10253-95-9Relevant articles and documents
4,5,6,7-Tetrachlorobenzo[d][1,3,2]dioxaborol-2-ol as an effective catalyst for the amide condensation of sterically demanding carboxylic acids
Maki, Toshikatsu,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 1431 - 1434 (2006)
4,5,6,7-Tetrachlorobenzo[d][1,3,2]dioxaborole (4a) and 4,5,6,7- tetrachlorobenzo[d][1,3,2]dioxaborol-2-ol (4b) are effective catalysts for the dehydrative amide condensation between an equimolar mixture of carboxylic acids and amines. In particular, these catalysts are greatly superior to 3,5-bis(trifluoromethyl)phenylboronic acid (1) for the amide condensation of sterically demanding carboxylic acids. In contrast, 4c, which is prepared from a 1:2 molar mixture of B(OH)3 and tetrachlorocatechol, is effective as a Lewis acid-assisted Bronsted acid (LBA) catalyst for Ritter reaction.
Tropylium-promoted Ritter reactions
Doan, Son H.,Hussein, Mohanad A.,Nguyen, Thanh Vinh
, p. 8901 - 8904 (2021)
The Ritter reaction used to be one of the most powerful synthetic tools to functionalize alcohols and nitriles, providing valuableN-alkyl amide products. However, this reaction has not been frequently used in modern organic synthesis due to its employment of strongly acidic and harsh reaction conditions, which often lead to complicated side reactions. Herein, we report the development of a new method using salts of the tropylium ion to promote the Ritter reaction. This method works well on a range of alcohol and nitrile substrates, giving the corresponding products in good to excellent yields. This reaction protocol is amenable to microwave and continuous flow reactors, offering an attractive opportunity for further applications in organic synthesis.
Environmentally Benign Ritter Reaction Using Bismuth Salts as a Catalyst
Ueno, Masaharu,Kusaka, Ryo,Ohmura, Satoshi D.,Miyoshi, Norikazu
, p. 1796 - 1800 (2019)
We developed an environmentally benign Ritter reaction of alcohols with nitriles using a commercially available bismuth salt as a less harmful catalyst. The detailed reaction profiles revealed that consumption of the ether by-product as the reaction proceeded was the key for optimizing this reaction, and the yield of the target amide was improved by adding a small amount of water. This finding clearly reveals the significance of using a bismuth salt as the catalyst, as it is not deactivated in the presence of water. This catalyst system has a broad substrate scope, and even with 1 mol-% of the catalyst, the reaction progresses smoothly. It is also possible to react stoichiometric amounts of nitriles and alcohols, thus reducing the amount of organic solvent required for the reaction. Furthermore, as the inexpensive bismuth catalyst can be easily removed using aqueous hydrochloric acid, a purification process that only required washing and drying without any organic solvents was successfully established.
Silica boron-sulfuric acid nanoparticles (SBSANs): Preparation, characterization and their catalytic application in the Ritter reaction for the synthesis of amide derivatives
Khalafi-Nezhad, Ali,Foroughi, Habib Ollah,Doroodmand, Mohammad Mahdi,Panahi, Farhad
experimental part, p. 12842 - 12851 (2012/01/14)
Among a number of different heterogeneous and homogeneous catalysts, silica boron-sulfuric acid nanoparticles (SBSANs) with both protic and Lewis acidic sites were shown to be the most active and recyclable catalyst in the Ritter reaction. Various amide d
