SYNTHESIS OF MANNICH BASES OF NORFLOXACIN: CONVENTIONAL AND MICROWAVE ASSISTED SYNTHESISAbstract
Quinolones are the organic compounds that act against the DNA-gyrase enzyme, a type II topoisomerase. Norfloxacin is one such quinolone which is characterized by a piperazinemoiety at C-7 position. This moiety plays a significant role in determining the antibacterial spectrum and potency and serves as a site amenable to significant modification. N-Mannich bases have proved to be potential prodrug candidates for amides, urea derivatives, imides and amines. It has proved to be a versatile base in current applications of organic chemistry. Mannich bases with N-4 substituted piperazine containing moieties were biologically active. We designed and synthesized new series of Mannich bases of Norfloxacin by conventional as well as microwave method by reacting them with isatin and various aromatic aldehydes. Their chemical structures have been confirmed by IR, 1H NMR and 13C NMR spectroscopy and evaluated for antibacterial activity by Agar well diffusion method. Antimicrobial evaluation was done against gram positive bacteria B. subtilis and gram negative bacteria E. coli. Among the compounds tested, 7a (i) and 7b (i) showed promising activity.
D. M. Gangrade * and N. N. Waghmare
Department of Pharmaceutical Chemistry, Oriental College of Pharmacy, Sanpada (West), Navi Mumbai, Maharashtra, India.
25 March, 2018
16 July, 2018
25 July, 2018
01 December, 2018