• Journal of the Korean Chemical Society
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• v.47 no.5
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• pp.530-532
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• 2003

• Journal of Life Science
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• v.13 no.6
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• pp.943-949
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• 2003

New quinolone derivatives of 7-(cis- or trans-3-amino-4-mehtylthiomethylpyrrolidinyl) quinolone-3-carboxylic acids were synthesized by condensation of 7-halo substituted quinolone-3-carboxylic acids with cis- or trans-3-amino-4-mehtylthiomethylpyrrolidine. Some of these compounds showed broad spectra of antibacterial activities against Gram-positive and Gram-negative organisms except Pseudomonas aeruginosa, and exhibited much stronger activity against MRSA.

• YAKHAK HOEJI
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• v.38 no.5
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• pp.520-524
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• 1994

A number of 7-[(3-methylthio or methylthiomethyl)-3-pyrrolinyl] quinolone-3-carboxylic acids were synthesised by condensation of 7-fluoro substituted quinolone-3-carboxylic acid with 3-methylthio-3-pyrroline or 3-methylthiomethyl-3-pyrroline. The in vitro antimicrobial activity of them were tested against twenty species of Gram-positive or Gram-negative microorganisms. It showed remarkable antibacterial activity, particularly against Gram-positive microoganisms. Among those 1-cyclopropyl-6,8-difluoro-7-[(3-methylthiomethyl) -3-pyrrolinyl]-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid(12a) and 1-cycl opropyl-6-fluoro-8-chlore-7-[(3-methylthiomethyl)-3-pyrrolinly]-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid(12b) showed the most potent in vitro antibacterial activity.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.221-221
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• 1994

The cross-coupling reaction of organo tin reagents with a variety of organic halides, catalyzed by palladium, provides a novel method for generating a carbon-carbon bond. We use this method for antibacterial agents, and synthesis of new quinolone derivatives which have carbon-carbon bond at C-7 position of general quinolone moieties. Aryl tin, quinolone moieties, and palladium catalyst were refluxed in DMF to afford new quinolone derivatives. This palladium catalyzed coupling reactions have capacity for further synthetic elaboration.

• YAKHAK HOEJI
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• v.37 no.6
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• pp.615-620
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• 1993

The cross-coupling reaction of organo tin reagents with a variety of organic halides, catalyzed by palladium, provides a novel method for generating a carbon-carbon bond. We used this method for the antibacterial agents, and synthesis of new quinolone derivatives which have carbon-carbon bond at C-7 position of general quinolone moieties. Aryl tin, quinolone moieties, and palladium catalyst were refluxed in DMF to afford new quinolone derivatives. This palladium catalyzed coupling reactions have capacity for further synthetic elaboration.

• YAKHAK HOEJI
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• v.38 no.2
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• pp.197-201
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• 1994

A number of 7-[(3-methylthio or methylthiomethyl)pyrrolidiny]qui nolone-3-carboxylic acids were synthesized by condensation of 7-fluoro substituted quinolone-3-carboxylic acid with 3-methylthiopyrrolidine or 3-methylthiomet hylpyrrolidne. 3-Methylthiopyrrolidine or 3-methylthio-methylpyrrolidine which was prepared from N-benzyl-3-hydroxy pyrrolidine or 3-hydroxymethylpyrrolidine. The in vitro antimicrobial activity of them were tested against twenty species of Gram-positive or Gram-negative microorganisms. It showed remarkable antibacterial activity, particularly against Gram-positive microorganisms. Among those 1-cyclopropyl-6,8-difluoro-7-(3-methylthiomethy-lpyrrolidinyl)-1,4-d ihydro-4-oxo-3-quinolinecarboxylic acid(7d) and 1-cyclopropyl-6- fluoro-8-chloro-7-(3-methylthiomethyl pyrrolidinyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (7f) showed the most potent in vitro antibacterial activity.

• YAKHAK HOEJI
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• v.43 no.4
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• pp.442-446
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• 1999

The synthesis and antimicrobial activity of N-substituted glycyl derivatives of Norfloxacin were described. Norfloxacin was treated with chloroacetyl chloride to yield chloroacetyl norfloxacin (1). This compounds was treated with alkylamines to obtain quinolone carboxylic acids (2-6), which were reacted with pivaloyloxymethyl chloride to get pivaloyloxymethyl quinolone carboxylates (7-11). Free carboxylic quinolones (2-6) showed little stronger activities to their pivaloyloxymethyl esters (7-11). In quinolone analogues, longer alkyl chain compounds showed stronger activities than shorter one.

• YAKHAK HOEJI
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• v.38 no.6
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• pp.664-672
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• 1994

Eighteen new hybrid bivalent ligand quinolones that contain two different type of pharmacophores in a single molecule were prepared and evaluated for in viかo antibacterial activity. Hybrid bivalent ligands p-nitrobenzyloxycarbonyl quinolones were prepared by the treatment of active esters of succinyl fluoroquinolones with 1,7-disubstituted fluoroquinolone carboxylic acids in DMF. Eighteen final quinolone carboxylic acids were obtained by the reduction of compounds $25{\sim}42$ with hydrogen in the presence of 10% Pd-C. Among these derivatives, compound[56] showed the most potent antibacterial activity against a wide range of microoranisms.

• YAKHAK HOEJI
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• v.35 no.6
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• pp.515-521
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• 1991

A number of 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-substitutedcarbamyl-1-piperazinyl) quinoline [or 1,8-naphthyridine]-3-carboxylic acid and their pivaloyloxymethyl esters were prepared. The compounds synthesized were evaluated for antibacterial activity in vitro against Escherichia coli, Bacillus subtilis, Proteus vulgaris, Klebsiella pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa. Among those 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-methylcarbamyl-1-piperazinyl) quinoline-3-carboxylic acid [1] and 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-methylcarbamyl-1-piperazinyl)1,8-naphthyridine-3-carboxylic acid [6] showed the most potent in vitro antibacterial activity.

• BMB Reports
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• v.28 no.5
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• pp.464-470
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• 1995

Quinolone antibiotics are DNA gyrase inhibitors, but their bactericidal action seems to involve more than the inhibition of DNA gyrase activity. Hence, the potentially crucial factors among possible mechanisms of quinolone action; cleavable complex formation, inhibition of DNA synthesis, and induction of SOS response were investigated. These parameters were measured in an Escherichia coli strain exposed to quinolones in the logarithmic growth phase, and correlated with the bactericidal activity of quinolones. Cleavable complex formation proved to be the factor most related to bactericidal action. Inhibition of DNA synthesis was substantially correlated with bactericidal activity, but induction of SOS response was least correlated with bactericidal activity. Therefore, it was concluded that quinolones exert bactericidal action primarily through cleavable complex formation, and subsequent unknown cellular processes together with inhibition of DNA synthesis contribute to the bactericidal activity of quinolones.