Discovery of new antitubercular oxazolyl thiosemicarbazones

Twenty 4-( 5-cyclobutyloxazol-2-yl) thiosemicarbazones were synthesized and evaluated for preliminary in vitro and in vivo activity against Mycobacterium tuberculosis H37Rv ( MTB) and multidrug-resistant Mycobacterium tuberculosis ( MDR-TB). Among them, ( 4-bromophenyl)( phenyl) methanone N-( 5-cyclobutyl-1,3-oxazol-2-yl)thiosemicarbazone 6q was found to be the most active compound in vitro with minimum inhibitory concentration of 0.05 mu g/mL against MTB and MDR-TB. In the in vivo animal model 6q decreased the bacterial load in lung and spleen tissues with 2.1 log 10 and 3.72 log 10 protections, respectively, at 50 mg/kg body weight dose.