25855-24-7Relevant articles and documents
Di-urea compounds as gelators for organic solvents
Van Esch, Jan,Kellogg, Richard M.,Feringa, Ben L.
, p. 281 - 284 (1997)
Simple diurea compounds form thermoreversible gels with several organic solvents. These gels are stable up to temperatures of 100°C, and can be stored for months. Electron microscopy reveals that in these solvents the gelation agents assemble into very thin rectangular sheets which are several tens of micrometers long.
Palladium-Catalyzed Aerobic Oxidative Carbonylation of Amines Enables the Synthesis of Unsymmetrical N,N′-Disubstituted Ureas
Zeng, Honglan,Du, Hongyan,Gong, Xu,Zhang, Jie,Han, Wei
, p. 1223 - 1226 (2021/06/02)
A ligand-free palladium-catalyzed aerobic oxidative carbonylation of amines for the synthesis of ureas, particular unsymmetrically N,N′-disubstituted ureas, which cannot be accessed by any other palladium-catalyzed oxidative carbonylation of amines to date, is presented. An array of symmetrical and unsymmetrical ureas were straightforwardly synthesized by using inexpensive, readily available, stable, and safe amines with good to excellent yields under a pressure of 1 atm. This novel method employs oxygen as the sole oxidant and offers an attractive alternative to transition-metal-based oxidant systems.
Formamides as Isocyanate Surrogates: A Mechanistically Driven Approach to the Development of Atom-Efficient, Selective Catalytic Syntheses of Ureas, Carbamates, and Heterocycles
Bruffaerts, Jeffrey,Von Wolff, Niklas,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
supporting information, p. 16486 - 16493 (2019/10/14)
Despite the hazardous nature of isocyanates, they remain key building blocks in bulk and fine chemical synthesis. By surrogating them with less potent and readily available formamide precursors, we herein demonstrate an alternative, mechanistic approach to selectively access a broad range of ureas, carbamates, and heterocycles via ruthenium-based pincer complex catalyzed acceptorless dehydrogenative coupling reactions. The design of these highly atom-efficient procedures was driven by the identification and characterization of the relevant organometallic complexes, uniquely exhibiting the trapping of an isocyanate intermediate. Density functional theory (DFT) calculations further contributed to shed light on the remarkably orchestrated chain of catalytic events, involving metal-ligand cooperation.
