the method¡¯s ability to distinguish their stereoisomers, metamers, and positional isomers [7¨C14]. The main characteristic of the so-called ¡°hard¡± electron-impact induced ionization (EI) of mass fragmentation of bis-quinolizidine alkaloid molecular ions is the dependence of the fragmentation pathway of the bis-quinolizidine skeleton on the stereochemistry of the A/B and C/D ring junctions. The stereochemical effects that are encountered with dissociations of stereoisomers incorporating saturated heterocycles rings are due to the ability of chemical bonds to be broken or formed. Mass spectrometry includes a broad range of techniques that have allowed us to prove the detailed structures of organic compounds in a variety of ways. Fast atom bombardment ionization (FAB) is classified as a soft ionization technique in mass spectrometry and is well suited to organic compounds which contain a basic functional group. Those compounds tend to run well in positive ion mode. In the positive FAB technique a high velocity, rare gas atom molecular beam was produced in the ionization source, and directed onto the sample which was in solution (in the matrix) on a target, thus causing desorption of protonated molecular ions from the sample. Generally, positive FAB produces protonated molecular ions M+H£¿+ with a little fragmentation, and so the
%U http://www.hindawi.com/journals/ijac/2011/652589/