Synthesis and antitubercular activity of substituted novel pyrazoline derivatives

Abstract

A series of 2-2-methoxy-4-[5-(substituted phenyl)1-(4-pyridylcarbonyl)-4,5-dihydro-1H-3-pyrazolyl] phenoxyacetic acid were synthesized by the reaction between isoniazid (INH) and chalcones, and were tested for their antimycobacterial activity in vitro against Mycobacterium tuberculosis H₃₇Rv and INH resistant M. tuberculosis using BACTEC-460 radiometric system and agar dilution method. Among the synthesized compounds, Compounds II 2-4-[5-(4-hydroxyphenyl)-1-(4-pyridylcarbonyl)-4,5-ihydro-1H-3-pyrazolyl]-2-methoxy phenoxy acetic acid was found to be most active agent against M. tuberculosis H₃₇Rv (MTB) and INH resistant M. tuberculosis (INHR-MTB), with minimum inhibitory concentration of 0.12 µM, when compared to INH 5.6-fold more active against MTB and 78-fold more active against INHR-MTB, respectively.

Keywords:

• Mycobacterium tuberculosis H₃₇Rv (MTB)
• INH resistant Mycobacterium tuberculosis (INHR-MTB)
• Isoniazid