Synthesis of new derivatives of quinolone class antibiotics containing thiazole ring

The objective of this study is to obtain new hybrid compounds where the quinolone ring and the triazole or thiazolidinone ring, which are heterocycles known to have biological activity, are combined in a single molecular structure. In this context, 3-alkyl-4- (alkylideneamino)-1H-1,2,4-triazol-5(4H) -one compounds (101a-h, 102a, b) were first synthesized starting from the appropriate nitriles. The synthesis of ethyl 6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate compound (106) was performed starting from 4-fluoroaniline. The treatment of norfloxazine with chloroethanoyl chloride yielded ethyl 7-(4-(2-chloroacetyl)piperazin-1-yl)-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate (108) . However, the desired products could not be obtained from the treatment of triazole compounds (101a-h, 102a, b) with the quinolone 106. Similarly, the same intermediates did not react with compound 108. The new thia(oxa)zolidinone-quinolone hybrid compounds were obtained by treatment of quinolones 106 with hydrazine hydrate and appropriate alkyl iso(thio)cyanates, followed by ring closure of the side chain. All experiments were performed using microwave and ultrasound irradiation techniques in addition to the traditional method, and it was observed that the microwave assisted method was superior to the other two methods in terms of reaction yields and time. The structures of all new compounds synthesized were illuminated using FT-IR, NMR, Mass spectroscopic techniques. Its antibacterial properties were investigated in KTU Faculty of Medicine Microbiology Department by Prof. Ali Osman Kılıç and his Group.