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Cloutier M, Lavoie S, Gauthier C. C7 Epimerization of Benzylidene-Protected β-d-Idopyranosides Brings Structural Insights into Idose Conformational Flexibility. J Org Chem 2022; 87:12932-12953. [PMID: 36137237 DOI: 10.1021/acs.joc.2c01504] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Idose is unique among other aldohexoses because of its high conformational flexibility in solution. We herein show that benzylidene acetal-protected 3-O-acyl-β-d-idopyranosides undergo Lewis acid-catalyzed C7 epimerization with concomitant 4C1 to 1C4 ring inversion. The reaction conditions and structural parameters for this transformation to occur have been thoroughly investigated through an extensive glycosylation study combined with NMR analyses, X-ray diffraction, and quantum molecular modeling. In addition to reporting a direct, β-stereoselective idosylation approach, our work brings fundamental structural insights into the conformational flexibility of idose.
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Affiliation(s)
- Maude Cloutier
- Unité Mixte de Recherche INRS-UQAC, Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 555, boulevard de l'Université, Chicoutimi, Québec, Canada G7H 2B1
| | - Serge Lavoie
- Laboratoire LASEVE, Département des Sciences Fondamentales, Université du Québec à Chicoutimi (UQAC), 555, boulevard de l'Université, Chicoutimi, Québec, Canada G7H 2B1
| | - Charles Gauthier
- Unité Mixte de Recherche INRS-UQAC, Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 555, boulevard de l'Université, Chicoutimi, Québec, Canada G7H 2B1.,Laboratoire LASEVE, Département des Sciences Fondamentales, Université du Québec à Chicoutimi (UQAC), 555, boulevard de l'Université, Chicoutimi, Québec, Canada G7H 2B1
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Glasson CRK, Luiten CA, Carnachan SM, Daines AM, Kidgell JT, Hinkley SFR, Praeger C, Andrade Martinez M, Sargison L, Magnusson M, de Nys R, Sims IM. Structural characterization of ulvans extracted from blade (Ulva ohnoi) and filamentous (Ulva tepida and Ulva prolifera) species of cultivated Ulva. Int J Biol Macromol 2022; 194:571-579. [PMID: 34813787 DOI: 10.1016/j.ijbiomac.2021.11.100] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 10/05/2021] [Accepted: 11/15/2021] [Indexed: 11/05/2022]
Abstract
Ulvans from Ulva ohnoi, Ulva tepida and Ulva prolifera were extracted under mild acidic conditions, isolated and their composition and structure determined. The ulvans contained mostly rhamnose (31.6-46.7 mol%) and glucuronic acid (26.6-37.5 mol%), with smaller amounts of xylose (3.4-10.4 mol%) and iduronic acid (3.1-7.6 mol%). In addition, the ulvan samples also contained galactose (4.4-26.0 mol%). Glycosyl linkage analysis showed that ulvan from U. ohnoi contained mostly →4)-GlcpA-(1→ and →3,4)-Rhap-(1→. Preparation of partially methylated alditol acetate standards of idose showed that U. ohnoi contained →4)-IdopA-(1→. In addition to these residues, glycosyl linkage analysis of U. tepida and U. prolifera showed the presence of →2,3,4)-Rhap-(1→, →4)-Xylp-(1→, →2,4)-GlcpA-(1→ and →3,4)-GlcpA-(1→. These two species also contained galactose linkages. These data, together with nuclear magnetic resonance (NMR) spectroscopy indicated that U. ohnoi comprised mostly of type A3S ulvanobiuronic acid repeats [→4)-β-D-GlcpA-(1→4)-α-L-Rhap3S-(1→], together with smaller amounts of type B3S ulvanobiuronic acid repeats [→4)-α-L-IdopA-(1→4)-α-L-Rhap3S-(1→] and ulvanobiose (U3S [→4)-β-D-Xylp-(1→4)-α-L-Rhap3S-(1→]). NMR spectra of U. tepida and U. prolifera showed resonances not detected in U. ohnoi, highlighting the complexity of the ulvans from these species. Regardless of the structural diversity of the ulvan samples there was very little antioxidant or inhibitory activity detected on enzymatic processes investigated.
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Affiliation(s)
- Christopher R K Glasson
- MACRO - The Centre for Macroalgal Resources and Biotechnology, College of Marine and Environmental Sciences, James Cook University, Townsville 4811, Australia; Environmental Research Institute, School of Science, University of Waikato, Tauranga 3110, New Zealand.
| | - Cara A Luiten
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5010, New Zealand.
| | - Susan M Carnachan
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5010, New Zealand.
| | - Alison M Daines
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5010, New Zealand.
| | - Joel T Kidgell
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5010, New Zealand; Environmental Research Institute, School of Science, University of Waikato, Tauranga 3110, New Zealand.
| | - Simon F R Hinkley
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5010, New Zealand
| | - Christina Praeger
- MACRO - The Centre for Macroalgal Resources and Biotechnology, College of Marine and Environmental Sciences, James Cook University, Townsville 4811, Australia; Environmental Research Institute, School of Science, University of Waikato, Tauranga 3110, New Zealand.
| | - Maria Andrade Martinez
- MACRO - The Centre for Macroalgal Resources and Biotechnology, College of Marine and Environmental Sciences, James Cook University, Townsville 4811, Australia.
| | - Liam Sargison
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5010, New Zealand.
| | - Marie Magnusson
- Environmental Research Institute, School of Science, University of Waikato, Tauranga 3110, New Zealand.
| | - Rocky de Nys
- MACRO - The Centre for Macroalgal Resources and Biotechnology, College of Marine and Environmental Sciences, James Cook University, Townsville 4811, Australia.
| | - Ian M Sims
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5010, New Zealand.
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