Structural Elucidation of the Main cis-β-Carotenes

Abstract

Different isomerization experiments on all trans-β-carotene (I) yielded multi-component mixtures of cis isomers. Separation and isolation of these isomers were achieved by classic adsorption chromatography on a lime column. Investigation of their 200 MHz 1H- and 50.3 MHz 13C-NMR spectra led to the structural elucidation of the main cis-fi-carotenes, namely the 9-monods' structure (II) for neo β-carotene U, and the 13-monocis structure (III) for neo β-carotene B. Formation of other hindered mono cis (1-cis and 11 -cis) and 15-monods isomers should be carefully examined by a suitable method such as high-performance liquid chromatography. © 1981, Center for Academic Publications Japan. All rights reserved.