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Epoxidierung von Cucurbitaxanthin A: Herstellung von Cucurbitaxanthin B und seines 5′,6′‐Epimeren
Author(s) -
Deli József,
Matus Zoltán,
Molnár Péter,
Tóth Gyula,
Décsy Zoltán,
Eugster Conrad Hans
Publication year - 1993
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19930760217
Subject(s) - chemistry , epimer , stereochemistry , polyene , diol , organic chemistry
Epoxidation of Cucurbitaxanthin A: Preparation of Cucurbitaxanthin B and of Its 5′,6′‐Epimer Cucurbitaxanthin A (= (3 S ,5 R ,6 R ,3′ S )‐3,6‐epoxy‐5,6‐dihydro‐β,β‐carotene‐5,3′‐diol; 1 ) isolated from red pepper ( Capsicum annuum var. longum nigrum ) was trimethylsiylated and then epoxidized with monoperphthalic acid. After deprotection and chromatographic separation, cucurbitaxanthin B (= (3 S ,5 R ,6 R , 3′ S ,5′ R ,6′ S )‐3,6:5′,6′‐diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotene‐5,3′‐diol; 2 ) and 5′,6′‐diepicucurbitaxanthin B (= (3 S ,5 R ,6 R , 3′ S ,5′ S ,6′ R )‐3,6:5′,6′‐diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotene‐5,3′‐diol; 5 ) were obtained and carefully characterized. They show mirror‐like CD spectra and, therefore, emphasize the importance of the torsion angle of C(6)–C(7) on the electronic interaction between the polyene chain and the chiral end group.