亚纳米德合试剂:起源和进展
1Affiliated Cancer Hospital, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, School of Pharmaceutical Sciences, Guangzhou Medical University, Guangzhou, 511436, China.
Accounts of chemical research
|March 7, 2024
概括
亚纳米德合试剂为合成提供了一种绿色化学方法,克服了聚合和种族化等挑战. 这些试剂能够使用未受保护的氨基酸进行高效的合成,并且可用于工业应用.
科学领域:
- 有机化学 有机化学
- 绿色化学 绿色化学
- 类合成 类合成
背景情况:
- 传统的合成依赖于传统的试剂,这给可持续发展带来了挑战.
- 目前用于从未受保护的氨基酸中合成的现有方法存在聚合或种族化问题.
- 对于新的合试剂和策略来解决合成中的种族化问题,有极大的需求.
研究的目的:
- 引入 ynamide 合试剂作为绿色合成的新型溶液.
- 为了证明 ynamide试剂在克服当前合成方法的局限性的有效性.
- 探索 ynamide 合试剂的制备,应用和可回收性.
主要方法:
- 开发和应用的 ynamide 合试剂,用于胺和 Ester 键的形成.
- 使用 ynamide试剂进行片凝聚,循环和 thioamide 结合.
- 使用未受保护的氨基酸进行逆合成的过渡性保护策略的实施.
主要成果:
- 亚纳米德合试剂有效地抑制了种族化/表皮化,从而实现了实际的逆合成.
- 在保持立体化学的前提下,实现了高效的雌激素键形成和巨乳化.
- 开发了一种可扩展的,单步合成的 ynamide试剂,以及一个可取水的变种和成功的回收利用.
结论:
- 胺合试剂代表了绿色合成的重大进步.
- 这些试剂为各种与相关的合成挑战提供了多功能和可持续的平台.
- 化联接试剂的开发为其更广泛的工业应用铺平了道路.
相关概念视频
01:29Preparation of Amides
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Amides are synthesized by treating carboxylic acids with amines in the presence of dehydrating agents like dicyclohexylcarbodiimide (DCC).
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
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01:19Amines to Amides: Acylation of Amines
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Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...
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01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
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The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the...
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01:07Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
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In the presence of an aqueous base and a halogen, primary amides can lose the carbonyl (as carbon dioxide) and undergo rearrangement to form primary amines. This reaction, called the Hofmann rearrangement, can produce primary amines (aryl and alkyl) in high yields without contamination by secondary and tertiary amines.
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01:22Preparation of 1° Amines: Azide Synthesis
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Direct alkylation of ammonia produces polyalkylated amines, along with a quaternary ammonium salt. To exclusively prepare primary amines, the azide synthesis method can be used.
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Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
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01:26Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
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The Hofmann and Curtius rearrangement reactions can be applied to synthesize primary amines from carboxylic acid derivatives such as amides and acyl azides. In the Hofmann rearrangement, a primary amide undergoes deprotonation in the presence of a base, followed by halogenation to generate an N-haloamide. A second proton abstraction produces a stabilized anionic species, which rearranges to an isocyanate intermediate via an alkyl group migration from the carbonyl carbon to the neighboring...
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