3,8-diphenyl-1-(4-nitrophenyl)-4-oxoimidazo[1,2-a]pyrimidin-5-ylium-2-olate | 1146939-54-9

• 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: 3,8-diphenyl-1-(4-nitrophenyl)-4-oxoimidazo[1,2-a]pyrimidin-5-ylium-2-olate
• 英文别名: 8-(4-Nitrophenyl)-7-oxo-1,6-diphenyl-2,3-dihydroimidazo[1,2-a]pyrimidin-4-ium-5-olate
• CAS: 1146939-54-9
• 化学式: C₂₄H₁₈N₄O₄
• 分子量: 426.431
• InChiKey: BJQYERYOFUFURA-UHFFFAOYSA-N

物化性质

• 熔点：
  350-351 °C

计算性质

• 辛醇/水分配系数(LogP)：
  4.2
• 重原子数：
  32
• 可旋转键数：
  3
• 环数：
  5.0
• sp3杂化的碳原子比例：
  0.08
• 拓扑面积：
  95.4
• 氢给体数：
  0
• 氢受体数：
  4

反应信息

• 作为产物：
  描述：

  异氰酸对硝基苯 、 2,7-Diphenyl-5H,6H,7H-imidazole[2,1-b]-1,4-thiazolium-3-thiolate 以 二氯甲烷 为溶剂， 以18%的产率得到3,8-diphenyl-1-(4-nitrophenyl)-4-oxoimidazo[1,2-a]pyrimidin-5-ylium-2-olate
  参考文献：
  名称：

  Thionation of Mesoionics with Isothiocyanates: Evidence Supporting a Four-Step Domino Process and Ruling Out a [2 + 2] Mechanism

  摘要：

  Mesoionic heterocycles derived from 1,3-thiazolium-4-olates (thioisomunchnones) undergo thionation with aryl isothiocyanates to afford the corresponding 4-thiolate derivatives. Here, we document this transformation in detail, giving a crystallographic characterization of the solid-state structures. From the mechanistic viewpoint, the formal thionation process could be consistent with a [2 + 2] reaction of the exocyclic C-O bond of the thioisomunchnone with the C=S double bond of the isothiocyanate moiety, which would be competing with a (3 + 2) process as usual in mesoionic rings. Theoretical computations at the [B3LYP/6-31G(d):PM3] level, in which only bond-forming and bond-breaking reactions and neighboring atoms are treated at the DFT level, do reproduce the experimental results and rule out the expected pathway. Calculations instead suggest the existence of a four-step domino pathway through several polar intermediates that agrees with the electronic nature of the substituents involved. The mechanistic hypothesis has further been corroborated by an experiment with isotopically C-13-labeled PhNCS that unambiguously shows the way in which the exchange reaction occurs.

  DOI：

  10.1021/jo900028c

文献信息

• Thionation of Mesoionics with Isothiocyanates: Evidence Supporting a Four-Step Domino Process and Ruling Out a [2 + 2] Mechanism
  作者：David Cantillo、Martín Ávalos、Reyes Babiano、Pedro Cintas、José L. Jiménez、Mark E. Light、Juan C. Palacios

  DOI：10.1021/jo900028c

  日期：2009.5.15

  Mesoionic heterocycles derived from 1,3-thiazolium-4-olates (thioisomunchnones) undergo thionation with aryl isothiocyanates to afford the corresponding 4-thiolate derivatives. Here, we document this transformation in detail, giving a crystallographic characterization of the solid-state structures. From the mechanistic viewpoint, the formal thionation process could be consistent with a [2 + 2] reaction of the exocyclic C-O bond of the thioisomunchnone with the C=S double bond of the isothiocyanate moiety, which would be competing with a (3 + 2) process as usual in mesoionic rings. Theoretical computations at the [B3LYP/6-31G(d):PM3] level, in which only bond-forming and bond-breaking reactions and neighboring atoms are treated at the DFT level, do reproduce the experimental results and rule out the expected pathway. Calculations instead suggest the existence of a four-step domino pathway through several polar intermediates that agrees with the electronic nature of the substituents involved. The mechanistic hypothesis has further been corroborated by an experiment with isotopically C-13-labeled PhNCS that unambiguously shows the way in which the exchange reaction occurs.