Synthesis and reactions of 1,2,4-oxadiazole derivatives of expected biological activity

An increasing interest in the chemistry of hydrazones appears because of their biological activities. Also, it was reported that oxadiazole derivatives possess herbicidal activity. This induced the authors to synthesise some derivatives of 1,2,4-Oxadiazole for the biological study. 5-Chloro-3-phenyl-l,2,4-oxadiazole [I] reacted with hydrazine hydrate, with ethyl glycinate and with anthranilic acids to yield 5-hydrazino-3-phenyl-1,2,4-Oxadiazole [II], ethyl 2<3-phenyl-l?2?4-oxadiazol-5-yl]-glycinate [III] and 5-[2-carboxyanilino]-3-phenyl-l,2,4-oxadiazoIe [IV], respectively. The IR spectra of compounds [IV] show absorption bands at 3300 cm[-1] [NH], at 1700 cm[-1] [C=O] and at 1620 cm[-1] [C=N]

Synthesis and reactions of some 1,2,4-oxadiazole derivatives for biological evaluation

3-Aryl-l,2,4-oxadiazole-5-thiol [I] reacted with maleic acid and some of its derivatives to give 2-[3-aryl-l,2, 4-oxadiazole-5-yl-thio] succinic acid derivatives [II] and [III]. Compound [la] reacted with benzoquinone to give [IV]. 5-Amino-3-phenyl-l,2,4-oxadiazole [V] reacted with certain acid chlorides to give 5-acylamino derivatives [VI]. Compounds [VIII] were prepared by the reaction of compounds [VII] with some amines. Compound [VHIf] condensed with several aromatic aldehydes to give 5-[p-cinnamoyl-anilino]-3-phenyl-l,2,4-oxadiazole [IX]