1-(4-nitrophenethyl)-3-phenylpyridin-1-ium bromide | 135041-79-1

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 吡啶及其衍生物
• 英文名称: 1-(4-nitrophenethyl)-3-phenylpyridin-1-ium bromide
• CAS: 135041-79-1
• 化学式: Br*C₁₉H₁₇N₂O₂
• 分子量: 385.26
• InChiKey: YMVVTSGLHKVZAQ-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  0.8
• 重原子数：
  24.0
• 可旋转键数：
  5.0
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.11
• 拓扑面积：
  47.02
• 氢给体数：
  0.0
• 氢受体数：
  2.0

反应信息

• 作为反应物：
  描述：

  1-(4-nitrophenethyl)-3-phenylpyridin-1-ium bromide 在 氢氧化钾 、 potassium chloride 作用下， 生成 3-苯基吡啶 、 4-硝基苯乙烯
  参考文献：
  名称：

  A change in the rate-determining step in the E1cB reactions of N-[2-(4-nitrophenyl)ethyl]pyridinium cations

  摘要：

  Second-order rate constants have been measured (aqueous solution, I = 1.0, 25-degrees-C) for the hydroxide ion catalyzed elimination reactions of 12 N-(2-(4-nitrophenyl)ethyl)pyridinium cations (3) bearing a variety of substituents in the pyridine ring. Bronsted plots as a function of the basicity of the pyridine leaving group are concave-down, which is consistent with a change in rate-determining step within an E1cB mechanism. These plots are characterized by beta-lg = -0.17 for the rate-determining deprotonation for pK(BH) < 6.5, and beta-lg = -0.39 for the rate-determining expulsion of the pyridine nucleofuge from the carbanionic intermediate for pK(BH) > 6.5. Elimination reactions in basic D2O occur without any significant incorporation of deuterium into the 4-nitrostyrene product, and require the presence of a hydrogen-bonded carbanionic intermediate in which nucleofuge expulsion occurs faster than exchange of hydrogen-bonding water molecules. Rate-determining deprotonation in these elimination reactions occurs 50-fold more slowly than for the corresponding reactions of the N-[2-(4-nitrophenyl)ethyl]quinuclidinium cations that have also been reported to have beta-lg = -0.17, but which do not show an analogous change in the rate-determining step upon variation of the nucleofuge basicity. The analogous elimination of the 1-methyl-3-[2-(4-nitrophenyl)ethyl]imidazolium cation occurs a further 30-fold more slowly than that predicted for 3 having a pyridine leaving group of the same basicity as 1-methylimidazole. The E1cB reactions of 3 are similar to the analogous reactions of N-(2-cyanoethyl)pyridinium cations (1) in displaying a change in the rate-determining step with nucleofuge basicity; however, the beta-lg values for 1 and 3 are quite different for both k1 and k2/k-1.

  DOI：

  10.1021/ja00018a036