Synthesis of (6Z,9Z,11E)-octadecatrienoic and (8Z,11Z,13E)-eicosatrienoic acids and their [1-(14)C]-radiolabeled analogs.
Chem Phys Lipids
; 112(2): 121-35, 2001 Aug.
Article
em En
| MEDLINE
| ID: mdl-11551536
ABSTRACT
In order to study the metabolic pathway and the physiological effects of 9c,11t-182 (major isomer of conjugated linoleic acid) and its C(183) and C(203) metabolites, 6c,9c,11t-183 and 8c,11c,13t-203 and their [1-(14)C]-radiolabeled analogs were prepared stereoselectively by total synthesis. The 8c,11c,13t-203 was obtained in 11 steps. The synthesis involves a highly stereoselective Wittig reaction between 3-(t-butyldiphenylsilyloxy)propanal and the ylide of 7-(2-tetrahydropyranyloxy)heptanylphosphonium salt which gave (3Z)-1-(t-butyldiphenylsilyloxy)-10-(2-tetrahydropyranyloxy)dec-3-ene in a first step. Then the t-butyldiphenylsilyl derivative was deprotected selectively and the resulting alcohol function was converted via a bromide into a phosphonium salt. The second stereoselective Wittig condensation between the phosphonium salt and commercial (2E)-non-2-enal under cis-olefinic conditions using Lithium hexamethyldisilazide as base afforded the (7Z,10Z,12E)-1-(2-tetrahydropyranyloxy)nonadeca-7,10,12-triene in a very good isomeric purity. The intermediate product was brominated and transformed by reaction with magnesium into Grignard reagent, which was one-carbon elongated by unlabeled or labeled carbon dioxide to obtain the 8c,11c,13t-203 in good isomeric purity (95%) and high radiochemical purity for its [1-(14)C]-radiolabeled analog (99%). 6c,9c,11t-183 was synthesized in a similar way by using 5-(2-tetrahydropyranyloxy)pentanylphosphonium salt in place of 7-(2-tetrahydropyranyloxy)heptanylphosphonium salt in a first step. Other reactions were unchanged and products were obtained in similar yields. Similar to 8c,11c,13t-203, the 6c,9c,11t-183 was obtained in a very good isomeric purity (95%) and its [1-(14)C]-radiolabeled analog in a high radiochemical purity (95%).
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01-internacional
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MEDLINE
Assunto principal:
Ácidos Graxos Insaturados
/
Hidroxiácidos
Idioma:
En
Ano de publicação:
2001
Tipo de documento:
Article