3,4-Dideuterio-1-methylpyrazole | 136828-05-2

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 唑类
• 英文名称: 3,4-Dideuterio-1-methylpyrazole
• CAS: 136828-05-2
• 化学式: C₄H₆N₂
• 分子量: 84.0892
• InChiKey: UQFQONCQIQEYPJ-PBNXXWCMSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.2
• 重原子数：
  6
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.25
• 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：

  3,4-Dideuterio-1-methylpyrazole 以 乙腈 为溶剂， 生成 2,5-dideuterio-1-methylimidazole 、 2,4-Dideuterio-1-methylimidazole 、 4,5-Dideuetro-1-methylimidazol
  参考文献：
  名称：

  Phototransposition chemistry of 1-methylpyrazole. Deuterium, methyl, and fluorine substitution

  摘要：

  1-Methylpyrazole (1) was observed to undergo photo-ring cleavage to 3-(N-methylamino)propenenitrile (17) and phototransposition to 1-methylimidazole (3). Although upon prolonged irradiation 17 is also converted to 3, the efficiency of the 1 --> 17 --> 3 pathway is low and cannot account for a significant fraction of 3 observed upon short-duration irradiation. Under these conditions, deuterium-labeling studies show that 1 phototransposes to 3 by the P4, P6, and P7 permutation patterns in a ratio of 4.8:6.5:1.0. These scrambling patterns are consistent with mechanisms involving ring contration-ring expansion (P4) and electrocyclic ring closure followed by one (P6) or two (P7) sigmatropic shifts of nitrogen. Methyl and fluorine substitution on the 1-methylpyrazole ring reduces reactivity via the P6 and P7 pathways. Thus, 1,5-dimethylpyrazole transposes by these pathways in a ratio of 3.5:1.8:1.0, whereas 5-fluoro-1-methylpyrazole isomerizes only by the P4 and P6 pathways in a ratio of 9.7:1.

  DOI：

  10.1021/jo00022a019
• 作为产物：
  描述：

  3-Deuterio-1-methylpyrazole 在 重水 、 氘代硫酸 作用下， 反应 240.0h， 生成 3,4-Dideuterio-1-methylpyrazole
  参考文献：
  名称：

  Phototransposition chemistry of 1-methylpyrazole. Deuterium, methyl, and fluorine substitution

  摘要：

  1-Methylpyrazole (1) was observed to undergo photo-ring cleavage to 3-(N-methylamino)propenenitrile (17) and phototransposition to 1-methylimidazole (3). Although upon prolonged irradiation 17 is also converted to 3, the efficiency of the 1 --> 17 --> 3 pathway is low and cannot account for a significant fraction of 3 observed upon short-duration irradiation. Under these conditions, deuterium-labeling studies show that 1 phototransposes to 3 by the P4, P6, and P7 permutation patterns in a ratio of 4.8:6.5:1.0. These scrambling patterns are consistent with mechanisms involving ring contration-ring expansion (P4) and electrocyclic ring closure followed by one (P6) or two (P7) sigmatropic shifts of nitrogen. Methyl and fluorine substitution on the 1-methylpyrazole ring reduces reactivity via the P6 and P7 pathways. Thus, 1,5-dimethylpyrazole transposes by these pathways in a ratio of 3.5:1.8:1.0, whereas 5-fluoro-1-methylpyrazole isomerizes only by the P4 and P6 pathways in a ratio of 9.7:1.

  DOI：

  10.1021/jo00022a019