3β-cholestanyl 2-O-benzyl-3,4-O-carbonyl-α-L-rhamnopyranoside | 629627-38-9

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 类固醇和类固醇衍生物
• 英文名称: 3β-cholestanyl 2-O-benzyl-3,4-O-carbonyl-α-L-rhamnopyranoside
• CAS: 629627-38-9
• 化学式: C₄₁H₆₂O₆
• 分子量: 650.94
• InChiKey: ZAOHIKDIGDPFOY-FBVKGLRQSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  9.73
• 重原子数：
  47.0
• 可旋转键数：
  10.0
• 环数：
  7.0
• sp3杂化的碳原子比例：
  0.83
• 拓扑面积：
  63.22
• 氢给体数：
  0.0
• 氢受体数：
  6.0

反应信息

• 作为反应物：
  描述：

  3β-cholestanyl 2-O-benzyl-3,4-O-carbonyl-α-L-rhamnopyranoside 在 sodium methylate 作用下， 以 甲醇 、 二氯甲烷 为溶剂， 反应 3.0h， 以76%的产率得到3β-cholestanyl 2-O-benzyl-α-L-rhamnopyranoside
  参考文献：
  名称：

  The 3,4-O-Carbonate Protecting Group as a β-Directing Group in Rhamnopyranosylation in Both Homogeneous and Heterogeneous Glycosylations As Compared to the Chameleon-like 2,3-O-Carbonates

  摘要：

  It is demonstrated that the beta-selectivity observed in the insoluble silver salt mediated couplings of 2,3-O-carbonate-protected rhamnosyl bromides is uniquely due to the heterogeneous nature of the reaction. In homogeneous solution these same donors are alpha-selective, a fact that is attributed to the half-chair conformation of these substances which reduces the energy barrier to oxacarbenium ion formation. It is suggested that the 2,3-O-carbonate group be dubbed torsionally arming in the manno- and rhamnopyranose series. When the carbonate group is removed to the 3,4-O-position a beta-selective system is formed, in both homogeneous and heterogeneous conditions, and it is demonstrated that this selectivity arises from the combination of the electron-withdrawing nature of the carbonate and its inability to take part in neighboring participation.

  DOI：

  10.1021/jo035003j
• 作为产物：
  描述：

  phenyl 2-O-benzyl-3,4-O-carbonyl-1-thio-β-L-rhamnopyranoside 在 溴 、 silver carbonate 作用下， 以 二氯甲烷 为溶剂， 反应 15.0h， 生成 3β-cholestanyl 2-O-benzyl-3,4-O-carbonyl-α-L-rhamnopyranoside
  参考文献：
  名称：

  The 3,4-O-Carbonate Protecting Group as a β-Directing Group in Rhamnopyranosylation in Both Homogeneous and Heterogeneous Glycosylations As Compared to the Chameleon-like 2,3-O-Carbonates

  摘要：

  It is demonstrated that the beta-selectivity observed in the insoluble silver salt mediated couplings of 2,3-O-carbonate-protected rhamnosyl bromides is uniquely due to the heterogeneous nature of the reaction. In homogeneous solution these same donors are alpha-selective, a fact that is attributed to the half-chair conformation of these substances which reduces the energy barrier to oxacarbenium ion formation. It is suggested that the 2,3-O-carbonate group be dubbed torsionally arming in the manno- and rhamnopyranose series. When the carbonate group is removed to the 3,4-O-position a beta-selective system is formed, in both homogeneous and heterogeneous conditions, and it is demonstrated that this selectivity arises from the combination of the electron-withdrawing nature of the carbonate and its inability to take part in neighboring participation.

  DOI：

  10.1021/jo035003j