2-Aroyl-3,4-dihydro-2H-benzopyrans的合成與氧化研究

Synthesis and oxidation of 2-aroyl-3,4-dihydro-2H-benzopyrans

陳亮宇(Liang-Yeu Chen)

指導教授 ： 王英基

高雄醫學大學/藥學院/藥學研究所/博士(2012年)

摘要

第一章
本論文敘述, 以新穎的碳陰離子-烯分子內的6-endo-trig環化反應得到2-aroyl-3,4-dihydro-2H-benzopyrans化合物。將柳醛(salicylaldehydes) 經由一連串的反應，包括Wittig反應、O-烷基化反應、及碳陰離子-烯分子內的環化反應，以二個步驟完成，或將所有反應在一鍋中反應完成，得到一系列新的2-aroyl-3,4-dihydro-2H- benzopyrans。

第二章
本論文敘述, 將2-aroyl-3,4-dihydro-2H-benzopyrans經DDQ調控氧化-脫氫以合成2-aroylbenzopyran-4-ones。對於氧化-脫氫反應,在許多不同的反應條件下，發現到以3.5當量的DDQ加入少量醋酸與水(1-2 滴)當添加物，在dioxane中加熱迴流下，是最佳氧化-脫氫條件。同時藉由反應中間體2-benzoyl-8-methoxy-3,4-dihydrobenzopyran-4-one的分離，以及利用EI-MS 偵測到反應最終產物2-benzoyl-8- methoxybenzo- pyran-4-one羰基上18O (在反應當初加入H218O) 的存在，使DDQ調控氧化-脫氫反應的反應機構，得到合理的推論。

關鍵字

碳陰離子-烯分子內環化 ； 柳醛 ； 2-aroyl-3,4-dihydro-2H-benzopyrans ； DDQ ； 2-aroylbenzopyran-4-ones

並列摘要

第一章
　　Utilization of a novel carbanion-olefin intramolecular 6-endo-trig cyclization reaction to provide 2-aroyl-3,4-dihydro-2H-benzopyrans is described. Through a sequence of a Wittig reaction, O-alkylation, and carbanion-olefin intramolecular cyclization, salicylaldehydes were converted into a series of new 2-aroyl-3,4-dihydro-2H-benzopyrans in two steps or in one-pot reactions.

第二章
　　DDQ mediated an oxidation-dehydrogenation of 2-aroyl-3,4-　dihydro-2H-benzopyran　prepared from salicylaldehyde to yield　2-aroylbenzopyran-4-one. Stochiometric amount (3.5 equv.) of DDQ, few amount of acetic acid and water (1-2 drops) in refluxing dioxane are the optimal condition for this oxidation-dehydrogenation reaction. A rationally proposed mechanism for this oxidation- dehydrogenation process is based on the isolation of a reaction intermediate, viz.2-benzoyl-
8-methoxy-3,4-di-hydrobenzopyran-4-one　and the identification of the 18O-labled carbonyl group of benzopyran-4-one demonstrating incorporation of labeled H218O.

並列關鍵字

carbanion-olefin intramolecular cyclization ； salicylaldehydes ； 2-aroyl-3,4-dihydro-2H-benzopyrans ； DDQ ； 2-aroylbenzopyran-4-ones

參考文獻

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