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Synthesen in der Carotinoid‐Reihe. 6. Mitteilung. Synthese von Crocetindialdehyd und Lycopin
Author(s) -
Isler O.,
Gutmann H.,
Lindlar H.,
Montavon M.,
Rüegg R.,
Ryser G.,
Zeller P.
Publication year - 1956
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.19560390217
Subject(s) - chemistry , wittig reaction , lycopene , crocetin , ether , vinyl ether , propenyl , pigment , stereochemistry , polyene , carotenoid , organic chemistry , biochemistry , copolymer , polymer
A simple and efficient synthesis of lycopene is described based on stepwise lengthening of a symmetrical C 10 ‐dialdehyde as central component. This C 10 ‐dialdehyde is lengthened at both ends, first with vinyl ether and then with propenyl ether, leading to a C 20 ‐dialdehyde which is transformed into crocetin dialdehyde by partial hydrogenation of the central triple bond. By means of a new reaction devised by Wittig, crocetin dialdehyde is condensed at both ends with geranylidene‐triphenylphosphorane and lycopene is obtained according to the scheme C 10 + C 20 + C 10 = C 40 . This synthetic pigment is identical with pure natural lycopene isolated from tomato juice. The Wittig reaction also allows a new β‐carotene synthesis using the components cyclogeranylidene‐triphenylphosphorane and 8,8′‐dehydro‐crocetin dialdehyde.