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
Unsymmetrical tetrasubstituted ureas from tertiary carbamoylimidazole: activation by AlMe3
作者:A. Velavan、S. Sumathi、K. K. Balasubramanian
DOI:10.1039/c2ob25412c
日期:——
An efficient and general method for the synthesis of unsymmetricaltetrasubstitutedureas from carbamoylimidazole is described. The conversion is achieved by the concurrent quarternization of the imidazole nitrogen and activation of amines with AlMe3.
α-Arylation of Cyclic Amines by Aryl Transfer in Lithiated Ureas
作者:Jonathan Clayden、Renaud Bach、Ulrich Hennecke
DOI:10.1055/s-0028-1087543
日期:2009.2
Treatment with base of N′-aryl urea derivatives of het-ero- or carbocyclic amines with benzylic nitrogen atoms promotes rearrangement with transfer of the arylring from N to C, giving rise to α-arylated products.
用含苄基氮原子的杂-或碳环胺的 N'-芳基脲衍生物的碱处理促进重排,芳环从 N 转移到 C,产生 α-芳基化产物。
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
Iron(II)-Catalyzed Oxidation of sp<sup>3</sup> C−H Bonds Adjacent to a Nitrogen Atom of Unprotected Arylureas with <i>tert</i>-Butyl Hydroperoxide in Water
With a FeSO4/TBHP system in water, direct oxidation of sp3 C−Hbondsadjacent to nitrogen of arylureas to give both unprecedented tert-butoxylated and hydroxylated products 2 was revealed. Under elevated temperatures, either 2-oxo-N-arylpyrrolidine-1-carboxamides 3 or 1,3-diarylureas 4 were attained, depending on the aliphatic ring size of the arylurea substrates.