Abstract
The reaction of pyrazole-3-carbohydrazide (1) or 1,2,3-triazole-4carbohydrazides 5a,b and 2-(ethoxymethylene)malononitrile (2) in ethanol under reflux conditions afforded the corresponding N,N'-diacylhydrazines 3 or 6a,b, respectively in high yields. Ring closure of 3 or 6a,b in the presence of phosphorus oxychloride furnished the corresponding 2,5-bis(heterocyclic)-1,3,4-oxadiazoles 4 or 7a,b, respectively in good yields. The synthesized heterocyclic compounds showed moderate activity against Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli.