110241-03-7Relevant academic research and scientific papers
Blue Carotenoids. Part 1. Novel Oxonium Ions Derived from Fucoxanthin
Haugan, Jarle Andre,Liaaen-Jensen, Synnoeve
, p. 68 - 75 (2007/10/02)
The reactions of fucoxanthin-derived ketals and hemiketals with dilute acid and of fucoxanthin with weak acid (AcOH) and strong organic (CF3COOH) or mineral (HCl) acids, have been examined.The blue products obtained in these reactions were identified as novel carotenoid oxonium ions, characterized by visible absorption spectra and chemical behaviour, including quantitative conversion into cyclic hemiketals of defined structure.The hemiketal products were identified by VIS, IR and mass spectroscopy in comparison with authentic hemiketals or related 5,8-furanoxides.Diagnostic features in the mass spectra of the hemiketals are rationalized.The reactions observed are rationalized mechanistically.Isofucoxanthins are not intermediates in the reaction of fucoxanthin with acids.The blue oxonium ions were obtained in reasonable yield in competition with electrophilic addition to the polyene chain.
Algal Carotenoids 50. Alkali Lability of Fucoxanthin - Reactions and Products
Haugan, Jarle Andre,Englert, Gerhard,Liaaen-Jensen, Synnoeve
, p. 614 - 624 (2007/10/02)
The reaction of fucoxanthin with bases has been examined by modern methods.The reactions studied were (i) fucoxanthin or protected fucoxanthin with NaH as strong base/weak nucleophile in THF followed by CH3I, (ii) protected fucoxanthin with NaH followed by H2O, and (iii) fucoxanthin with KOH in methanol in different molar ratios.Kinetic studies are reported.All coloured products were identified.Novel cyclic carotenoid hemiketal and methyl ketal products were characterized by means of VIS, MS, IR, 1H NMR and 13C NMR data, including COSY and hetero-COSY.Isofucoxanthin and isofucoxanthinol were identified by means of VIS, CD, MS, IR and detailed 1H NMR and 13C NMR data, including COSY, hetero-COSY, ROESY and TOCSY, demonstrating the configuration of the cross-conjugated chromophore.The reactions observed have been rationalized mechanistically.Isofucoxanthinol is the kinetically controlled product upon reaction of fucoxanthin with KOH, and fucoxanthinol hemiketal the thermodynamically controlled product.A high molar ratio of KOH:fucoxanthin increases the rate of production of fucoxanthinol hemiketal.
