Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

The Photochemical Reaction Center01:29

The Photochemical Reaction Center

4.1K
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
4.1K
Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

1.8K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
1.8K
Radical Reactivity: Overview01:11

Radical Reactivity: Overview

2.1K
Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired...
2.1K
Reaction Mechanisms03:06

Reaction Mechanisms

25.9K
Chemical reactions often occur in a stepwise fashion, involving two or more distinct reactions taking place in a sequence. A balanced equation indicates the reacting species and the product species, but it reveals no details about how the reaction occurs at the molecular level. The reaction mechanism (or reaction path) provides details regarding the precise, step-by-step process by which a reaction occurs.
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
25.9K
Introduction to Chemical Reactions01:23

Introduction to Chemical Reactions

8.7K
All chemical reactions begin with a reactant, the general term for one or more substances entering the reaction. Sodium and chloride ions, for example, are the reactants in the production of table salt. One or more substances produced by a chemical reaction are called the product. Chemical reactions follow the law of conservation of mass, which means that matter cannot be created nor destroyed in a chemical reaction. The components of the reactants—the number of atoms and the...
8.7K
Chemical Reactions01:19

Chemical Reactions

88.8K
A chemical reaction is a process by which the bonds in the atoms of substances are rearranged to generate new substances. Matter cannot be created or destroyed in a chemical reaction—the same type and number of atoms that make up the reactants are still present in the products. Merely, the rearrangement of chemical bonds produces new compounds.
Chemical Reactions Rearrange Atoms into New Substances
A chemical reaction takes starting materials—the reactants—and changes them...
88.8K

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

Activation of Thioglycosides with Ferric Chloride: Scope and Mechanism.

ACS omega·2026
Same author

Correction to "Halophilic Metal Salts for the Cooperatively Catalyzed Activation of Thioglycosides".

The Journal of organic chemistry·2026
Same author

Correction to "Differentially Substituted Galactosyl Chlorides Reveal Unusual Reactivity Trends under the 4K Reaction Conditions".

The Journal of organic chemistry·2026
Same author

Correction to "Chemoselective Activation of Thioglycosides with Alkyl Trichloroacetimidates".

The Journal of organic chemistry·2026
Same author

First evidence of the H-bonding with picoloylated compounds used as building blocks for HAD.

Carbohydrate research·2026
Same author

Human Milk Oligosaccharides Inhibit Group B Streptococcal Growth by Binding PcsB, an Essential Cell Wall Separation Protein.

JACS Au·2026

相关实验视频

Updated: Jun 29, 2025

Optimization of the Ugi Reaction Using Parallel Synthesis and Automated Liquid Handling
08:24

Optimization of the Ugi Reaction Using Parallel Synthesis and Automated Liquid Handling

Published on: November 11, 2008

16.4K

这就是4K反应.

Alexei V Demchenko1, Cristina De Meo2

  • 1Department of Chemistry, Saint Louis University, 3501 Laclede Ave, St. Louis, Missouri, 63103, United States.

Carbohydrate research
|April 3, 2024
PubMed
概括

4K反应增强了使用催化易斯酸与银盐的糖化反应. 这一突破改善了产量和速度,特别是在碳水化合物化学中的无反应基质.

科学领域:

  • 碳水化合物化学 碳水化合物化学
  • 有机合成 有机合成
  • 催化剂是一种催化剂.

背景情况:

  • 经典的Köenigs-Knorr糖化,使用像Ag2O这样的银盐,仅限于活性基质.
  • 不反应的捐赠体,如per-O-基化曼诺基化物,往往产生不良结果.

研究的目的:

  • 为了提高白银促进的糖化反应的效率和基质范围.
  • 研究催化易斯酸对糖化率和产量的影响.

主要方法:

  • 在糖化反应中使用银盐 (Ag2O或Ag2CO3).
  • 引入易斯酸的催化量到银促进系统.
  • 描述反应产物和优化条件,以应对具有挑战性的基质.

主要成果:

  • 添加催化易斯酸显著增加了反应速率和产量.
  • 这种称为4K反应的增强方法,在以前不反应的甘氨酸捐赠者身上被证明是有效的.
  • 提出了合作催化过程的初步机制,解释了观察到的改进.

结论:

  • 4K反应代表了糖化方法学的重大进步.
关键词:
碳水化合物 碳水化合物葡萄糖基酶化是什么? 葡萄糖基酶化化物化物是指一种化物.机理机制 机理机制橄糖 橄糖 橄糖立体选择性是一种选择性.综合合成 综合合成

更多相关视频

Optimization of Radiochemical Reactions using Droplet Arrays
10:54

Optimization of Radiochemical Reactions using Droplet Arrays

Published on: February 12, 2021

3.4K
4D Imaging of Protein Aggregation in Live Cells
08:59

4D Imaging of Protein Aggregation in Live Cells

Published on: April 5, 2013

17.4K

相关实验视频

Last Updated: Jun 29, 2025

Optimization of the Ugi Reaction Using Parallel Synthesis and Automated Liquid Handling
08:24

Optimization of the Ugi Reaction Using Parallel Synthesis and Automated Liquid Handling

Published on: November 11, 2008

16.4K
Optimization of Radiochemical Reactions using Droplet Arrays
10:54

Optimization of Radiochemical Reactions using Droplet Arrays

Published on: February 12, 2021

3.4K
4D Imaging of Protein Aggregation in Live Cells
08:59

4D Imaging of Protein Aggregation in Live Cells

Published on: April 5, 2013

17.4K
  • 这种方法扩大了银促进糖化酶的适用性,使其适用于更广泛的基质.
  • 进一步了解合作催化机制有助于制定更高效的协议.