Synthesis, antibacterial and antioxidant activities of new 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides

Gram‐negative pathogens represent a significant global health threat, while the emergency and widespread of drug resistance make the situation even worse. As “privileged building blocks,” 4‐quinolones including fluoroquinolones are mainstays of chemotherapy against various bacterial infections. However, as other antibiotics, the resistance of Gram‐negative bacteria to 4‐quinolones develops rapidly and spreads widely throughout the world. To overcome the resistance and improve the potency, a number of 4‐quinolone derivatives were designed, synthesized, and screened for their in vitro and in vivo activities against representative Gram‐negative pathogens. This review aims to summarize the recent advances made towards the discovery of 4‐quinolone derivatives as anti‐Gram‐negative agents as well as their structure–activity relationship. The enriched structure–activity relationship paves the way to the further rational development of 4‐quinolones with excellent potency against both drug‐susceptible and drug‐resistant Gram‐negative pathogens.

Section: Structure–activity Relationshipmentioning

confidence: 99%

4‐Quinolone Derivatives and Their Activities Against Gram‐negative Pathogens

Jiang

2018

“…Azaflavones and diazaflavones are analogues of flavones with an annular nitrogen atom in the phenyl ring . Over the last 30 years, N ‐alkylpyridinum salts of many compounds that comprise the azaflavone have been synthesized by several researchers and shown to have antibacterial, antimicrobial, antituberculostatic, and anti‐inflammatory activities . N ‐Alkylpyridinium salts also have many other usage such as being phase transfer catalysts, acylating agents, potential solvents in synthesis, biocides, dyes, and cationic surfactants.…”

Section: Introductionmentioning

confidence: 99%

“…The classical methods for synthesizing N ‐alkylpyridinium salts were given in the literature . Recently, a 1,4‐diazaflavone compound was synthesized by a simple solid‐phase microwave‐assisted method with the cyclization of 2‐amino ( E )‐4‐aza‐chalcone .…”

Section: Introductionmentioning

confidence: 99%

Naked Eye Detection of Carbonate, Hydroxide, and Cyanide Ions with 1,4′‐Diazaflavonium Bromides: A Simple Spectrophotometric Method for Cyanide Determination

Kahriman

Gün

Gümrükçüoğlu

et al. 2019

Self Cite

Anion sensor properties of N‐alkyl‐substituted 1,4′‐diazaflavonium bromides in methanol–water were evaluated by UV–vis spectrometry. Pronounced changes were observed in the absorption spectra of all compounds for only OH−, CO32−, and CN− among F−, Cl−, Br−, I−, OH−, CO32−, NO3−, PO43−, CN−, SO42−, HSO4−, HCO3−, SCN−, NO2−, and P2O72− ions. Two new absorption bands at 385 and 685 nm accompanying the distinct color change for OH−, CO32−, and CN− ions were observed in case of all compounds. The color changes were from pink to blue for CO32− and OH− ions and from pink to purple for CN− ion. Thanks to the distinct color change, the compounds can be used as selective colorimetric anion sensors. Linear changes of absorbance of N‐heptyl‐substituted compound at 385 nm as a function of the ion concentration were used to determine CN− ion in water samples. Detection and quantification limits of the proposed method were 0.94 and 2.82 mg/L, respectively.

“…On the other hand, many of the pyrazolo, isoxazolo, pyridineo, pyrimidino, and benzodiazepino derivatives have been reported to exhibit antioxidant activity . Studies have shown that integration of such analogues into quinoline moiety may enhance their biological activities or generate new medicinal properties . This attracted our attention towards the preparation of some heterocyclic derivatives combining both quinolinones and such analogues in one molecular frame.…”

Section: Introductionmentioning

confidence: 99%

An Efficient New Route for the Synthesis of Some 3‐Hterocyclylquinolinones via Novel 3‐(1,2‐Dihydro‐4‐hydroxy‐1‐methyl‐2‐oxoquinolin‐3‐yl)‐3‐oxopropanal and Their Antioxidant Screening

Hassan

Hassanin

2017

3‐(4‐hydroxy‐1‐methylquinoline‐3‐yl)‐3‐oxoproponal (5) was synthesized from 3‐[(E)‐3‐(dimethylamino)‐2‐propenoyl]‐4‐hydroxy‐1‐methyl‐2(1H)‐quinolinone (3) and was utilized as a starting precursor material. A convenient new route to functionalized 3‐heterocyclyl 4‐hydroxy‐2(1H)‐quinolinones such as pyrazolyl, isoxazolyl, pyrimidinyl, azepineyl, pyridonyl, and pyranyl heterocycles was described via cyclization of compound 5 with some N and C‐nucleophiles. The newly synthesized aldehyde 5 showed only one ring closure possibility with maximum yield instead of using compound 3 that exhibited different regioselective ring closure routes with minimum yields. All newly synthesized products were structurally elucidated on the basis of their relevant spectroscopic data and elemental microanalyses. The antioxidant activity of the products was screened in a series of in vitro tests.