Synthesis, Characterization, and Antimicrobial Evaluation for New Azo-linked Derivative of Heterocyclic Compounds

Abstract

Objectives: Using different activated heterocyclic amines to prepare diazonium salts to be coupled with ornidazole (heterocyclic agent) to form the azo linkage compounds (A1, A2) as possible antimicrobial agent.

Methods: The synthetic process involves the preparation of diazonium salts by diazotization reaction of sulfamethoxazole and 5-amino-1,3,4-thiadiazole-2-thiol that contain primary amino groups with (HNO2) acid in the presence of HCl at about 0 oC. Then, azo compounds (A1, A2) were synthesized, by the reaction of nitroimidazole derivative (ornidazole) with the prepared diazonium salts at 0-5 oC, and the chemical structure of these compounds were characterized and confirmed by measuring its Fourier Transform Infrared (FT-IR) spectrum and Proton Nuclear Magnetic Resonance (H1-NMR) spectrum.                    

Results: Thin layer chromatography and melting point measurements were used to establish the product’s purity. This compound was tested for antimicrobial activity using the broth microdilution spectrometric method on five different strains of bacteria and one strain of fungi, as well as the BACTEC MGIT 960 system for mycobacterium tuberculosis bacilli.

Conclusion: Using levofloxacin and nystatin as reference drugs, the compounds (A1, A2) showed moderate to good action against tested gram-positive and gram-negative bacteria, and fungi, but no activity against mycobacterium tuberculosis.