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。
The first one-pot ambient-temperature synthesis of 1,2,4-oxadiazoles from amidoximes and carboxylic acid esters
作者:Sergey Baykov、Tatyana Sharonova、Anton Shetnev、Sergey Rozhkov、Stanislav Kalinin、Alexey V. Smirnov
DOI:10.1016/j.tet.2017.01.007
日期:2017.2
The first one-pot room-temperature protocol for the synthesis of 3,5-disubstituted-1,2,4-oxadiazoles via the condensation between amidoximes and carboxylic acid esters in superbase medium MOH/DMSO is reported. A broad spectrum of alkyl, aryl and hetaryl amidoximes and esters was examined. This reaction route provides convenient access to 1,2,4-oxadiazoles, which is highly desirable because in the light
Synthesis of 1,2,4-Oxadiazoles via DDQ-Mediated Oxidative Cyclization of Amidoximes
作者:Joshua Pierce、Patrick Parker
DOI:10.1055/s-0035-1561597
日期:——
cyclization of amidoximes to form 1,2,4-oxadiazoles, mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), is described. A range of alkyl, aryl, and heteroaryl substrates are tolerated under these conditions. This reaction serves as an alternate approach for the synthesis of functionally diverse oxadiazoles via a rapid and straightforward synthetic procedure. An oxidative cyclization of amidoximes to form
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...