The synthesis of two novel carbasugar analogues of alpha-L-iduronic acid is described in which the ring-oxygen is replaced by a methylene group. In analogy with the conformational equilibrium described for alpha-L-IdopA, the conformation of the carbasugars was investigated by (1)H and (13)C NMR spectroscopy. Hadamard transform NMR experiments were utilised for rapid acquisition of (1)H,(13)C-HSQC spectra and efficient measurements of heteronuclear long-range coupling constants. Analysis of (1)H NMR chemical shifts and J(H,H) coupling constants extracted by a total-lineshape fitting procedure in conjunction with J(H,C) coupling constants obtained by three different 2D NMR experiments, viz., (1)H,(13)C-HSQC-HECADE, J-HMBC and IPAP-HSQC-TOCSY-HT, as well as effective proton-proton distances from 1D (1)H,(1)H T-ROE and NOE experiments showed that the conformational equilibrium [formula in text] is shifted towards (4)C(1) as the predominant or exclusive conformation. These carbasugar bioisosteres of alpha-l-iduronic acid do not as monomers show the inherent flexibility that is anticipated to be necessary for biological activity.
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http://dx.doi.org/10.1016/j.carres.2010.03.002 | DOI Listing |
Mar Drugs
March 2023
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow 119991, Russia.
Crude anionic polysaccharides extracted from the Pacific starfish were purified by anion-exchange chromatography. The main fraction having MW 14.5 kDa and dispersity 1.
View Article and Find Full Text PDFCarbohydr Polym
June 2021
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, Moscow 119991, Russia. Electronic address:
Crude anionic polysaccharides extracted from the Pacific starfish Lysastrosoma anthosticta were separated by anion-exchange chromatography into fractions LA-F1 and LA-F2. The main fraction LA-F1 was solvolytically desulfated giving rise to preparation LA-F1-DS with a structure of dermatan core [→3)-β-d-GalNAc-(1→4)-α-l-IdoA-(1→]. Reduction of LA-F1 afforded preparation LA-F1-RED composed mainly of the repeating disaccharide units →3)-β-d-GalNAc4R-(1→4)-α-l-Ido2S3S-(1→, where R was SO- or H.
View Article and Find Full Text PDFJ Pharm Biomed Anal
April 2021
Semmelweis University, Department of Pharmacognosy, Üllői út. 26, H-1085, Budapest, Hungary. Electronic address:
The highly anionic synthetic pentasaccharide fondaparinux (FDPX) - representing the antithrombin binding sequence of heparin - is in clinical use as a potent anticoagulant. Contrary to the unfractionated heparin, FDPX lacks potent antidote completely reversing its anticoagulant activity, therefore it is of great importance to identify new structures exhibiting strong intermolecular interactions towards FDPX. The polycationic heptakis(6-amino-6-deoxy)-beta-cyclodextrin (NH-β-CD) can serve as an excellent model compound to mimic these interactions between the oppositely charged oligosaccharides.
View Article and Find Full Text PDFChembiochem
March 2018
Department NMR and Carbohydrates, Istituto di Ricerche Chimiche e Biochimiche "G. Ronzoni", via G. Colombo 81, 20133, Milan, Italy.
Heparin is a highly sulfated glycosaminoglycan (GAG) of natural origin used as an anticoagulant and antithrombotic drug. These properties are principally based on the binding and activation of antithrombin (AT) through the pentasaccharide sequence GlcNAc/NS,6S-GlcA-GlcNS,3,6S-IdoA2S-GlcNS,6S (AGA*IA). Literature data show that the population of the S ring conformation of the 2-O-sulfo-α-l-iduronic acid (IdoA2S) motif correlates with the affinity and activation of AT.
View Article and Find Full Text PDFJ Pharm Biomed Anal
May 2018
Spectral Service AG, Emil-Hoffmann-Straße 33, 50996 Köln, Germany.
Heparin is a linear, highly sulfated glycosaminoglycan (GAG), which consists of repeating disaccharide units of β-d-glucuronic acid or α-l-iduronic acid and α-d-glucosamine. While robust analytical approaches exist for the characterization of organic composition of heparin preparations, there is a lack of methods for the simultaneous quantification of inorganic compounds (water, anions, cations) in this matrix. A nuclear magnetic resonance (NMR) spectrometric method for heparin characterization described in US Pharmacopeia was extended to simultaneous analysis of the inorganic ions (sodium, calcium, and chloride), acetate as well as water content.
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