5-甲氧基-2-硝基苯酚钾 | 56536-70-0

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯和取代衍生物
• 中文名称: 5-甲氧基-2-硝基苯酚钾
• 英文名称: potassium 5-methoxy-2-nitrophenolate
• 英文别名: potassium 5-methoxy-2-nitrophenoxide
• CAS: 56536-70-0
• 化学式: C₇H₆NO₄*K
• 分子量: 207.227
• InChiKey: UPVZGTCWVFHKCQ-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  -2.32
• 重原子数：
  13.0
• 可旋转键数：
  2.0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.14
• 拓扑面积：
  75.43
• 氢给体数：
  0.0
• 氢受体数：
  4.0

反应信息

• 作为反应物：
  描述：

  5-甲氧基-2-硝基苯酚钾 在 Pt(S)/C 甲醇 、 氢气 作用下， 以 甲苯 为溶剂， 20.0~25.0 ℃ 、101.33 kPa 条件下， 反应 1.0h， 生成 7-methoxy-4H-2,3-dioxo-1,4-benzoxazine
  参考文献：
  名称：

  Syntheses of Cyclic Hydroxamic Acids and Lactams with 2,3-dioxo-1,4-benzoxazine skeleton

  摘要：

  Ethyl 2-nitrophenyl oxalate (1 a) and its 5-methoxy derivative (1 b) were subjected to catalytic hydrogenations over 3 % Pt (S) on carbon in different solvents. Thus, hydrogenation in acetic acid yielded 4-hydroxy-2,3-dioxo-1,4-benzoxazine (2a) and its 7-methoxy derivative (2 b) by reductive cyclization, the dehydro forms of the naturally occurring cyclic hydroxamic acids DIBOA and DIMBOA from Gramineae. In contrast, hydrogenation of esters 1 in methanol results in the formation of amides 3 by acyl group migration. On heating, amides 3 undergo lactonization to form lactone-lactames 4, which in turn undergo ring opening to give amides 3 when refluxed in ethanol.

  DOI：

  10.1002/prac.19933350409

文献信息

• Completion of the Spectroscopical Data for the Synthesis of DIMBOA
  作者：Norbert Handler、Thomas Erker

  DOI：10.3797/scipharm.aut-05-08

  日期：——

  important role in the defense-system of plants against a variety of enemies. To investigate new mechanism and effects we synthesized the molecules using known synthetic pathways. Since the chemical data of DIMBOA are not complete or even false, we decided to publish the missing ones in this journal.

  环状异羟肟酸，例如2,4-二羟基-7-甲氧基-2 H -1,4-苯并恶嗪-3（4 H）-1（DIMBOA）和2,4-二羟基-2 H -1,4-苯并恶嗪-3 （4 H）-1（DIBOA）被发现在几种植物中，在植物防御各种敌人的防御系统中起着重要作用。为了研究新的机理和作用，我们使用已知的合成途径合成了分子。由于DIMBOA的化学数据不完整甚至是虚假的，我们决定在此期刊上发表缺失的数据。
• Analogs of the cyclic hydroxamic acid 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one (DIMBOA): decomposition to benzoxazolinones and reaction with .beta.-mercaptoethanol
  作者：Jeffrey Atkinson、Peter Morand、John T. Arnason、Hermann M. Niemeyer、Hector R. Bravo

  DOI：10.1021/jo00005a025

  日期：1991.3

  Analogues of the aglucones of naturally occurring cyclic hydroxamic acids (2,4-dihydroxy-1,4-benzoxazin-3-ones) from Gramineae (Poaceae) have been synthesized by the reductive cyclization of the ring-substituted methyl alpha-(o-nitrophenoxy)-alpha-methoxyacetates, followed by demethylation of the C-2 methoxy group with BBr3 or BCl3 to reveal the 2-hydroxy group. A structure-activity series was produced by varying the substituent at C-7 on the aromatic ring [R = MeO (1), t-Bu (6), Me (7), H (8), Cl (9), F (10), CO2Me (11a)]. The pK(a) values for the hydroxamic acid and the phenol moieties were determined for each member of the C-7 series. They correlated well with sigma in a linear free energy relationship (LFER) yielding values of rho = 0.71 (with sigma-p) for pK(a1) (the hydroxamic acid) and rho = 1.6 (with sigma-m) for pK(a2) (the phenol). A LFER also existed between the rate constants for the unimolecular decomposition of these hydroxamic acids to benzoxazolinones and sigma+ (rho = 1.1). The rates of hydroxamic acid reduction to lactams by beta-mercaptoethanol were also investigated. It was found that only compounds with electron-rich aromatic rings and specifically an oxa functionality para to the hydroxamic acid nitrogen atom (compounds 1 and 3-5) had measurable rates of reduction. H-1 NMR spectra recorded during this reaction in D2O buffers (pD9), however, showed that compounds 1, 2, 6-9 (the only ones investigated) formed a hemithioacetal at C-2 even though only 1 has a measurable rate of reduction by the same thiol. The remarkable rate enhancement provided by an oxa functionality suggests that reduction occurs by direct attack of thiolate on the hydroxamic nitrogen of a resonance-stabilized ion pair.