6,8-dibromo-2’-hydroxyquercetin | 1569852-28-3

• 分子结构分类: 有机化合物 - 苯丙烷和聚酮 - 黄酮类化合物
• 英文名称: 6,8-dibromo-2’-hydroxyquercetin
• 英文别名: 6,8-Dibromo-3,5,7-trihydroxy-2-(2,3,4-trihydroxyphenyl)chromen-4-one；6,8-dibromo-3,5,7-trihydroxy-2-(2,3,4-trihydroxyphenyl)chromen-4-one
• CAS: 1569852-28-3
• 化学式: C₁₅H₈Br₂O₈
• 分子量: 476.032
• InChiKey: GMTCAEWDJZLIDK-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.2
• 重原子数：
  25
• 可旋转键数：
  1
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.0
• 拓扑面积：
  148
• 氢给体数：
  6
• 氢受体数：
  8

反应信息

• 作为反应物：
  描述：

  6,8-dibromo-2’-hydroxyquercetin 在 盐酸 作用下， 以 丙酮 为溶剂， 生成 C₁₅H₉BrO₈
  参考文献：
  名称：

  Solvent-dependent release of bromine from bromoquercetins

  摘要：

  Quercetin, 6-bromoquercetin (3), and 8-bromoquercetin (4) undergo H/D exchange at 6- and 8-positions, in acetone-d(4) and methanol-d(4), catalyzed by acids and bases. The base-catalyzed process is faster, and in acetone-d(6) the half-lives of H-8 and H-6 are 56.5 and 48.6 h, respectively. A high regioselectivity at the position 8 of quercetin is observed under acid-catalysis in both solvents but in methanol-d(4) regioselectivity is retained even under base-catalysis. On the other hand, 6,8-dibromoquercetin (2), 4 and 6,8-dibromo-2'-hydroxyquercetin (5) manifest the ability of exchanging bromine with hydrogen (or deuterium) under acid-catalysis in acetone and other enolizable ketones (e.g., methyl ethyl ketone, acetylacetone, and isophorone). These bromophenols release bromine from their 8-position only, in a slow bromination process that likely involves their protonated form (arenium ion I) as brominating agent and the enol of the above ketones as Br-acceptor. The arenium ion I of these bromophenols is expected to be a powerful electrophile and its formation is most likely to be rate-determining. (C) 2014 Elsevier Ltd. All rights reserved.

  DOI：

  10.1016/j.tetlet.2014.05.110
• 作为产物：
  描述：

  槲皮素 在 N-溴代丁二酰亚胺(NBS) 、 sodium hydroxide 、 盐酸 、 sodium dithionite 作用下， 以 水 、 丙酮 为溶剂， 反应 0.03h， 生成 6,8-dibromo-2’-hydroxyquercetin 、 6,8-二溴槲皮素
  参考文献：
  名称：

  Unveiling the chemistry behind bromination of quercetin: the ‘violet chromogen’

  摘要：

  Bromination of quercetin with N-bromosuccinimide in neutral aqueous methanol occurs surprisingly in the electron-deficient A-ring only. Deprotonation of the acidic 7-OH is a major driver of this regioselective reaction. The increase of electron density makes in fact the quercetin anion suitable for an electrophilic attack by bromine at positions 8 and 6. Several pieces of evidence (NMR spectra and HID exchange) are presented to substantiate the mechanism advanced. Bromoquinones/quinomethides produced in excess of N-bromosuccinimide are responsible for the formation of a stable 'violet chromogen'. (C) 2014 Elsevier Ltd. All rights reserved.

  DOI：

  10.1016/j.tetlet.2014.01.081

文献信息

• Solvent-dependent release of bromine from bromoquercetins
  作者：Mario C. Foti、Concetta Rocco

  DOI：10.1016/j.tetlet.2014.05.110

  日期：2014.7

  Quercetin, 6-bromoquercetin (3), and 8-bromoquercetin (4) undergo H/D exchange at 6- and 8-positions, in acetone-d(4) and methanol-d(4), catalyzed by acids and bases. The base-catalyzed process is faster, and in acetone-d(6) the half-lives of H-8 and H-6 are 56.5 and 48.6 h, respectively. A high regioselectivity at the position 8 of quercetin is observed under acid-catalysis in both solvents but in methanol-d(4) regioselectivity is retained even under base-catalysis. On the other hand, 6,8-dibromoquercetin (2), 4 and 6,8-dibromo-2'-hydroxyquercetin (5) manifest the ability of exchanging bromine with hydrogen (or deuterium) under acid-catalysis in acetone and other enolizable ketones (e.g., methyl ethyl ketone, acetylacetone, and isophorone). These bromophenols release bromine from their 8-position only, in a slow bromination process that likely involves their protonated form (arenium ion I) as brominating agent and the enol of the above ketones as Br-acceptor. The arenium ion I of these bromophenols is expected to be a powerful electrophile and its formation is most likely to be rate-determining. (C) 2014 Elsevier Ltd. All rights reserved.
• Unveiling the chemistry behind bromination of quercetin: the ‘violet chromogen’
  作者：Mario C. Foti、Concetta Rocco

  DOI：10.1016/j.tetlet.2014.01.081

  日期：2014.2

  Bromination of quercetin with N-bromosuccinimide in neutral aqueous methanol occurs surprisingly in the electron-deficient A-ring only. Deprotonation of the acidic 7-OH is a major driver of this regioselective reaction. The increase of electron density makes in fact the quercetin anion suitable for an electrophilic attack by bromine at positions 8 and 6. Several pieces of evidence (NMR spectra and HID exchange) are presented to substantiate the mechanism advanced. Bromoquinones/quinomethides produced in excess of N-bromosuccinimide are responsible for the formation of a stable 'violet chromogen'. (C) 2014 Elsevier Ltd. All rights reserved.