- Preparation method of all-trans beta-carotene
-
The invention discloses a preparation method of all-trans beta-carotene. The all-trans beta-carotene is obtained by carrying out an isomerization reaction on a carotene cis-trans isomer mixture in the presence of a catalyst and an assistant under nitrogen and dark conditions, wherein the catalyst is a platinum or ruthenium complex. The method has the advantages that isomerization time is short, temperature is low, the total trans content of the product is high, and a relatively good isomerization effect is achieved on a relatively wide range of cis-trans isomer mixtures.
- -
-
Paragraph 0030; 0036-0055
(2021/08/25)
-
- Animal carotenoids. 31. Structure elucidation of a sponge metabolite via mesylate elimination.
-
The structure of a sponge metabolite from Microciona prolifera, previously considered to be (6S)-2,3-didehydro- or 3,4-didehydro-gamma, chi-carotene, has been further studied. Attempted total synthesis of the 3,4-didehydro derivative provided the hitherto unknown gamma, chi-carotene, the synthesis of which is described. Hydrolysis of lutein methanesulfonate diester (dimesylate) gave elimination products possessing the 3,4-didehydro gamma end-group. 1H NMR data for this gamma end-group were identical with those for the sponge carotenoid. The mesylate elimination reaction described may mimic the metabolic formation of the 3,4-didehydro-gamma-carotenoid end-group. In connection with other investigations on functionalized carotenoids we further report the preparation of zeaxanthin and lutein mesylates and their base-catalyzed elimination reactions. SN2 type substitution reactions of zeaxanthin dimesylate with appropriate nucleophiles did not produce beta, beta-carotene, zeaxanthin diacetate or thiozeaxanthin.
- Sliwka,N?kleby,Liaaen-Jensen
-
p. 245 - 252
(2007/10/02)
-