Synthesis of 4(5)-substituted 2-amino-5(4)-hydroxyimino-5(4)H-imidazoles and their transformation into the corresponding 3-substituted 5-amino-1,2,4-oxadiazoles

Treatment of 4(5)-phenyl(or alkyl)-2-aminoimidazoles with isoamyl nitrite in acetic acid afforded the corresponding 4(5)-substituted 2-amino-5(4)-hydroxyimino-5(4)H-imidazoles which by heating in water were transformed into 3-benzoyl(or acyl)-5-amino-1,2,4-oxadiazoles.