1-(N-Imidazolyl)-4-methylcyclohexene

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 唑类
• 英文名称: 1-(N-Imidazolyl)-4-methylcyclohexene
• 英文别名: 1-(4-Methylcyclohexen-1-yl)imidazole
• 化学式: C₁₀H₁₄N₂
• 分子量: 162.235
• InChiKey: XIPGWXXZMZRMRY-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2
• 重原子数：
  12
• 可旋转键数：
  1
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.5
• 拓扑面积：
  17.8
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为反应物：
  描述：

  1-(N-Imidazolyl)-4-methylcyclohexene 在 platinum on activated charcoal 氢气 、 三氟乙酸 作用下， 以 乙醇 为溶剂， 反应 72.0h， 生成 trans-N-(4-Methylcyclohexyl)imidazole 、 cis-N-(4-Methylcyclohexyl)imidazole
  参考文献：
  名称：

  Solvation Effect on Steric Bulk of Ionic Substituents: Imidazolium vs Imidazole

  摘要：

  To compare the steric bulk of a cationic substituent with that of the corresponding neutral one, the conformational equilibria of cis-N-(4-methylcyclohexyl)imidazole (l-c), cis-N-(4-phenylcyclohexyl)imidazole (2-c), and their conjugate acids were measured by low-temperature NMR. The A value of an imidazolyl group (equatorial-to-axial free-energy change of N-cyclohexylimidazole) is 2.2 +/- 0.1 kcal/mol, in both dichloromethane and methanol. The A value of an N-protonated imidazolyl group in these solvents is 2.2 +/- 0.1 kcal/mol. Within the experimental error of this method, the cationic substituent is the same size as the neutral. To measure the relative sizes more precisely, an NMR, titration method, applicable to a mixture of isomers, was developed. The ratio of acidity constants of cis- and trans-N-(4-phenylcyclohexyl)imidazoles could be determined from the variation of H1 chemical shifts as a 1:1 mixture was titrated with DC1. In aqueous acetone the cis isomer is found to be 0.048 +/- 0.002 pK unit less basic. This corresponds to a Delta A = A(N-imidazolylH+) - A(N-imidazolyl) of 0.089 +/- 0.004 kcal/mol, with the protonated imidazolyl slightly but detectably larger. In CD2Cl2 the difference is smaller, and in DMSO-d(6) it reverses. The significance of this result for the reverse anomeric effect in N-glycosylimidazolium ions is discussed.

  DOI：

  10.1021/jo00097a028
• 作为产物：
  描述：

  咪唑 、 4-甲基环己酮 在 氯化亚砜 作用下， 以 二氯甲烷 为溶剂， 反应 72.0h， 以39%的产率得到1-(N-Imidazolyl)-4-methylcyclohexene
  参考文献：
  名称：

  Solvation Effect on Steric Bulk of Ionic Substituents: Imidazolium vs Imidazole

  摘要：

  To compare the steric bulk of a cationic substituent with that of the corresponding neutral one, the conformational equilibria of cis-N-(4-methylcyclohexyl)imidazole (l-c), cis-N-(4-phenylcyclohexyl)imidazole (2-c), and their conjugate acids were measured by low-temperature NMR. The A value of an imidazolyl group (equatorial-to-axial free-energy change of N-cyclohexylimidazole) is 2.2 +/- 0.1 kcal/mol, in both dichloromethane and methanol. The A value of an N-protonated imidazolyl group in these solvents is 2.2 +/- 0.1 kcal/mol. Within the experimental error of this method, the cationic substituent is the same size as the neutral. To measure the relative sizes more precisely, an NMR, titration method, applicable to a mixture of isomers, was developed. The ratio of acidity constants of cis- and trans-N-(4-phenylcyclohexyl)imidazoles could be determined from the variation of H1 chemical shifts as a 1:1 mixture was titrated with DC1. In aqueous acetone the cis isomer is found to be 0.048 +/- 0.002 pK unit less basic. This corresponds to a Delta A = A(N-imidazolylH+) - A(N-imidazolyl) of 0.089 +/- 0.004 kcal/mol, with the protonated imidazolyl slightly but detectably larger. In CD2Cl2 the difference is smaller, and in DMSO-d(6) it reverses. The significance of this result for the reverse anomeric effect in N-glycosylimidazolium ions is discussed.

  DOI：

  10.1021/jo00097a028