(S)-iso-Propyl-N-(2-methylbenzoyl)pyroglutamate

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羧酸及其衍生物
• 英文名称: (S)-iso-Propyl-N-(2-methylbenzoyl)pyroglutamate
• 英文别名: propan-2-yl (2S)-1-(2-methylbenzoyl)-5-oxopyrrolidine-2-carboxylate
• 化学式: C₁₆H₁₉NO₄
• 分子量: 289.331
• InChiKey: HYPNAIWUPGLJSJ-ZDUSSCGKSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.3
• 重原子数：
  21
• 可旋转键数：
  4
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.44
• 拓扑面积：
  63.7
• 氢给体数：
  0
• 氢受体数：
  4

反应信息

• 作为反应物：
  描述：

  (S)-iso-Propyl-N-(2-methylbenzoyl)pyroglutamate 在 Rh on carbon 氢气 作用下， 以 乙醇 为溶剂， 20.0 ℃ 、5.0 MPa 条件下， 生成 (1R,2S,2'S)-iso-Propyl-N-(2-methyl-cyclohexanecarbonyl)pyroglutamate 、 (1S,2R,2'S)-iso-Propyl-N-(2-methyl-cyclohexanecarbonyl)pyroglutamate 、 (S)-iso-Propyl-(2-methyl-cyclohex-1-enecarbonyl)pyroglutamate
  参考文献：
  名称：

  Asymmetric Synthesis of 2-Methyl Cyclohexane Carboxylic Acids by Heterogeneous Catalysis: Mechanistic Aspects

  摘要：

  The catalytic hydrogenation of (S)-alkyl-N-(2-methylbenzoyl)pyroglutamates was studied over supported rhodium and ruthenium catalysts at room temperature and a pressure of 5 MPa. The reaction was diastereoselective with the predominant formation of (1S,2R)-2-methylcyclohexane carboxylic acid with a diastereomeric excess (de) of up to 96%. The most stable conformation was determined by means of a combination of modelling calculations, NMR spectroscopy and X-ray structural determination. In this conformation, the carbonyl group of the pyroglutamate auxiliary shields one face of the aromatic ring. The observed selectivity may thus be explained by a preferential adsorption at the unshielded face which avoids steric repulsion by the C=O group to result in a cis hydrogenation. The addition of an amine, the nature of the support (alumina or active carbon) or of the metal (Rh or Ru) were shown to give additional stabilisation of the adsorption at the unshielded face to increase the diastereoisomeric excess.

  DOI：

  10.1002/(sici)1521-3765(20000317)6:6<949::aid-chem949>3.0.co;2-h
• 作为产物：
  描述：

  L-焦谷氨酸 在 氯化亚砜 、 三乙胺 作用下， 以 甲苯 为溶剂， 反应 6.5h， 生成 (S)-iso-Propyl-N-(2-methylbenzoyl)pyroglutamate
  参考文献：
  名称：

  Asymmetric Synthesis of 2-Methyl Cyclohexane Carboxylic Acids by Heterogeneous Catalysis: Mechanistic Aspects

  摘要：

  The catalytic hydrogenation of (S)-alkyl-N-(2-methylbenzoyl)pyroglutamates was studied over supported rhodium and ruthenium catalysts at room temperature and a pressure of 5 MPa. The reaction was diastereoselective with the predominant formation of (1S,2R)-2-methylcyclohexane carboxylic acid with a diastereomeric excess (de) of up to 96%. The most stable conformation was determined by means of a combination of modelling calculations, NMR spectroscopy and X-ray structural determination. In this conformation, the carbonyl group of the pyroglutamate auxiliary shields one face of the aromatic ring. The observed selectivity may thus be explained by a preferential adsorption at the unshielded face which avoids steric repulsion by the C=O group to result in a cis hydrogenation. The addition of an amine, the nature of the support (alumina or active carbon) or of the metal (Rh or Ru) were shown to give additional stabilisation of the adsorption at the unshielded face to increase the diastereoisomeric excess.

  DOI：

  10.1002/(sici)1521-3765(20000317)6:6<949::aid-chem949>3.0.co;2-h