- Synthesis and biological evaluation of the thionated antibacterial agent nalidixic acid and its organoruthenium(II) complex
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The thionated derivative of the antibacterial agent nalidixic acid and its organoruthenium complex were prepared, and their crystal structures were determined. The aqueous stability of the complex was studied and, unlike the case for the nalidixicato complex, increased stability of the ruthenium complex in aqueous solution was observed with only a minor degree of thionalidixicato ligand dissociated within 1 week. While the derivatization caused the antibacterial activity of the ligand against E. coli to decrease, the cytotoxicity of the complex against three cancer cell lines was significantly increased and the inhibitory potency against two enzymes of the cathepsin family was increased by 10-fold.
- Hudej, Rosana,Kljun, Jakob,Turk, Boris,Turel, Iztok,Miklavcic, Damijan,Kandioller, Wolfgang,Hartinger, Christian G.,Keppler, Bernhard K.,Repnik, Urska
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- Microwave-assisted and conventional synthesis of novel antimicrobial 1,2,4-triazole derivatives containing nalidixic acid skeleton
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Carbothioamides 4a,b, obtained from nalidixic acid, were converted to the corresponding 1,3-thiazolidine derivatives 5a,b by cyclocondensation with 2-bromo-1-(4-chlorophenyl)ethanone. Treatment of 4a,b with base afforded 1,2,4-triazoles 6a,b. The synthesis of 1,3-oxazolidine 7 was performed by the reaction of compound 4a with ethyl bromoacetate. Treatment of 4a with acid produced 1,3,4-thiadiazole 8. The reaction of compounds 6a and 6b with several heterocyclic amines in the presence of formaldehyde gave the corresponding Mannich bases 9-15 containing various pharmacophore groups. Conventional and microwave-assisted methods were used for the synthesis. The effect of an acid catalyst on Mannich reactions was investigated. The structures of the newly synthesized compounds were elucidated on the basis of 1H NMR, 13C NMR, FTIR, EIMS techniques, and elemental analysis. All compounds were screened for their antimicrobial activity.
- Ceylan, Sule,Bayrak, Hacer,Basoglu Ozdemir, Serap,Uygun, Yildiz,Mermer, Arif,Demirbas, Neslihan,Ulker, Serdar
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- Re-engineering nalidixic acid's chemical scaffold: A step towards the development of novel anti-tubercular and anti-bacterial leads for resistant pathogens
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Occurrence of antibacterial and antimycobacterial resistance stimulated a thrust to discover new drugs for infectious diseases. Herein we report the work on re-engineering nalidixic acid's chemical scaffold for newer leads. Stepwise clubbing of quinoxaline, 1,2,4-triazole/1,3,4-oxadiazole with nalidixic acid yielded better compounds. Compounds were screened against ciprofloxacin resistant bacteria and Mycobacterium tuberculosis H37Rv species. Results were obtained as minimum inhibitory concentration, it was evident that molecule with quinoxaline linked azide as side chain served as antitubercular lead (6.25 μg/ml) whilst molecule with oxadiazole or triazole linked quinoxaline side chain served as anti-bacterial lead. Few compounds were significantly active against Escherichia coli and Proteus vulgaris with MIC less than 0.06 μg/ml and relatively potent than ciprofloxacin. No true compound was potentially active against Salmonella species as compared to amoxicillin.
- Peraman, Ramalingam,Varma, Raghu Veer,Reddy, Y. Padmanabha
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- Novel microwave assisted synthesis and antimicrobial activity of new quinolone-hybrids
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Background: Carbo(thio)amid derivatives 4a, 4b were obtained starting from nalidixic acid in three steps. The acidic treatment of compound 4a generated the corresponding 1,3,4-oxadiazole (5), while the compound 4a gave 1,2,4-triazole derivatives 8a, 8b in basic media. The condensation of 4a with ethyl bromoacetate and 4-chlorophenacyl bromide afforded 1,3-oxazolidine, 6 and 1,3-thiazolidine, 7 derivatives. The synthesis of Mannich bases of 9-15 and 17-19 were achieved from the reaction of 1,2,4- triazoles, 8a, 8b and 1,3,4-oxadiazole, 16, with several heterocyclic amines that has biological activity. Methods: In this article, a series of triazole or 1,3,4-oxadiazole rings containing some novel biologically active quinolone derivatives. Conventional and microwave assisted methods were used for all syntheses. Moreover, the effect of acid catalyst on Mannich reactions was investigated. The structures of newly synthesized compounds were elucidated on the basis of 1H NMR, 13C NMR, FT IR, EI MS techniques and elemental analysis. All these compounds were screened in vitro for their antimicrobial activity against various gram-positive and gram-negative bacterial and fungal strains. Results: This study reports the successful synthesis of some new hybrid compounds starting from nalidixic acid. Two methods containing conventional and microwave assistance with/without catalyst were used to obtain the target compounds. Microwave assistance supplied more efficient way leading the formation of target compounds. Moreover, the effect of acid catalyst on Mannich reactions was investigated. The antimicrobial activity screening studies were also performed in the study. Conclusion: The antimicrobial screening suggests that the compounds containing norfloxacin (9a,b and 17), ciprofloxacin (10a,b and 18) or 7-aminocephalosporanic (12) acid nucleus displayed excellent antimicrobial activity. Moreover, some of them (5-7, 8-13, 15-18) displayed inhibition properties on Escherichia coli (Ec) and Mycobacterium smegmatis (Ms) better from ampicillin or streptomycin with the mic value 0.24 μg/mL.
- Ceylan, Sule,Bayrak, Hacer,Ozdemir, Serap Basoglu,Uygun, Yildiz,Mermer, Arif,Demirbas, Neslihan,Ulker, Serdar
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p. 636 - 651
(2017/01/13)
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- Towards calixarene-based prodrugs: Drug release and antibacterial behaviour of a water-soluble nalidixic acid/calix[4]arene ester adduct
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A water-soluble calixarene-based heterocyclic podand incorporating a quinolone antibiotic subunit, the nalidixic acid, was synthesised and fully characterised. Its prodrug behaviour was assessed in vitro by HPLC, demonstrating the release of the tethered
- Dibama, Hugues Massimba,Clarot, Igor,Fontanay, Stephane,Salem, Adel Ben,Mourer, Maxime,Finance, Chantal,Duval, Raphael E.,Regnouf-de-Vains, Jean-Bernard
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scheme or table
p. 2679 - 2682
(2010/02/28)
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- Synthesis of selected novel covalently linked flavoquinolones
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The synthesis of novel covalently linked flavoquinolones via amide bond is described using mixed anhydride method and their spectroscopic studies have been done by UV/Vis and 1H NMR spectroscopic data. Georg Thieme Verlag Stuttgart.
- Singh, Ram,Geetanjali
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p. 2315 - 2320
(2007/10/03)
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- Synthesis and evaluation of quinoline carboxyguanidines as antidiabetic agents
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The synthesis and in vivo activities of a series of substituted quinoline carboxyguanidines as a possible novel class of antidiabetic agents is described. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Edmont, Dolores,Rocher, Richard,Plisson, Christophe,Chenault, Jacques
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p. 1831 - 1834
(2007/10/03)
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- On the Mechanism of the Alkylation of Quinoline and Naphthyridine Derivatives
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Ethylation studies on substituted 3-ethoxycarbonyl-4-oxo-quinolines and -naphthyridines as well as of the potassium salts of their enolates has revealed that the pathway suggested by Frank et al. for the alkylation of 4-quinolone with (Et3O)PO, i.e., thermal rearrangement of an O- to N-alkyl product cannot be extended to this class of compound since no O-alkylated intermediates could be detected.The mechanism of the alkylation was revised and the site of attack was rationalised using Klopman's theorem and Pearson's HSAB (hard-soft acid-base) theory based on AM1 level semiempirical calculations.Our results suggest a nucleophile enolate intermediate, the alkylation of which can only lead to the N-alkylated product.In accordance with our calculations, the reactive enolates of the title compounds could be selectively transformed into the corresponding N-alkylated products.The selective formation of the N-alkylated product was explained by an analysis of the total charge distribution and frontier orbitals.The conclusions can be generalised for other alkylations.
- Makara, Gergely,Keserue, Gyoergy M.,Kovacs, Attila
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p. 591 - 594
(2007/10/02)
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- Preparation of 1-(lower alkyl)-1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carboxylic acids
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A process for producing a compound of the formula: SPC1 Wherein Z is CH or N; R is a lower alkyl group, a lower alkenyl group, a cycloalkyl group or a hydroxyalkyl group; R1 is a hydrogen atom or lower alkyl group; when Z is N, R2, R3 and R4 are a hydrogen atom, a halogen atom a lower alkyl group, a lower alkoxyl group, a lower hydroxyalkyl group, a lower acyloxyalkyl group, trihalogenoalkyl group, a carboxyl group, a cyano group, or an aralkyl group; when Z is CH, R2, R3 and R4 are a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxyl group, a trihalogenoalkyl group, a cyano group, a nitro group, an alkylmercapto group, a lower alkylenedioxy group, or a lower alkylene bridge attached to the quinoline nucleus, which comprises heating a compound of the formula SPC2 Wherein R, R1, R2, R3, R4 and Z are as defined above, followed, if desired, by hydrolyzing the product obtained, is disclosed. The product is useful as an antibacterial agent. An intermediate having the formula: SPC3 Wherein A is OR or a halogen atom, and R, R1, R2, R3, R4 and Z are as defined above, and a process for its preparation are also disclosed.
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