Synthesis of S-linked thiooligosaccharide analogues of Nod factors: synthesis of new protected thiodisaccharide and thiotrisaccharide intermediates
作者:Latino Loureiro Morais、Khalil Bennis、Isabelle Ripoche、Liang Liao、France-Isabelle Auzanneau、Jacques Gelas
DOI:10.1016/s0008-6215(03)00149-6
日期:2003.6
influence of our protecting group strategy, the glycosylation of 1,6-anhydro-2-azido-3-O-benzyl-2-deoxy-beta-D-glucopyranoside (7) with two trichloroacetimidate glycosyl donors carrying an azido group at C-2 and either benzyl or benzoyl protecting groups on O-3 and O-4 was first attempted under catalysis with BF(3).Et(2)O in toluene. While glycosylation with the benzoylated glycosyl donor gave only a poor
我们正在研究结瘤因子的硫代类似物的合成,该结节因子对几丁质酶的降解具有抗性。为了研究我们保护基策略的影响,将1,6-脱水-2-叠氮基-3-O-苄基-2-脱氧-β-D-吡喃葡萄糖苷(7)与两个带有叠氮基的三氯乙酰亚氨酸糖基供体进行糖基化首先在BF(3).Et(2)O的甲苯催化下,尝试在C-2上的C2和O-3和O-4上的苄基或苯甲酰基保护基团进行尝试。虽然用苯甲酰化的糖基供体进行糖基化仅产生较差的二糖(27%),但与苄基化的供体的类似反应以良好的收率(77%)给出了相应的二糖。尽管两种产物均以异头混合物形式获得,但苄基化的供体导致改善的立体选择性,有利于所需的β-端基异构体(α:β3:7)。基于这些结果,通过7与6-O-乙酰基-4-S-(3,4,6-三-O-乙酰基-2-苄氧基羰基氨基-2-脱氧-β-D的偶联反应合成了一种新型的硫代三糖还新合成了-(吡喃葡萄糖基)-2-叠氮基-3-O-苄基-2-