5-methyl-1H-pyrazole-3,4-dicarboxylic acid dimethyl ester | 37387-73-8

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 唑类
• 英文名称: 5-methyl-1H-pyrazole-3,4-dicarboxylic acid dimethyl ester
• 英文别名: dimethyl 5-methyl-1H-pyrazole-3,4-dicarboxylate；5-methyl-1(2)H-pyrazole-3,4-dicarboxylic acid dimethyl ester；5-Methyl-pyrazol-3,4-dicarbonsaeure-dimethylester
• CAS: 37387-73-8
• 化学式: C₈H₁₀N₂O₄
• 分子量: 198.178
• InChiKey: LCJRTFMRGXYRAF-UHFFFAOYSA-N

物化性质

• 熔点：
  106 °C
• 沸点：
  313.9±37.0 °C(Predicted)
• 密度：
  1.294±0.06 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  0.7
• 重原子数：
  14
• 可旋转键数：
  4
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.38
• 拓扑面积：
  81.3
• 氢给体数：
  1
• 氢受体数：
  5

反应信息

• 作为产物：
  描述：

  在 三氟乙酸 作用下， 以 二氯甲烷 为溶剂， 反应 6.0h， 以46 mg的产率得到5-methyl-1H-pyrazole-3,4-dicarboxylic acid dimethyl ester
  参考文献：
  名称：

  Sydnones固相合成氨基酸衍生的N-未取代的吡唑

  摘要：

  描述了一种在固体载体上合成N-未取代的吡唑的新方法。固体支持物充当氨基酸的保护基。N-保护的氨基酸被N-亚硝化，随后在微波反应器中用乙酸酐处理会产生中离子sydnones，它们在与炔烃的1,3-偶极环加成反应中原位反应。产物的无痕裂解以高的总收率得到N-未取代的吡唑。

  DOI：

  10.1021/ol900704b

文献信息

• Photolysis of 5,5-dibenzyl-Δ³-1,3,4-oxadiazolines
  作者：John Warkentin、John Mck.R. Woollard

  DOI：10.1139/v97-033

  日期：1997.3.1

  Photolysis of dibenzyl-Δ3-1,3,4-oxadiazolines (3) in the presence of dimethyl acetylenedicarboxylate (DMAD) gives only modest yields of the expected symmetrical 3,3-dibenzylcyclopropenes (4), but these are accompanied by more than six by-products, including unsymmetrical cyclopropenes, methylenecyclopropanes, and various pyrazoles. The origin of this array of products can be explained by a series of

  在乙炔二甲酸二甲酯 (DMAD) 存在下二苄基-Δ3-1,3,4-恶二唑啉 (3) 的光解仅产生预期的对称 3,3-二苄基环丙烯 (4) 的适度产率，但这些伴随着超过六个副产物，包括不对称环丙烯、亚甲基环丙烷和各种吡唑。这一系列产品的起源可以通过一系列步骤来解释，从 3 的光解开始形成重氮烷，该重氮烷经过 1,3-偶极环加成到 DMAD，生成 3H-吡唑作为初始产物。后者通过热 1,5-sigmatropic 或离子对重排进一步光解为对称的环丙烯，与苄基迁移竞争，得到 4H-吡唑。4H-吡唑依次经过光解生成不对称的环丙烯，重排为亚甲基环丙烷。4H-吡唑也在空气存在下进行自氧化，得到苯甲酰基-4H-吡唑。此外，在与重排的竞争中，v...
• Studies of formal [1,5]-sigmatropic thermal rearrangements of dimethyl 3-alkyl-3-methyl-3H-pyrazole-4,5-dicarboxylates and dimethyl 4-alkyl-5-methyl-4H-pyrazole-3,4-dicarboxylates
  作者：Elizabeth A. Jefferson、John Warkentin

  DOI：10.1021/ja00042a007

  日期：1992.7

  Studies of the thermal rearrangements of 3H-pyrazoles, 10a-e, in benzene/toluene, chloroform, and methanol solvents are described. The mechanism for rearrangement appears to be two-step, involving discrete ion-pair intermediates. Large rate enhancements for these rearrangements in methanol and cation trapping by methanol are consistent with the proposed mechanism. Observed rate constants for the rearrangements of 3H-pyrazoles 10c, 10d, and 10e in benzene-d6 were determined. Insight into the sense of rearrangement by an ion-pair mechanism is also provided by analysis of the H-1 NMR spectra of the product mixtures. 3H-Pyrazoles 10b and 10e rearrange to afford 4H-pyrazoles 13b and 13e, respectively, and the thermal rearrangements of these pyrazoles in benzene-d6 and methanol are described. Rate constants for the rearrangements of these more stable pyrazole isomers in benzene-d6 were also determined. Cation-trapping experiments with methanol suggest that the 4H-pyrazoles also rearrange by a two-step mechanism, involving discrete ion-pair intermediates. Furthermore, it appears that different ion-pair intermediates are formed from the 3H-pyrazoles 10b and 10e, compared to the 4H-pyrazoles 13b and 13e, on the basis of cation-trapping experiments.
• Stepwise mechanism of formal 1,5-sigmatropic rearrangement of dimethyl 3,3-dialkyl-3H-pyrazole-4,5-dicarboxylates
  作者：Michael W. Majchrzak、Elizabeth Jefferson、John Warkentin

  DOI：10.1021/ja00162a072

  日期：1990.3
• MAJCHRZAK, MICHAEL W.;JEFFERSON, ELIZABETH;WARKENTIN, JOHN, J. AMER. CHEM. SOC., 112,(1990) N, C. 2449-2451
  作者：MAJCHRZAK, MICHAEL W.、JEFFERSON, ELIZABETH、WARKENTIN, JOHN

  DOI：——

  日期：——