3-acetyl-5-benzoyl-4,5-dihydro-1H-pyrazole | 820972-86-9

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: 3-acetyl-5-benzoyl-4,5-dihydro-1H-pyrazole
• 英文别名: Ethanone, 1-(5-benzoyl-4,5-dihydro-1H-pyrazol-3-yl)-；1-(5-benzoyl-4,5-dihydro-1H-pyrazol-3-yl)ethanone
• CAS: 820972-86-9
• 化学式: C₁₂H₁₂N₂O₂
• 分子量: 216.239
• InChiKey: PHUIRMVWTXCOAA-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.1
• 重原子数：
  16
• 可旋转键数：
  3
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.25
• 拓扑面积：
  58.5
• 氢给体数：
  1
• 氢受体数：
  4

反应信息

• 作为反应物：
  描述：

  3-acetyl-5-benzoyl-4,5-dihydro-1H-pyrazole 在 2,3-二氯-5,6-二氰基-1,4-苯醌 作用下， 以 苯 为溶剂， 反应 5.0h， 以29%的产率得到1-(3-benzoyl-1H-pyrazol-5-yl)ethan-1-one
  参考文献：
  名称：

  Synthesis and Relative Stability of 3,5-Diacyl-4,5-dihydro-1H-pyrazoles Prepared by Dipolar Cycloaddition of Enones and α-Diazoketones

  摘要：

  An unusual reaction process that produced unexpected heterocyclic systems by a fragmentation-recombination mechanism is described. Thus treatment of the triketone, 3-acetyl-2,6-heptanedione, 1, with methanesulfonyl azide gave, in addition to the expected alpha-diazo ketone 3a, the dihydropyrazole 3c and its oxidation product, the pyrazole 3d. We propose that the initially formed alpha-diazo ketone 3a fragments into the simple alpha-diazomethyl ketone and methyl vinyl ketone which then undergo an intermolecular [2,3]-dipolar cycloaddition. Analogous treatment of the trifluoromethyl trione 2 again afforded a pyrazole 4c. Further experiments were carried out to lend evidence to our mechanistic hypothesis. Thus alpha-diazoacetophenone 5 and MVK underwent a [2,3]-dipolar cycloaddition under mild conditions to give the two regioisomeric dihydropyrazoles 6a and 6b. Interestingly these were formed in a 2:1 ratio, which suggested that 6a was more stable than 6b. The structures of 6a and 6b were optimized by using the B3LYP density functional method and the 6-31G* basis set and isomer 6a was predicted to be 1.5 kcal/mol more stable than isomer 6b. This energy difference could be rationalized by the greater capacity of the acetyl group than the benzoyl group to conjugate with the hydrazone. This difference in conjugation is reflected by key bond length differences. Thus we have discovered a novel fragmentation-cycloaddition process. We have also presented evidence for the mechanism of the formation of the dihydropyrazoles and carried out calculations to support these findings.

  DOI：

  10.1021/jo048741w
• 作为产物：
  描述：

  苯甲酰氯 、 alkaline earth salt of/the/ methylsulfuric acid 以 乙醚 为溶剂， 反应 11.0h， 生成 3-acetyl-5-benzoyl-4,5-dihydro-1H-pyrazole
  参考文献：
  名称：

  Synthesis and Relative Stability of 3,5-Diacyl-4,5-dihydro-1H-pyrazoles Prepared by Dipolar Cycloaddition of Enones and α-Diazoketones

  摘要：

  An unusual reaction process that produced unexpected heterocyclic systems by a fragmentation-recombination mechanism is described. Thus treatment of the triketone, 3-acetyl-2,6-heptanedione, 1, with methanesulfonyl azide gave, in addition to the expected alpha-diazo ketone 3a, the dihydropyrazole 3c and its oxidation product, the pyrazole 3d. We propose that the initially formed alpha-diazo ketone 3a fragments into the simple alpha-diazomethyl ketone and methyl vinyl ketone which then undergo an intermolecular [2,3]-dipolar cycloaddition. Analogous treatment of the trifluoromethyl trione 2 again afforded a pyrazole 4c. Further experiments were carried out to lend evidence to our mechanistic hypothesis. Thus alpha-diazoacetophenone 5 and MVK underwent a [2,3]-dipolar cycloaddition under mild conditions to give the two regioisomeric dihydropyrazoles 6a and 6b. Interestingly these were formed in a 2:1 ratio, which suggested that 6a was more stable than 6b. The structures of 6a and 6b were optimized by using the B3LYP density functional method and the 6-31G* basis set and isomer 6a was predicted to be 1.5 kcal/mol more stable than isomer 6b. This energy difference could be rationalized by the greater capacity of the acetyl group than the benzoyl group to conjugate with the hydrazone. This difference in conjugation is reflected by key bond length differences. Thus we have discovered a novel fragmentation-cycloaddition process. We have also presented evidence for the mechanism of the formation of the dihydropyrazoles and carried out calculations to support these findings.

  DOI：

  10.1021/jo048741w

文献信息

• Synthesis and Relative Stability of 3,5-Diacyl-4,5-dihydro-1<i>H</i>-pyrazoles Prepared by Dipolar Cycloaddition of Enones and α-Diazoketones
  作者：Michael E. Jung、Sun-Joon Min、K. N. Houk、Daniel Ess

  DOI：10.1021/jo048741w

  日期：2004.12.1

  An unusual reaction process that produced unexpected heterocyclic systems by a fragmentation-recombination mechanism is described. Thus treatment of the triketone, 3-acetyl-2,6-heptanedione, 1, with methanesulfonyl azide gave, in addition to the expected alpha-diazo ketone 3a, the dihydropyrazole 3c and its oxidation product, the pyrazole 3d. We propose that the initially formed alpha-diazo ketone 3a fragments into the simple alpha-diazomethyl ketone and methyl vinyl ketone which then undergo an intermolecular [2,3]-dipolar cycloaddition. Analogous treatment of the trifluoromethyl trione 2 again afforded a pyrazole 4c. Further experiments were carried out to lend evidence to our mechanistic hypothesis. Thus alpha-diazoacetophenone 5 and MVK underwent a [2,3]-dipolar cycloaddition under mild conditions to give the two regioisomeric dihydropyrazoles 6a and 6b. Interestingly these were formed in a 2:1 ratio, which suggested that 6a was more stable than 6b. The structures of 6a and 6b were optimized by using the B3LYP density functional method and the 6-31G* basis set and isomer 6a was predicted to be 1.5 kcal/mol more stable than isomer 6b. This energy difference could be rationalized by the greater capacity of the acetyl group than the benzoyl group to conjugate with the hydrazone. This difference in conjugation is reflected by key bond length differences. Thus we have discovered a novel fragmentation-cycloaddition process. We have also presented evidence for the mechanism of the formation of the dihydropyrazoles and carried out calculations to support these findings.