Synthesis and in-vitro-antibacterial activity of [5-(furan-2-yl)-phenyl]-4,5-carbothioamide-pyrazolines

Abstract

Cyclization of various different alkoxy [1-[2-(alkoxy)phenyl]-5-(furan-2-yl)-prop-2-en-1-one] chalcone with thiosemicarbazide in the presence of NaOH in ethanol afforded a series of novel 1-N-substituted cyclized pyrazoline analogues [5-(furan-2-yl)-3-[2-(alkoxy) phenyl]-4,5-dihydro-1H-pyrazole-1-carbothioamide 2a–2d. The structures of these compounds were elucidated by IR, 1H NMR, 13C NMR, Fab mass spectrometry and their purities were confirmed by elemental analyses. In vitro antibacterial activity of these compounds were evaluated by the disk diffusion assay and then the minimum inhibitory concentration (MIC) strain of two Gram-positive and two Gram-negative bacteria like Aeromonas hydrophila, Yersinia enterocolitica, Listeria monocytogenes, and Staphylococcus aureus, among all the compounds, alkoxy [5-(furan-2-yl)-2-(benzyloxy)phenyl]-4,5-dihydro-1H-pyrazole-1-carbothioamide 2b and 5-(furan-2-yl)-1-[2-(naphthalen-2-ylmethoxy) phenyl]-4,5-dihydro-1H-pyrazole-1-carbothioamide 2d showed the most promising antibacterial agent when compared to gentamicin and tetracycline.