Synthesis, structural activity relationship and anti-tubercular activity of novel pyrazoline derivatives

In the present investigation, a series of 5-(-4-(substituted) phenyl)-3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolyl-2-toluidino methane thione and 5-(substituted) phenyl-3-(4-hydroxy-3-methylphenyl)-4,5-dihydro-1H-1-pyrazolyl-2-methoxyanilino methane thione were synthesized by the reaction between hydrazine hydrate and chalcones (3a-k) followed by condensation with appropriate aryl isothiocyanate which yielded N-substituted pyrazoline derivatives. Newly synthesized compounds were tested for their in vitro anti-tubercular activity against Mycobacterium tuberculosis H37Rv using the BACTEC 460 radiometric system. Among the synthesized compounds, compound anilino-3-(4-hydroxy-3-methylphenyl)-5-(2,6-dichlorophenyl)-4,5-dihydro-1H-1-pyrazolylmethanethione (6i) was found to be more active agent against M. tuberculosis H37Rv with minimum inhibitory concentration of 0.0034 microM.