Synthesis, characterization and In vitro antimicrobial evaluation of novel pyrazolothiazol-4(5H)-one derivatives
Department of Pharmaceutical Chemistry, Bharati Vidyapeeth's College of Pharmacy, Belapur, Navi Mumbai-400614, India
Priyanka L Gaikwad Department of Pharmaceutical Chemistry, Bharati Vidyapeeth's College of Pharmacy, Belapur, Navi Mumbai-400614 India E-mail: [email protected]
Antimicrobial screening of several novel pyrazolothiazol-4(5H)-one derivatives (3a-3j) has been performed. Reaction of aromatic aldehydes with aromatic ketones yielded starting chalcones (1a-1j) which have been subsequently reacted with thiosemicarbazide for obtaining N-thiocarbamoylpyrazole derivatives (2a-2j). These were further cyclized to pyrazolothiazol-4(5H)-one derivatives (3a-3j) in the presence of ethylbromoacetate. The structures of newly synthesized compounds were confirmed by FTIR and 1 H NMR and/or MS. The in vitro antimicrobial activity of these compounds was evaluated against Gram positive bacteria, Gram negative bacteria and fungi. Their minimum inhibitory concentration was determined by tube dilution method. The results showed that most of the compounds have promising antimicrobial activity as compared to standard drugs. Among the test compounds, 2-[5(4-chlorophenyl)-3-phenyl-4,5-dihydropyrazol-1-yl]-thiazol-4(5H)-one (3e) was found to show the most potent antimicrobial activity.