Synthesis of ureas in the bio-alternative solvent Cyrene
作者:Liam Mistry、Kopano Mapesa、Thomas W. Bousfield、Jason E. Camp
DOI:10.1039/c7gc00908a
日期:——
Cyrene as a bio-alternative solvent: a highly efficient, waste minimizing protocol for the synthesis of ureas from isocyanates and secondary amines in the bio-available solvent Cyrene is reported. This method eliminated the use of toxic solvents, such as DMF, and established a simple work-up procedure for removal of the Cyrene, which led to a 28-fold increase in molar efficiency versus industrial standard
Visible-light-promoted oxidative desulphurisation: a strategy for the preparation of unsymmetrical ureas from isothiocyanates and amines using molecular oxygen
作者:Ziyu Gan、Guoqing Li、Qiuli Yan、Weiseng Deng、Yuan-Ye Jiang、Daoshan Yang
DOI:10.1039/d0gc00070a
日期:——
A green and efficient visible-light promoted oxidative desulphurisation protocol has been proposed for the construction of unsymmetrical ureas under mild conditions with broad substrate scope and good functional group tolerance. Most appealingly, the reaction can proceed smoothly without adding any strong oxidants. Control experiments and computational studies support a mechanism involving water-assisted
Synthesis of Unsymmetrical Urea Derivatives via Cu‐Catalyzed Reaction of Acylazide and Secondary Amine
作者:Jivan Shinde、Prakash Bhimrao Patil、Veerababurao Kavala、Ching‐Fa Yao
DOI:10.1002/cbdv.202200346
日期:2022.8
The synthesis of unsymmetricalurea generally requires toxic reagent, solvent and harsh reaction condition. Herein, we introduce Cu-catalyzed greener and safer unsymmetricalurea derivatives synthesis in ethyl acetate. This method minimized utilization of toxic reagent. A variety of indole, amines, and azides with bis-indole successfully employed leading to high yields and gram scale synthesis of isolated
Amine-Induced Selective C–C Bond Cleavage of 2,2,2-Trifluoroethyl Carbonyls for the Synthesis of Ureas and Amides
作者:Kuantao Mao、Leiyang Lv、Zhiping Li
DOI:10.1021/acs.joc.3c00979
日期:2023.7.21
An efficient and selective transformation of 2,2,2-trifluoroethyl carbonyls into ureas/amides with amines is reported. This protocol allows the selective cleavage of the C–C bond of 2,2,2-trifluoroethyl carbonyls undertransitionmetal-free and oxidant-free conditions, which is in contrast to the analogous C–F or C–CF3 bond functionalization. This reaction reveals the unexplored reactivity of 2,2,2-trifluoroethyl
Treatment of widely available isocyanates with monohalolithium and dihalolithium carbenoids provides a valuable protocol for the one-pot preparation of -halo- and ,-dihaloacetamide derivatives. While monohalolithium carbenoids can be prepared by a smooth lithium-halogen exchange, the preparation of the corresponding dihalo compounds proved to be highly dependent on the base used to realize the deprotonation, with lithium 2,2,6,6-tetramethylpiperidine emerging as optimal. The clear advantages of the procedure are: (a) broad scope of isocyanates that can be employed; (b) preservation of the optical purity when chiral materials are used; (c) divergent access to different haloamides by simply selecting the homologating agents. We also report an application of Charette's imidoyl triflate activation of a secondary amide to the synthesis of an -chloro ketone and N-15 NMR data for selected compounds.