4-Bromo-2-(α-bromocyclopentyl)-3,5-diphenyl-2H-pyrazole

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 唑类
• 英文名称: 4-Bromo-2-(α-bromocyclopentyl)-3,5-diphenyl-2H-pyrazole
• 英文别名: 4-Bromo-1-(2-bromocyclopentyl)-3,5-diphenylpyrazole
• 化学式: C₂₀H₁₈Br₂N₂
• 分子量: 446.184
• InChiKey: ZHPRERUIAUIYAE-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  5.9
• 重原子数：
  24
• 可旋转键数：
  3
• 环数：
  4.0
• 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

• 作为产物：
  描述：

  4,4-Dibromo-3,5-diphenyl-4H-pyrazole 、 环戊烯 在 三氟乙酸 作用下， 以 二氯甲烷 为溶剂， 以26%的产率得到4-Bromo-2-(α-bromocyclopentyl)-3,5-diphenyl-2H-pyrazole
  参考文献：
  名称：

  4-Halo-4H-pyrazoles: Cycloaddition with Cyclopentadiene to Azoalkanes of the 2,3-Diazabicyclo[2.2.1]hept-2-ene Type versus Electrophilic Addition with Cyclopentene

  摘要：

  The acid-catalyzed reactions of the 4-halogen-substituted 4H-pyrazoles 3 with cyclopentadiene and cyclopentene in methylene chloride have been examined. The 4,4-dichloro-3,5-diphenyl-4H-pyrazole (3a) cycloadded quantitatively with cyclopentadiene to the gem-dichloro-substituted azoalkane 4a of the 2,3-diazabicyclo[2.2.1]hept-2-ene type, whose structure was established by X-ray analysis. The azoalkane 4a was catalytically hydrogenated to the azoalkane 6 with reduced C=C double bond and the relatively persistent (toward autoxidation) hydrazine 7 with reduced C=C and N=N double bonds. The cycloaddition of 4-chloro-4-methyl-3,5-diphenyl-4H-pyrazole (3b) with cyclopentadiene gave the azoalkane anti-4b in high yield and diastereoselectivity. The azoalkanes 4a,b and 6 were reluctant toward photolysis and thermolysis and the expected housanes were not produced under these conditions. The acid-catalyzed reaction of the 4-bromo-substituted 4H-pyrazoles 3c-e with cyclopentadiene gave, instead of the desired cycloadducts, complex product mixtures. In the presence of acid, the 4H-pyrazoles 3 gave with cyclopentene the 2-(alpha-halocyclopentyl)-substituted 2H-pyrazoles 5 as products of electrophilic addition.

  DOI：

  10.1021/jo00102a036

文献信息

• Adam Waldemar, Ammon Horst, Nau Werner M., Peters Karl, J. Org. Chem, 59 (1994) N 23, S 7067- 7071
  作者：Adam Waldemar, Ammon Horst, Nau Werner M., Peters Karl

  DOI：——

  日期：——
• 4-Halo-4H-pyrazoles: Cycloaddition with Cyclopentadiene to Azoalkanes of the 2,3-Diazabicyclo[2.2.1]hept-2-ene Type versus Electrophilic Addition with Cyclopentene
  作者：Waldemar Adam、Horst Ammon、Werner M. Nau、Karl Peters

  DOI：10.1021/jo00102a036

  日期：1994.11

  The acid-catalyzed reactions of the 4-halogen-substituted 4H-pyrazoles 3 with cyclopentadiene and cyclopentene in methylene chloride have been examined. The 4,4-dichloro-3,5-diphenyl-4H-pyrazole (3a) cycloadded quantitatively with cyclopentadiene to the gem-dichloro-substituted azoalkane 4a of the 2,3-diazabicyclo[2.2.1]hept-2-ene type, whose structure was established by X-ray analysis. The azoalkane 4a was catalytically hydrogenated to the azoalkane 6 with reduced C=C double bond and the relatively persistent (toward autoxidation) hydrazine 7 with reduced C=C and N=N double bonds. The cycloaddition of 4-chloro-4-methyl-3,5-diphenyl-4H-pyrazole (3b) with cyclopentadiene gave the azoalkane anti-4b in high yield and diastereoselectivity. The azoalkanes 4a,b and 6 were reluctant toward photolysis and thermolysis and the expected housanes were not produced under these conditions. The acid-catalyzed reaction of the 4-bromo-substituted 4H-pyrazoles 3c-e with cyclopentadiene gave, instead of the desired cycloadducts, complex product mixtures. In the presence of acid, the 4H-pyrazoles 3 gave with cyclopentene the 2-(alpha-halocyclopentyl)-substituted 2H-pyrazoles 5 as products of electrophilic addition.