一种oxazaphospholidine方法,用于立体控制的聚核酸酸酸的合成
Natsuhisa Oka1, Takeshi Wada, Kazuhiko Saigo
1Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Bioscience Building 702, Kashiwa, Chiba 277-8562, Japan.
Journal of the American Chemical Society
|July 3, 2003
概括
这项研究详细介绍了一种新方法,用于使用oxazaphospholidine单体合成酸寡氧化核化物 (PS-ODN) 的立体控制合成. 这种方法实现了高立体选择性,允许生产纯 (R(p)) -和 (S(p)) -PS-ODN,用于固体相合成等应用.
科学领域:
- 有机化学 有机化学
- 核酸化学的核酸化学
- 药用化学 医学化学
背景情况:
- 氧化核酸酸 (PS-ODN) 由于其核酶耐药性,在反感和siRNA疗法中至关重要.
- 对PS-ODN的立体控制合成对于优化它们的生物活性和减少非目标效应至关重要.
- 现有的PS-ODN合成方法往往缺乏在中心的精确立体化学控制.
研究的目的:
- 开发一种新的立体控制方法来合成二聚体纯的PS-ODN.
- 调查影响PS-ODN单体和二元体合成中的二选择性因素.
- 将开发的方法应用于立体调节的PS-ODN的固体相合成.
主要方法:
- 合成2-chloro-1,3,2-oxazaphospholidine衍生物的合成,从1,2-氨基醇.
- 使用这些oxazaphospholidine衍生物对5'-O受保护的核酸化.
- 核酸氧化聚胺的灾难选择凝结反应使用新型dialkyl ((cyanomethyl) ammonium盐激活剂.
- Ab initio分子轨道计算以阐明反应机制.
- 在聚烯树脂上固相合成立体调节的PS-ODN.
主要成果:
- 研究人员发现,化酶的二元选择性取决于氨基醇结构,反应温度和HCl清除剂.
- 最初的计算表明,LUMO参与了P-Cl键,这可能解释了立体化学保留.
- 新型激活剂使得快速凝结反应具有出色的二聚体选择性,取决于氨基结构.
- 在硫化和脱保护后获得高产的二二核酸酸 (R(p)) -和 (S(p)) -二核酸酸.
- 该方法成功应用于合成立体调节的PS-ODN,包括所有-R-T-PS-T和所有-S-T-PS-T.
结论:
- 已经建立了一个强大的和有效的方法,用于对PS-ODNs的立体控制合成.
- 开发的方法允许精确控制立体化学,对于治疗应用至关重要.
- 这种方法适用于立体调节的PS-ODN的溶液阶段和固体阶段合成.
相关概念视频
Preparation of Alkynes: Alkylation Reaction
Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Preparation of 1° Amines: Azide Synthesis
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.
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...
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...
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
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.
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...
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
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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