Synthesis and Antibacterial Activity of Some Novel 1-(4-Oxo-3-(3- methoxyphenyl)-3H-quinazolin-2-yl)-4-(substituted) thiosemicarbazides

A new series of novel 1-(4-oxo-3-(3-methoxyphenyl)-3H-quinazolin-2-yl)-4-(substituted) thiosemicarbazides were synthesized by the reaction of 2-hydrazino-3-(3-methoxyphenyl) quinazolin-4(3H)-one with various methyl esters of dithiocarbamic acid. When tested for their in vitro antitubercular activity using H37Rv strain on Middle brook 7H11 agar slants with OADC growth supplement, all the test compounds inhibited the growth of Mycobacterium tuberculosis at microgram concentration. Among the test compounds, three compounds 1-(4-oxo-3-(3-methoxy phenyl)-3H-quinazolin-2-yl)-4-(thiazol- 2-yl) thiosemicarbazide (A1), 1-(4-oxo-3-(3-methoxyphenyl)-3H-quinazolin-2-yl)-4-(4-chlorophenyl) thiosemi-carbazide (A6) and 1-(4-oxo-3-(3-methoxyphenyl)-3H-quinazolin-2-yl)-4-(4-nitrophenyl) thiosemicarbazide (A7) were inhibited at the 6 μg/mL concentration. The title compounds are also screened for the antimicrobial activity against some other gram positive and gram negative bacteria by agar dilution method, compounds A6 and A7 were emerged as the most active compounds of the series. Compound A6 showed most potent activity against E. coli, K. pneumoniae and B. subtilis.