2,3-bis-O-acetyl-4,6-bis-O-(p-bromobenzoyl)-α-D-galactopyranosyl bromide | 217970-64-4

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯和取代衍生物
• 英文名称: 2,3-bis-O-acetyl-4,6-bis-O-(p-bromobenzoyl)-α-D-galactopyranosyl bromide
• 英文别名: [(2R,3S,4S,5R,6R)-4,5-diacetyloxy-6-bromo-3-(4-bromobenzoyl)oxyoxan-2-yl]methyl 4-bromobenzoate
• CAS: 217970-64-4
• 化学式: C₂₄H₂₁Br₃O₉
• 分子量: 693.137
• InChiKey: LWXWCJXXPZMXDG-CTWRKMMKSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  6.2
• 重原子数：
  36
• 可旋转键数：
  11
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.33
• 拓扑面积：
  114
• 氢给体数：
  0
• 氢受体数：
  9

反应信息

• 作为反应物：
  描述：

  2,3-bis-O-acetyl-4,6-bis-O-(p-bromobenzoyl)-α-D-galactopyranosyl bromide 在 silver trifluoromethanesulfonate 、 三氯化铁 、 1,1,3,3-四甲基脲 作用下， 以 二氯甲烷 为溶剂， 生成 (1R,2S,5R)-(-)-1-menthyl 2,3-bis-O-acetyl-4,6-bis-O-(p-bromobenzoyl)-α-D-galactopyranoside
  参考文献：
  名称：

  Alkyl Galactopyranosides:  Rotational Population Dependence of the Hydroxymethyl Group on the Aglycon and Its Absolute Configuration and on the Anomeric Configuration

  摘要：

  The rotational populations of the hydroxymethyl group in chiral and nonchiral alkyl alpha- and beta-galactopyranosides proved, on the basis of circular dichroism (CD) and H-1 NMR data, to be dependent on the structure of the aglycon: the population of the gt and tg rotamers increased and decreased, respectively, as the pK(a) of the bonded alcohol (aglycon) increased, while the population of the gg rotamer remained practically constant. Furthermore, low-temperature CD measurements proved that the most stable rotamer is the gt, and not the tg. In addition, a clear correlation between the rotational populations and the absolute configuration of the chiral aglycon was observed; namely, higher and smaller gt and tg populations were observed for the (S)-alkyl beta-D-galactopyranosides than for their (R)-alkyl beta-D-galactopyranoside counterparts, the opposite behavior being observed for the cl-anomers. The results point to the exo anomeric effect as being responsible for these rotational dependencies, as well as to nonbonding interactions between the aglycon and the chromophore at C6 for those stereoisomers having in their aglycon a bulky substituent syn to the endocyclic oxygen (O5). In addition, the chemical shift differences (Delta delta) of the aglyconic protons of galactosylated chiral alcohols proved to be characteristic of the absolute configuration of the bonded chiral alcohol.

  DOI：

  10.1021/jo981002t
• 作为产物：
  描述：

  1,2,3-tris-O-acetyl-4,6-bis-O-(p-bromobenzoyl)-D-galactopyranoside 在 氢溴酸 、 溶剂黄146 作用下， 以 二氯甲烷 为溶剂， 以71%的产率得到2,3-bis-O-acetyl-4,6-bis-O-(p-bromobenzoyl)-α-D-galactopyranosyl bromide
  参考文献：
  名称：

  Alkyl Galactopyranosides:  Rotational Population Dependence of the Hydroxymethyl Group on the Aglycon and Its Absolute Configuration and on the Anomeric Configuration

  摘要：

  The rotational populations of the hydroxymethyl group in chiral and nonchiral alkyl alpha- and beta-galactopyranosides proved, on the basis of circular dichroism (CD) and H-1 NMR data, to be dependent on the structure of the aglycon: the population of the gt and tg rotamers increased and decreased, respectively, as the pK(a) of the bonded alcohol (aglycon) increased, while the population of the gg rotamer remained practically constant. Furthermore, low-temperature CD measurements proved that the most stable rotamer is the gt, and not the tg. In addition, a clear correlation between the rotational populations and the absolute configuration of the chiral aglycon was observed; namely, higher and smaller gt and tg populations were observed for the (S)-alkyl beta-D-galactopyranosides than for their (R)-alkyl beta-D-galactopyranoside counterparts, the opposite behavior being observed for the cl-anomers. The results point to the exo anomeric effect as being responsible for these rotational dependencies, as well as to nonbonding interactions between the aglycon and the chromophore at C6 for those stereoisomers having in their aglycon a bulky substituent syn to the endocyclic oxygen (O5). In addition, the chemical shift differences (Delta delta) of the aglyconic protons of galactosylated chiral alcohols proved to be characteristic of the absolute configuration of the bonded chiral alcohol.

  DOI：

  10.1021/jo981002t