Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: quinolinium salts

Sortuj według:

Ogranicz wyniki do:

Zastosowanie soli chinoliniowych i pirydyniowych do oznaczania wybranych związków siarki w próbkach biologicznych

Furmaniak P., Wyszczelska-Rokiel M., Kubalczyk P., Głowacki R.

Wiadomości Chemiczne

2014

[Z] 68, 3-4

211--232

Quinolinium and pyridinium salts belong to the group of onium compounds and are widely used in organic, structural and analytical chemistry. Their synthesis is mainly based on quaternization of the nitrogen atom in a heterocyclic ring [4, 13, 23]. In analytical chemistry quinolinium and pyridinium salts such as 2-chloro-1-methylquinolinium tetrafluoroborate (CMQT) or 1-benzyl-2-chloropyridinium bromide (BCPB) perform very well as thiol specific derivatization reagents in terms of derivatization reaction velocity, stability, chromatographic properties of the derivatives, and thus, amenability to automatization [18–22, 32–42]. Analytical procedures for thiol determination usually involve reduction of disulfide bonds with tris(2-carboxyethyl)phosphine, tri-n-butylphosphine or mercaptoethanol, chemical derivatization of the sulfur compound with the use of 2-halopyridinium or 2-haloquinolinium salts and then deproteinization, followed by ion-pair reversed-phase HPLC or CE separation and spectrophotometric detection. Derivatization reaction takes advantage of great susceptibility of quinolinium or pyridinium molecules at 2-position to nucleophilic displacement, and a high nucleophilicity of the thiol group. Derivatization reaction mixture is usually ready to be analyzed just after mixing of the substrates. CMQT and BCPB exhibit very high reactivity toward thiols [44, 45], sulfides [63] as well as thiosulfates [40, 54]. 2-S-quinolinium and 2-S-pyridinium derivatives possess advantageous spectrophotometric and chromatographic properties. They are stable and more hydrophobic than thiols themselves, possessing a well-defined absorption maximum in the UV region. The reaction is accompanied by an analytically advantageous bathochromic shift from reagent maximum to the maximum of the derivative. Thanks to this phenomenon it is possible to use a large excess of derivatization reagent in order to drive the reaction to completion and avoid a huge signal of unreacted compound on the chromatogram [26]. Elaborated with the use of onium salts methods have proven to be useful in quantitative HPLC and CE analysis of endogenous and exogenous low-molecular-weight biological thiols in human body fluids, plant extracts and some groceries [44, 45].

3-Acylsulfanyl-1-methyl-4-methylsulfanyl-quinolinium Salts and Their Transformation into 4-Aminoquinolinium-3-thiolates and Azaphenothiazine Derivatives

Zięba A.

Polish Journal of Chemistry

2008

Vol. 82, nr 7

1399-1399

3-Acylsulfanyl-1-methyl-4-methylsulfanyl-quinolinium methyl sulfates 3 were obtained via acylation of 1-methyl-3-sulfanyl-1H-quinoline-4-thione (1) in the presence of a base and subsequent alkylation with dimethyl sulfate. Reactions of 3-acylsulfanyl-1-methyl- 4-methylsulfanyl-quinolinium chlorides 4 with primary aliphatic and aromatic amines led to 4-amino-1-methylquinolinium-3-thiolates (5). When the reactions of chlorides 4 with aniline were carried out in the presence of atmospheric oxygen, the 3-thiolate 5 formed in the first step of the reaction under went cyclization to 5-methyl-12H-quino-[3,4-b][1,4]benzo thiazinium chloride (6).