Facile direct synthesis of unsymmetrical ureas from N-Alloc-, N-Cbz-, and N-Boc-protected amines using DABAL-Me3
作者:Soosung Kang、Hee-Kwon Kim
DOI:10.1016/j.tet.2018.06.011
日期:2018.7
A practical synthetic method for the direct synthesis of unsymmetrically substituted ureas from N-Alloc-, N-Cbz-, and N-Boc-protected amines is described. In this study, efficient direct conversion of the Alloc-, Cbz-, and Boc-carbamate compounds to ureas was achieved in the presence of DABAL-Me3, an air stable and easily handled reagent. Using this reaction method, both protected aromatic and aliphatic
Oximes as reusable templates for the synthesis of ureas and carbamates by an in situ generation of carbamoyl oximes
作者:Gopal Chandru Senadi、Mohana Reddy Mutra、Ting-Yi Lu、Jeh-Jeng Wang
DOI:10.1039/c7gc01449j
日期:——
Oximes have been identified as a reusable template for the synthesis of ureas and carbamates by an in situ generation of carbamoyl oximes under metal-free conditions. The recycled oxime has been carried out for three trials in the synthesis of urea derivatives without any loss in the yield and efficiency. In addition, this template approach could override the usage of hazardous and less stable isocyanates
A Facile Method for the Preparation of Unsymmetrical Ureas Utilizing Zirconium(IV) Chloride
作者:Anna Lee、Hee-Kwon Kim、David H. Thompson
DOI:10.1002/bkcs.10646
日期:2016.2
ureas from amines is described. Carbamoyl imidazole compounds were prepared by the reaction of 1,1‐carbonyldiimidazole with primary or secondary amines, and further activation by treatment with zirconium(IV) chloride to generate the desired urea. This reaction protocol was applied to the synthesis of tri and tetrasubstituted ureas with high yields. This study provides an alternative guideline for the
(TFE) promoted synthesis of unsymmetric ureas was described. This approach enabled the construction of a variety of ureas from the readily prepared and easy-to-handle dioxazolones and amines viatandem Lossen rearrangement/condensation process. The reaction featured mild conditions for the urea synthesis under metal-free conditions, which was successively applied in the scale-up synthesis of herbicides
Catalyst‐Free Electrosynthesis of Benzimidazolones through Intramolecular Oxidative C−N Coupling
作者:Jiang‐Sheng Li、Pan‐Pan Yang、Xin‐Yun Xie、Si Jiang、Li Tao、Zhi‐Wei Li、Cui‐Hong Lu、Wei‐Dong Liu
DOI:10.1002/adsc.202000198
日期:2020.5.12
The electrochemicalsynthesis of N, N’‐disubstituted benzimidazolones from ureas through an intramolecular anodic dehydrogenative N−H/C−H coupling has been developed. The reaction undergoes under the undivided electrolysis conditions and obviates the need for any catalysts and chemical oxidants.