- An efficient reduction of azide to amine: A new methodology to synthesize ethyl 7-amino-1-ethyl-6,8-difluoroquinolone-3-carboxylate and its spectroscopic characterization
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Most of the quinolone antibacterial research has been focused on the functionality at C-7 position where the nature of substituents is responsible for antibacterial spectrum, potency, bioavailability, and side effects of the quinolones. Then, a 7-amino-fluoroquinolone could be the starting point of a wide variety of potentially useful compounds like tetracyclic and tricyclic quinolones or secondary amines with side chain derivatives. This attracted our attention to synthesize a 7-azide-fluoroquinolone, which could be converted to amine performing a photochemical reaction using CuI as catalyst. FT-IR and H1 NMR spectra of the final product, ethyl 7-amino-1-ethyl-6,8-difluoroquinolone-3-carboxylate, suggests the formation of dimers, a feature already observed in norfloxacin.
- Leyva-Ramos, Socorro,Hernández-López, Hiram,Jiménez-Cata?o, Rogelio,Chacón-García, Luis,Vega-Rodríguez, Sarai
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p. 939 - 947
(2017/05/01)
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- Photochemistry of some non zwitterionic fluoroquinolones
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Two non zwitterionic analogues of fluoroquinolone drugs, viz. 1-ethyl-7-piperidino-8-fluoroquinol-4- one-3-carboxylic acid and 1-ethyl-7-piperidino-6,8-difluoroquinol-4-one-3-carboxylic acids have been synthesized and their photochemistry has been investigated. Both compound undergo photoheterolysis of the C8 F bond generating a triplet cation that either inserts into the 1-alkyl chain or is trapped or reduced by external nucleophiles. The reaction is analogous to that observed with the corresponding (zwitterionic) 7-piperazino derivatives, but the quantum yield is ca five times lower. This supports the rationalization that in the latter case assistance to defluorination by the N+ H bond has a determining role.
- Dichiarante, Valentina,Pretali, Luca,Fasani, Elisa,Albini, Angelo
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- Synthesis and antibacterial evaluation of novel 8-fluoro Norfloxacin derivatives as potential probes for methicillin and vancomycin-resistant Staphylococcus aureus
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A series of novel 8-fluoro Norfloxacin derivatives and the hybrids of its piperazinyl derivatives incorporated with 1,3,5-triazine and pyrimidine were synthesized. All the above compounds were evaluated for their antibacterial activity against Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus and methicillin & vancomycin-resistant S. aureus. Among all, compounds having Morpholine, N-methyl/phenyl/benzyl/pyrimidinyl piperazines and n-butylamine substitution at C-7 position, have shown increased potency in comparison to norfloxacin and ciprofloxacin.
- Sunduru, Naresh,Gupta, Leena,Chauhan, Kuldeep,Mishra, Nripendra N.,Shukla, Praveen K.,Chauhan, Prem M.S.
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experimental part
p. 1232 - 1244
(2011/04/22)
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- Synthesis and in vitro antimicrobial evaluation of novel fluoroquinolone derivatives
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A series of 1-ethyl-6,8-difluoro-4-oxo-7(4-aryl piperazin-1-yl) 1,4-dihydro-quinoline-3-carboxylic acid derivatives (6a-f) and 1-ethyl-6,8-difluoro-4-oxo-7(4-piperidin-1-yl) 1,4-dihydro-quinoline-3- carboxylic acid derivatives (7a-e) were synthesized and evaluated for antibacterial and antifungal activities. The antimicrobial activities of the compounds were assessed by the microbroth dilution technique. The compounds were also evaluated for antifungal activity against Candida albicans (ATCC 90028) and Cryptococcous neoformans (ATCC 14116) pathogens. The preliminary in vitro evaluation studies revealed that some of the compounds have promising antimicrobial activities.
- Srinivasan, Shanmugam,Beema Shafreen, Raja Mohmed,Nithyanand, Paramasivam,Manisankar, Paramasivam,Pandian, Shunmugiah Karutha
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experimental part
p. 6101 - 6105
(2011/01/13)
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- QUINOLONE DERIVATIVE OR SALT THEREOF
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A platelet aggregation inhibitor comprising a quinolone derivative or a pharmaceutically acceptable salt thereof as an active ingredient, and a novel quinolone derivative or a pharmaceutically acceptable salt thereof useful as a platelet aggregation inhibitor.
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Page/Page column 23-24
(2008/06/13)
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- Process for making antimicrobial compounds
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The present invention provides a process for making a compound having a structure according to Formula (I) STR1 wherein A1, A2 and A3 are independently carbon or nitrogen and R1, R3, R4 and R6 are known quinolone substituents; and wherein one of R1, R3 or R6 may be a lactam-containing moiety; or a protected form, salt, pharmaceutically-acceptable salt, biohydrolyzable ester, or solvate thereof; the process comprising reacting one or more organosilicon compounds with a compound having a structure according to Formula (II) STR2 wherein A1, A2 and A3, R1, R3, R4 and R6 as described above; wherein one of R1, R3 or R6 may be a lactam-containing moiety; and X is a leaving group; or a protected form, salt, biohydrolyzable ester, or solvate thereof. The compounds prepared according to the processes of the invention are themselves useful as antimicrobials, or they may be used as intermediates for making other quinolone-containing antimicrobials.
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- Quinolonecarboxylic acids
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The invention relates to novel derivatives of quinolonecarboxylic acid and naphthyridonecarboxylic acid which are linked to a β-lactam antibiotic, to their salts, to processes for their preparation and to antibacterial agents containing these derivatives.
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- 7-(substituted)piperazinyl-1-ethyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids
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7-(substituted)piperazinyl-1-ethyl-6-fluoro-4-oxo-3-quinolinecarboxylic acids, the pharmacologically acceptable salts thereof, compositions containing them, processes and intermediates for producing them, and methods of using them to treat bacterial infections in warm-blooded animals.
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- 1-Substituted 7--1-pyrrolidinyl>-6,8-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic Acids. New Quantitative Structure-Activity Relationships at N1 for the Quinolone Antibacterials
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A series of 18 1-substituted 7--1-pyrrolidinyl>-6,8-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (N1 analogues of CI-934) was synthesized and evaluated for antibacterial activity and DNA-gyrase inhibition.Correlations between the inhibition of DNA gyrase and antibacterial potency were established.A quantitative structure-activity relationship (QSAR) was derived by using the antibacterial potency of each of 11 strains of bacteria and the Gram-negative mean.The equations indicated that antibacterial potency was strongly dependent on STERIMOL length and width and the level of unsaturation of the N1 substituent.Some strains also showed a dependence on the presence of heteroatoms (O, N, S) in the N1 group.No significant correlations between gyrase inhibition and correlations of these parameters were found.These QSAR results are discussed in conjunction with the conformational analyses from molecular modeling studies.The substituent that most enhanced the activity of the quinolone in all regards was the cyclopropyl group.This analogue, 1-cyclopropyl-7--1-pyrrolidinyl>-6,8-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (PD 117558), demonstrated outstanding broad spectrum activity both in vitro and in vivo when compared to relevant standards.
- Domagala, John M.,Heifetz, Carl L.,Hutt, Marland P.,Mich, Thomas F.,Nichols, Jeffry B.,et al.
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p. 991 - 1001
(2007/10/02)
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