In order to characterise the presumed epitopes of arabinogalactans, isolated from the extract of the cell-cultured Echinacea purpurea, two oligosaccharides were synthesized. The whole synthetic route was based on the successful combination of the (methoxydimethyl)methyl (MIP) and the (2-naphthyl)methyl ether (NAP) protecting groups. A β-(1→6)-linked trigalactoside was prepared, which contained a NAP ether at position 2′.This protecting group was selectively removed using either DDQ or Pd-C/H2 and the acceptor was ready for further glycosylation.We have used two arabinofuranosyl donor compounds: 2,3,5-tri-O-acetyl arabinofuranosyl trichloroacetimidate and a peracetylated α-(1→5)-linked diarabinofuranosyl trichloroacetimidate. For the deprotection of the tetra- and pentasaccharides a common procedure was used. All of the synthesized compounds were characterized by 1H and 13C NMR spectroscopy, as well as by MALDI-TOF mass-spectrometry.
为了确定从
细胞培养的紫锥菊
提取物中分离出来的
阿拉伯半乳聚糖的假定表位特征,我们合成了两种
寡糖。整个合成路线基于(甲氧基二甲基)甲基(MIP)和(2-
萘基)甲基醚(NAP)保护基团的成功结合。使用
DDQ 或 Pd-C/H2 可以选择性地去除该保护基团,然后就可以将受体进一步糖基化。我们使用了两种阿拉伯
呋喃糖基供体化合物:2,3,5-三-O-乙酰基阿拉伯
呋喃糖基三
氯乙酰亚
氨酸酯和过乙酰化的δ-(1→5)-连接二阿拉伯
呋喃糖基三
氯乙酰亚
氨酸酯。四糖和五糖的脱保护采用了相同的程序。所有合成的化合物都通过 1H 和 13C NMR 光谱以及 MALDI-TOF 质谱法进行了表征。