2,3-Diphenyl-2-hydroxy-5,6-dihydro-1-methylpyrazine | 141089-25-0

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 吡咯啉
• 英文名称: 2,3-Diphenyl-2-hydroxy-5,6-dihydro-1-methylpyrazine
• CAS: 141089-25-0
• 化学式: C₁₇H₁₈N₂O
• 分子量: 266.343
• InChiKey: QRLGUYPHYPDPPJ-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.27
• 重原子数：
  20.0
• 可旋转键数：
  2.0
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.24
• 拓扑面积：
  35.83
• 氢给体数：
  1.0
• 氢受体数：
  3.0

反应信息

• 作为产物：
  描述：

  联苯甲酰 、 N-甲基乙二胺 生成 2,3-Diphenyl-2-hydroxy-5,6-dihydro-1-methylpyrazine
  参考文献：
  名称：

  Reaction of .alpha.-diketones with 2-amino alcohols. Intramolecular competitive 6-exo-trig vs 5-endo-trig processes. A systematic and kinetic study

  摘要：

  2-Aminoethanol and C-substituted derivatives 1 react with diacetyl, benzil, and 1-phenyl-1,2-propanedione, models of alpha-diketones 2 to give with remarkable regio- and stereoselectivity 2-hydroxy-5,6-dihydro-2H-1,4-oxazines 3, cis-octahydro[1,4]oxazino[3,2-b]oxazines 4, alpha-imino ketones 6, 2-acetyl-1,3-oxazolidines 7, N,N'-bis(2-hydroxy-2-methylpropyl)-2,3-butanediimines 8, and 2,2'-dimethyl-2,2'-bioxazolidines 9 depending on the nature of the reagents and the reaction conditions. On the basis of isolated intermediates, a reasonable mechanism taking into account the stereoelectronic effects observed on the cyclization has been proposed for these processes. In addition, a kinetic study of the ring-chain-ring tautomeric equilibrium of oxazines 3a-c, 3i-k, and 3o-q has been studied by H-1 NMR and C-13 NMR. In solution, compounds 3a-c and 3i-k exhibit a three-component tautomeric equilibria consisting of the following: the beta-iminohemiacetal 3, the beta-hydroxyimino ketone 6, and the 2-acetyl- or 2-benzoyl-1,3-oxazolidine 7. The calculated rate constants for this process show that the equilibrium is shifted toward the formation of the five-membered ring by 0.4-4.8 kJ mol-1 over the six-membered ring depending on the substitution patterns. Compounds 3p-q exist in solution as equimolar mixtures of the ring and open-chain tautomers. Compound 3o exists predominantly in the open-chain form. In addition, 2-acylthiazolidines 13a-c do not evidence any dynamic processes in solution.

  DOI：

  10.1021/jo00034a046