Imidazole hydrochloride as an additive promotes the reaction of amidoximes and DMA derivatives to generated 3,5-disubstituted-1,2,4-oxadiazoles in low to excellent yields without the use of coupling reagents, oxidants, strong acids or bases and other additives.
Copper-Catalyzed Direct Synthesis of 1,2,4-Oxadiazoles from Amides and Organic Nitriles by Oxidative N-O Bond Formation
作者:Malleswara Rao Kuram、Woo Gyum Kim、Kyungjae Myung、Sung You Hong
DOI:10.1002/ejoc.201501502
日期:2016.1
Cu-catalyzed one-step method for the synthesis of 1,2,4-oxadiazolesfrom stable, less toxic, and readily available amides and organicnitriles by a rare oxidativeN–Obondformation using O2 as sole oxidant. This method has a broad substrate scope and a good tolerance for diverse functional groups. Moreover, the synthetic utility of this method is highlighted by the synthesis of biologically active 3,5-disubstituted
在此,我们报告了第一个 Cu 催化一步法,通过使用 O2 作为唯一的稀有氧化 N-O 键,从稳定、毒性较低且易于获得的酰胺和有机腈合成 1,2,4-恶二唑。氧化剂。该方法具有广泛的底物范围和对不同官能团的良好耐受性。此外,该方法的合成效用通过具有生物活性的 3,5-二取代衍生物的合成而突出。
A metal-free tandem approach to prepare structurally diverse N-heterocycles: synthesis of 1,2,4-oxadiazoles and pyrimidinones
作者:Puneet K. Gupta、Mohd. Kamil Hussain、Mohd. Asad、Ruchir Kant、Rohit Mahar、Sanjeev K. Shukla、Kanchan Hajela
DOI:10.1039/c4nj00361f
日期:——
N-heterocycles, namely 1,2,4-oxadiazoles and 2,6 disubstituted pyrimidin-4-ones, have been synthesised in one pot via carboxamidation of amidines with aryl carboxylic acids and aryl propargylic acids under metal-free conditions.
Various 3,5-disubstituted-1,2,4-oxadiazoles are smoothly formed via copper-catalyzed cascade annulation of amidines and methylarenes. This tandem oxidation-amination-cyclization transformation represents a straightforward protocol to prepare 1,2,4-oxadiazoles from easily available starting materials, with...
A reaction involving an efficient NBS-mediated oxidative N‒O bond formation has been established for the synthesis of 1,2,4-oxadiazoles from readily accessible N-acyl amidines. The features of this synthetic method include simplicity of operation, mild reaction conditions, short reaction times, high yields, and eco-friendliness. The reaction also works well with crude N-acyl amidines obtained by amidation