Synthesis of Unsymmetrical Ureas by Sulfur-Assisted Carbonylation with Carbon Monoxide and Oxidation with Molecular Oxygen under Mild Conditions
作者:Takumi Mizuno、Takeo Nakai、Masatoshi Mihara
DOI:10.1055/s-0029-1216863
日期:2009.8
pressure of carbonmonoxide and oxygen at room temperature, N,N-dialkyl-N′-arylureas were selectively accessible from secondary amines, aromaticamines, and sulfur in good to excellent yields. For example, N-butyl-N-methyl-N′-(3,4-dichlorophenyl)urea, which is used as a herbicide (neburon), was afforded successfully from butylmethylamine (2 equiv), 3,4-dichloroaniline (1 equiv) and sulfur (1 equiv) in
Rhodium(<scp>iii</scp>)-catalysed aerobic synthesis of highly functionalized indoles from N-arylurea under mild conditions through C–H activation
作者:Subban Kathiravan、Ian A. Nicholls
DOI:10.1039/c4cc06020b
日期:——
arylation of alkynes using copper as the terminal oxidant for regeneration of the catalytically active species under aerobic conditions is described. This novel C-H activation reaction was applied to the synthesis of a wide range of substituted indolesfrom N-arylureas.
Lewis acid-catalyzed insertion of isocyanides 2 into nitrogen–sulfur bonds of sulfenamides 1 was developed. This method provided a convenient method for the synthesis of isothioureas 3. Among Lewis acids examined, AlCl3 brought about the best result. Acetic acid assisted one-pot preparation of unsymmetrical ureas was also described.
On the Thermal Dissociation of Organic Compounds. XII. The Effects of the Substituents on the Thermal Dissociation of Substituted Phenylureas
作者:Shoichiro Ozaki、Tsutomu Nagoya
DOI:10.1246/bcsj.30.444
日期:1957.5
synthesized. The rate constants and ρ values of thermaldissociation of these ureas in fattyacids were determined. In 1,1-diethyl-3-arylureas, the ρ value of the dissociation reaction at 95°C. in chloro-acetic acid was −0.196, and it may be concluded that the protonation process seems to be the rate-determining step in the dissociation reaction of ureas in fattyacid. The activation energy was compared with
A Convenient Method of Synthesis of Unsymmetrical Urea Derivatives
作者:Grażyna Groszek
DOI:10.1021/op020055g
日期:2002.11.1
A method for the preparation of unsymmetrical urea derivatives that may contain functional groups such as hydroxyl, amine, amide, and carboxyl is described. The method consists of a one-pot modified Curtiusrearrangement starting with appropriate aromatic acid chloride and carried out in a nonaqueous system