7176-05-8Relevant academic research and scientific papers
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.
