isocyanates via base-induced β-elimination of haloform N-monosubstituted trihaloacetamides is described. The rate of reaction exhibits a strong dependence on the nature of the trihalomethyl group. Thus, while the reaction of tribromoacetamides proceeds at room temperature and the reaction of trichloroacetamides requires heating in polar solvents, no reaction could be observed for any of the corresponding
Metal-Free Synthesis of Unsymmetrical Ureas and Carbamates from CO<sub>2</sub> and Amines via Isocyanate Intermediates
作者:Yiming Ren、Sophie A. L. Rousseaux
DOI:10.1021/acs.joc.7b02905
日期:2018.1.19
A mild and metal-free synthesis of aryl isocyanates from arylamines under an atmosphere of CO2 was developed. The carbamic acid intermediate, derived from the arylamine starting material and CO2 in the presence of DBU, is dehydrated by activated sulfonium reagents to generate the corresponding isocyanate. The latter can be detected by in situ IR and trapped by various amines and alcohols to make unsymmetrical
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 series of N-alkyl substituted urea derivatives were synthesized and evaluated for their in vitro antibacterial and antifungal activities. The N-alkyl substituted urea derivatives bearing morpholine moiety (3a–3k) showed better activities than those bearing diethylamine moiety (2a–2f). Compounds having fluoro substituent at ortho (3c) and para (3b) positions of the phenyl ring exhibited potent antimicrobial
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.