2-methoxy-2,5-dimethyl-5-(2,2-dimethylethyl)-(Δ³)-1,3,4-oxadiazole | 141981-43-3

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 环氧化物
• 英文名称: 2-methoxy-2,5-dimethyl-5-(2,2-dimethylethyl)-(Δ³)-1,3,4-oxadiazole
• 英文别名: 2-methoxy-2,5-dimethyl-5-(1,1-dimethylethyl)-Δ³-1,3,4-oxadiazoline；2-tert-butyl-5-methoxy-2,5-dimethyl-1,3,4-oxadiazole
• CAS: 141981-43-3
• 化学式: C₉H₁₈N₂O₂
• 分子量: 186.254
• InChiKey: DITGTWGIJZUYQA-UHFFFAOYSA-N

物化性质

• 沸点：
  205.6±40.0 °C(Predicted)
• 密度：
  1.02±0.1 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  2.55
• 重原子数：
  13.0
• 可旋转键数：
  1.0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  1.0
• 拓扑面积：
  43.18
• 氢给体数：
  0.0
• 氢受体数：
  4.0

反应信息

• 作为反应物：
  描述：

  2-methoxy-2,5-dimethyl-5-(2,2-dimethylethyl)-(Δ³)-1,3,4-oxadiazole 以 甲苯 为溶剂， 反应 7.0h， 生成 3-tert-Butyl-3-methyl-3H-pyrazole-5-carboxylic acid methyl ester
  参考文献：
  名称：

  Studies of thermal rearrangements of methyl 3-alkyl-3-methyl-3H-pyrazole-5-carboxylates. Concerted, stepwise, and unclassified mechanisms

  摘要：

  Studies of the thermal rearrangements of five 3H-pyrazoles are described, in which the migrating groups were methoxymethyl, tert-butyl, 1-adamantyl, p-methoxybenzyl, and benzyl. On the basis of reaction products, rearrangement of the (methoxymethyl)pyrazole in benzene, dichloromethane, and methanol at room temperature occurs by a stepwise mechanism, involving discrete ion-pair intermediates. Observed first-order rate constants, for the rearrangement of four of the 3H-pyrazoles in benzene-d(6) and acetone-d(6) at higher temperatures, were determined The tert-butyl compound also rearranges by a stepwise mechanism in benzene d(6), acetone-d(6), and methanol-d(4) based on the fact that isobutene and tert-butyl methyl ether (in methanol) are coproducts of rearrangement. The mechanism of rearrangement of the adamantyl and methoxybenzyl systems, in both benzene d(6) and acetone-d(6) solvents, is ambiguous, the distinction between stepwise, with tight ion-pair intermediates, and concerted, with some charge separation, being unclear. However, both afforded a methyl ether in low yield during rearrangement in methanol solvent, which suggests a stepwise, ion-pair mechanism for rearrangement in that medium. No methanolysis product could be detected from the rearrangement of the benzyl compound in methanol, which suggests concerted rearrangement. Additional evidence that it rearranges by a concerted mechanism is the fact that it affords only one pyrazole product, whereas the others afford two or more.

  DOI：

  10.1021/jo00081a028
• 作为产物：
  描述：

  频哪酮 在 lead(IV) acetate 、 溶剂黄146 作用下， 以 乙醇 为溶剂， 反应 24.0h， 生成 2-methoxy-2,5-dimethyl-5-(2,2-dimethylethyl)-(Δ³)-1,3,4-oxadiazole
  参考文献：
  名称：

  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

  摘要：

  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.

  DOI：

  10.1021/ja00042a007

文献信息

• Photochemical Synthesis of Prochiral Dialkyl 3,3-Dialkylcyclopropene-1,2-dicarboxylates with Facial Shielding Substituents and Related Substrates
  作者：A. Stephen K. Hashmi、Marc A. Grundl、Andreas Rivas Nass、Frank Naumann、Jan W. Bats、Michael Bolte

  DOI：10.1002/1099-0690(200112)2001:24<4705::aid-ejoc4705>3.0.co;2-j

  日期：2001.12

  types of cyclopropene-1,2-dicarboxylates 1 have been obtained by photochemical methods from the corresponding pyrazoles 11, 12, or 13. These pyrazoles were synthesized by 1,3-dipolar cycloadditions of alkynes 8 or 9 with either preformed diazoalkanes or diazoalkanes generated photochemically in situ, by use of oxadiazolines as diazoalkane precursors. The numerous substrates have clearly established the

  通过光化学方法从相应的吡唑 11、12 或 13 中获得了不同类型的环丙烯-1,2-二羧酸酯 1。这些吡唑是通过炔烃 8 或 9 与预先形成的重氮烷烃或重氮烷烃的 1,3-偶极环加成反应合成的通过使用恶二唑啉作为重氮烷前体，光化学原位产生。众多的底物明确规定了不同途径合成前体和环丙烯的范围和局限性；甚至可以合成前手性和对映体纯的手性衍生物。许多前体和环丙烯可以通过 X 射线晶体结构分析进行表征，这揭示了有趣的结构特征，并允许明确指定不同的非对映异构体或结构异构体。一些光化学反应产生了独特的副产物；晶体结构分析对于明确的结构分配绝对至关重要。
• MAJCHRZAK, MICHAEL W.;BEKHAZI, MICHEL;TSE-SHEEPY, IRENE;WARKENTIN, JOHN, J. ORG. CHEM., 54,(1989) N, C. 1842-1845
  作者：MAJCHRZAK, MICHAEL W.、BEKHAZI, MICHEL、TSE-SHEEPY, IRENE、WARKENTIN, JOHN

  DOI：——

  日期：——