在d-Galactosamine的Schiff基中对Pyranose和Furanose异构体的逆异构效应
Esther Matamoros1,2,3, Esther M S Pérez1, Pedro Cintas1
1Departamento de Química Orgánica e Inorgánica, Facultad de Ciencias, and Instituto del Agua, Cambio Climático y Sostenibilidad (IACYS), Universidad de Extremadura, 06006 Badajoz, Spain.
The Journal of organic chemistry
|September 17, 2025
概括
这项研究揭示了来自2-amino-2-deoxyaldoses的imines中的 furanose结构,显示出由于反向异构效应而偏爱β-异构体. 这一发现影响了对碳水化合物化学和异构平衡的理解.
科学领域:
- 碳水化合物化学 碳水化合物化学
- 有机化学 有机化学
- 结构生物学 结构生物学
背景情况:
- 从2-amino-2-deoxyaldoses中衍生的胺在生物系统中至关重要.
- 了解异质平衡是碳水化合物结构和功能的关键.
- 异构效应通常有利于轴向异构,影响分子构造.
研究的目的:
- 为了识别和描述从2-amino-2-deoxyaldoses中衍生的 imines中的 furanose结构.
- 为了研究这些 imine 结构的异质平衡.
- 阐明观察到的异种偏好背后的驱动力.
主要方法:
- 从d-galactosamine中合成伊米因.
- 在DMSO溶液中进行核磁共振 (NMR) 光谱.
- 结构分析的计算化学方法.
主要成果:
- 在从2-amino-2-deoxyaldoses中衍生的 imines中首次确定了 furanose结构.
- 观察到pyranose和furanose形式的α和β异常之间的平衡.
- 发现了对β-异构体的显著偏好,这归因于反向异构体效应.
结论:
- 这项研究证实了这些 imines 中的 furanose 形式的存在,扩大了已知的碳水化合物结构.
- 由分子内键和溶解驱动的反向无分子效应解释了β-无分子偏好.
- 这些发现为氨基糖的 imine衍生物的结构偏好和稳定性提供了新的见解.
相关概念视频
02:23SN2 Reaction: Stereochemistry
11.6K
In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not...
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not...
11.6K
![[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12422.jpg&w=3840&q=75)
01:21[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
3.4K
The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.
3.4K
02:15SN1 Reaction: Stereochemistry
10.2K
This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
10.2K
01:30Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)
4.6K
Nucleophilic substitution in aromatic compounds is feasible in substrates bearing strong electron-withdrawing substituents positioned ortho or para to the leaving group. The reaction proceeds via two steps: the addition of the nucleophile and the elimination of the leaving group.
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...
4.6K
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
9.5K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
9.5K
01:12Stereochemical Effects of Enolization
2.6K
The chiral α-carbon of the carbonyl compound is the stereocenter of the molecule. As shown in the figure below, when such a carbonyl compound undergoes racemization under an acidic or basic condition, an achiral enol is formed.
2.6K