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Search Results: 1 - 10 of 67338 matches for " N-Oxides "
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Unexpected Reduction of Ethyl 3-Phenylquinoxaline-2- carboxylate 1,4-Di-N-oxide Derivatives by Amines
Lidia M. Lima,Esther Vicente,Beatriz Solano,Silvia Pérez-Silanes,Ignacio Aldana,Antonio Monge
Molecules , 2008, DOI: 10.3390/molecules13010078
Abstract: The unexpected tendency of amines and functionalized hydrazines to reduceethyl 3-phenylquinoxaline-2-carboxylate 1,4-di-N-oxide (1) to afford a quinoxaline 1c andmono-oxide quinoxalines 1a and 1b is described. The experimental conditions werestandardized to the use of two equivalents of amine in ethanol under reflux for two hours,with the aim of studying the distinct reductive profiles of the amines and thechemoselectivity of the process. With the exception of hydrazine hydrate, which reducedcompound 1 to a 3-phenyl-2-quinoxalinecarbohydrazide derivative, the amines only actedas reducing agents.
Anew role of N-arylbenzoquinoneimine N-oxides in the von Richter reaction
Journal of the Serbian Chemical Society , 2006,
Abstract: The title nitrones react with cyanide ions to give benzoic acids and N-aryl-4-hydroxy-2-cyanophenylamines via two different pathways.
NMR Spectra of Sparteine N1-oxide and α-Isosparteine N-oxide
Beata Jasiewicz
Molecules , 2008, DOI: 10.3390/molecules13010003
Abstract: Sparteine N1-oxide and α-isosparteine N-oxide were prepared and theirstructures determined for the first time by 1H- and 13C-NMR spectroscopy using twodimensionaltechniques. The N-oxide effects were also calculated.
Synthesis and Antiplasmodial Activity of 3-Furyl and 3-Thienylquinoxaline-2-carbonitrile 1,4-Di-N-oxide Derivatives
Esther Vicente,Sarah Charnaud,Emily Bongard,Raquel Villar,Asunción Burguete,Beatriz Solano,Saioa Ancizu,Silvia Pérez-Silanes,Ignacio Aldana,Livia Vivas,Antonio Monge
Molecules , 2008, DOI: 10.3390/molecules13010069
Abstract: The aim of this study was to identify new compounds active againstPlasmodium falciparum based on our previous research carried out on 3-phenylquinoxaline-2-carbonitrile 1,4-di-N-oxide derivatives. Twelve compounds weresynthesized and evaluated for antimalarial activity. Eight of them showed an IC50 less than 1 μMagainst the 3D7 strain. Derivative 1 demonstrated high potency (IC50= 0.63 μM) and goodselectivity (SI=10.35), thereby becoming a new lead-compound.
Substitutions of Fluorine Atoms and Phenoxy Groups in the Synthesis of Quinoxaline 1,4-di-N-oxide Derivatives
Esther Vicente,Raquel Villar,Asunción Burguete,Beatriz Solano,Saioa Ancizu,Silvia Pérez-Silanes,Ignacio Aldana,Antonio Monge
Molecules , 2008, DOI: 10.3390/molecules13010086
Abstract: The unexpected substitution of fluorine atoms and phenoxy groups attached toquinoxaline or benzofuroxan rings is described. The synthesis of 2-benzyl- and 2-phenoxy-3-methylquinoxaline 1,4-di-N-oxide derivatives was based on the classical Beirut reaction.The tendency of fluorine atoms linked to quinoxaline or benzofuroxan rings to be replacedby a methoxy group when dissolved in an ammonia saturated solution of methanol wasclearly demonstrated. In addition, 2-phenoxyquinoxaline 1,4-di-N-oxide derivativesbecame 2-aminoquinoxaline 1,4-di-N-oxide derivatives in the presence of gaseousammonia.
International Journal of Bioinformatics Research , 2011,
Abstract: N-Oxides were found to have antimicrobial activity. In continuation of our work on synthesis, characterizationand biological activities (in vitro method) of N-Oxides and knowing their biological activities against micro organisms, wehave correlated the biological activity of these N-Oxides against the micro organisms like Staphylococcus aureus,Salmonella typhi “H”, Escherichia Coli, Pseudomonas aeruginosa, Klebsiella aerogenes, Enterobacteraerogenes,Citrobacter, Staphylococcus epidermidis, and Aeromonas hydrophila by Insilico method. The target molecules(microorganism) were taken from Protein data bank. Various soft wares were used to find out the drug likeness propertiesof these N-Oxides. Online software “Molinspiration” was used to calculate log P (ie) Hydrophobicity of a drug. ACD/Chemsketch was used to draw the structures of N-Oxides. Hex 4.2, docking software was used to predict the drugactivities of these N-Oxides. The drug activities were measured in terms of drug likeness property by recording the ETotalvalue and compared with the marketed standard drugs for the above micro organism infections. Standard drugswere taken from drug bank. As per the standard norms, it was observed that the compounds that have negative E-Totalvalues could be used as a drug. We have selected Ceftazidime ,Cefepime and Ceftizoxime as standard drugs among theavailable drugs for these microorganism for correlating the drug activities of these N-Oxides. We observed that some ofour N-Oxides were found to have higher drug activities compared to standard drugs.
An Attempt to Assign the NMR Spectra in 7-Methyl-and 7-Benzyl-substituted 7H-Purine 1-Oxides Using the ACD/Labs Software Package
Stanis?aw Ostrowski
Molecules , 2003, DOI: 10.3390/80900649
Abstract: Commercially available 4-nitroimidazole can be transformed in a few simple steps into 4-aminoimidazoyl-5-carboximes, from which the respective purine mono-1-oxides may be synthesized. The N→O functionality in these products significantly changes the electron density in the purine skeleton and consequently, the determination of the 1H- and 13C-NMR spectra of these simple compounds is somewhat troublesome. The use of the ACD/Labs software package for this purpose is discussed.
Experimental Studies on the UV-Spectra of Several Substituted Pyridine N-Oxides and Conjugated Cationic Acids in Acetonitrile
Lech Chmurzynski
Molecules , 1997, DOI: 10.3390/21100169
Abstract: The ultraviolet spectra of heterocyclic N-oxides of pyridine N-oxide series and the conjugated cationic acids (simple cations of protonated N-oxides) in acetonitrile as the representative of polar aprotic solvents, were determined. The obtained spectra of N-oxides studied (mainly tri-substituted pyridine N-oxides) and their cations obtained by the protonation of free N-oxides by the excess of perchloric acid, have been collected and discussed. Taking into account the spectroscopic results, a scheme of acid-base equilibria in polar aprotic solvents has been discussed. The influence of the traces of water on acid-base equilibria in nonaqueous media has been stressed.
Synthesis of N-7-Substituted Purines from Imidazole Precursors
Stanislaw Ostrowski
Molecules , 1999, DOI: 10.3390/41000287
Abstract: Synthesis of purines and purine mono-1-oxides from the respective 5-substituted 4-nitroimidazole derivatives is described. The commercially available 4-nitroimidazole, in a few simple steps (including Vicarious Nucleophilic Substitution of Hydrogen), was transformed into: 4-aminoimidazoyl-5-carboximes, N-[1-(4-amino-1H-imidazol-5-yl)methylidene]-N-(aryl)amine derivatives or into 4-amino-5-aminomethyl-imidazole. These intermediates were cyclized to the final products.
New Conjugated Benzothiazole-N-oxides: Synthesis and Biological Activity
Peter Gajdo?,Peter Magdolen,Pavol Zahradník,Pavlína Foltínová
Molecules , 2009, DOI: 10.3390/molecules14125382
Abstract: Eleven new 2-styrylbenzothiazole-N-oxides have been prepared by aldol – type condensation reactions between 2-methylbenzothiazole–N-oxide and para-substituted benzaldehydes. Compounds with cyclic amino substituents showed typical push-pull molecule properties. Four compounds were tested against various bacterial strains as well as the protozoan Euglena gracilis as model microorganisms. Unlike previously prepared analogous benzothiazolium salts, only weak activity was recorded.
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