NMR investigation of the complexation and chiral discrimination of pyrazole sulfonamide derivatives with cyclodextrins. (22nd January 2015)

• Record Type: Journal Article
• Authors: Rogez-Florent, Tiphaine; Azaroual, Nathalie; Goossens, Laurence; Goossens, Jean-François; Danel, Cécile
• Is Part Of: Carbohydrate polymers. Volume 115(2015)
• Page Start: 598
• Page End: 604
• Publication Date: 2015-01-22
• Subjects: Cyclodextrin -- Sulfonamide derivatives -- Inclusion complex -- NMR spectroscopy -- Chiral discrimination; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2014.09.046
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Complexation of 6 chiral sulfonamide derivatives with 6 cyclodextrins. Determination of stoichiometry and apparent binding constants by 1D 1 H NMR. Study of the supramolecular assembly by 2D ROESY experiments. The inclusion of the aliphatic part occurs via the smaller opening of the toroid. Weak interactions (unquantifiable) are proved by chiral discrimination. Abstract: The complexes formed between six original chiral diaryl-pyrazole sulfonamide derivatives, displaying poor solubility, and various CDs (native α-, β- and γ-CDs, hydroxypropylated HP-β-CD, methylated Me-β-CD or amino NH2 -β-CD) were studied by 1D and 2D 1 H NMR at physiological pH in order to determine their apparent binding constant, stoichiometry and structure of the supramolecular assembly. For some complexes, the spectra obtained for free racemic compound and for racemic compound in presence of CD indicate a splitting of signal(s). Additional experiments with pure enantiomer and enriched enantiomer allow us to attribute this behavior to chiral discrimination. The complexing ability of the native β-CD towards our compounds appears the most promising since binding values around 7 × 10 2 M −1 are obtained. The two-dimensional ROESY ( 1 H– 1 H) experiments prove the inclusion of the aliphatic part of the compound in the CD cavity. It is noteworthy that this inclusion occurs via the smaller opening of the cavity.