Synthesis of Pk Antigen Analogue and Development of New Method for the Synthesis of Per-O-acetylation
| Autor: | Shu-Yi Hsieh, 謝書宜 |
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| Rok vydání: | 2003 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 91 The main goal of the thesis is to synthesize Pk antigen analogues. Because the structure of Pk antigen is a trisaccharide, we used a lactose as acceptor and galactose as donor to perform glycosylation and construct the trisaccharide scaffold. Starting from per-acetyl lactose and through the hydroxyl groups protecting and deprotecting manipulation, the 4’-hydroxyl lactose was obtained as an acceptor. Because of the usage of benzoate as protecting group, the nucleophilicity of this acceptor is weak. A strong donor, 1-phosphite-2, 3, 4, 6-benzylgalactose, was prepared and used to couple with lactose acceptor. The glycosylation was achieved at room temperature with excellentα-selectivity and high yield. By this synthetic pathway, Pk antigen analogue was successfully synthesized in gram scale. To prepare large scale of per-acetyl lactose as starting material, we developed a new method to achieve high yield per-O-acetylation by using catalytic amount of LiClO4 and acetic anhydride at 40℃. The desired per-acetyl lactose was obtained by simple workup procedure (95% yield) with 98% purity. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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