1-Methyl-2-(bromomethyl)-4,7-dimethoxybenzimidazole | 103003-03-8

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 苯并咪唑类
• 英文名称: 1-Methyl-2-(bromomethyl)-4,7-dimethoxybenzimidazole
• 英文别名: 2-(Bromomethyl)-4,7-dimethoxy-1-methylbenzimidazole
• CAS: 103003-03-8
• 化学式: C₁₁H₁₃BrN₂O₂
• 分子量: 285.14
• InChiKey: SCODXVGPGIGFMP-UHFFFAOYSA-N

物化性质

• 沸点：
  418.1±35.0 °C(Predicted)
• 密度：
  1.49±0.1 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  2
• 重原子数：
  16
• 可旋转键数：
  3
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.36
• 拓扑面积：
  36.3
• 氢给体数：
  0
• 氢受体数：
  3

反应信息

• 作为反应物：
  描述：

  氰化钠[13C] 、 1-Methyl-2-(bromomethyl)-4,7-dimethoxybenzimidazole 以 二甲基亚砜 为溶剂， 反应 4.0h， 以74%的产率得到1-Methyl-2-(cyanomethyl)-4,7-dimethoxybenzimidazole-2'-13C
  参考文献：
  名称：

  A mechanistic study of 2-vinylbenzimidazole formation from 2-(2'-haloethyl)benzimidazoles. Synthesis of highly electron-rich vinylic compounds by general base and specific acid-general base catalysis

  摘要：

  The mechanism of halide elimination from 2-(haloethyl)-1-methyl-4,7-dihydroxybenzimidazole was studied in aqueous buffer by means of a pH-rate profile, buffer dilution studies, and C-13 scrambling. It was anticipated that a spiro-fused cyclopropyl species could arise from the above benzimidazole derivative by loss of HX. However, the results of our studies were consistent with both the general base and the specific acid/general base-catalyzed 1,2-elimination of HX. Since the loss of the leaving group occurs in the same transition state as proton abstraction, the elimination mechanism is of the ''E2'' type. The specific acid/general base process permits facile elimination reactions in acidic (pH < 6) media. Thus, protonation of the benzimidazole nitrogen (specific acid) at low pH electrostatically favors proton abstraction by the general base (acetate and phosphate).

  DOI：

  10.1021/jo00079a025

文献信息

• Formation and fate of benzimidazole-based quinone methides. Influence of pH on quinone methide fate
  作者：Edward B. Skibo

  DOI：10.1021/jo00048a020

  日期：1992.10

  The influence of pH on quinone methide fate was assessed from a comparative hydrolytic study of benzimidazole hydroquinones and their O-methylated analogues. Elimination of a leaving group from the hydroquinones affords the carbocation or the quinone methide depending on the pH. The O-methylated analogues, on the other hand, can only afford the carbocation species. Evidence is presented herein that the quinone methide species is reversibly protonated to afford the carbocation species. The acid dissociation constant for this equilibrium is pK(a) 5.5. Above pH 5.5, the quinone methide species traps both nucleophiles and the proton. Below pH 5.5, the quinone methide species is protonated to afford the carbocation species, which exclusively traps nucleophiles. Therefore, the carbocation acid dissociation constant can be used to predict quinone methide fate as a function of pH.
• A mechanistic study of 2-vinylbenzimidazole formation from 2-(2'-haloethyl)benzimidazoles. Synthesis of highly electron-rich vinylic compounds by general base and specific acid-general base catalysis
  作者：Romesh C. Boruah、Edward B. Skibo

  DOI：10.1021/jo00079a025

  日期：1993.12

  The mechanism of halide elimination from 2-(haloethyl)-1-methyl-4,7-dihydroxybenzimidazole was studied in aqueous buffer by means of a pH-rate profile, buffer dilution studies, and C-13 scrambling. It was anticipated that a spiro-fused cyclopropyl species could arise from the above benzimidazole derivative by loss of HX. However, the results of our studies were consistent with both the general base and the specific acid/general base-catalyzed 1,2-elimination of HX. Since the loss of the leaving group occurs in the same transition state as proton abstraction, the elimination mechanism is of the ''E2'' type. The specific acid/general base process permits facile elimination reactions in acidic (pH < 6) media. Thus, protonation of the benzimidazole nitrogen (specific acid) at low pH electrostatically favors proton abstraction by the general base (acetate and phosphate).