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首页> 外文期刊>Computational Chemistry >A Proposed Stereochemical Mechanism for the Improved Preparation of Maleic Anhydride Cycloadduct of CLA
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A Proposed Stereochemical Mechanism for the Improved Preparation of Maleic Anhydride Cycloadduct of CLA

机译：一种提出的立体化学机制，用于改进克拉的马来酸酐环形加湿制剂

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The fatty acid derivatives, prepared from renewable natural oils, can be used as highly promising and potential substitutes for petrochemicals. The study of process improvement and stereochemical mechanism for preparing these derivatives would be beneficial for their industrial production. Conjugated linoleic acid (CLA) containing 9 cis -11 trans (9 c , 11 t ) and 10 trans -12 cis (10 t , 12 c ) isomers was prepared from Salicornia herbacea seed oil. Maleic anhydride cycloadduct of CLA (MAC) was prepared by an improved process, and it was characterized by FTIR, ~(1)H and ~(13)C NMR, etc . A new method to calculate conformers-ratio of CLA or MAC was also developed. Furthermore, the stereochemical mechanism for the improved preparation of MAC was proposed primarily by the calculation method above. The following observations were made: 1) The yield of MAC could reach as high as 96.7% under mild reaction conditions and with an easy and efficient product separation; 2) The trans-trans CLA in the s-cis conformation acted as a predominant reactant to Diels-Alder [4 + 2] cycloaddition of maleic anhydride, which was the main reaction occurred simultaneously with catalytic configurational isomerizations of CLA in one step; 3) From all studied CLA conformers, the most stable conformation was the s-trans conformation of trans-trans CLA, while the s-cis conformation of trans-trans CLA had the most favorable structural parameters for cyclohexenyl ring formation; 4) Four MAC conformers derived from 9 c , 11 t - and 10 t , 12c-CLA, were obtained as final main products that were determined to be cis -cycloadducts; 5) The endo/exo ratios of the cis - cycloadducts derived from 9 c , 11 t - and 10 t , 12 c -CLA, were 2.14:1 and 1.99:1, respectively; and 6) The results obtained from the calculation method above were in excellent accordance with those from our experiments.
机译：由可再生天然油制备的脂肪酸衍生物可用作高效和潜在的石油化学替代品。用于制备这些衍生品的过程改进和立体化学机制的研究将有利于其工业生产。含有9个CIS -11反式（9c，11 t）和10反式-12的CIS（10吨，12℃）异构体的共轭亚油酸（CLA）由Salicornia Herbacea籽油制备。通过改进的方法制备了CLA（MAC）的马来酸酐环形化合物，其特征在于FTIR，〜（1）H和〜（13）C NMR等。还开发了一种计算CLA或MAC的赋容剂的新方法。此外，主要通过上述计算方法提出了改善MAC制剂的立体化学机制。进行了以下观察结果：1）MAC的产率在温和的反应条件下可高达96.7％，并且具有易于高效的产品分离; 2）S-CIS构象中的反式反式CLA作用为对Diels-Alder的主要反应物[4 + 2]循环加入的马来酸酐，其在一个步骤中与CLA的催化配置异构同时发生的主要反应; 3）从所有研究的CLA符合子，最稳定的构象是反式反式CLA的S-Trans构象，而Trans-Trans CLA的S-CIS构象具有最有利的环己烯环形成的结构参数; 4）获得来自9c，11 t - 和10 t，12c-cla的四个MAC符合特，作为确定为CIS-Cycloadducts的最终主要产物; 5）衍生自9 C，11 T - 和10 T，12 C-CLA的顺式循环道的Endo / EXO比分别为2.14：1和1.99：1; 6）从上述计算方法获得的结果是根据我们实验的计算方法。

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