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Updated: Jul 17, 2026

11:51
Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
(-) -テトラサイクリン合成
Mark G Charest1, Dionicio R Siegel, Andrew G Myers
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Journal of the American Chemical Society
|June 9, 2005
まとめ
本研究では,ベンゾ酸から (-) - テトラサイクリンを17段階のエナチオセレクティブ合成により,総収量1.1%を達成した. 主なステップは,効率的な抗生物質生産のためのダイエルス-アルダーサイクル添加とステレオ選択的酸化を含んでいた.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成化学 合成化学とは
- 薬用化学 薬用化学について
背景:
- テトラサイクリン抗生物質は,細菌感染症の治療に不可欠です.
- テトラサイクリンのような複雑な天然製品のための効率的な合成経路の開発は,薬剤の発見と開発に不可欠です.
- 以前の合成は,ステレオ選択性と総収量において課題に直面していた.
研究 の 目的:
- (-) - テトラサイクリンの収束性およびエナチオセレクティブ合成を確立する.
- Diels-Alderサイクル添加と酸化を含む主要なステップを最適化して,効率を向上させる.
- 将来の研究のために, (-) - テトラサイクリンを生産するための信頼性の高い方法を提供すること.
主な方法:
- ベンゾ酸から始まる17段階の合成です.
- アルファフェニルチオ群の導入によるAB前駆体の活性化,ダイエルス-アルダーサイクル添加.
- ステレオ選択的酸化と,その後の自己酸化と水素分解を含む変換.
- アルファ-フェニルチオエノンやベンゾサイクロブテンの誘導体などの主要な中間物質が使用されています.
主要な成果:
- ベンゾ酸から1.1%の総収量で (-) - テトラサイクリンをコンバージェントでエナンチオセレクティブに合成した.
- ディエルス・アルダー・サイクロアディションにより,エンドアダクトが64%の収穫率で得られました.
- 最終的な水素分解段階では,中間 7.から42%の収量で (-) - テトラサイクリンを生成した.
- 合成された (-) - テトラサイクリンは,本物のサンプルと区別できなかった.
結論:
- (-) - テトラサイクリンへの実行可能でエナンチオセレクティブな合成経路が開発されています.
- 記述された方法論は,複雑なテトラサイクリン構造を構築するための戦略的アプローチを提供します.
- この合成は,潜在的な大規模生産とアナログ開発のための基盤を提供します.
関連する概念動画
Synthesis and Decomposition Reactions
Synthesis and decomposition are two types of redox reactions. Synthesis means to make something, whereas decomposition means to break something. The reactions are accompanied by chemical and energy changes.
Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
Radical Formation: Addition
Radicals can be formed by adding a radical to a spin-paired molecule. This is typically observed with unsaturated species, where the addition of a radical across the π bond leads to the production of a new radical by dissolving the π bond. For example, the addition of a Br radical to an alkene yields a carbon-centered radical.
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an unpaired...
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an unpaired...
Radical Formation: Elimination
Another method of radical formation is the elimination process. It is the opposite of the addition route and is driven by the instability of the radical. For example, as depicted in Figure 1, dibenzoyl peroxide yields a pair of unstable radicals upon homolysis. Given its instability, this radical spontaneously undergoes elimination via a C–C bond cleavage to form a relatively more stable phenyl radical. The mechanism involves cleavage of the bond between the α and β positions with respect to...
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)
α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic attack via two modes: conjugate or 1,4-addition and direct or 1,2-addition.
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are formed faster owing to...
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are formed faster owing to...

