8-quinolinol
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Na vhodně volené skupině derivátů 8-chinolinolu bylo prokázáno, že oxidační kopulace techto látek se 4-aininofenazonem (4-aminoantipyrinem) probíhá v poloze para k fenolické hydroxyskupině. Je-li v této poloze přítomen halogen nebo sulfoskupina, dochází k jejich kvantitativní eliminaci a reakce je rovněž pozitivní za vzniku příslušného červeného chinoniminového barviva. Tím bylo potvrzeno, že reakce probíhá analogicky jako u benzenových derivátů a nikoliv ve smyslu reakčního schématu navrženého Belalem (Talanta 31, 648 (1984)).
It has been shown that the oxidative coupling reaction of a systematicafly selected group of halogenand sulfo derivatives of 8-quinolinol with 4-aminophenazone (4-aminoantipyrine) takes place in the para position to the phenolic hydroxy group. If this position is occupied by a halogen atom or a sulfo group, these substituents are eliminated quantitatively and the reaction is positive under the formation of the corresponding red quinoneimine dye. Thus, it has been found that the reaction of 8-quinolinols proceeds analogously to the benzene derivatives and not according to the reaction scheme proposed by Belal (Talanta 31, 648 (1984)).
- MeSH
- chromatografie na tenké vrstvě metody přístrojové vybavení využití MeSH
- farmaceutická technologie metody přístrojové vybavení MeSH
- farmakologické a toxikologické jevy účinky záření MeSH
- fenoly farmakologie chemie MeSH
- hydroxychinoliny analýza chemie MeSH
- kyselina chlorovodíková chemie MeSH
- kyselina octová chemie MeSH
- kyseliny sírové chemie MeSH
- nitrososloučeniny analýza chemie MeSH
- spektrofotometrie metody přístrojové vybavení využití MeSH
Popis přípravy 5-acetylhydrokotarninu působením kyseliny acetylsírové na hydrokotarnin. Podrobná analýza připravené látky
BACKGROUND: Cobalt is an essential trace element, but it can also rarely cause cobalt toxicity due to its release from cobalt-containing medical devices. Currently, there are no approved selective cobalt chelators, which would represent an optimal treatment modality. OBJECTIVE: This study aimed to develop a simple and complex methodological approach for screening potential cobalt chelators and evaluating their potential toxicity. METHODS: Firstly, a simple spectrophotometric assay employing 1-nitroso-2-naphthol-3,6- disulfonic acid disodium salt (NNDSA) for screening cobalt chelation was standardized at a pathophysiologically relevant range of pH 4.5-7.5. Then, the suitability of the method was verified using four known metal chelators (EDTA, 8-hydroxyquinoline, chloroxine and nitroxoline). As cobalt can catalyse the Fenton reaction, the potential toxicity of cobalt-chelator complexes was also determined by employing a novel HPLC method with coulometric detection. The effect on erythrocyte haemolysis was tested as well. RESULTS: The NNDSA method had high sensitivity enabling the detection of 25-200 nM of cobalt ions depending on pH conditions. Measurements could be carried out in a wide range of wavelengths from 470 to 540 nm. All tested complexes of the selected chelators decreased the rate of the Fenton reaction. Interestingly, chloroxine mixed with cobalt ions caused marked lysis of erythrocytes in contrast to the other compounds. CONCLUSION: The described complex methodological approach could serve as a simple yet precise tool for evaluating novel, effective and safe cobalt chelators.
- MeSH
- chelátory * MeSH
- ionty MeSH
- kobalt * chemie MeSH
- oxychinolin MeSH
- Publikační typ
- časopisecké články MeSH
Copper is an essential trace element involved in many physiological processes. Since disorder of copper homeostasis is observed in various pathologies, copper chelators may represent a promising therapeutic tool. This study was aimed at: 1) formation of an in vitro methodology for screening of copper chelators, and 2) detailed analysis of the interaction of copper with clinically used D-penicillamine (D-PEN), triethylenetetramine (trientine), experimentally tested 8-hydroxyquinolines, and the disodium salt of EDTA as a standard chelator. Methodology based on bathocuproinedisulfonic acid disodium salt (BCS), usable at (patho)physiologically relevant pHs (4.5-7.5), enabled assessment of both cuprous and cupric ions chelation and comparison of the relative affinities of the tested compounds for copper. In the case of potent chelators, the stoichiometry could be estimated too. Clioquinol, chloroxine and EDTA formed very stable complexes with Cu(+)/Cu(2+) at all tested pHs, while copper complexes with trientine were stable only under neutral or slightly acidic conditions. Non-substituted 8-hydroxyquinoline was a less efficient copper chelator, but still unequivocally more potent than D-PEN. Both 8-hydroxyquinoline and D-PEN chelation potencies, similarly to that of trientine, were pH-dependent and decreased with pH. Moreover, only D-PEN was able to reduce cupric ions. Conclusively, BCS assay represents a rapid, simple and precise method for copper chelation measurement. In addition, lower binding affinity of D-PEN compared with 8-hydroxyquinolines and trientine was demonstrated.
- MeSH
- fenantroliny chemie MeSH
- měď chemie MeSH
- oxychinolin chemie MeSH
- penicilamin chemie MeSH
- trientin chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
