Synthesis, Spectroscopic Characterization and Antimicrobial Activity of Some New 2-Substituted Imidazole Derivatives

Abstract

The reaction of imidazole-2-thione derivative 1 with 2-chloro- N - p -tolylacetamide afforded the corresponding 2-(1 HI -imidazol-2-ylthio)- N - p -tolylacetamide 2. Reaction compound 2 with different reagents such as p -chlorobenzaldehyde and p -chlorophenyl diazonium chloride afforded the corresponding arylidene derivative 3 and hydrazone derivative 6. Reactions of 2 with carbon disulfide in dimethylformamide (DMF) in one equivalent potassium hydroxide afforded intermediate potassium sulphide salt 8, which treatment with dilute hydrochloric acid and phenacyl bromide afforded the corresponding 2-[ p -tolylcarbamoyl]ethanedithioic acid 9 and 3-[benzo-ylmethylthio]- N - p -tolyl-3-thioxo-propaneamide 10. While the reaction 2 with carbon disulphide in the presence of two equivalent potassium hydroxide in DMF gave non-isolated potassium salt 11, which was allowed to react with halogenated compounds namely ethyl chloroacetate and methyl iodide afforded the corresponding 3, 3-bis[(ethoxycarbonyl)methylthio]- N - p -tolylacrylamide 12 and 3,3-bis-(methylthio)- N - p -tolylacrylamide 13 respectively. Reaction 2 with phenyl isothiocyanate in basic DMF yielded the intermediate potassium sulphide salt 18. Acidification 18 with dilute hydro-chloric acid afforded the corresponding thiocarbamoyl derivative 19. Treatment of intermediate 18 with methyl iodide, phenacyl bromide and ethylchloroacetate afforded the 3-anilino-3-(methylthio)- N - p -tolylacrylamide 20, 2-(1,3-thiazol-2(3H)-ylidene)- N - p -tolylacetamide 21 and 2-(4-oxo-3-phenyl-1,3-thiazolidin-2-ylidene)- N - p -tolylacetamide 22 respectively. The structure of the newly synthesized compounds has been confirmed by elemental analysis and spectra data. Synthesized compounds 2, 3, 6, 13, 15a, 15b, 17, 20, 21, 22 and 23 were screened for their antibacterial activities in vitro against Gram-positive ( Staphylococcus aureus and Bacillus subtilis ), Gram-negative ( Pseudomonas aeuroginosa and Escherichia coli ) and antifungal activities against ( Aspergillus fumigates , Syncephalastrum racemosum , Geotrichum candidum and Candida albicans ).