1,3,6-Trimethyl-5,6-dihydrouracil | 89851-80-9

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 二嗪类
• 英文名称: 1,3,6-Trimethyl-5,6-dihydrouracil
• 英文别名: 1,3,6-Trimethyl-1,3-diazinane-2,4-dione
• CAS: 89851-80-9
• 化学式: C₇H₁₂N₂O₂
• 分子量: 156.184
• InChiKey: NAPOZSSVEUJGRA-UHFFFAOYSA-N

物化性质

• 沸点：
  216.2±23.0 °C(Predicted)
• 密度：
  1.103±0.06 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  -0.3
• 重原子数：
  11
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.71
• 拓扑面积：
  40.6
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  巴豆酸 、 1,3-二甲基脲 在 对苯二酚 作用下， 反应 2.0h， 以44%的产率得到1,3,6-Trimethyl-5,6-dihydrouracil
  参考文献：
  名称：

  Photoinduced Electron Transfer to Pyrimidines and 5,6-Dihydropyrimidine Derivatives:  Reduction Potentials Determined by Fluorescence Quenching Kinetics

  摘要：

  The dynamics of flourescence quenching of excited state electron donor sensitizers by various pyrimidine and 5,6-dihydropyrimidine substrates was examined. For all of the substrates studied the rate constant of fluorescence quenching (k(q)) increases as the excited state oxidation potential (E-ox*) becomes more negative. The dependence of k(q) on E-ox* in each case is well described by the Rehm-Weller relationship. Fits of the data to this relationship allow for the estimation of the reduction potentials of the substrates (E-red) The pyrimidines 1,3-dimethylthymine, 1,3-dimethyluracil, and 1,3,6-trimethyluracil give E-red values (in CH3CN) ranging from -2.06 (vs SCE) to -2.14 V. Their dihydro derivatives, 1,3-dimethyl-5,6-dihydrothymine, 1,3-dimethyl-5,6-dihydrouracil, and 1,3,6-trimethyl-5,6-dihydrouracil gave E-red values ranging from -1.90 to -2.07 V. The higher E-red values for the dihydropyrimidines compared with their unsaturated derivatives is attributed to aromatic stabilization in the pyrimidines, which is not present in the dihydro derivatives. In addition, the E-red for both the trans-syn and cis-syn diastereomers of the dimethylthymine cyclobutane dimer was examined using the same method. The trans-syn dimer gives an E-red Of -1.73 V and the cis-syn dimer gives an E-red Of -2.20 V. This remarkable difference is attributed to a stereoelectronic effect. The cis-syn dimer anion radical suffers from an unfavorable charge-dipole interaction between the added electron and the O-4 carbonyl group in the remaining pyrimidine ring. In contrast, the trans-syn dimer anion radical shows mainly a stabilizing inductive electron-withdrawing effect of the remaining O-4 carbonyl group. Solvent effects on E-red were also examined. It is shown that the protic solvent, CH3OH, significantly stabilizes the anion radicals, raising E-red by ca. 400 mV over the value in CH3CN.

  DOI：

  10.1021/jp970164a

文献信息

• Photoinduced Electron Transfer to Pyrimidines and 5,6-Dihydropyrimidine Derivatives:  Reduction Potentials Determined by Fluorescence Quenching Kinetics
  作者：Michael P. Scannell、Gautam Prakash、Daniel E. Falvey

  DOI：10.1021/jp970164a

  日期：1997.6.1

  The dynamics of flourescence quenching of excited state electron donor sensitizers by various pyrimidine and 5,6-dihydropyrimidine substrates was examined. For all of the substrates studied the rate constant of fluorescence quenching (k(q)) increases as the excited state oxidation potential (E-ox*) becomes more negative. The dependence of k(q) on E-ox* in each case is well described by the Rehm-Weller relationship. Fits of the data to this relationship allow for the estimation of the reduction potentials of the substrates (E-red) The pyrimidines 1,3-dimethylthymine, 1,3-dimethyluracil, and 1,3,6-trimethyluracil give E-red values (in CH3CN) ranging from -2.06 (vs SCE) to -2.14 V. Their dihydro derivatives, 1,3-dimethyl-5,6-dihydrothymine, 1,3-dimethyl-5,6-dihydrouracil, and 1,3,6-trimethyl-5,6-dihydrouracil gave E-red values ranging from -1.90 to -2.07 V. The higher E-red values for the dihydropyrimidines compared with their unsaturated derivatives is attributed to aromatic stabilization in the pyrimidines, which is not present in the dihydro derivatives. In addition, the E-red for both the trans-syn and cis-syn diastereomers of the dimethylthymine cyclobutane dimer was examined using the same method. The trans-syn dimer gives an E-red Of -1.73 V and the cis-syn dimer gives an E-red Of -2.20 V. This remarkable difference is attributed to a stereoelectronic effect. The cis-syn dimer anion radical suffers from an unfavorable charge-dipole interaction between the added electron and the O-4 carbonyl group in the remaining pyrimidine ring. In contrast, the trans-syn dimer anion radical shows mainly a stabilizing inductive electron-withdrawing effect of the remaining O-4 carbonyl group. Solvent effects on E-red were also examined. It is shown that the protic solvent, CH3OH, significantly stabilizes the anion radicals, raising E-red by ca. 400 mV over the value in CH3CN.