1
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Anderson T, Jiang H, Cheallaigh AN, Bengtsson D, Oscarson S, Cairns C, St Michael F, Cox A, Kuttel MM. Formation and immunological evaluation of Moraxella catarrhalis glycoconjugates based on synthetic oligosaccharides. Carbohydr Polym 2024; 332:121928. [PMID: 38431400 DOI: 10.1016/j.carbpol.2024.121928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/31/2024] [Accepted: 02/06/2024] [Indexed: 03/05/2024]
Abstract
Published work has shown that glycoconjugate vaccines, based on truncated detoxified lipopolysaccharides from Moraxella catarrhalis attached through their reducing end to a carrier protein, gave good protection for all three serotypes A, B, and C in mice immunisation experiments. The (from the non-reducing end) truncated LPS structures were obtained from bacterial glycosyl transferase knock-out mutants and contained the de-esterified Lipid A, two Kdo residues and five glucose moieties. This work describes the chemical synthesis of the same outer Moraxella LPS structures, spacer-equipped and further truncated from the reducing end, i.e., without the Lipid A part and containing four or five glucose moieties or four glucose moieties and one Kdo residue, and their subsequent conjugation to a carrier protein via a five‑carbon bifunctional spacer to form glycoconjugates. Immunisation experiments both in mice and rabbits of these gave a good antibody response, being 2-7 times that of pre-immune sera. However, the sera produced only recognized the immunizing glycan immunogens and failed to bind to native LPS or whole bacterial cells. Comparative molecular modelling of three alternative antigens shows that an additional (2 → 4)-linked Kdo residue, not present in the synthetic structures, has a significant impact on the shape and volume of the molecule, with implications for antigen binding and cross-reactivity.
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Affiliation(s)
- Taigh Anderson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Hao Jiang
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Aisling Ní Cheallaigh
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dennis Bengtsson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Chantelle Cairns
- Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, Ontario K1A 0R6, Canada
| | - Frank St Michael
- Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, Ontario K1A 0R6, Canada
| | - Andrew Cox
- Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, Ontario K1A 0R6, Canada
| | - Michelle M Kuttel
- Department of Computer Science, University of Cape Town, Cape Town 7701, South Africa
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2
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Miao H, Lu S, Chen H, Shang J, Zheng J, Yang Y. Additive-assisted synthesis of α-Kdo glycosides with peracetylated glycosyl ynenoate as a donor. Org Biomol Chem 2024; 22:2365-2369. [PMID: 38416050 DOI: 10.1039/d4ob00182f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
A DMF-modulated glycosylation approach for the stereoselective synthesis of α-Kdo glycosides with readily accessible peracetylated Kdo ynenoate as a donor was described. By utilizing this approach, we completed the synthesis of various linkage types of Kdo-Kdo disaccharides and the α-Kdo-containing protected trisaccharide variant relevant to the lipopolysaccharide of Coxiella burnetii strain Nine Mile.
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Affiliation(s)
- He Miao
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai Key Laboratory of New Drug Design, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Siqian Lu
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai Key Laboratory of New Drug Design, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Hongyu Chen
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai Key Laboratory of New Drug Design, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Jintao Shang
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai Key Laboratory of New Drug Design, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Jibin Zheng
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai Key Laboratory of New Drug Design, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - You Yang
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai Key Laboratory of New Drug Design, Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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3
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Sun A, Li Z, Wang Y, Meng S, Zhang X, Meng X, Li S, Li Z, Li Z. Stereocontrolled Synthesis of α-3-Deoxy-d-manno-oct-2-ulosonic Acid (α-Kdo) Glycosides Using C3-p-Tolylthio-Substituted Kdo Donors: Access to Highly Branched Kdo Oligosaccharides. Angew Chem Int Ed Engl 2024; 63:e202313985. [PMID: 38014418 DOI: 10.1002/anie.202313985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/05/2023] [Accepted: 11/27/2023] [Indexed: 11/29/2023]
Abstract
3-Deoxy-d-manno-oct-2-ulosonic acid (Kdo) is an eight-carbon monosaccharide found widely in bacterial lipopolysaccharides (LPSs) and capsule polysaccharides (CPSs). We developed an indirect method for the stereoselective synthesis of α-Kdo glycosides with a C3-p-tolylthio-substituted Kdo phosphite donor. The presence of the p-tolylthio group enhanced the reactivity, suppressed the formation of elimination by-products (2,3-enes), and provided complete α-stereocontrol. A variety of Kdo α-glycosides were synthesized by our method in excellent yields (up to 98 %). After glycosylation, the p-tolylthio group can be efficiently removed by free-radical reduction. Subsequently, the orthogonality of the phosphite donor and thioglycoside donor was demonstrated by the one-pot synthesis of a trisaccharide in Helicobacter pylori and Neisseria meningitidis LPS. Moreover, an efficient total synthesis route to the challenging 4,5-branched Kdo trisaccharide in LPSs from several A. baumannii strains was highlighted. To demonstrate the high reactivity of our approach further, the highly crowded 4,5,7,8-branched Kdo pentasaccharide was synthesized as a model molecule for the first time. Additionally, the reaction mechanism was investigated by DFT calculations.
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Affiliation(s)
- Ao Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Zipeng Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Yuchao Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Shuai Meng
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, College of Marine Science, Hainan University, Haikou, 570228, China
| | - Xiao Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Xiangbao Meng
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Shuchun Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Zhongtang Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Zhongjun Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
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4
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Steber HB, Singh Y, Demchenko AV. Bismuth(iii) triflate as a novel and efficient activator for glycosyl halides. Org Biomol Chem 2021; 19:3220-3233. [PMID: 33885577 PMCID: PMC8112625 DOI: 10.1039/d1ob00093d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Presented herein is the discovery that bismuth(iii) trifluoromethanesulfonate (Bi(OTf)3) is an effective catalyst for the activation of glycosyl bromides and glycosyl chlorides. The key objective for the development of this methodology is to employ only one promoter in the lowest possible amount and to avoid using any additive/co-catalyst/acid scavenger except molecular sieves. Bi(OTf)3 works well in promoting the glycosidation of differentially protected glucosyl, galactosyl, and mannosyl halides with many classes of glycosyl acceptors. Most reactions complete within 1 h in the presence of only 35% of green and light-stable Bi(OTf)3 catalyst.
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Affiliation(s)
- Hayley B Steber
- Department of Chemistry and Biochemistry, University of Missouri - St Louis, One University Boulevard, St Louis, Missouri 63121, USA.
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5
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Lou Q, Hua Q, Zhang L, Yang Y. Dimethylformamide-Modulated Kdo Glycosylation for Stereoselective Synthesis of α-Kdo Glycosides. Org Lett 2020; 22:981-985. [PMID: 31917587 DOI: 10.1021/acs.orglett.9b04509] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A simple and direct DMF-modulated α-selective Kdo glycosylation approach for the stereoselective synthesis of the α-linked Kdo glycosides is developed. Glycosylation of the readily available peracetylated Kdo ortho-hexynylbenzoate with common acceptor alcohols using SPhosAuNTf2 as a promoter and DMF as a modulating molecule afforded a range of Kdo glycosides with good α-selectivities. Furthermore, the present method is effectively applied in the latent-active synthesis of the α-linked di-Kdo glycoside bearing a linker at the reducing end. Finally, the first observation of a Kdo imidinium ion in the low-temperature NMR provides evidence for the plausible mechanism of the DMF-modulated α-selective Kdo glycosylation.
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Affiliation(s)
- Qixin Lou
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Qingting Hua
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Liangliang Zhang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - You Yang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
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6
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Mi X, Lou Q, Fan W, Zhuang L, Yang Y. Gold(I)-catalyzed synthesis of β-Kdo glycosides using Kdo ortho-hexynylbenzoate as donor. Carbohydr Res 2017; 448:161-165. [DOI: 10.1016/j.carres.2017.04.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 04/25/2017] [Accepted: 04/25/2017] [Indexed: 11/28/2022]
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7
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Abstract
Glycosylation chemistry of 3-deoxy-D-manno-oct-2-ulosonic acid units has been considerably developed within the last decade. This review covers major achievements with respect to improved yields and anomeric selectivity as well as suppression of the elimination side reaction via selection of dedicated protecting groups and appropriate activation of the anomeric center.
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Affiliation(s)
- Paul Kosma
- University of Natural Resources and Life Sciences-Vienna, Department of Chemistry, Muthgasse 18, A-1190 Vienna, Austria
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8
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Pokorny B, Kosma P. Synthesis of 5-O-oligoglucosyl extended α-(2→4)-Kdo disaccharides corresponding to inner core fragments of Moraxellaceae lipopolysaccharides. Carbohydr Res 2016; 422:5-12. [PMID: 26795079 DOI: 10.1016/j.carres.2015.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/10/2015] [Accepted: 12/24/2015] [Indexed: 12/16/2022]
Abstract
The heptose-deficient inner core of the lipopolysaccharide of several pathogenic strains of the Moraxellaceae family (Moraxella, Acinetobacter) and of Bartonella henselae, respectively, comprises an α-D-glucopyranose attached to position 5 of Kdo. In continuation of the synthesis of fragments of Acinetobacter haemolyticus LPS, the branched α-Glcp-(1 → 5)[α-Kdo-(2 → 4)]-α-Kdo trisaccharide motif was elaborated. The glycosylation of a suitably protected, α-(2 → 4)-interlinked Kdo-disaccharide was achieved in high yield and fair anomeric selectivity using a 4,6-O-benzylidene N-phenyltrifluoroacetimidate glucosyl donor. Subsequent regioselective reductive benzylidene opening afforded a trisaccharide acceptor, which was extended with β-D-glucopyranosyl and isomaltosyl residues. Global deprotection provided tri- to pentasaccharide structures corresponding to the inner core region of A. haemolyticus lipopolysaccharide.
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Affiliation(s)
- Barbara Pokorny
- Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
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9
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Pokorny B, Kosma P. Scope and Limitations of 3-Iodo-Kdo Fluoride-Based Glycosylation Chemistry using N-Acetyl Glucosamine Acceptors. ChemistryOpen 2015; 4:722-8. [PMID: 27308198 PMCID: PMC4906502 DOI: 10.1002/open.201500126] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Indexed: 12/11/2022] Open
Abstract
The ketosidic linkage of 3-deoxy-d-manno-octulosonic acid (Kdo) to lipid A constitutes a general structural feature of the bacterial lipopolysaccharide core. Glycosylation reactions of Kdo donors, however, are challenging due to the absence of a directing group at C-3 and elimination reactions resulting in low yields and anomeric selectivities of the glycosides. While 3-iodo-Kdo fluoride donors showed excellent glycosyl donor properties for the assembly of Kdo oligomers, glycosylation of N-acetyl-glucosamine derivatives was not straightforward. Specifically, oxazoline formation of a β-anomeric methyl glycoside, as well as iodonium ion transfer to an allylic aglycon was found. In addition, dehalogenation of the directing group by hydrogen atom transfer proved to be incompatible with free hydroxyl groups next to benzyl groups. In contrast, glycosylation of a suitably protected methyl 2-acetamido-2-deoxy-α-d-glucopyranoside derivative and subsequent deiodination proceeded in excellent yields and α-specificity, and allowed for subsequent 4-O-phosphorylation. This way, the disaccharides α-Kdo-(2→6)-α-GlcNAcOMe and α-Kdo-(2→6)-α-GlcNAcOMe-4-phosphate were obtained in good overall yields.
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Affiliation(s)
- Barbara Pokorny
- Department of ChemistryUniversity of Natural Resources and Life Sciences-ViennaMuthgasse 181190ViennaAustria
| | - Paul Kosma
- Department of ChemistryUniversity of Natural Resources and Life Sciences-ViennaMuthgasse 181190ViennaAustria
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10
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Pradhan TK, Mong KKT. Glycosylation Chemistry of 3-Deoxy-D-manno-Oct-2-ulosonic Acid (Kdo) Donors. Isr J Chem 2015. [DOI: 10.1002/ijch.201400145] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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11
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Pokorny B, Kosma P. Synthesis of chlamydia lipopolysaccharide haptens through the use of α-specific 3-iodo-Kdo fluoride glycosyl donors. Chemistry 2015; 21:305-13. [PMID: 25354167 PMCID: PMC4768360 DOI: 10.1002/chem.201405424] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Indexed: 12/20/2022]
Abstract
A scalable approach towards high-yielding and (stereo)selective glycosyl donors of the 2-ulosonic acid Kdo (3-deoxy-D-manno-oct-2-ulosonic acid) is a fundamental requirement for the development of vaccines against Gram-negative bacteria. Herein, we disclose a short synthetic route to 3-iodo Kdo fluoride donors from Kdo glycal esters that enable efficient α-specific glycosylations and significantly suppress the elimination side reaction. The potency of these donors is demonstrated in a straightforward, six-step synthesis of a branched Chlamydia-related Kdo-trisaccharide ligand without the need for protecting groups at the Kdo glycosyl acceptor. The approach was further extended to include sequential iteration of the basic concept to produce the linear Chlamydia-specific α-Kdo-(2→8)-α-Kdo-(2→4)-α-Kdo trisaccharide in a good overall yield.
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Affiliation(s)
- Barbara Pokorny
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, A-1190 Vienna, Austria
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences-Vienna, Muthgasse 18, A-1190 Vienna, Austria
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12
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Pokorny B, Kosma P. First and stereoselective synthesis of an α-(2→5)-linked disaccharide of 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo). Org Lett 2015; 17:110-3. [PMID: 25496419 PMCID: PMC4284650 DOI: 10.1021/ol5033128] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Indexed: 12/02/2022]
Abstract
Resistance of bacterial pathogens toward antibiotics has revived interest in lipopolysaccharide (LPS) motifs as potential therapeutic targets. The LPS of several pathogenic Acinetobacter strains comprises a 4,5-branched Kdo trisaccharide containing an uncommon (2→5)-linkage. In this contribution the first stereoselective glycosylation method for obtaining an α-Kdo-(2→5)-α-Kdo disaccharide in good yield is highlighted. The synthetic approach used for accessing this linkage type will allow for future studies of the immunoreactivity associated with this unique bacterial Kdo inner core structure.
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Affiliation(s)
- Barbara Pokorny
- Department
of Chemistry, University of Natural Resources
and Life Sciences-Vienna, Muthgasse 18, A-1190 Vienna, Austria
| | - Paul Kosma
- Department
of Chemistry, University of Natural Resources
and Life Sciences-Vienna, Muthgasse 18, A-1190 Vienna, Austria
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13
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Pokorny B, Müller-Loennies S, Kosma P. Synthesis of α-d-glucosyl substituted methyl glycosides of 3-deoxy-α-d-manno- and d-glycero-α-d-talo-oct-2-ulosonic acid (Kdo/Ko) corresponding to inner core fragments of Acinetobacter lipopolysaccharide. Carbohydr Res 2014; 391:66-81. [PMID: 24785390 PMCID: PMC4019464 DOI: 10.1016/j.carres.2014.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 02/26/2014] [Accepted: 03/05/2014] [Indexed: 11/18/2022]
Abstract
Synthesis of Acinetobacter LPS fragments with orthogonal protecting pattern. First synthesis of Ko-glycosides substituted at position 5. α-Selective glucosylation using benzylidene trifluoroacetimidate donor. Regioselective phosphorylation at C-6 of a glucosyl substituent.
The α-d-glucopyranosyl-(1→5)-substituted methyl glycosides of 3-deoxy-α-d-manno-oct-2-ulosonic acid (Kdo), 3-deoxy-α-d-lyxo-hept-2-ulosonic acid (Kdh), and d-glycero-α-d-talo-oct-2-ulosonic acid (Ko) were prepared using orthogonally protected glycosyl acceptor derivatives via glycosylation with a torsionally disarmed 4,6-O-benzylidene protected trifluoroacetimidate glucosyl donor followed by global deprotection. The related 6-O-phosphoryl-α-d-glucopyranosyl-(1→5)-substituted Kdo and Kdh derivatives were derived from a benzylidene-protected glucosyl intermediate using phosphoramidite and phosphoryl chloride-based phosphorylation steps, respectively. The deprotected disaccharides serve as ligands to study lectin binding of Acinetobacter lipopolysaccharide core oligosaccharides.
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Affiliation(s)
- Barbara Pokorny
- Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | | | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
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14
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Synthesis of a novel pentasaccharide core component from the lipooligosaccharide of Moraxella catarrhalis. Carbohydr Res 2011; 346:2805-11. [DOI: 10.1016/j.carres.2011.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 09/29/2011] [Accepted: 10/03/2011] [Indexed: 11/18/2022]
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15
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Crich D, Sharma I. Influence of the O3 protecting group on stereoselectivity in the preparation of C-mannopyranosides with 4,6-O-benzylidene protected donors. J Org Chem 2010; 75:8383-91. [PMID: 21070063 DOI: 10.1021/jo101453y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
α-C-Glucopyranosides and mannopyranosides are obtained in 65-85% yields from 4,6-O-benzylidene-protected glucosyl and mannosyl thioglycosides bearing ester functionality at the 3-O-position by a coupling reaction with C-nucleophiles on activation with diphenyl sulfoxide, 2,4,6-tri-tert-butylpyrimidine, and trifluoromethanesulfonic anhydride.
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Affiliation(s)
- David Crich
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
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16
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Kaeothip S, Akins SJ, Demchenko AV. On the stereoselectivity of glycosidation of thiocyanates, thioimidates, and thioglycosides. Carbohydr Res 2010; 345:2146-50. [PMID: 20817156 DOI: 10.1016/j.carres.2010.08.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 08/05/2010] [Accepted: 08/05/2010] [Indexed: 11/16/2022]
Abstract
Comparative side-by-side glycosylation studies demonstrated that glycosyl thiocyanates, thioimidates, and thioglycosides provide comparative stereoselectivities in glycosylations. Very high α-stereoselectivity that was previously recorded for glycosyl thiocyanates can be achieved, but only if glycosyl acceptors are equipped with electron-withdrawing acyl substituents. Partially benzylated glycosyl acceptors provided relatively modest stereoselectivity, which was on a par with other common glycosyl donors. Accordingly, thioimidates and thioglycosides showed high stereoselectivity similarly to that of thiocyanates with different classes of acylated primary and secondary glycosyl acceptors.
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Affiliation(s)
- Sophon Kaeothip
- Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Boulevard, St. Louis, MO 63121, USA
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17
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Mannerstedt K, Ekelöf K, Oscarson S. Evaluation of thioglycosides of Kdo as glycosyl donors. Carbohydr Res 2006; 342:631-7. [PMID: 17027943 DOI: 10.1016/j.carres.2006.08.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Accepted: 08/22/2006] [Indexed: 10/24/2022]
Abstract
The use of Kdo thioglycosides as glycosyl donors using DMTST, IBr/AgOTf and NIS/AgOTf as promoters has been evaluated. Activation at low temperature allowed to escape the formation of 2,3-glycal byproducts to give glycosides in high yield and with good beta-anomeric selectivity. The use of diethyl ether as solvent and (especially) isopropylidene acetals as protecting groups improved the alpha-anomeric selectivity. NIS/AgOTf as promoter surprisingly yielded the 3-iodo-product via the glycal intermediate.
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Affiliation(s)
- Karin Mannerstedt
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
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18
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Ichiyanagi T, Yamasaki R. Anomeric O-acylation of Kdo using alkyl and aryl isocyanates. Carbohydr Res 2005; 340:2682-7. [PMID: 16199022 DOI: 10.1016/j.carres.2005.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 08/18/2005] [Accepted: 09/01/2005] [Indexed: 10/25/2022]
Abstract
To develop a convenient method for the preparation of an alpha-Kdo derivative carrying a functional spacer at the reducing end, we examined anomeric O-acylation using Kdo and halogenated alkyl/aryl isocyanates as nucleophile and electrophiles, respectively. Reaction of a Kdo derivative with 2-chloroethyl isocyanate in the presence of DMAP gave an alpha-spiro product (82%) and an alpha-Kdo derivative of a dimeric isocyanate adduct (10%). Similar reaction with 4-(chloromethyl)phenyl isocyanate gave only the corresponding alpha-spiro product (81%). The NMR data show that the pyranose rings of both the alkyl and aryl spiro products adopt the 5C2 conformation. Thus, we accomplished alpha-selective anomeric O-acylation by coupling the Kdo derivative with alkyl and aryl isocyanates.
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Affiliation(s)
- Tsuyoshi Ichiyanagi
- Department of Biochemistry and Biotechnology, Tottori University, Tottori 680-8553, Japan
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Holme T, Rahman M, Jansson PE, Widmalm G. The lipopolysaccharide of moraxella catarrhalis structural relationships and antigenic properties. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 265:524-9. [PMID: 10504382 DOI: 10.1046/j.1432-1327.1999.00731.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Moraxella catarrhalis has recently been shown to be both widespread and pathogenic, in contrast to previous reports. Several factors have been suggested as virulence factors, lipopolysaccharide (LPS) being one. Recent studies have shown the LPS to be without the O-chain, i.e. the polysaccharide part, and to have specific structural features corresponding to each of the three serogroups, A, B and C. The structures resemble in many respects those present in other Gram-negative nonenteric bacteria, with a galabiosyl element as a prominent common denominator. The presence of such common structures suggests that the LPS of these bacteria might be a part of a mechanism of survival for bacteria colonizing the human host.
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Affiliation(s)
- T Holme
- Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden
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Bernlind C, Oscarson S. Synthesis of a Branched Heptose- and Kdo-Containing Common Tetrasaccharide Core Structure of Haemophilus influenzae Lipopolysaccharides via a 1,6-Anhydro-l-glycero-β-d-manno-heptopyranose Intermediate. J Org Chem 1998. [DOI: 10.1021/jo9808573] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christian Bernlind
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
| | - Stefan Oscarson
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
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Oscarson S, Tedebark U, Turek D. Synthesis of colitose-containing oligosaccharide structures found in polysaccharides from Vibrio cholerae O139 synonym Bengal using thioglycoside donors. Carbohydr Res 1997; 299:159-64. [PMID: 9163895 DOI: 10.1016/s0008-6215(97)00003-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The syntheses of the two colitose-containing trisaccharides 8-methoxycarbonyloctyl (3,6-dideoxy-alpha-L-xylo-hexopyranosyl)-(1-->2)-beta-D-galactopyranosyl -(1-->3)-2-acetamido-2-deoxy-beta-D-glucopyranoside and 8-methoxycarbonyloctyl beta-D-galactopyranosyl-(1-->3)-[(3,6- dideoxy-alpha-L-xylo-hexopyranosyl)-(1-->4)]-2-acetamido-2-deoxy-beta-D- glucopyranoside, and tetrasaccharide 8-methoxycarbonyloctyl (3,6-dideoxy-alpha-L-xylo-hexopyranosyl)-(1-->2)-beta-D-galactopyranosyl - (1-->3)-[(3,6-dideoxy-alpha-L-xylo-hexopyranosyl)-(1-->4)]-2-acetamido-2 -deoxy- beta-D-glucopyranoside are described. The oligosaccharides correspond to structures found in the capsular polysaccharide and the lipopolysaccharide of Vibrio cholerae O139 and also to lipopolysaccharide structures of E. coli O55 and Salmonella greenside. The colitose residues were introduced via dimethyl(methylthio)sulfonium trifluoromethanesulfonate promoted glycosylations using colitose thioglycosides as glycosyl donors.
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Affiliation(s)
- S Oscarson
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Sweden
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Ekelöf K, Oscarson S. Synthesis of Oligosaccharide Structures from the Lipopolysaccharide of Moraxella catarrhalis. J Org Chem 1996; 61:7711-7718. [PMID: 11667725 DOI: 10.1021/jo960789p] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis of the octasaccharide [p-(trifluoroacetamido)phenyl]ethyl 4-O-[2-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-beta-D-glucopyranosyl]-6-O-[2-O-[4-O-(4-O-alpha-D-galactopyranosyl-beta-D-galactopyranosyl)-alpha-D-glucopyranosyl]-beta-D-glucopyranosyl]-3-O-beta-D-glucopyranosyl-alpha-D-glucopyranoside, representing the outer part of the lipooligosaccharide from Moraxella catarrhalis serotype A, is described, together with a hepta-, a hexa-, and a pentasaccaride, composing parts thereof with shorter oligosaccharide chains substituted in the 6-position of the central 3,4,6-branched glucose moiety. The versatility of the use of thioglycosides in oligosaccharide synthesis is shown, since throughout the synthesis thioglycosides are used as glycosyl donor precursors, either directly in dimethyl(methylthio)sulfonium triflate (DMTST)-promoted coupling reactions or after conversion to the corresponding glycosyl bromide in silver triflate-promoted couplings. The effects of different protecting groups, anomeric leaving groups, and solvents used in the various coupling reactions are often substantial, which necessitates the use of easily convertible intermediates.
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Affiliation(s)
- Kerstin Ekelöf
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
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