4-methoxy-2-(4,5-dimethyl-1H-imidazol-2-yl)phenol | 1604034-46-9

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 唑类
• 英文名称: 4-methoxy-2-(4,5-dimethyl-1H-imidazol-2-yl)phenol
• 英文别名: 2-(4,5-dimethyl-1H-imidazol-2-yl)-4-methoxyphenol
• CAS: 1604034-46-9
• 化学式: C₁₂H₁₄N₂O₂
• 分子量: 218.255
• InChiKey: BVCNOCQPBDAQSS-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.1
• 重原子数：
  16
• 可旋转键数：
  2
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.25
• 拓扑面积：
  58.1
• 氢给体数：
  2
• 氢受体数：
  3

反应信息

• 作为反应物：
  描述：

  4-methoxy-2-(4,5-dimethyl-1H-imidazol-2-yl)phenol 、 palladium diacetate 反应 12.0h， 以88%的产率得到bis[4-methoxy-2-(4,5-dimethyl-1H-imidazol-2-yl)phenolato]palladium(II)
  参考文献：
  名称：

  Cyclometallation, steric and electronic tendencies in a series of Pd(II) complex pre-catalysts bearing imidazole–phenol ligands and effects on Suzuki–Miyaura catalytic efficiencies

  摘要：

  A series of new structurally and electronically diversified palladium complexes derived from seven less sterically crowded 2-(4,5-diinethyl-1H-imidazol-2-yl) pheno1/2-(4,5-diethyl-1H-imidazol-2-yl) phenol ligands and fourteen 2-(4,5-diphenyl-1H-imidazol-2-yl) phenols/2-(1H-phenanthro[9,10-d]imidazol-2-yl) phenols bearing varying degrees of higher steric bulk have been prepared and characterized. While single crystals grown from precipitated products of complexation reactions confirmed the bis-ligand Pd(NO)(2) coordination, few crystals obtained from reaction filtrates involving the 244,5-diphenyl-1H-imidazol-2-yl) phenols provided evidence for formation of N (O) over cap(C) over cap chelation species achieved by cyclometallation. Results from structural analyses and catalytic outcomes generally indicate that desirable variables on the ligand frameworks for obtaining superior catalyst activities either provides hemilabile or sterically strained chelation characters, which would both favour generation of monodentate coordination species at the catalysis temperature. In particular, correlation was observed between tendency for cyclometallation in the palladium complexes and poor Suzuki-Miyaura catalytic prospects. Based on hopeful activity obtained for the complex bearing 4-bromo-2-(4,5-dimethyl-1H-imidazol-2-yl) phenol, it was also concluded that sterically bulky ligand is not a necessity for high coupling efficiency, while presence of potentially cyclometallating substituent moieties in the vicinity of the palladium centre may in fact destroy catalytic prospects. (C) 2015 Elsevier B.V. All rights reserved.

  DOI：

  10.1016/j.molcata.2015.06.001
• 作为产物：
  描述：

  2-羟基-5-甲氧基苯甲醛 、 2,3-丁二酮 在 ammonium acetate 、 溶剂黄146 作用下， 反应 1.5h， 以16%的产率得到4-methoxy-2-(4,5-dimethyl-1H-imidazol-2-yl)phenol
  参考文献：
  名称：

  Ligand characteristics and in situ generation of Pd active species towards CC coupling using series of 2-(1H-imidazol-2-yl)phenols

  摘要：

  Series of systematically varied 2-(1H-imidazol-2-yl)phenol ligand frameworks, which were synthesized and properly characterized, have been used to investigate favourable ligand characteristics towards in situ formation of active palladium species in Suzuki-Miyaura coupling. Structures of 2-(4,5-diethy1-1Himidazol-2-y1)-4-nitrophenol (p-N similar to de) and 4-(tert-butyl)-2-(4,5-dipheny1-1H-imidazol-2-yl)phenol (p-tBu similar to dp) as well as the palladium complex of 2-(4,5-diethyl-1H-imidazol-2-y1)phenol (Pd.de(2)) were confirmed. Structural analyses show that para-nitro-substituted phenol moieties bear poor oxo-donor atom while the reverse was observed for para-dlu-substituted analogues. Ligand donor strengths were also determined by pK(a) analysis.Under the same reaction conditions for palladium catalyzed Suzuki-Miyaura coupling in the presence of 'ligand + palladium( II) acetate' catalyst system, results show that electronic properties of the ligands are more important than the variation in steric properties. In particular, ligands with strong bidentate chelate coordination potentials acted as poisons while those with monodentate coordination potential proved to be very beneficial towards in situ generation of superior active species. Furthermore, correlation between donor strength pKa data and the trends in catalytic efficiencies as a consequence of ligand presence was studied. Therefore, it was concluded that ligands with strong chelation tendencies adversely impacted in situ palladium catalyst generation efficiency and that there appears to be moderate steric requirement from ligands for optimal catalyst efficiency. (C) 2014 Elsevier B.V. All rights reserved.

  DOI：

  10.1016/j.molcata.2014.02.032