Synthesis, Characterization And Antimicrobial Screening Of New Pyrazolyl-1,2,3-Triazolyl-Thiazolyl-Ethanol Derivatives

Novel 2-{4-[3-aryl-1-phenylpyrazol-4-yl]-1,2,3-triazol-1-yl}-1-(4-methyl-2-aryl-1,3-thiazol-5-yl)ethanol derivatives, (5a-l) are synthesized by applying click reaction between 4-ethynyl-1,3-diphenyl-1H-pyrazole, (2a-c) and 2-azido-1-(4-methyl-2-arylthiazol-5-yl)ethanone (3a-d) followed by reduction of carbonyl with sodiumborohydride. The starting compounds 4-ethynyl-3-aryl-1-phenyl-1H-pyrazole (2a-c) were synthesized in good yield from 3-aryl-1-phenyl-1H-pyrazole-4-carbaldehyde (1a-c) using Bestmann-Ohira reagents.The newly synthesized azole derivatives (5a-l) were screened for in vitro antimicrobial activity against Proteus mirabilis (NCIM2388), Escherichia coli (NCIM2065), Bacillus subtilis (NCIM2063), Staphylococcus albus (NCIM 2178) and in vitro antifungal activity against Candida albicans (NCIM 3100), Aspergillus niger (ATCC 504). 2-{4-[3-(4-Methoxyphenyl)-1-phenylpyrazol-4-yl]-1,2,3-triazol-1-yl}-1-(4-methyl-2-phenyl-1,3-thiazol-5-yl)ethanol, (5a) 2-{4-[3-(4-fluorophenyl)-1-phenylpyrazol-4-yl]-1,2,3-triazol-1-yl}-1-[4-methyl-2-(4-methylphenyl)-1,3-thiazol-5-yl]ethanol, (5 h) 2-{4-[3-(4-bromophenyl)-1-phenylpyrazol-4-yl]-1,2,3-triazol-1-yl}-1-(4-methyl-2-phenyl-1,3-thiazol-5-yl)ethanol, (5i) 2-{4-[3-(4-bromophenyl)-1-phenylpyrazol-4-yl]-1,2,3-triazol-1-yl}-1-[2-(4-chlorophenyl)-4-methyl-1,3-thiazol-5-yl]ethanol (5j) and 2-{4-[3-(4-bromophenyl)-1-phenylpyrazol-4-yl]-1,2,3-triazol-1-yl}-1-[2-(4-fluorophenyl)-4-methyl-1,3-thiazol-5-yl]ethanol, (5k) reportedgoodantifungal activity against A. niger with MIC 31.25-62.5 mu g/mL. Most of the compounds showed moderate activity against bacterial strains. The antifungal activity of pyrazolyl-1,2,3-triazolyl-thiazolylethanol derivatives suggested that these derivatives could lead to compounds for treatment against fungal infection.