A series of novel 3-(substituted)-2-(substituted quinazolinylamino)quinazolin-4(3H)-ones were synthesized by the reaction of 3-(substituted)-2-hydrazino-quinazoline-4(3H)-ones with 2-phenyl-3,1-benzoxazin-4-one. The starting materials 3-(substituted)-2-hydrazino-quinazolin-4(3H)-ones were synthesized from various primary amines by a multistep synthesis. All the title compounds were tested for their antibacterial activity using ciprofloxacin as reference standard. Compounds 3-(4-fluorophenyl)-2-(4-oxo-2-phenylquinazolin-3(4H)-ylamino)quinazolin-4(3H)-one (9a) and 3-(4-chlorophenyl)-2-(4-oxo-2-phenylquinazolin-3(4H)-ylamino)quinazolin-4(3H)-one (9h) emerged as the most active compounds of the series. These compounds have shown most potent antibacterial activity against the tested organisms of Proteus vulgaris and Bacillus subtilis having zone of inhibition values of 1.1 cm and 1.4 cm for compound 9a 1.2 cm and 1.0 cm for compound 9h, respectively.
A new series of 1-(4-oxo-3-(4-fluorophenyl)-3H-quinazolin-2-yl)-4-(substituted) thiosemicarbazides (AR1-AR10) were obtained by the reaction of 2-hydrazino-3-(4-fluorophenyl) quinazolin-4(3H)-one (6) with different dithiocarbamic acid methyl ester derivatives. The key intermediate 3-(4-fluorophenyl)-2-thioxo-2,3-dihydro-1H-quinazolin-4-one (4) was obtained by reacting 4-fluoroaniline (1) with carbon disulphide and sodium hydroxide in dimethyl sulphoxide to give sodium dithiocarbamate, which was methylated with dimethyl sulfate to yield the dithiocarbamic acid methyl ester (2) and condensed with methyl anthranilate (3) in ethanol yielded the desired compound (4) via the thiourea intermediate. The SH group of compound (4) was methylated for the favorable nucleophilic displacement reaction with hydrazine hydrate, which afford 2-hydrazino-3-(4-fluorophenyl)-3H-quinazolin-4-one (6). All synthesized compounds (AR1-AR10) were also screened for their antimicrobial activity against selective gram positive and gram negative by agar dilution method. In the present study compounds AR8 and AR9 were emerged as the most active compounds of the series.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.