A ligand-free copper catalyzed approach has been developed to the synthesis of 3,4,5-triaryl-1,2,4-triazoles and 2,5-diaryl-1,3,4-oxadiazoles by the direct arylation of corresponding 3,4-diaryl-1,2,4-triazoles and 2-aryl-1,3,4-oxadiazoles with aryl iodides using PEG-400 as reaction medium. The procedure is experimentally simple and free from addition of external chelating ligands or co-catalysts.
A facile and highly efficient synthesis of 3,4,5-trisubstituted 1,2,4-triazoles and 3,5-disubstituted 1,2,4-oxadiazoles from 2,2,2-trichloroethyl imidates using PEG as a solvent and employing PTSA as the catalyst under mild conditions is described.
A general and practicalmethod for the construction of various 3,4,5-trisubstituted 1,2,4-triazoles via I2-catalyzed cycloaddition of N-functionalized amidines with hydrazones is reported. This strategy features cheap and readily available catalyst and starting materials, broader substrate scope, and moderate-to-good yields. The mechanism study shows that the existence of hydrogen on the nitrogen of
报道了一种通过 I 2催化N官能化脒与腙的环加成反应构建各种 3,4,5-三取代 1,2,4-三唑的通用且实用的方法。该策略的特点是廉价且易于获得的催化剂和起始材料、更广泛的底物范围以及中等至良好的产率。机理研究表明,腙氮上氢的存在对于这种转变至关重要。