Antimicrobial activities of some synthesized 1-(3-(2-methylphenyl)-4-Oxo-3H-quinazolin-2-yl-4-(substituted)thiosemicarbazide derivatives

Abstract

The substituted thiosemicarbazide moiety was placed at the C-2 position and 2-methylphenyl group at N-3 position of quinazoline ring and obtained compounds were tested for their antitubercular activities and antibacterial activities against selected gram-positive and gram-negative bacteria. The target compounds 1-(3-(2-methylphenyl)-4-oxo-3H-quinazolin-2-yl)-4-(substituted) thiosemicarbazides were obtained by the reaction of 2-hydrazino-3-(2-methylphenyl) quinazolin-4(3H)-one with different dithiocarbamic acid methyl ester derivatives. All synthesized compounds were also screened for their antimicrobial activity against selective gram-positive and gram-negative bacteria by agar dilution method. Among the series, 1-[3-(2-methylphenyl)-4-oxo-3H-quinazolin-2-yl]-4-[4-chlorophenyl]-thiosemicarbazide exhibited the most potent activity against S. typhi, E. coli, and B. subtilis, while 1-[3-(2-methylphenyl)-4-oxo-3H-quinazolin-2-yl]-4-[4-nitrophenyl]-thiosemicarbazide was the most potent against E. coli, B. subtilis, P. aeruginosa, S. typhi, and S. flexneri. These two compounds exhibited the antitubercular activity at the minimum concentration (3 μg/mL) that offered potential for further optimization and development of new antitubercular agents. The obtained results demonstrated promising antimicrobial and antitubercular activities of the synthesized quinazoline compounds which could be used as new scaffolds for improving their antimicrobial activity.