ニトロニル酸化窒素を用いたニトロキシルと酸化窒素の区別について
Uri Samuni1, Yuval Samuni, Sara Goldstein
1Department of Chemistry and Biochemistry, Queens College, City University of New York, Flushing, New York 11367, USA.
Journal of the American Chemical Society
|May 28, 2010
まとめ
ニトロニル酸化窒素を用いた酸化窒素 (NO) の検出は,酸化窒素 (HNO) が反応してヒドロキシラミンを形成することで複雑になります. ニトロニル酸化窒素は,低濃度でのみNOとHNOを区別することができます.
科学分野:
- バイオケミストリー バイオケミストリー
- 化学生物学 化学生物学とは
- 生理学 生理学とは
背景:
- 酸化窒素 (NO) と窒素ヒドリド (HNO) の正確な検出は,それらの生物学的役割を理解するために不可欠です.
- C-PTIOのようなニトロニル酸化窒素は,イミノ酸化窒素を形成する反応を通じてNOを検出するために一般的に使用されます.
研究 の 目的:
- HNOとニトロニル酸化窒素の反応機構を調査する.
- HNOとC-PTIOの反応の速度定数を決定する.
- ニトロニル酸化窒素がNOとHNOを区別する可能性を評価する.
主な方法:
- HNOドナーとしてアンジェリ塩 (AS) を利用しました.
- 反応速度を定量化するために,競合剤としてメトミオグルビンを使用した.
- 反応産物を特定するための光譜分析.
主要な成果:
- HNOは,ニトロニル窒酸化物 (C-PTIO,PTIOなど) と素早く反応し,イミノ窒酸化物とヒドロキシラミンを形成する.
- HNOによるC-PTIO還元の速度定数は,pH 7.0で (1.4 ± 0.2) x 10^5 M^-1 s^-1 と決定されました.
- イミノヒドロキシラミンへの完全な変換は,より高いASとニトロニル酸化窒素の比率で起こります.
結論:
- ニトロニル酸化窒素はHNOによってヒドロキシラミンに還元され,その後イミノ酸化窒素とイミノヒドロキシラミンに変換されます.
- 反応経路は,ニトロニル酸化窒素濃度がHNO生成量より著しく低い場合にのみ,NOとHNOの区別を可能にします.
関連する概念動画
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
Nitrosation of Enols
The nitrosation reaction is one of the methods of preparing 1,2-diketones. The enol tautomer of the starting ketone reacts with sodium nitrite in hydrochloric acid, generating the 1,2-diketone after hydrolysis.
2° Amines to N-Nitrosamines: Reaction with NaNO2
Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
Resonance
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O bonds.
Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...


