| 摘要: | Calixarenes 為環狀聚合物，因其分子內具有中空的構型，所以藉由此特性可嵌合一些小型的有機分子或金屬離子，進而形成 “主-客化合物”，理論上利用這種特性，可以應用於離子分離、微量金屬檢驗和酵素模擬的研究上。本論文主要目的為合成出對位羥基的 calix[4]arenes 及乙醯酯化的衍生物。
p-tert-butylphenol 和甲醛在鹼性環境中，會進行聚合而形成黃綠色的固態前驅物；此前驅物在二苯醚中進行迴流，可被轉換成 p-tert-butylcalix[4]arene (1)；若再以三氯化鋁作為催化劑，進行反向Friedel-Crafts 反應，來移除環狀聚合物上的對位三級丁基，可得到對未無取代calix[4]arene (6)。
文獻中曾報導，當 calix[4]arene 與 benzoyl chloride 及碳酸鉀在乙腈中進行酯化反應時，僅會生成 1,3-雙苯甲酸酯化 calix[4]arene 26。為避免使用毒化物乙腈，在經過一系列的測試後，發現試藥級丙酮能取代乙腈，而製備出相同的雙苯甲酸酯化產物 26。如利用二氧化氯在 pH 7 的緩衝溶液中，對雙苯甲酸酯化calix[4]arene 26 進行氧化反應，則未被苯甲酸酯化的苯酚官能團可被氧化成苯醌，而得到雙苯甲酸酯化的calix[4]diquinone 27；calix[4]diquinone 27 的苯醌官能團，可在二硫亞磺酸鈉水溶液中進行非均勻相的還原，而得到苯醌被還原成氫苯醌 (hydroquinone) 的雙苯甲酸酯化 5,17-dihydroxycalix[4]arene 28。此還原產物會在空氣中被氧化成紅棕色固體，因此，必須製備出其乙醯酯化的衍生物。
若雙苯甲酸酯化 5,17-dihydroxycalix[4]arene 28 在乙醯氯與吡啶下進行反應，僅能得到無法分離的乙醯酯化取代的混合產物，但如使用反應性更好的乙醯氯和三氯化鋁在二氯甲烷的反應條件，則會製備出四乙醯酯化的衍生物 29，來進行產物結構的鑑定。
相同的，利用二氧化氯對 calix[4]arene 進行氧化反應時，所有的苯酚官能團都可被氧化成苯醌，而得到 calix[4]tetraquinone 30。產物 30的苯醌官能團，亦可在二硫亞磺酸鈉的水溶液中進行非均勻相的還原，而得到苯醌被還原成氫苯醌的產物 5,11,17,23-tetrahydroxycalix[4]arene 31。此產物比化合物 28 更容易在空氣中被氧化，通常置放於空氣中約 8 小時，固體的顏色便會由白色轉變成紅棕色，所以產物結構的鑑定，亦需要利用乙醯氯和三氯化鋁的反應條件，將其轉換成完全乙醯酯化的衍生物 32 來證實。
這些合成的研究過程中之產物皆利用 1H-NMR、COSY 及 13C-NMR的分析來鑑定，在本論文中，產物的合成和鑑定的過程皆會做敘述與討論。
alixarenes, which are cyclic oligomers of p-substituted phenols and formaldehyde, are able to include small organic molecules or metal ions within the molecular cavities to form “host-guest” complexes. These phenomena have been proposed in the applications of micro-analysis, ion separation, and enzyme-mimic studies. The main purpose of this thesis is to study the synthesis of p-hydroxycalix[4]arene and its acetate derivatives.
In the basic condition, p-tert-butylphenol were polymerized with formaldehyde to form a yellowish precursor. Refluxing of this precursor in diphenyl ether yielded the p-tert-butylcalix[4]arene (1). The AlCl3 catalyzed reverse Friedel-Crafts reaction removed the p-tert-butyl groups and afforded parent calix[4]arene (6).
It was known that the benzoylation of calix[4[arene in acetonitrile yielded only the 1,3-dibenzoated product 26. Some toxic issue was concerned on acetonitrile as reaction solvent, therefore, an alternative reaction conditions were required for the dibenzoate reaction. After series studies on the solvent selection project, it was found that the reagent grade acetone produced the same result as in acetonitrile case. The dibenzoate product 26 was converted to the corresponding calix[4]diquinone 27 by chlorine dioxide oxidation process. The quinone moiety of the compound 27 was then reduced in heterogeneous system by aqueous sodium hydrosulfite solution and yielded the corresponding 5,17-dihydroxycalix[4]arene dibenzoate 28. The product 28 was gradually changed its color to brownish red in the atmosphere, therefore, the acetate derivative was needed for the structure determination. In the presence of AlCl3 as catalyst compound 28 was able to react with acetyl chloride in CH2Cl2 and yielded only the tetraacetate product 29.
The calix[4]arene (6) was also able to oxidize by chlorine dioxide, and yielded the calix[4]tetraquinone 30. Heterogeneous reduction of compound 30 by aqueous sodium hydrosulfite solution yielded the corresponding 5,11,17,23-tetrahydroxycalix[4]arene 31. The product 31 would oxidize to brownish red solid in the atmosphere within 8 hours, therefore, the acetate derivative was needed for the structure determination. In the presence of AlCl3 as catalyst compound 31 was able to react with acetyl chloride in CH2Cl2 and yielded the octaacetate product 32.
All the new products which were produced in this thesis were characterized by 1H-NMR, COSY, and 13C-NMR. The synthetic produced for p-hydroxycalix[4]arenes and their acetate derivatives were also discussed in this thesis. |
