Synthesis and in-vitro antifungal activity of 6-substituted-phenyl-2- {[(4'-substituted phenyl-5'-thioxo)-1,2,4-triazol-3-yl]-methyl}-2,3,4,5-tetrahydropyridazin-3-one derivatives.

The synthetic pathway for 6-substituted phenyl-2-[{(4'-substituted phenyl-5'-thioxo)-1,2,4-triazol-3-yl}-methyl]-2,3,4,5-tetrahydropyridazin-3-one compounds was achieved by a sequence of reactions starting from respective aryl hydrocarbons and is illustrated in Scheme 1. All the compounds were tested for their in vitro antifungal activity on five fungal species, namely Candida albicans, Trichophyton rubrum, Aspergillus flavus, Aspergillus niger and Penicillium citrinium. The chloro substituent derivative (compound 5g) showed the highest activity against all the fungal species. The MIC of the standard drug voriconazole was between 0.10 - 0.40 microg/mL against all the fungal species except A. fumigatus. The two electronegative groups of Cl were increasing the activity of 1,2,4-triazole. As we increased the bulky group or aromatic group on benzene ring, there was a decrease of activity as in case of compound 1.