Synthesis and Biological activity of new hydrazon\Oxadiazole derivatives based on 2-Indole Carboxylic acid

Al- Masoudi, Hanan Q.

	Synthesis and Biological activity of new hydrazon\Oxadiazole derivatives based on 2-Indole Carboxylic acid
Al-Zahraa Journal for Health and Medical Sciences
Volume 4, Issue 1, March 2026, Pages 88-107 PDF (1.88 M)
Document Type: Research Article
Author
Hanan Q. Al- Masoudi^*
Department of Chemistry, College of Education for Pure Sciences, Unversity of Kerbala, Iraq
Abstract
Abstract A two-step reaction procedure was used to develop and synthesis a three of new oxadiazole derivatives that have a 2-indole carboxylate scaffold. Initially, 5-Bromo indole-2-carbohydrazide were condensed with three different heteroaromatic aldehydes (furan-2-carbaldehyde, 5-methylfuran-2-carbaldehyde, and oxazole-2-carbaldehyde), to produce the required hydrazone intermediate (Hn1, Hn2, and Hn3). Following cyclization in DMSO with iodine and potassium carbonate, the desired 1,3,4-oxadiazole derivatives (CHn1, CHn2, and CHn3), were produced in high yield. The synthesized derivatives were characterized and their structures were confirmed using FT-IR, 1H NMR, and 13C NMR techniques. The antibacterial activity of the produced compounds was tested on a panel of Gram-positive and Gram-negative bacterial strains using the agar diffusion technique. The results showed that oxadiazole derivatives had much higher antibacterial activity than their comparable hydrazone predecessors. The synthesized compounds showed significant antibacterial effect was observed against Escherichia coli and Pseudomonas aeruginosa , Proteus, Klebsiella pneumoniae and Staphylococcus aureus), with the CHn series showing improved efficacy compared to Hn analogs; notably, CHn3 showed the highest broad-spectrum activity, and in some cases was comparable to or exceeding that of amoxicillin.
Keywords
Pseudomonas aeruginosa; Proteus; Klebsiella pneumoniae; hydrazone; indole

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