Preparation of sydnone-4-carboxamide oximes and their conversion into 4-(1,2,4-oxadiazol-3-yl)sydnones.

3-Arylsydnone-4-carboxamide oximes (2) were prepared from the corresponding 3-arylsydnone-4-carbonitriles and hydroxylamine in high yields. The amide oximes 2 reacted with orthoesters to give 3-aryl-4-(1,2,4-oxadiazol-3-yl)sydnones.