Immunogens related to the synthetic tetrasaccharide side chain of the Bacillus anthracis exosporium
作者:Rina Saksena、Roberto Adamo、Pavol Kováč
DOI:10.1016/j.bmc.2007.03.057
日期:2007.6
The known methyl 2-O-acetyl-3,4-di-O-benzyl-1-thio-alpha-L-rhamnopyranoside (3) was converted to the corresponding 5-methoxycarbonylpentyl glycoside 4 which was deacetylated. The product 5 was used as the initial glycosyl acceptor to construct two trirhamnoside glycosyl acceptors having HO-3(III) flanked by either benzoyl or benzyl groups, compounds 10 and 29, respectively [fully protected, except HO-3(III)
将已知的甲基2-O-乙酰基-3,4-二-O-苄基-1-硫代-α-L-鼠李糖吡喃糖苷(3)转化为相应的5-甲氧基羰基戊基糖苷4,其被去乙酰化。产物5用作起始的糖基受体,以构建两个侧接苯甲酰基或苄基的HO-3(III)的三鼠李糖苷糖基受体,分别是化合物10和29 [除HO-3(III)外,均得到充分保护,α -L-Rha-(1-> 3)-alpha-L-Rha-(1-> 2)-alpha-L-Rha-1-O-(CH2)5COOCH3]。当将它们用乙基4-叠氮基-3-O-苄基-4,6-二脱氧-2-O-溴乙酰基-1-硫代β-D-吡喃葡萄糖苷糖基化时(18),只有苄基化的糖基受体29给出了良好的收率。所需的四糖30。α和β连接的产物,以及相应的原酸酯23,当用带有2-O-溴乙酰基保护基的糖基供体进行10个糖基化时,几乎以相等的量形成α-β。在O-2为30时脱保护,然后进一步使分子官能化并整体脱保护,