4-hydroxypyridine | 33630-91-0

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 吡啶及其衍生物
• 英文名称: 4-hydroxypyridine
• 英文别名: 4-oxydopyridine；Pyridyl-(4)-hydroxylat；Pyridin-4-olate
• CAS: 33630-91-0
• 化学式: C₅H₄NO
• 分子量: 94.0929
• InChiKey: GCNTZFIIOFTKIY-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  1.1
• 重原子数：
  7
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.0
• 拓扑面积：
  36
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  4-hydroxypyridine 、 (2,4-二硝基苯基)苯甲酸酯 以 水 、 二甲基亚砜 为溶剂， 以100%的产率得到
  参考文献：
  名称：

  亲电中心由C O改变为C S对速率和机理的影响：O -2,4-二硝基苯基亚硫代苯甲酸酯的吡啶解及其氧类似物

  摘要：

  已分光光度法测定了O -2,4-二硝基苯基硫代苯甲酸酯（1）和2,4-二硝基苯基苯甲酸酯（2）与一系列取代吡啶在80 mol％H 2 O / 20 mol中的反应的二级速率常数在25.0±0.1°C下的％DMSO。得到的布朗斯台德型曲线是非线性的β 1 = 0.26，β 2 = 1.07，且p ķ一个°= 7.5的反应1和β 1 = 0.40，β 2 = 0.90，且p ķ一个°= 9.5 2的反应，表明1和图2所示的流程通过两性离子四面体中间体T ±进行，其中速率确定步骤的变化分别在p K a °= 7.5和9.5处进行。除了与所研究的最强碱性吡啶的反应（p K a = 11.30）以外，硫代磺酸酯1比其氧类似物2具有更高的反应性。所述ķ 1值是用于的反应中较大的1比那些的2在低p- ķ一个区域，但在差ķ 1值变得可忽略随吡啶的碱性。另一方面，1在低p K a区域中，K 2 / k -

  DOI：

  10.1021/jo0492160
• 作为产物：
  描述：

  1-(3-oxo-butyl)-1H-pyridin-4-one 在 hydroxide 水 作用下， 生成 4-hydroxypyridine 、 丁烯酮
  参考文献：
  名称：

  Rate-determining steps in Michael-type additions and E1cb reactions in aqueous solution

  摘要：

  Rates of equilibration of a series of 10 substituted pyridines and five Michael acceptors (CH2=CHZ, Z = CHO, COCH3, SO2CH3, CN, and CONH2) with the corresponding N(ZCH2CH2) pyridinium cations have been measured in aqueous solution at ionic strength 0.1 and 25-degrees-C. Analysis of the dependence of the pseudo-first-order rate constants for equilibration as a function of acceptor concentration and of pH allows the evaluation of the second-order rate constants (k(Nu)) for the nucleophilic attack of each of these pyridines upon each of these acceptors and also the second-order rate constants (k(OH)) for the hydroxide ion catalyzed E1cb elimination reaction which is the microscopic reverse of each of these Michael-type addition reactions. Bronsted-type plots for each of these processes as a function of the basicity of the substituted pyridine are concave down for each of Z = CHO, COCH3, and CN and are consistent with a change from rate-determining nucleophilic attack for the more basic pyridines to rate-determining protonation of the carbanionic intermediate by a water molecule for less basic pyridines and the corresponding microscopic reverse processes in the elimination reactions. The "break" in these Bronsted-type plots is shown to occur at a pyridine basicity that is a function of the Z-activating substituent. Bronsted beta-1g, and beta(nuc) are evaluated for each rate-determining step (wherever accessible); these two parameters are shown to pass through minima as a function of reactivity. beta(eq), is shown to be a simple linear function of reactivity (as log k(Nu)) for nucleophilic addition to the acceptor species, although K(eq) is relatively insensitive to the nature of the Z-activating substituent.

  DOI：

  10.1021/jo00039a013

文献信息

• Kinetic and Theoretical Studies on Pyridinolysis of 2,4-Dinitrophenyl X-Substituted Benzoates: Effect of Substituent X on Reactivity and Mechanism
  作者：Ik-Hwan Um、Eun-Hee Kim、Li-Ra Im、Masaaki Mishima

  DOI：10.5012/bkcs.2010.31.9.2593

  日期：2010.9.20

  Second-order rate constants ($k_N$) have been measured spectrophotometrically for reactions of 2,4-dinitrophenyl X-substituted benzoates (X = 4-MeO, H and 4-$NO_2$) with a series of Z-substituted pyridines in 80 mol % $H_2O$/20 mol % DMSO at $25.0\pm}0.1^\circ}C$. The Br$\o}$nsted-type plots exhibit downward curvature (e.g., $\beta_2$ = 0.89 ~ 0.96 when $pK_a$ < 9.5 while $\beta_1$ = 0.38 ~ 0.46 when $pK_a$ > 9.5), indicating that the reaction proceeds through a stepwise mechanism with a change in rate-determining step (RDS). The $pK_a}^o$, defined as the $pK_a$ at the center of Br$\o}$nsted curvature, has been analyzed to be 9.5 regardless of the electronic nature of the substituent X in the benzoyl moiety. Dissection of $k_N$ into the microscopic rate constants $k_1$ and $k_2/k_-1}$ ratio has revealed that $k_1$ is governed by the electronic nature of the substituent X but the $k_2/k_-1}$ ratio is not. Theoretical calculations also support the argument that the electronic nature of the substituent X in the benzoyl moiety does not influence the $k_2/k_-1}$ ratio.

  已通过分光光度法测量 2,4-二硝基苯基 X 取代的苯甲酸酯（X = 4-MeO、H 和 4-$NO_2$ 的反应）的二阶速率常数 ($k_N$) ) 与一系列 Z-取代吡啶在 80 mol % $H_2O$/20 mol % DMSO 中在 $25.0\pm}0.1^\circ}C$< /TEX>。 Br$\o}$nsted 型图呈现向下曲率（例如，当 $pK_a$ 时，$\beta_2$ = 0.89 ~ 0.96 > < 9.5 while $\beta_1$ = 0.38 ~ 0.46 when $pK_a$ > 9.5)，表明反应通过逐步机制进行，速率决定发生变化步骤（RDS）。 $pK_a}^o$，定义为 Br$\o}$nsted 曲率中心的 $pK_a$，无论苯甲酰基部分中取代基 X 的电子性质如何，分析结果为 9.5。将 $k_N$ 分解为微观速率常数 $k_1$ 和 $k_2/k_-1}$ 比率表明 $k_1$ 受取代基 X 的电子性质控制，但 $k_2/k_-1}$ 比率则不然。理论计算也支持这样的论点：苯甲酰基部分中取代基 X 的电子性质不会影响 $k_2/k_-1}$ 比率。
• Modification of Both the Electrophilic Center and Substituents on the Nonleaving Group in Pyridinolysis of <i>O</i>-4-Nitrophenyl Benzoate and Thionobenzoates
  作者：Ik-Hwan Um、So-Jeong Hwang、Mi-Hwa Baek、Eun Ji Park

  DOI：10.1021/jo061682x

  日期：2006.11.1

  [GRAPHICS]A kinetic study is reported for reactions of 4-nitrophenyl benzoate (1c) and O-4-nitrophenyl X-substituted thionobenzoates (2a-e) with a series of pyridines in 80 mol % H2O/20 mol % dimethyl sulfoxide ( DMSO) at 25.0 +/- 0.1 degrees C. O-4-Nitrophenyl thionobenzoate (2c) is more reactive than its oxygen analogue 1c toward all the pyridines studied. The Bronsted-type plot is linear with beta(nuc) = 1.06 for reactions of 1c but curved for the corresponding reactions of 2c with beta(nuc) decreasing from 1.38 to 0.38 as the pyridine basicity increases, indicating that the reaction mechanism is also influenced on changing the electrophilic center from C=O to C=S. The curvature center of the curved Bronsted-type plots (defined as pK(a)(o)) occurs at pK(a) = 9.3 regardless of the electronic nature of the substituent X in the nonleaving group. The Hammett plot for reactions of 2a-e with 4-aminopyridine is nonlinear, i.e., the substrates having an electron-donating substituent exhibit negative deviations from the Hammett plot. However, the Yukawa-Tsuno plot for the same reactions exhibits good linear correlation, indicating that the negative deviations shown by these substrates arise from stabilization of the ground state through resonance interaction between the electron-donating substituent X and the C=S bond.
• Effect of Changing Electrophilic Center from CO to CS on Rates and Mechanism:  Pyridinolyses of <i>O</i>-2,4-Dinitrophenyl Thionobenzoate and Its Oxygen Analogue
  作者：Ik-Hwan Um、Hyun-Joo Han、Mi-Hwa Baek、Sun-Young Bae

  DOI：10.1021/jo0492160

  日期：2004.9.1

  rate constants have been measured spectrophotometrically for the reactions of O-2,4-dinitrophenyl thionobenzoate (1) and 2,4-dinitrophenyl benzoate (2) with a series of substituted pyridines in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 °C. The Brønsted-type plots obtained are nonlinear with β1 = 0.26, β2 = 1.07, and pKa° = 7.5 for the reactions of 1 and β1 = 0.40, β2 = 0.90, and pKa° = 9.5 for the reactions

  已分光光度法测定了O -2,4-二硝基苯基硫代苯甲酸酯（1）和2,4-二硝基苯基苯甲酸酯（2）与一系列取代吡啶在80 mol％H 2 O / 20 mol中的反应的二级速率常数在25.0±0.1°C下的％DMSO。得到的布朗斯台德型曲线是非线性的β 1 = 0.26，β 2 = 1.07，且p ķ一个°= 7.5的反应1和β 1 = 0.40，β 2 = 0.90，且p ķ一个°= 9.5 2的反应，表明1和图2所示的流程通过两性离子四面体中间体T ±进行，其中速率确定步骤的变化分别在p K a °= 7.5和9.5处进行。除了与所研究的最强碱性吡啶的反应（p K a = 11.30）以外，硫代磺酸酯1比其氧类似物2具有更高的反应性。所述ķ 1值是用于的反应中较大的1比那些的2在低p- ķ一个区域，但在差ķ 1值变得可忽略随吡啶的碱性。另一方面，1在低p K a区域中，K 2 / k -
• Rate-determining steps in Michael-type additions and E1cb reactions in aqueous solution
  作者：Christina K. M. Heo、John W. Bunting

  DOI：10.1021/jo00039a013

  日期：1992.6

  Rates of equilibration of a series of 10 substituted pyridines and five Michael acceptors (CH2=CHZ, Z = CHO, COCH3, SO2CH3, CN, and CONH2) with the corresponding N(ZCH2CH2) pyridinium cations have been measured in aqueous solution at ionic strength 0.1 and 25-degrees-C. Analysis of the dependence of the pseudo-first-order rate constants for equilibration as a function of acceptor concentration and of pH allows the evaluation of the second-order rate constants (k(Nu)) for the nucleophilic attack of each of these pyridines upon each of these acceptors and also the second-order rate constants (k(OH)) for the hydroxide ion catalyzed E1cb elimination reaction which is the microscopic reverse of each of these Michael-type addition reactions. Bronsted-type plots for each of these processes as a function of the basicity of the substituted pyridine are concave down for each of Z = CHO, COCH3, and CN and are consistent with a change from rate-determining nucleophilic attack for the more basic pyridines to rate-determining protonation of the carbanionic intermediate by a water molecule for less basic pyridines and the corresponding microscopic reverse processes in the elimination reactions. The "break" in these Bronsted-type plots is shown to occur at a pyridine basicity that is a function of the Z-activating substituent. Bronsted beta-1g, and beta(nuc) are evaluated for each rate-determining step (wherever accessible); these two parameters are shown to pass through minima as a function of reactivity. beta(eq), is shown to be a simple linear function of reactivity (as log k(Nu)) for nucleophilic addition to the acceptor species, although K(eq) is relatively insensitive to the nature of the Z-activating substituent.