title: Elimination of isocyanate and isothiocyanate molecules at the electrospray ionization ion trap, electrospray ionization quadrupole time-of-flight and matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry fragmentation of sodium cationized brassitin, brassinin and their glycosides.
abstract: Fragmentation mechanisms of phytoalexin analogs, including brassitin and brassinin and their glucosylated analogs, have been studied by electrospray (ESI) ion trap (IT) multistage (MS(n), n = 1-4) mass spectrometry, matrix-assisted laser desorption/ionization time-of-flight (MALDI ToF/ToF) and ESI-Q/ToF tandem mass spectrometry techniques. At the fragmentation of sodium adducts a hitherto not described process has been elucidated The proposed mechanism of this process includes cyclization of the brassitin and brassinin cationized adducts through a six-membered cycle of the molecules and the elimination of isocyanate or isothiocyanate from the thio- or dithiocarbamate moiety, giving rise to [M + Na - 43](+) or [M + Na - 59](+) adducts. The elimination of NH=C=O or NH=C=S molecules has been confirmed by the high resolution measurement of the elemental composition of the ions produced and quantum-chemical calculations of the six-membered transition state. Other fragmentation routes include cleavage of an alkane linker, while numerous characteristic hexopyranose pathways are taking place in the glucosylated compounds. The presented theoretical data on the ESI and MALDI behavior of the saccharidic, as well as of the indole aglycon parts, can facilitate structural elucidation of the analogous compounds.
authors: Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 38 Bratislava, Slovakia.
authors: Slávka
authors: S
authors: Bekesová
authors: Vladimír
authors: V
authors: Kovácik
authors: Igor
authors: I
authors: Tvaroska
authors: Zuzana
authors: Z
authors: Curillová
authors: L'udovít
authors: L
authors: Skultéty
authors: Pavel
authors: P
authors: Rehulka
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry*; D016588:Anticarcinogenic Agents / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D004365:Drugs, Chinese Herbal / Q000737:chemistry; D006027:Glycosides / Q000737:chemistry; D007211:Indoles / Q000737:chemistry*; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013859:Thiocarbamates / Q000737:chemistry*; D000094162:Phytoalexins
chemical_list: D000890:Anti-Infective Agents; D016588:Anticarcinogenic Agents; D002412:Cations; D004365:Drugs, Chinese Herbal; D006027:Glycosides; D007211:Indoles; D010936:Plant Extracts; D013859:Thiocarbamates; C524085:brassitin; C089020:brassinin; D000094162:Phytoalexins