2-(1-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 唑啉类
• 英文名称: 2-(1-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline
• 英文别名: 1-(2,4,5-trimethyl-5H-1,3-oxazol-2-yl)ethanol
• 化学式: C₈H₁₅NO₂
• 分子量: 157.213
• InChiKey: NPWNWJUEQVYXIZ-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.1
• 重原子数：
  11
• 可旋转键数：
  1
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.88
• 拓扑面积：
  41.8
• 氢给体数：
  1
• 氢受体数：
  3

反应信息

• 作为产物：
  描述：

  3-羟基-2-丁酮 在 ammonium acetate 作用下， 反应 4.0h， 生成 2-(1-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline
  参考文献：
  名称：

  Mechanistic Studies of 2-(1-Hydroxyethyl)-2,4,5-trimethyl-3- oxazoline Formation under Low Temperature in 3-Hydroxy-2-butanone/Ammonium Acetate Model Systems

  摘要：

  Volatile compounds formed from the reaction of 3-hydroxy-2-butanone/ammonium acetate at 25, 55 and 85 degrees C were investigated. Six compounds were characterized by gas chromatography-mass spectrometry (EI and CI). Among the volatile compounds identified, an interesting intermediate compound, 2-(1-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline, was found. N-15-Labeled ammonium acetate was used to confirm the structure of 2-(P-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline. The formation pathway of these volatile compounds was proposed. In these model systems, 2-(1-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline was formed at the reaction temperature below 25 degrees C. On the other hand, tetramethylpyrazine was the major component when the reaction temperature was higher than 85 degrees C. The amounts of 2-(1-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline and tetramethylpyrazine increased linearly with the increasing heating time at 55 degrees C. Protic solvents did not promote 2-(1-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline formation but did favor the formation of tetramethylpyrazine. A kinetic study of 2-(1-hydroxyethyl)-2,4,5-trimethyl-3-oxazoline formation was also performed, and the activation energy was found to be 16.5 kcal/mol.

  DOI：

  10.1021/jf960734o

文献信息

• Characterization of Volatile Compounds from the Reaction of 3-Hydroxy-2-butanone and Ammonium Sulfide Model System
  作者：Junwu Xi、Tzou-Chi Huang、Chi-Tang Ho

  DOI：10.1021/jf980536s

  日期：1999.1.1

  The reactions between 3-hydroxy-2-butanone and ammoniun sulfide at 25, 50, 75, 100, 125, and 150 degrees C were studied. Four well-known flavor compounds, 2,4,5-trimethyloxazole, 2,4, 5-trimethyl-3-oxazoline, 2,4,5-trimethylthiazole, and 2,4, 5-trimethyl-3-thiazoline, were identified. Another four interesting intermediate compounds, 2-(1-hydroxyethyl)-2,4, 5-trimethyl-3-oxazoline, 2-(1-mercaptoethyl)-2

  研究了在25、50、75、100、125和150摄氏度下3-羟基-2-丁酮与氨磺化物之间的反应。鉴定了四种著名的风味化合物2,4,5-三甲基恶唑，2,4,5-三甲基-3-恶唑啉，2,4,5-三甲基噻唑和2,4,5-三甲基-3-噻唑啉。另四种有趣的中间体化合物，2-（1-羟乙基）-2,4，5-三甲基-3-恶唑啉，2-（1-巯基乙基）-2,4，5-三甲基-3-恶唑啉，2-（1还通过GC-EIMS和GC-CIMS鉴定了-羟乙基）-2,4,5-三甲基-3-噻唑啉和2-（1-巯基乙基）-2,4,5-三甲基-3-噻唑啉。所有这些中间体化合物都是在25摄氏度下形成的。另一方面，四甲基吡嗪是反应温度高于100摄氏度的主要产物。
• Formation of 2-(1-Hydroxyalkyl)-3-oxazolines from the Reaction of Acyloins and Ammonia Precursors under Mild Conditions
  作者：Chi-Kuen Shu、Brian M. Lawrence

  DOI：10.1021/jf00059a028

  日期：1995.11

  Studies on the reaction between acetoin and an ammonia precursor under mild conditions revealed that two major products were formed, one of which was tetramethylpyrazine (TMP) and the other an unknown compound. By spectral elucidation (MS, IR, NMR), this unknown compound has been identified as 2,4,5-trimethyl-2-(1-hydroxyethyl)-3-oxazoline (OXZ). Two homologs of OXZ were also prepared. A 3-week storage study demonstrated that OXZ was readily formed, after which its formation declined. In contrast, TMP formation gradually increased before it leveled out in 15-20 days. At the end of this experiment, only TMP remained as the product, while OXZ was not found. Mechanistically, it is proposed that condensation of acetoin and ammonia generates alpha-hydroxyimine or alpha-amino ketone by tautomerism, which may lead to product formation via two pathways. One of the pathways is to form TMP via self-condensation of the alpha-amino ketone, dehydration, and dehydrogenation, which is well-known. The other pathway may be that the alpha-hydroxyimine condenses with a second molecule of acetoin and then is cyclized by Schiff base formation to OXZ. These storage results also indicate that the second pathway may be reversible, so that OXZ initially formed is able to be converted back to alpha-hydroxyimine, which, in turn, was tautomerized to alpha-amino ketone, so that the first pathway to form TMP could be followed.