Large-scale preparation of (9Z,12E)-[1-13C]-octadeca-9,12-dienoic acid, (9Z,12Z,15E)-[1-13C]-octadeca-9,12,15-trienoic acid and their [1-13C] all-cis isomers
摘要:
Several grams of labelled trans linoleic and linolenic acids with high chemical and isomeric purities (> 97%) have been prepared for human metabolism studies. A total of 12.5 g of (9Z,12E)-[1-C-13]-octadeca-9,12-dienoic acid and 6.3 g of (9Z,12Z,15E)-[1-C-13]-octadeca-9,12,15-trienoic acid were obtained in, respectively: seven steps (7.8% overall yield) and 11 steps (7% overall yield) from 7-bromo-heptan-1-ol. The trans bromo precursors used for the labelling were synthesised by using copper-catalysed couplings. The trans fatty acids were then obtained via the nitrile derivatives. A total of 23.5 g of (9Z,12Z)-[1-C-13]-octadeca-9,12-dienoic acid and 10.4 g of (9Z,12Z,15Z)-[1-C-13]-octadeca-9,12,15-trienoic acid were prepared in five steps in, respectively, 32 and 18% overall yield. Large quantities of bromo and chloro precursors were synthesised from the commercially available acid according to Barton's procedure. In all cases, the main impurities ( > 0.5%) of each labelled fatty acid have been characterised. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.
A divergent synthesis of [1-14C]-mono-E isomers of fatty acids
作者:D. Georgin、F. Taran、C. Mioskowski
DOI:10.1016/s0009-3084(03)00054-9
日期:2003.9
A convenient synthesis of [1-14C]-mono-trans fatty acid using olefininversion as a key-step is described. This methodology allows for a facile synthesis of [1-14C]-labelled mono-trans analogues of oleic, linoleic and linolenic acids. As an example, only eleven steps were necessary to obtain the [1-14C]-mono-E isomers of linolenic acid from its commercial all-Z form. In the first step, Barton's decarboxylation
描述了使用烯烃转化作为关键步骤方便地合成[1-14C]-单反式脂肪酸的方法。这种方法可以轻松合成油酸,亚油酸和亚麻酸的[1-14C]标记的单反式类似物。例如,仅需十一个步骤即可从其商业全Z形式获得亚麻酸的[1-14C]-单-E异构体。在第一步中,Barton的脱羧过程产生了溴中间体。该化合物的环氧化导致形成三个单环氧化物,可以通过HPLC进行分离。通过1 H NMR和MS鉴定后,然后对纯单环氧化物进行转化,该转化包括立体定向脱氧,然后进行β消除步骤。最后,