SYNTHESIS, ISOLATION, AND FULL SPECTROSCOPIC CHARACTERIZATION OF 11 (Z)-ISOMERS OF (3R,3'R)-ZEAXANTHIN

Developmental efforts to improve the yield of the chemical synthesis of (3R,3'R)-zeaxanthin resulted in the isolation, partly by chromatography from reaction mixtures, and full spectroscopic characterization by H-1-NMR, UV/VIS, and CD spectroscopy of eleven (Z/E)-isomers of zeaxanthin: (7Z)-, (9Z)-, (13Z)-, (15Z)-, (7Z,7'Z)-, (9Z,9'Z)- (7Z,9Z,7'Z)-, (7Z,11Z,7'Z)-, (9Z,13Z,9'Z)-, (7Z,9Z,7'Z,9'Z)-, and (7Z,9Z,11Z,7'Z,9'Z)-zeaxanthin. Five of these isomers were obtained by specific synthesis, namely the (7Z)-, (7Z,7'Z)-, (9Z,9'Z)-, (7Z,9Z,7'Z)-, and (7Z,9Z,7'Z,9'Z)-isomers.