S-ethyl 2,3-di-O-benzyl-4,6-O-(α-methoxycarbonyl)ethylidene-1-thio-α-D-mannopyranoside | 887700-26-7

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: S-ethyl 2,3-di-O-benzyl-4,6-O-(α-methoxycarbonyl)ethylidene-1-thio-α-D-mannopyranoside
• CAS: 887700-26-7
• 化学式: C₂₆H₃₂O₇S
• 分子量: 488.602
• InChiKey: XWJONRDJOGILBP-VEFUSMDZSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.94
• 重原子数：
  34.0
• 可旋转键数：
  9.0
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.5
• 拓扑面积：
  72.45
• 氢给体数：
  0.0
• 氢受体数：
  8.0

反应信息

• 作为反应物：
  描述：

  S-ethyl 2,3-di-O-benzyl-4,6-O-(α-methoxycarbonyl)ethylidene-1-thio-α-D-mannopyranoside 在 三氟甲磺酸酐 molecular sieve 、 二苯基亚砜 、 2,4,5-tri-tert-butylpyrimidine 、 三甲基铝 作用下， 以 正己烷 、 二氯甲烷 、 甲苯 为溶剂， 反应 8.5h， 生成 methyl 4-O-(2,3-di-O-benzyl-4,6-O-[α-2-(2-iodophenyl)ethylthiocarbonyl]ethylidene-β-D-mannopyranosyl)-2,3-O-isopropylidene-α-L-rhamnopyranoside
  参考文献：
  名称：

  4,6-O-[1-Cyano-2-(2-iodophenyl)ethylidene] Acetals. Improved Second-Generation Acetals for the Stereoselective Formation of β-d-Mannopyranosides and Regioselective Reductive Radical Fragmentation to β-d-Rhamnopyranosides. Scope and Limitations

  摘要：

  The [1-cyano-2-(2-iodophenyl)]ethylidene group is introduced as an acetal-protecting group for carbohydrate thioglycoside donors. The group is easily introduced under mild conditions, over short reaction times, and in the presence of a wide variety of other protecting groups by the reaction of the 4,6-diol with triethyl (2-iodophenyl)orthoacetate and camphorsulfonic acid, followed by trimethylsilyl cyanide and boron trifluoride etherate. The new protecting group conveys strong beta-selectivity with thiomannoside donors and undergoes a tin-mediated radical fragmentation to provide high yields of the synthetically challenging beta-rhamnopyranosides. The method is also applicable to the glucopyranosides when high beta-selectivity is observed in the coupling reaction and alpha-quinovosides are formed selectively in the radical fragmentation step. In the galactopyranoside series, beta-glycosides are formed selectively on coupling to donors protected by the new system, but the radical fragmentation is unselective and gives mixtures of the 4- and 6-deoxy products. Variable-temperature NMR studies for the glycosylation step, which helped define an optimal protocol, are described.

  DOI：

  10.1021/jo0526688
• 作为产物：
  描述：

  丙酮酸甲酯 、 ethyl 2,3-di-O-benzyl-1-thio-α-D-mannopyranoside 在 三氟化硼乙醚 作用下， 以 乙腈 为溶剂， 反应 4.0h， 以20%的产率得到S-ethyl 2,3-di-O-benzyl-4,6-O-(α-methoxycarbonyl)ethylidene-1-thio-α-D-mannopyranoside
  参考文献：
  名称：

  4,6-O-[1-Cyano-2-(2-iodophenyl)ethylidene] Acetals. Improved Second-Generation Acetals for the Stereoselective Formation of β-d-Mannopyranosides and Regioselective Reductive Radical Fragmentation to β-d-Rhamnopyranosides. Scope and Limitations

  摘要：

  The [1-cyano-2-(2-iodophenyl)]ethylidene group is introduced as an acetal-protecting group for carbohydrate thioglycoside donors. The group is easily introduced under mild conditions, over short reaction times, and in the presence of a wide variety of other protecting groups by the reaction of the 4,6-diol with triethyl (2-iodophenyl)orthoacetate and camphorsulfonic acid, followed by trimethylsilyl cyanide and boron trifluoride etherate. The new protecting group conveys strong beta-selectivity with thiomannoside donors and undergoes a tin-mediated radical fragmentation to provide high yields of the synthetically challenging beta-rhamnopyranosides. The method is also applicable to the glucopyranosides when high beta-selectivity is observed in the coupling reaction and alpha-quinovosides are formed selectively in the radical fragmentation step. In the galactopyranoside series, beta-glycosides are formed selectively on coupling to donors protected by the new system, but the radical fragmentation is unselective and gives mixtures of the 4- and 6-deoxy products. Variable-temperature NMR studies for the glycosylation step, which helped define an optimal protocol, are described.

  DOI：

  10.1021/jo0526688

文献信息

• Chemical Synthesis and Antigenicity Evaluation of <i>Shigella dysenteriae</i> Serotype 10 O-Antigen Tetrasaccharide Containing a (<i>S</i>)-4,6-<i>O</i>-Pyruvyl Ketal
  作者：Chunjun Qin、Lingxin Li、Guangzong Tian、Meiru Ding、Shengyong Zhu、Wuqiong Song、Jing Hu、Peter H. Seeberger、Jian Yin

  DOI：10.1021/jacs.2c05953

  日期：2022.11.23

  resistance of this pathogen. The Shigella O-antigen is a promising vaccine target. To identify the immune epitopes of the glycan, the first total synthesis of Shigella dysenteriae serotype 10 O-antigen tetrasaccharide containing a (S)-4,6-O-pyruvyl ketal was completed. The 1,2-trans-β-glycosylation & C2 epimerization and conformational locking strategies facilitated the construction of two 1,2-cis-β-glycosidic

  志贺氏菌是导致儿童急性腹泻的第二大常见病原体。由于这种病原体的耐药性不断增加，人们仍热切期待抗志贺氏菌疫苗的出现。志贺氏菌O抗原是一个很有前途的疫苗靶点。为了鉴定聚糖的免疫表位，首次全合成了含有 ( S )-4,6 - O-丙酮酰缩酮的痢疾杆菌血清型 10 O-抗原四糖。1,2-反式-β-糖基化和 C2 差向异构化和构象锁定策略促进了两个 1,2-顺式的构建-β-糖苷键。通过添加给电子苄基提高了糖基供体和受体的反应性，从而实现了四糖的有效组装。( S )-4,6- O -丙酮酰缩酮由于其对糖基化立体特异性和效率的影响而在最后阶段引入。此外，还合成了 ( R ) -4,6- O-丙酮酸化和非丙酮酸化四糖以及另外三个片段。聚糖微阵列筛选显示四糖重复单元是 O 抗原的关键抗原表位。此外，( S )-4,6- O-丙酮酰缩酮是该抗原的一个基本结构特征，用于设计针对S. dysenteriae血清型