Synthesis of Indolizine derivatives and Screeining of Their Antimycobacterial and 15-Lipoxygenase Activity

Abstract

Around one-third of the world s population has been infected with Mycobacterium tuberculosis and 5-10% of those with latent infection are expected to develop clinical tuberculosis (TB). It is the major cause of death in developing countries and there has been an unfortunate resurgence of TB in the industrialized countries. There are about eight million new cases of TB each year, and it has been estimated that about thirty million people will die from tuberculosis in about ten years. Screening of a number of heterocyclic compounds for antimycobacterial activity has resulted in identification of certain indolizine derivatives inhibitors of M. tuberculosis. In this study a number of indolizines were synthesized, their structure elucidated using 1D and 2D NMR techniques, mass spectrometry and elemental analysis. Antimycobacterial activity was determined by the Tuberculosis Antimicrobial Acquisition and Coordinating Facility (TAACF). Most of the synthesized indolizines are found to be active against M. tuberculosis particularly 1-(1-hdroxy-pentyl)-2,3-diphenyl-indolizine-7-carbonitrile 16i, is the most potent indolizine, which showed 100% inhibition at a concentration of 3.3 µg/mL. Some novel indolizines were also tested as inhibitors of 15-lipoxygenase and all of them have, except 35a and 36a, showed better inhibitory activity than quercetin, the well known 15-LO inhibitor. In this study, a one pot synthesis of target compound 26b from 13, with very high yield, developed which otherwise needs multi step synthesis with very low over all yield.