α-Haloalkyl Haloformates and Related Compounds 3.<sup>1</sup>A Facile Synthesis of Symmetrical and Unsymmetrical Ureas<i>via</i>Chloromethyl Carbamates
Abstract Chloromethyl carbamates were prepared by the reaction of chloromethyl chloroformates with amines and found to produce mono-, symmetrically or unsymmetrically di-and trisubstituted ureas including their N-hydroxy and N-alkoxy derivatives in moderate to good yield.
Chemoselective isocyanide insertion into the N–H bond using iodine–DMSO: metal-free access to substituted ureas
作者:Porag Bora、Ghanashyam Bez
DOI:10.1039/c8cc05019h
日期:——
Insertion of isocyanides into the N–H bond gives access to many medicinally important and structurally diverse complex nitrogen-containing heterocycles. Although the transition metal catalyzed isocyanideinsertion into the N–H bond is very common, polymerization of isocyanides in the presence of a transition metal and their strong coordination with metals are the common drawbacks. On the other hand
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
Ureaderivatives are obtained in mild to good yield from the reactions of primary aliphatic amines with CO2 in the absence of any catalysts, organic solvents or other additives. To optimize reaction conditions, experimental variables including temperature, pressure, the concentration of amine, reaction time etc. were studied. Satisfactory yields were obtained at the optimized conditions that are comparable