| 摘要: | p-tert-Butylphenol 和甲醛在鹼環境中，會進行聚合反應而形成黃綠色之聚合前驅物。此前驅物在二苯醚 (diphenyl ether) 中迴流，可以轉換成 p-tert-butylcalix[4]arene (1)；若再以三氯化鋁 (AlCl3)為催化劑，進行反向的 Friedel-Crafts 反應，來移除環狀聚合物上的對位三級丁基，可得到對位無取代之 calix[4]arene (6)。
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”，理論上可以利用這種特性，進而推廣應用於離子分離、微量金屬檢驗和酵素模擬的研究上。而本論文主要的目的分為兩部份；第一部份為將calix[4]arene 鍵結於矽膠上，以製備出 calix[4]arene grafted silica gel，然後再進行金屬離子之選擇性的研究。第二部份則探討對calix[4]arene進行結構上的修飾，而得到下緣鄰位烷基醚化雙取代的calix[4]arenes。
本論文利用標準的四步驟製程，可以將 calix[4]arene 鍵結至矽膠上。首先利用 3-aminopropyl triethoxy silane 可將 3-aminopropyl 的官能基團鍵結於矽膠上，以得到化合物 aminopropyl silica gel；然後利用 aminopropyl silica gel上的胺基和 p-nitrobenzoyl chloride 作用，來引進硝基苯官能團；接著使用 sodium dithionite 來還原硝基苯官能團以生成苯胺官能基團；最後再利用偶氮偶合反應和 calix[4]arene 作用，便得到calix[4]arene grafted silica gel化合物。
而本實驗室在過去的研究中發現，可利用苯甲酸酯的保護官能團，設計出一個四步驟的合成法來合成出1,2-雙烷基醚化calix[4]arenes。首先將 calix[4]arene 和過量的鹵烷類和NaOCH3 在 CH3CN 中迴流，可一步合成出單烷基醚化之 calix[4]arenes；如將單烷基醚化之 calix[4]arenes再與benzoyl chloride 進行酯化反應，可得到1-單烷基醚化-3-單苯甲酸酯化產物。針對1-單烷基醚化-3-單苯甲酸酯化之化合物利用 NaH 及鹵烷類在CH3CN中進行第二醚化反應，得到1,2-雙烷基醚化-3-單苯甲酸酯化產物；如再對1,2-雙烷基醚化-3-單苯甲酸酯化進行鹼性水解反應，便可得到1,2-雙烷基醚化之 calix[4]arenes，本實驗室在鹼性水解的反應中發現，除了預期的1,2-雙烷基醚化calix[4]arenes之外，另外還會分離得到非預期之1,3-雙烷基醚化之 calix[4]arene。由於烷基醚的官能基團，在鹼性水解的條件下不會受到任何影響。因此，本論文推論，在進行第二烷基醚化反應時，反應物可能會進行苯甲酸酯的轉移，而生成非預期的1,3-雙烷基醚化-2-苯甲酸酯化之 calix[4]arenes產物；針對1,2-雙烷基醚化-3-苯甲酸酯化 calix[4]arenes 之轉移現象，本論文將對1-單烷基醚化-3-單苯甲酸酯化之 calix[4]arenes 在K2CO3的條件下，觀察其轉位特性。
Under the basic conditions, p-tert-butylphenol polymerized with formaldehyde to form a yellowish precursor. Refluxing of the yellowish precursor in diphenyl ether yielded the p-tert-butylcalix[4]arene (1). The p-tert-butyl guoups were then removed by AlCl3-catalyzed reverse Friedel-Crafts reaction to give a parent calix[4]arene (6).
Calixarenes, which are cyclic oligomers, 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 goal of this thesis is divided into two parts. The first subject is to develope a standard procedure for the preparation of calix[4]arene grafted silica gel. The second subject is to modify the calix[4]arene structure for the preparation of 1,2-dialkoxy calix[4]arenes.
The calix[4]arene grafted silica gel was prepared in a four-step procedure. The 3-aminopropyl group was introduced by reacting 3-aminopropyltriethoxysilane with silica gel to give aminopropyl silica gel. The result aminopropyl silica gel was then treated with p-nitrobenzoyl chloride to incorporate a nitro moiety. The nitro group was reduced by sodium dithionite, and the diazotization of the resulting aniline moiety followed with diazo-coupling reaction gave the red calix[4]arene grafted silica gel.
The monoalkylated calix[4]arenes were prepared by refluxing calix[4]arene with excess amount of alkyl halides in CH3CN with the presence of sodium methoxide as the reacting base. Esterification of those monoalkylated calix[4]arenes with excess amount of benzoyl chloride yielded the corresponding monobenzoate products. A second ether linkage was introduced by treating compounds with NaH and alkyl halides to yield the 25,26-dialkoxy-27-benzoyloxy products. The removal of 27-benzoyl- oxy moiety in alkaline hydrolysis condition yielded 25,26-dialkoxy- calix[4]arenes. In the alkaline hydrolysis reaction, an unexpected 25,27- dialkoxycalix[4]arene was detected. As a well-known phenomena, the ether linkage was not affected in the alkaline hydrolysis conditions. Therefore, a benzoyl-migration mechanism was proposed in the second alkyl etherification stage. In this thesis, the benzoyl-migration behavior on the 25-alkoxy-27-benzoyloxycalix[4]arenas system with K2CO3 as the reaction base was studied. |
