2-methoxy-5-(4-methoxybenzyl)-2,5-dimethyl-Δ³-1,3,4-oxadiazoline | 154196-69-7

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯酚醚
• 英文名称: 2-methoxy-5-(4-methoxybenzyl)-2,5-dimethyl-Δ³-1,3,4-oxadiazoline
• 英文别名: 2-methoxy-5-[(4-methoxyphenyl)methyl]-2,5-dimethyl-1,3,4-oxadiazole
• CAS: 154196-69-7
• 化学式: C₁₃H₁₈N₂O₃
• 分子量: 250.298
• InChiKey: UNQCIOQGVUTQCW-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.76
• 重原子数：
  18.0
• 可旋转键数：
  4.0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.54
• 拓扑面积：
  52.41
• 氢给体数：
  0.0
• 氢受体数：
  5.0

反应信息

• 作为反应物：
  描述：

  2-methoxy-5-(4-methoxybenzyl)-2,5-dimethyl-Δ³-1,3,4-oxadiazoline 以 丙酮 、 甲苯 为溶剂， 反应 7.0h， 生成 1-(4-Methoxybenzyl)-5-methyl-1H-pyrazole-3-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：

  甲醇 、 1-acetyl-2-<1-(4-methoxyphenyl)-2-propylidene>hydrazine 在 lead(IV) acetate 作用下， 生成 2-methoxy-5-(4-methoxybenzyl)-2,5-dimethyl-Δ³-1,3,4-oxadiazoline
  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

文献信息

• 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.