[W(CO)5(4-acetamidopyridine)] | 522595-62-6

• 英文名称: [W(CO)5(4-acetamidopyridine)]
• 英文别名: [W(CO)5(4-Acampy)]
• CAS: 522595-62-6
• 化学式: C₁₂H₈N₂O₆W
• 分子量: 460.055
• InChiKey: QQNURGOZNKJTKA-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
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• 重原子数：
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• 可旋转键数：
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• 环数：
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• sp3杂化的碳原子比例：
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• 拓扑面积：
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• 氢给体数：
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• 氢受体数：
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反应信息

• 作为产物：
  描述：

  4-乙酰氨基嘧啶 、 六羰基钨 、 丙酮 以 丙酮 为溶剂， 生成 [W(CO)5(4-acetamidopyridine)] 、 [W(CO)5(4-acetamidopyridine)]
  参考文献：
  名称：

  Tipping the energy balance toward exocyclic-amino coordination of W(CO)5 by methylation of the amino group of 2- and 4-aminopyridines, but not with adenosine

  摘要：

  2-Aminopyridine (2-ampy) substitutes on [W(CO)(5)(acetone)] or [W(CO)(5)(thf)] to produce 100% endocyclic N-1 coordinated [W(CO)(5)(2-ampy)]. Both N-1 coordinated and exocyclic-amine-bound isomers of [W(CO)(5)(4-ampy)] are formed by the substitution of 4-aminopyridine (4-ampy) on [W(CO)(5)(acetone)] in the ratio of 58% exo-amine coordination: 42% endocyclic amine under kinetic control. The distribution adjusts by linkage isomerism over 15 days to >86% exo-amine bound for the thermodynamic distribution. Within limit of H-1 NMR detection >95% exo-amine coordination occurs for 4-(dimethylamino)pyridine (4-Me(2)ampy), in spite of increased steric hindrance. Coordination of 2-(dimethylamino)pyridine to W(CO)(5) occurs only as the exo-amine donor, reversing the observations of the 2-ampy case. Coordination of W(CO)(5) with adenosine takes place with purine ring N donors (45% N-1, 33% N-3, and 22% N-7). The monomethylated N-6-methyladenosine produced only N-1 coordination in low yield. Apparently steric blocking by the N-6-methyl group retards coordination at N-7, and hydrogen bonding of the 5'- alcohol to N-3 of the purine ring in response to enhanced basicity of the N-3 site upon methylation of the exo-amine retards addition at N-3 for [W(CO)(5)(N(methyl adenosine)]. Surprisingly in relation to the effects of amino methylation for the simple aminopyrimidines where W(CO)(5) adopts >91% of 2-ampym and 100% of 4-ampym coordination via the exo-amine, N-1 is the preferred site of coordination for adenosines over the exo-amine position. The known releasing effect of the five-member portion of the adenine ring, enhancing 6 basicity at N-1 is not overcome by N-6-methylation which directs much of its enhancement of ring basicity to N-3. N-6,N-6-Dimethyladenosine produced no coordination with W(CO)(5) under equivalent photosynthetic conditions; the second methyl group only provides additional steric hindrance to coordination at N-1, showing the powerful influence of conjugation of the amino lone pair with the purine ring in preventing a sufficiently basic exo-amine that can coordinate W(CO)(5) in contrast to the outcome with the analogous pyridine (2-Me(2)ampy). Acetylation of 4-ampy (4-acetamidopyridine = 4-Acampy) should favor the pyridyl coordination; however, coordination to the carbonyl group is observed for [W(CO)(5)(4-Acampy)]. (C) 2002 Elsevier Science B.V. All rights reserved.

  DOI：

  10.1016/s0020-1693(02)01189-1