一二三四区视频,亚洲少妇熟女色,日本久热无码视频网,欧美国产日韩大尺度,亚洲a视频,久久少妇一区二区,日韩999无码视频,刺激久久久久久久,啊啊啊啊不要啊在线

Condensing agent

Condensing agent refers to an adjuvant which would be added in the condensation reaction. Generally there are catalytic adjuvants and catalytic adjuvants which can combine with the isolated atom or group of atoms generated during the process of condensation. About the former one, there are adjuvants such as the acid catalyst in esterification reaction and aluminum chloride in Friedl-Crafts reaction. And about the latter, there is metallic sodium in Wurtz-Fittig reaction.

A condensation reaction is a chemical reaction in which two molecules or moieties, often functional groups, combine to form a larger molecule, together with the loss of a small molecule like water, ammonia, hydrogen chloride, etc. Sometimes two organic molecules interact to form a larger molecule without emission of simple molecules. This is also known as condensation (reaction), such as aldol condensation.

The selection of condensing agents depends on the type of reaction, structure of the reactant, reaction conditions and the removed substances during the process of the reaction. Protecting groups and condensing agents in chemical synthesis: during chemical synthesis of nucleic acids, both of the nucleoside which plays the role of raw material monomers and the mononucleotide are compounds of polyfunctional group. When they are carrying chemical connections, except the groups of required reaction, other groups would also participate in the reaction, so as to generate by-products of auto-agglutination, misconnection and degradation. This will not only reduce the productivity of synthetic product, but also causes great difficulty in the separation and purification of the product. In order to ensure the phosphate diester bond structure and the nucleotide sequence, it requires a high degree of directionality and specificity in the synthetic reaction. The solution is to use a suitable protecting group and temporarily protect the group which is not required to be involved in the reaction, such as hydroxyl groups on the sugar, amino and hydroxyl phosphate on the base, etc.

Therefore, the selection of protecting groups has a great impact in whether the reaction could success or not. The selection of the condensing agents is important as well. The main reaction in the nucleic acid synthesis reaction is hydroxy reaction between phosphoric acid and RNA or DNA, which could generate phosphate ester linkage. At present, we usually use a kind of condensating agent with high activity and low side effects to react with Phosphate components and form an activated phosphate, and then accomplish the step of components condensation.

HomePage | Member Companies | Advertising | Contact us | Previous WebSite | MSDS | CAS Index | CAS DataBase
Copyright © 2016 ChemicalBook All rights reserved.
嵩明县| 樟树市| 康保县| 灵台县| 盖州市| 嘉峪关市| 阿巴嘎旗| 株洲市| 武平县| 新乡县| 历史| 白朗县| 丹江口市| 长岭县| 贡觉县| 常山县| 且末县| 右玉县| 奈曼旗| 繁昌县| 芦山县| 东乡族自治县| 繁昌县| 突泉县| 拜城县| 罗平县| 保康县| 阿尔山市| 浑源县| 林周县| 苍梧县| 龙海市| 鱼台县| 铅山县| 安化县| 崇义县| 洛南县| 个旧市| 鄂州市| 乐至县| 望都县|