Synthesis and preliminary pharmacological studies of some 3-substituted 5-amino-1,2,4-oxadiazoles

Treatment of 4(5)-alkyl (or aryl)-2-aminoimidazoles with isoamyl nitrite in acetic acid gave rise to the corresponding 5(4)-substituted 2-amino-4(5)-hydroxyimino-4(5)H-imidazoles which were transformed into 3-acyl (or aroyl)-5-amino-1,2,4-oxadiazoles when treated in aqueous suspension. The results of a preliminary pharmacological investigation showed an interesting depressant activity on the CNS for one of these compounds, 5-amino-3-benzoyl-1,2,4-oxadiazole (III c). The pharmacological activities are correlated with the chemical substitutions on the oxadiazole ring.