omethyleneoxazol-5(4H)-ones 2, followed by opening into 2-aroylamino-3-dimethylamino-propenoates 3, and nitrosation to give the oximes 4 as intermediates, which cyclize spontaneously into 5-substituted-1,2,4-oxadiazole-3-carboxylates 5. The compounds 2 can be transformed into 5 without isolation of 3 and 4.
由N-酰基甘
氨酸1合成5取代的1,
1,2,4-恶二唑-3-
羧酸酯5的新方法,在
氯氧化
磷存在下,用
DMF将其转化为2取代的-4-二甲基-
氨基亚甲基
恶唑-5 (4 H)-ones 2,接着打开2-芳酰基
氨基-3-二甲基
氨基-
丙酸酯3,进行亚硝化,得到
肟4作为中间体,
肟自发环化成5-取代的1,2,4,4-恶二唑-3 -
羧酸盐5。化合物2可以转化为5,而无需分离3和4。