SYNTHESIS, TENTATIVE CHARACTERISATION AND ANTIMICROBIAL ACTIVITIES OF 1-ETHYL-2-METHYL-4-NITROIMIDAZOLE-5-THIOL AND ITS DERIVATIVES

B.J. Owolabi, G.E. Okpara, H.C. Ndibe

Abstract


The study is on the synthesis, characterization and antimicrobial activities of 1-ethyl-2-methyl-4-nitroimidazole-5-thiol and its derivatives. 5-chloro-1-ethyl-2-methylimidazole (2) was synthesized by reacting N, N-diethyloxamide (1) with PCl5. Compound (2) was nitrated to yield 5-chloro-1-ethyl-2-methyl-4-nitroimidazole (3). Reaction of (3) with H2S in sodium ethoxide yielded 1-ethyl-2-methyl-4-nitroimidazole-5-thiol (4). The latter was coupled with benzyl chloride to give 1-ethyl-2-..methyl-4-nitroimidazole-5-benzylsulphide (4A) and with acetyl chloride to give 1-ethyl-2-methyl-4-nitroimidazole-5-acetylsulphide (4B). Thin layer chromatography, recrystallization and melting point determination were used to determine the purity of the compounds. Structural elucidation of the synthesized compounds was done by infrared (IR) spectroscopy and gas chromatography-mass spectrometry (GC-MS) analysis. The compounds, 4, 4A, 4B, were screened for their antibacterial activities against Staphylococcus aureus,  Escherichia coli, Pseudomonas aeroginosa and Proteus vulgaris and antifungal activities were carried out against Aspergillus niger, Aspergillus flavus, Candida albicans and Penicillium notatum. Most of the synthesized compounds showed good activities against the tested organisms. Compound 4B exhibited an excellent antibacterial activity against all the tested bacteria species than compounds  4 and 4A. Moreover, compounds 4, 4A and 4B showed comparable antibacterial activity against Pseudomonas aeroginosa when compared with the standard, septrin. Compounds 4, 4A and 4B revealed an excellent antifungal activities against Candida albicans when compared with the standard, penicillin. This presents these synthesized compounds as a lead in the search for medicinally active compounds against these organisms.

Keywords: imidazole, synthesis, antimicrobial, spectroscopy.


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Chemical Society of Nigeria