Hypervalent iodine(III) mediated synthesis of novel unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles as antibacterial and antifungal agents.

A series of novel 2,5-disubstituted 1,3,4-oxadiazoles 4 have been conveniently synthesized by oxidative cyclization of pyrazolylaldehyde N-acylhydrazones 3 promoted by iodobenzene diacetate under mild conditions (11 examples, up to 92% isolated yields). All the eleven compounds were tested in vitro for their antibacterial activity against gram-positive bacteria namely, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria namely, Escherichia coli and Pseudomonas aeruginosa. All the synthesized compounds were also tested for their inhibitory action against two strains of fungus. 2010 Elsevier Masson SAS. All rights reserved.