活环开放聚合N-硫尼拉齐里丁:高分子量线性聚氨酸的合成
Ian C Stewart1, Cameron C Lee, Robert G Bergman
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|December 15, 2005
概括
硫尼拉齐里丁可以通过核性硫胺基实现受控聚合. 单体的反纯度对聚合物溶解度和分子量产生了重大影响,影响了材料的性能.
科学领域:
- 聚合物化学 聚合物化学
- 有机合成 有机合成
背景情况:
- 硫尼拉齐里丁是用于环开放聚合的有效单体.
- 核硫胺开始聚合,产生具有受控分子量和低多分散性的聚合物.
研究的目的:
- 为了研究单体抗纯度在硫尼拉齐里丁环开放聚合中的作用.
- 为了了解 enantiopurity 如何影响聚合物特性,如溶解度和分子量.
主要方法:
- 活环开放聚合利用硫尼拉齐里丁单体.
- 聚合物特性分析,包括分子量和多分散性.
- 使用动态光散射来研究聚合动力学和聚合动力学.
主要成果:
- 种族硫尼拉齐里丁单体产生具有可预测分子重量的可溶性聚合物.
- 乙酸硫尼拉齐里丁单体产生不溶性聚合物,其分子重量低于理论预测.
- 聚合动力学受到单体立体化学的影响.
结论:
- 单体反净度是控制硫尼拉齐里丁聚合结果的关键因素.
- 对聚合物的立体化学控制允许调整聚合物的溶解度和分子量.
- 这些发现为设计具有特定性质的聚合物提供了新的策略.
相关概念视频
Acid Halides to Amides: Aminolysis
Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
Preparation of Amides
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...
Preparation of 1° Amines: Gabriel Synthesis
Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Ziegler–Natta Chain-Growth Polymerization: Overview
Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta catalyst, high molecular...
Preparation of Carboxylic Acids: Hydrolysis of Nitriles
Nitriles (R–CN) can be converted into carboxylic acids (R–COOH) upon treatment with aqueous acids, i.e., upon hydrolysis of nitriles. Under base-catalyzed conditions, carboxylate anions (R–COO−) are formed.
Peptidoglycan Synthesis
Structure of PeptidoglycanPeptidoglycan is a vital structural component of the bacterial cell wall, providing mechanical strength and shape to the cell. It consists of repeating units of two sugars—N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)—linked by β-1,4 glycosidic bonds. These sugar chains are cross-linked by short peptide chains, forming a mesh-like polymer that surrounds the bacterial plasma membrane.Cytoplasmic Phase – Precursor SynthesisPeptidoglycan biosynthesis begins in...


