5,6-二甲基-3,4-二氢吡喃-2-酮 | 4054-96-0

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 吡喃
• 中文名称: 5,6-二甲基-3,4-二氢吡喃-2-酮
• 英文名称: 5,6-Dimethyl-3,4-dihydro-2-pyrone
• 英文别名: 5,6-dimethyl-3,4-dihydro-pyran-2-one；5-Hydroxy-4-methyl-hex-4t-ensaeure-lacton；5.6-Dimethyl-2-oxo-2.3-dihydro-4H-pyran；5.6-Dimethyl-3.4-dihydro-pyranon-(2)；5,6-Dimethyl-3,4-dihydro-pyron-(2)；5,6-Dimethyl-3,4-dihydropyron-2；5,6-Dimethyl-3,4-dihydro-2H-pyran-2-one；5,6-dimethyl-3,4-dihydropyran-2-one
• CAS: 4054-96-0
• 化学式: C₇H₁₀O₂
• 分子量: 126.155
• InChiKey: CZEOXNDFAPPJHG-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.8
• 重原子数：
  9
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.57
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  2

安全信息

• 海关编码：
  2932999099

反应信息

• 作为反应物：
  描述：

  5,6-二甲基-3,4-二氢吡喃-2-酮 在 lithium aluminium tetrahydride 作用下， 以 乙醚 为溶剂， 反应 24.0h， 以33%的产率得到5,6-dimethyl-3,4-dihydro-2H-pyran
  参考文献：
  名称：

  Dye-sensitized photooxygenation of 2,3-dihydrofurans: competing [2 + 2] cycloadditions and ene reactions of singlet oxygen with a rigid cyclic enol ether system

  摘要：

  Singlet oxygen reacts with 2,3-dihydrofuran (1), 5-methyl- (7), 4,5-dimethyl- (13), and 4-carbomethoxy-5-methyl-2,3-dihydrofuran (20), 5,6-dimethyl-3,4-dihydro-2H-pyran (26), and 3-methoxy-2-methyl-2-butene (32) in nonpolar and polar aprotic solvents to yield dioxetanes and allylic hydroperoxides, except 32, which gives only allylic hydroperoxides. The dioxetanes were isolated, but decompose slowly with weak chemiluminescence at room temperature to yield the corresponding dicarbonyl compounds. The allylic hydroperoxides produced by the cyclic enol ethers could not be isolated or separated by high vacuum distillation or by chromatography; the endocyclic allylic hydroperoxides arising from the dihydrofurans eliminate H2O2 to yield the corresponding furans while the exocyclic allylic hydroperoxides give unknown products. Allylic hydroperoxides 28 and 29 and the dioxetane 27 obtained from 26 yield the same dicarbonyl compound 31. The proportion of dioxetanes to allylic hydroperoxides depends on ring size and substitution of the enol ethers and on solvent polarity. Smaller ring size, greater electron-donor substitution, and solvent polarity favor the formation of dioxetanes at the expense of allylic hydroperoxides. It is noteworthy that enol ether 20, an alpha,beta-unsaturated ester, forms appreciable amounts of a dioxetane in polar solvents (44% in acetonitrile). Kinetic results show that the rate and product distribution of the ene reaction are independent of solvent polarity, whereas the rate of dioxetane formation increases with solvent polarity. It is suggested that [2 + 2] cycloadditions and ene reactions occur via different transition states and intermediates, zwitterions and perepoxides, respectively. Furthermore, the remarkable propensity to dioxetane formation of dihydrofurans compared to that of dihydropyrans and the other enol ethers seems to be due to the rigidity of the five-membered ring in the transition state and intermediate zwitterion.

  DOI：

  10.1021/jo00012a040
• 作为产物：
  描述：

  4-methyl-5-oxohexanoic acid 在 乙酸酐 、 乙酰氯 作用下， 反应 3.0h， 以76%的产率得到5,6-二甲基-3,4-二氢吡喃-2-酮
  参考文献：
  名称：

  Dye-sensitized photooxygenation of 2,3-dihydrofurans: competing [2 + 2] cycloadditions and ene reactions of singlet oxygen with a rigid cyclic enol ether system

  摘要：

  Singlet oxygen reacts with 2,3-dihydrofuran (1), 5-methyl- (7), 4,5-dimethyl- (13), and 4-carbomethoxy-5-methyl-2,3-dihydrofuran (20), 5,6-dimethyl-3,4-dihydro-2H-pyran (26), and 3-methoxy-2-methyl-2-butene (32) in nonpolar and polar aprotic solvents to yield dioxetanes and allylic hydroperoxides, except 32, which gives only allylic hydroperoxides. The dioxetanes were isolated, but decompose slowly with weak chemiluminescence at room temperature to yield the corresponding dicarbonyl compounds. The allylic hydroperoxides produced by the cyclic enol ethers could not be isolated or separated by high vacuum distillation or by chromatography; the endocyclic allylic hydroperoxides arising from the dihydrofurans eliminate H2O2 to yield the corresponding furans while the exocyclic allylic hydroperoxides give unknown products. Allylic hydroperoxides 28 and 29 and the dioxetane 27 obtained from 26 yield the same dicarbonyl compound 31. The proportion of dioxetanes to allylic hydroperoxides depends on ring size and substitution of the enol ethers and on solvent polarity. Smaller ring size, greater electron-donor substitution, and solvent polarity favor the formation of dioxetanes at the expense of allylic hydroperoxides. It is noteworthy that enol ether 20, an alpha,beta-unsaturated ester, forms appreciable amounts of a dioxetane in polar solvents (44% in acetonitrile). Kinetic results show that the rate and product distribution of the ene reaction are independent of solvent polarity, whereas the rate of dioxetane formation increases with solvent polarity. It is suggested that [2 + 2] cycloadditions and ene reactions occur via different transition states and intermediates, zwitterions and perepoxides, respectively. Furthermore, the remarkable propensity to dioxetane formation of dihydrofurans compared to that of dihydropyrans and the other enol ethers seems to be due to the rigidity of the five-membered ring in the transition state and intermediate zwitterion.

  DOI：

  10.1021/jo00012a040

文献信息

• Studies toward the syntheses of functionally substituted .gamma.-butyrolactones and spiro-.gamma.-butyrolactones and their reaction with strong acids: a novel route to .alpha.-pyrones
  作者：A. K. Mandal、D. G. Jawalkar

  DOI：10.1021/jo00271a023

  日期：1989.5
• Photoisomerization of 4-hydroxypyrylium cations in concentrated sulfuric acid
  作者：James W. Pavlik、Arthur D. Patten、David R. Bolin、Kenneth C. Bradford、Edward L. Clennan

  DOI：10.1021/jo00197a040

  日期：1984.11
• Shusherina,N.P. et al., Journal of Organic Chemistry USSR (English Translation), 1966, vol. 2, p. 1771 - 1773
  作者：Shusherina,N.P. et al.

  DOI：——

  日期：——
• Lewina et al., Zhurnal Obshchei Khimii, 1954, vol. 24, p. 1439,1443; engl. Ausg. S. 1423, 1426
  作者：Lewina et al.

  DOI：——

  日期：——
• Semet,R.; Longeray,R., Bulletin de la Societe Chimique de France, 1978, vol. <II>, p. 185 - 192
  作者：Semet,R.、Longeray,R.

  DOI：——

  日期：——