Heterocyclic rearrangements: rearrangement of N-(1,2,4-oxadiazol-3-yl)-β-anamino ketones into pyrimidine N-oxides

The behaviour of N-(5-R-1,2,4-oxadiazol-3-yl)-β-enamino ketones towards rearrangement has been investigated. In the presence of anionic reagents in ethanol solution, they rearrange to pyrimidine N-oxides. The synthesis and hydrolytic ring opening of a [1,2,4]oxadiazolo[2,3-a]pyrimidinium system is also reported.