Design, synthesis and antimycobacterial activity of various 3-(4-(substitutedsulfonyl)piperazin-1-yl)benzo[d]isoxazole derivatives

Abstract

In this communication, we synthesized a series of twenty four novel 3-(4-(substitutedsulfonyl)piperazin-1-yl)benzo[d]isoxazole analogues, characterized using various spectroscopic techniques and evaluated for their in vitro anti-tubercular activity against Mycobacterium tuberculosis (MTB) H37Rv strain. The titled compounds exhibited Minimum inhibitory concentration (MIC) between 3.125 and >50 μg/mL. Among the tested compounds, 5c, 6a, 6j and 6p exhibited moderate activity (MIC = 12.5 μg/mL), while 5a and 6i exhibited good activity (MIC = 6.25 μg/mL) and 6b (MIC = 3.125 μg/mL) exhibited very good anti-tubercular activity. In addition, the analogues 5a, 5c, 6a, 6b, 6i, 6j and 6p were subjected to toxicity studies against mouse macrophage (RAW 264.7) cell lines to analyse the selectivity profile of the newly synthesized compounds and selectivity index of the most active compound was found to be >130 indicating suitability of the compound for further drug development. Structure of 6b was further substantiated through single crystal XRD.