Synthesis and antimicrobial study of b is-[thiadiazol-2-yl- tetrahydro-2H-pyrazolo[3,4-d][1,3]thiazole]methanes

A new series of B is-[thiadiazol-2-yl-tetrahydro-2H-pyrazolo[3,4-d][1,3]thiazole]methanes 7a-h has been synthesized by the reaction of arylidine derivative 6 with aryl/alkyl hydrazines. Chemical structures of all the new compounds were established by IR, 1H, 13C NMR, MS and elemental data. The compounds 7a-h were evaluated for their antibacterial activity against Gram-positive bacteria viz. Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538p) and Micrococcus luteus (IFC 12708), and Gram-negative bacteria viz. Proteus vulgaris (ATCC 3851), Salmonella typhimu um (ATCC 14028) and Escherichia coli (ATCC 25922). Amongst them, compounds containing N-(4-methoxyphenyl)pyrazole moiety 7c, N-(3-fluorophenyl)pyrazole moiety 7e and N-methylpyrazole moiety 7h showed significant antibacterial activity, almost equal to the activity of the standard drug Ampicillin. Further, these compounds 7a-h were screened for their antifungal activity against Candida albicans (ATCC 10231), Aspergillus fumigatus (HIC 6094), Trichophyton rubrum (IFO 9185) and Trichophyton mentagrophytes (IFO 40996). Most of these new compounds showed appreciable activity against the test fungi, and emerged as potential molecules for further development.