Acid–Base Equilibria of Rupatadine Fumarate in Aqueous Media

2018 ◽  
Vol 63 (8) ◽  
pp. 3150-3156 ◽  
Author(s):  
Marija R. Popović-Nikolić ◽  
Gordana V. Popović ◽  
Kristina Stojilković ◽  
Maja Dobrosavljević ◽  
Danica D. Agbaba
Keyword(s):  
Aqueous Media ◽  
Acid Base

scholarly journals Formation of highly quaternized N,N,N-trimethylchitosan: a chemoselective methodology in aqueous media

2019 ◽  
Vol 91 (3) ◽  
pp. 489-496 ◽  
Author(s):  
Youssouf D. Soubaneh ◽  
Steeven Ouellet ◽  
Caroline Dion ◽  
Jonathan Gagnon
Keyword(s):  
Biomedical Applications ◽  
Chemical Shifts ◽  
Aqueous Media ◽  
Acid Base ◽  
Specific Chemical ◽  
H Nmr ◽  
Low Degree ◽  
Simple Step ◽  
Carbonate Salt

Abstract N,N,N-Trimethylchitosan (TMC) represents a rare example of cationic polysaccharides and numerous studies have shown its potential in biological and biomedical applications. TMC with high degrees of quaternization (DQ) were synthesized from N-methylation of N,N-dimethylchitosan (DMC), which was obtained by reductive alkylation of high molecular weight chitosan in a simple step process and in good yields. The effects of base and solvents were evaluated on the quaternization reaction. The N-methylation of DMC was performed selectively by CH3I and carbonate in water where quaternization was achieved quantitatively with a low degree of O-methylation (17 %). Moreover, the greener procedure allows easy recovery and purification by conventional filtration as a carbonate salt, in which the anion can be exchanged by an acid-base reaction. Quantification of DQ involving 1H NMR integration of methyl peaks must be performed on protonated TMC. High field NMR spectra of TMC showed two specific chemical shifts for anomeric peaks (5.0 and 5.4 ppm) that can also be used for the determination of DQ. This latter method avoids the superimposition problems with other pyranosyl peaks.

N-confused porphyrin possessing glucamine-appendants: Aggregation and acid/base properties in aqueous media

2008 ◽  
Vol 18 (24) ◽  
pp. 6394-6397 ◽  
Author(s):  
Yoshiya Ikawa ◽  
Hiroaki Ogawa ◽  
Hiroyuki Harada ◽  
Hiroyuki Furuta
Keyword(s):  
Aqueous Media ◽  
Acid Base ◽  
Base Properties

An interfacial voltaic cell for monitoring acid—base reactions in non-aqueous media

1980 ◽  
Vol 119 (2) ◽  
pp. 375-377 ◽  
Author(s):  
Bolesław Wàligóra ◽  
Maria Paluch
Keyword(s):  
Aqueous Media ◽  
Acid Base ◽  
Voltaic Cell

An intermediate of reaction of 2-naphthol with activated sludge

1988 ◽  
Vol 53 (7) ◽  
pp. 1574-1578 ◽  
Author(s):  
Karel Komers ◽  
Antonín Lyčka ◽  
Josef Jirman ◽  
Ivan Kolb
Keyword(s):  
Activated Sludge ◽  
Nmr Spectra ◽  
Dissociation Constants ◽  
Aqueous Media ◽  
Standard State ◽  
Acid Base ◽  
C Nmr

A redbrown intermediate has been isolated from a reaction mixture of 2-naphthol and the activated sludge, and its structure has been determined on the basis of its IR, MS, and especially 2D 1H and 13C NMR spectra. It corresponds to 4-(2-hydroxy-1-naphthyl)-6-hydroxy-1,2-naphthoquinone (I). In aqueous media I behaves as an acid-base indicator with the colour transition from yellow to redbrown. The concentration dissociation constants of I have been determined spectrophotometrically: K1 = 3·47 . 10-7, K2 = 3·80 . 10-10 for the standard state c0 = 1 mol dm-3, 298 K, 105 Pa.

Acid–base and coordination properties of 2-phenyl-3-hydroxy-4-quinolones in aqueous media

RSC Advances ◽  
2015 ◽  
Vol 5 (76) ◽  
pp. 62116-62127 ◽  
Author(s):  
Arturo Jiménez-Sánchez ◽  
Anatoly K. Yatsimirsky
Keyword(s):  
Metal Ions ◽  
Aqueous Media ◽  
Acid Base ◽  
Fluorescence Response ◽  
Coordination Properties

2-Phenyl-3-hydroxy-4-quinolones bind metal ions with selective fluorescence response in aqueous media.

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