伊米达-2-伊利登的水解
Oldamur Hollóczki1, Péter Terleczky, Dénes Szieberth
1Department of Inorganic and Analytical Chemistry, Hungarian Academy of Sciences, Budapest University of Technology and Economics, Szt. Gellért tér 4., Budapest, H-1111 Hungary.
Journal of the American Chemical Society
|December 23, 2010
概括
伊米达-2-伊利丁在水中的直接反应产生稳定的伊米达-氧化物. 相比之下,在近距离的环境中,碳酸-水复合物形成,慢慢转化为环开放的产品.
科学领域:
- 有机金属化学 有机金属化学
- 物理化学 物理化学
背景情况:
- 伊米达-2-烯是重要的N-异环碳化合物.
- 它们在水性环境中的反应性尚不清楚.
研究的目的:
- 为了研究伊米达-2-伊利丁在水和近离子环境中的反应.
- 为了阐明反应机制和识别反应产物.
主要方法:
- 使用NMR和IR光谱仪进行实验调查.
- 使用ab initio分子动力学模拟的计算力学研究.
主要成果:
- 在主要的水溶液中,形成稳定的伊米达氧化 (pH13).
- 在近极环境中,观察到一种桥式碳酸-水复合体.
- 这种复合物转化为环开产品,其稳定性受到水度和溶剂效应的影响.
结论:
- 溶剂稳定和氧化离子基本性对于碳素水解至关重要.
- 增加的水分子通过伊米达氧化中间体促进了环开放产品的形成.
- 在imidazol-2-ylidenes中的芳香稳定优于环开放产品而不是碳素水复合物.
相关概念视频
Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imine formation involves the addition of carbonyl compounds to a primary amine. It begins with the generation of carbinolamine through a series of steps involving an initial nucleophilic attack and then several proton transfer reactions. The second part includes the elimination of water, as a leaving group, to give the imine.
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Basicity of Heterocyclic Aromatic Amines
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
Amides to Carboxylic Acids: Hydrolysis
Amides can undergo either acid-catalyzed hydrolysis or base-promoted hydrolysis through a typical nucleophilic acyl substitution. Each hydrolysis requires severe conditions.
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Aldehydes and Ketones with Amines: Imine and Enamine Formation Overview
Primary amines react with carbonyl compounds—aldehydes and ketones—to generate imines. Imines consist of a C=N double bond and are named Schiff bases after its discoverer—the German chemist Hugo Schiff. On the other hand, secondary amines react with carbonyl compounds to give enamines. In enamines, the presence of a C=C double bond adjacent to the nitrogen atom leads to the delocalization of the lone pair.
Acid Halides to Carboxylic Acids: Hydrolysis
Hydrolysis of acid halides is a nucleophilic acyl substitution reaction in which acid halides react with water to give carboxylic acids. The reaction occurs readily and does not require acid or a base catalyst.
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
Acid Halides to Esters: Alcoholysis
Alcoholysis is a nucleophilic acyl substitution reaction in which an alcohol functions as a nucleophile. Acid halides react with alcohol to produce esters. The mechanism proceeds in three steps:


