DETERMINATION OF THE GEOMETRIC CONFIGURATION OF THE POLYENE CHAIN OF MONO-CIS C40 CAROTENOIDS II A 13C NMR STUDY OF MONO-CIS LUTEINS AND MONO-CIS CAPSANTHINS

Article abstract of DOI:10.1016/S0040-4020(01)97736-1

Systematic chromatography has resulted in the isolation of four geometric isomers as products of iodine-catalysed isomerisation of lutein. 13C NMR spectral analysis has established their stereochemistry as mono-cis luteins with a cis-configured double bond at C-9, C-9', C-13 and C-13', respectively.Carbon-13 NMR has also provided unambiguous stereochemical assignment for the previously isolated four mono-cis capsanthins.