本論文第一部分為對位偶氮化取代calix[4]arene的合成,calixarenes 為一種酚和甲醛的環狀聚合物,因其分子內具有中空的構型,所以可嵌合一些小型的有機分子或金屬離子形成 “主-客化合物”,利用這種特性,可推廣應用於離子分離和微量金屬檢驗上。而對位偶氮化 calix[4]arene 的衍生物,因具有發光色團,理論上應可利用顏色的變異來研究 calix[4]arene 與其他分子形成鍵結的指標。
p-tert-Butylphenol 和甲醛在鹼性的環境中,會進行聚合反應而形成黃綠色的聚合前驅物;此前驅物在二苯醚 (diphenyl ether) 中迴流,可以轉換成 p-tert-butylcalix[4]arene;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,便可得到對位無取代之 calix[4]arene。
當 calix[4]arene 與過量的 benzoyl chloride 在 pyridine 中攪拌,可製備出三苯甲酸酯化 calix[4]arene,將三苯甲基酸化 calix[4]arene 在丙酮中利用二氧化氯水溶液進行氧化反應,可得到三苯甲基酯化 calix[4]monoquinone,如將具有 quinone 結構的 calix[4]arene 衍生物與具有不同取代基的 phenylhydrazines 作用,便可得到對位偶氮化取代的calix[4]arenes。
本論文的第二部分為葡萄醣胺多醣體的合成研究,研究重點在規劃並使用化學合成法來製備 β-(1-6)-linked的 N-acetyl-D-glucosamine 多醣體,其合成步驟是利用 N-乙醯葡糖胺作為起始物,首先將所有的羥基利用乙醯化保護起來,然後在 tin(IV) chloride 作用下,將 C-1 的乙醯基轉換成一個良好離去基的thiophenyl ether 官能團;然後利用 NaOMe 來去除其它被乙醯化保護的羥基,其中 C-6 的一級醇羥基可使用具有立體障礙的 TBDPS 保護基來進行選擇性保護,C-3和C-4 的二級羥基則再利用乙醯化保護以得到 Building block A;C-6 上的 TBDPS 保護基可使用TBAF移除,可得到C-6為羥基取代的 Building block B。Builiding block B C-6上的羥基可與 Building block A C-1上的 thiophenyl ether作用,而得到雙醣體的產物。理論上重複C-6 上羥基 和 C-1 上 thiophenyl ether的聚合,便可得到β-(1-6)-linked的聚合多醣體衍生物。
Two sections are included in this thesis, and the first section will describe the preparation of p-phenylazocalix[4]arenes. Calixarenes are the cyclic oligomers of p-substituted phenols and formaldehyde condensed product. The structure of the calixarenes contains a molecular cavity, which is able to occlude small organic molecules or metal ions to from “host-guest”complex. These phenomena have been proposed in the application of ion separation and micro-analysis. It is known that the formation of the complexes may alter the absorption maximum of the phenylazo chromophore, therefore, the preparation of the p-phenylazocalix[4]arenes will be able to study the ion bonding ability between the metal ions and calixarenes.
In the presence of a base, p-tert-butylphenol and formaldehyde was polymerized to form a yellowish precursor. Refluxing of this precursor in diphenyl ether afforded the p-tert-butylcalix[4]arene. The p-tert-butyl groups were removed with AlCl3 via the reverse Friedel-Crafts reaction to give the parent calix[4]arene.
Literature reported that calix[4]arene was tribenzoated by treating with excess benzoyl chloride in pyridine at ice bath temperature for 2 hours. The phenol portion was oxidized with chlorine dioxide to yielded calix[4]monoquinone tribenzoate. The quinone moiety was then react with various p-substitute phenylhydrazine to give the corresponding hydrazone intermediate, which was converted to p-phenylazocalix[4]arenes upon tautomerization.
The second section of the thesis is concentrated on the preparation of β-(1-6)-linked N-acetyl-D-glucosamine polysaccharide. The procedure started with acetylation of D-glucosamine to afford D-glucosamine pentacetate; and the pentacetylated product was then treated with thiophenol and tin(IV) chloride to yield C-1 thiophenyl ether derivative. The protected acetyl groups were removed by NaOCH3 in methanol. The free C-1 primary hydroxyl group was selective converted with bulky TBDPS group, and the two other secondary hydroxyl groups (C-3 and C-4) were then reprotected by acetylation to afforded Building Block A.
Removal of C-6 TBDPS group from Building Block A by TBAF yielded Building Block B. The free C-6 hydroxyl group of Building Block B was able to replace the C-1 thiophenyl ether group of Building Block A to give a disaccharide product. In theory, repeating the coupling reaction between C-6 hydroxyl of Building Block B and C-1 thiophenyl ether group of Building Block A will afford the desired β-(1-6)-linked N-acetyl-D-glucosamine polysaccharide.