Synthesis of (9Z,12E)- and (9E,12Z)-[1-14C]linoleic acid and (5Z,8Z,11Z,14E)-[1-14C]arachidonic ácid
作者:Olivier Berdeaux、Jean-Michel Vatèle、Thierry Eynard、Mohammed Nour、Didier Poullain、Jean-Pierre Noël、Jean-Louis Sébédio
DOI:10.1016/0009-3084(95)02486-3
日期:1995.10
(3Z,6E)-1-Bromododeca-3,6-diene, a common intermediate in the synthesis of labelled 12t linoleic acid and 14t arachidonic acid, was obtained from (E)-3-nonyl-1-ol, in four steps, via conventional functional manipulations. Cross-coupling of this bromododecadiene with the Grignard reagent of 1-chloro-5-(tetrahydropyranyloxy)pentane gave a C17 dienic ether which was further transformed in three steps to 12t-[1-C-14]linoleic acid in 22% overall field from 3-nonyl-1-ol (eight steps). The synthesis of 14t arachidonic acid involves a Wittig reaction between (Z)-7-(t-butyldiphenylsilyloxy)hept-3-enal and the ylide of (3Z,6E)-dodeca-3,6-dienyl-triphenylphosphonium bromide. The resulting C19 tetraenic ether was transformed in three steps to 14t[1-C-14]arachidonic acid (isomeric and radiochemical purities > 99%). 9t Linoleic acid was obtained by a stepwise six-carbon elongation chain of both ends of (E)-6-(2-tetrahydropyranyloxy)-hex-3-enyltriphenylphosphonium salt in 20% overall yield.
(3Z,6E)-1-溴十八碳-3,6-二烯是一种在标记的12t亚油酸和14t花生四烯酸合成中的常见中间体。它通过四种传统的官能团操作步骤,由(E)-3-壬基-1-醇制得。将此溴代十八碳-3,6-二烯与1-氯-5-(四氢吡喃氧基)-戊烷的伯格曼试剂进行交叉偶联反应,得到了一个C17的二烯醚。进一步经过三个步骤的转化,最终在从3-壬基-1-醇出发的总体路线中,于第八步得到了12t-[1- C-14]亚油酸,其总产率为22%。14t花生四烯酸的合成涉及(Z)-7-(t-丁基二苯基硅氧基)-7-烯丙基甲醛与(3Z,6E)-十八碳-3,6-二烯基三苯基溴化膦的叶利德之间的维蒂希反应。所得的C19四烯醚经过三个步骤的转化,最终得到了14t[1-C-14]花生四烯酸,其异构体和放射化学纯度均大于99%。9t亚油酸则通过逐步对(E)-6-(2-四氢吡喃氧基)-6-烯基-三苯基磷盐的两端进行六碳链的延伸,最终以20%的整体产率获得。