(4-nitrophenyl)methyl (6R,7S)-3-chloro-8-oxo-7-[(2-phenoxyacetyl)amino]-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate | 108493-70-5

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 内酰胺类
• 英文名称: (4-nitrophenyl)methyl (6R,7S)-3-chloro-8-oxo-7-[(2-phenoxyacetyl)amino]-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate
• CAS: 108493-70-5
• 化学式: C₂₃H₂₀ClN₃O₇
• 分子量: 485.881
• InChiKey: CXDSGJIEDGYWKL-QUCCMNQESA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.2
• 重原子数：
  34
• 可旋转键数：
  8
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.26
• 拓扑面积：
  131
• 氢给体数：
  1
• 氢受体数：
  7

反应信息

• 作为产物：
  描述：

  p-nitrobenzyl 7β-[(phenoxyacetyl)amino]-3-hydroxy-1-carba-1-dethia-3-cephem-4-carboxylate 在 (PhO)3P⁽¹⁺⁾*Cl^(1-) 、 水 作用下， 生成 (4-nitrophenyl)methyl (6R,7S)-3-chloro-8-oxo-7-[(2-phenoxyacetyl)amino]-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate
  参考文献：
  名称：

  Kinetic Differences in the Chlorination of Cephalosporin versus Carbacephalosporin Enols: Evidence of Sulfur Neighboring Group Participation

  摘要：

  Intermediates in the chlorination of carbacephalosporin and cephalosporin enols with chlorotriph-enoxyphosphonium chloride, (PHO)(3)P+Cl Cl-, have been characterized at low temperatures by NMR. P-31 NMR has been used to determine the rate constants and Arrhenius activation energies for the chlorination of the cephalosporin enol 1b and the carbacephalosporin enol 1c. The results show a 3.7 kcal/mol lower activation energy for the chlorination of the cephalosporin enol. Semiempirical and ab initio calculations have been employed to evaluate chloride attack and phosphate departure for model cephalosporin and carbacephalosporin enols. The experimental and computational results are consistent with a chlorination mechanism that involves rapid, reversible chloride addition to an intermediate enol phosphonium species followed by rate-limiting phosphate departure. The lower activation energy for phosphate departure in the cephalosporin case is attributed to sulfur neighboring group participation.

  DOI：

  10.1021/jo00098a034

文献信息

• Kinetic Differences in the Chlorination of Cephalosporin versus Carbacephalosporin Enols: Evidence of Sulfur Neighboring Group Participation
  作者：John E. Burks、Erik C. Chelius、Ross A. Johnson

  DOI：10.1021/jo00098a034

  日期：1994.9

  Intermediates in the chlorination of carbacephalosporin and cephalosporin enols with chlorotriph-enoxyphosphonium chloride, (PHO)(3)P+Cl Cl-, have been characterized at low temperatures by NMR. P-31 NMR has been used to determine the rate constants and Arrhenius activation energies for the chlorination of the cephalosporin enol 1b and the carbacephalosporin enol 1c. The results show a 3.7 kcal/mol lower activation energy for the chlorination of the cephalosporin enol. Semiempirical and ab initio calculations have been employed to evaluate chloride attack and phosphate departure for model cephalosporin and carbacephalosporin enols. The experimental and computational results are consistent with a chlorination mechanism that involves rapid, reversible chloride addition to an intermediate enol phosphonium species followed by rate-limiting phosphate departure. The lower activation energy for phosphate departure in the cephalosporin case is attributed to sulfur neighboring group participation.