All cells are coated in carbohydrates and glycoconjugates. Today, after decades where sugars were regarded mainly as a means of energy storage or simply as molecular material, it is now known that carbohydrates are deeply involved in cellular communication. This awareness of the biological importance of carbohydrates has led to glycosciences becoming an intriguing and fascinating field of interdisciplinary research. However, the structural diversity found in the carbohydrate regime is unparalleled which makes the biological study of carbohydrate recognition and understanding the processes involved rather complicated. In addition, the multivalent nature of most carbohydrate ligands constitutes a special challenge in glycoscience.
See also the Thematic Series:
Synthesis in the glycosciences II
Multivalent glycosystems for nanoscience
See videos about glycoscience at Beilstein TV.
Graphical Abstract
Figure 1: Structure of Lex analogues 1–3.
Figure 2: Monosaccharide glycosyl acceptors (4–6) and donors (7–9) used in this study.
Scheme 1: Synthesis of monosaccharide glycosyl acceptors 4–6.
Scheme 2: Synthesis of the galactosyl donor 8.
Scheme 3: Convergent synthesis of trisaccharides 29–32.
Scheme 4: Proposed mechanism for the desulfurization of thioacetate 31 under dissolving metal conditions.
Graphical Abstract
Figure 1: Structures of pentasaccharides 1 and 2.
Scheme 1: Preparation of pentasaccharide 8. 1) MeOH, acidic ion exchange resin; 2) Ac2O, pyridine; 3) 80% HOA...
Scheme 2: Preparation of pentasaccharide 14. 1) MeOH, acidic ion exchange resin; 2) Ac2O, pyridine; 3) 80% HO...
Figure 2: Roman numbering of saccharide units in all pentasaccharides for NMR assignment.
Graphical Abstract
Scheme 1: a) Boons’ chiral auxiliary-based approach to α-stereoselective glycosylations. b) Modified strategy...
Scheme 2: Benzyne generation from 1-ABT.
Scheme 3: Oxathiane donor synthesis.
Scheme 4: Arylation/acetate glycosylation of oxathiane glycosyl donors.
Graphical Abstract
Figure 1: Schematic representation of sugar aminoacids (SAAs) and (pseudo)amide oligosaccharide mimetics.
Figure 2: Natural SAAs structures and natural nucleosidic antibiotics.
Scheme 1: Synthetic route to the target amide-linked sialooligomers. (a) Fmoc-Cl, NaHCO3, H2O, dioxane, 0 °C....
Figure 3: The general structure of glycoamino acids and their corresponding oligomers.
Figure 4: Conformational analysis of the β(1→2)-amide-linked glucooligomer 9.
Figure 5: Short oligomeric chains of C-glycosyl D-arabino THF amino acid oligomers.
Figure 6: (A) Stereoview of the minimized structure of compound 16 (produced by a 500 ps simulation) that mos...
Figure 7: Structures of linear oxetane-β- and δ-SAA homo-oligomers 19–20.
Figure 8: 10-Membered ring H-bonds in compound 21 consistent with NMR and modelling investigations.
Figure 9: General structure of carbopeptoid-oligonucleotide conjugates.
Figure 10: Protected derivatives of 2,6-diamino-2,6-dideoxy-β-D-glucopyranosyl carboxylic acid 22 and 23.
Figure 11: Cyclic homo-oligomers containing glucopyranoid-SAAs.
Scheme 2: Strategy for solid-phase synthesis of cyclic trimers and tetramers containing pyranoid δ-SAAs.
Figure 12: Cyclic tetramers of L-rhamno- and D-gulo-configured oxetane-SAAs.
Figure 13: Aminoglycosidic antibiotics of the glycocinnamoylspermidine family.
Scheme 3: Synthesis of (thio)trehazoline, via triflate, from β-hydroxy(thio)urea.
Figure 14: Approaches to access pseudoamide-type oligosaccharide mimics.
Figure 15: Calystegine B2 analogues 38 and 39 with urea-linked disaccharide structure.
Figure 16: Rotameric equilibrium shift of 40 by formation of a bidentate hydrogen bond.
Figure 17: Nucleotide analogues with thiourea and S-methylisothiouronium linkers.
Scheme 4: Retrosynthetic approach to synthesize thiourea-linked glycooligomers.
Figure 18: Rotameric equilibria for β-(1→6)-thiourea-linked glucodimer 41.
Figure 19: Schematic representation of (a) cyclodextrin (CDs) and (b) cyclotrehalan (CTs) family members.
Scheme 5: Synthesis of guanidine-linked pseudodisaccharides via carbodiimide.
Figure 20: β(1→6)-Guanidine-linked pseudodi- and pseudotrisaccharides 47 and 48.
Scheme 6: Synthesis of N-benzylguanidine-linked CT2 50.
Figure 21: Structure of RNG and DNG.
Figure 22: Preparation of Fmoc-guanidinium derivatives.
Figure 23: Structures of the homo-oligomeric RNG derivatives 51–55.
Figure 24: Phosphoramidite building block 56.
Figure 25: Structures of DNGs 57–65.
Figure 26: Structure of the phosphoramidite building block 66.
Graphical Abstract
Figure 1: Typical representatives of iminosugars.
Figure 2: N-Modified iminosugars 5–9 as potential pharmacological chaperones.
Figure 3: Structure of NOEV 10.
Scheme 1: Three-step-synthesis of partially protected 1-deoxy-D-galactonojirimycin derivative 12 from 10 via ...
Scheme 2: Synthesis of N-(6-aminohexyl)-1-deoxygalactonojirimycin (15) from 12 via 14.
Scheme 3: Synthesis of lipophilic 1-deoxy-D-galactonojirimycin derivatives 16–18 by chemoselective acylation ...
Scheme 4: Synthesis of compounds 19 as well as 20 from primary amine 15.
Scheme 5: Synthesis of compound 22.
Graphical Abstract
Scheme 1: New glucosamine-based bis(oxazoline) ligands with their pyranose conformation and application in as...
Figure 1: Planned modifications at pyranose position 3 of carbohydrate bis(oxazolines).
Scheme 2: Synthesis of allo-configured bis(oxazolines) 3-O-Ac alloBox (14) and Ac alloBox (16) from thiogluco...
Scheme 3: Preparation of ligands 3-deoxy glucoBox (21) and Ac 3-deoxy glucoBox (23) from key intermediate 7.
Scheme 4: Preparation of ligand 3-O-Formyl glucoBox (26) from bis(amide) 24.
Figure 2: Impact of structural ligand modifications on the stereoselectivity of cyclopropanations.
Graphical Abstract
Scheme 1: The natural forms of sialic acids, human N-acetylneuraminic acid (Neu5Ac, 1) and mammalian N-glycol...
Scheme 2: Synthesis of N-(1-oxohex-5-ynyl)neuraminic acid (Neu5Hex 3).
Scheme 3: Metabolic pathway of Ac4GlcNAz and the genetic control of Neu5Ac 1 synthesis by feedback inhibition...
Scheme 4: Proposed metabolic pathway of Neu5Hex 3 based on known mechanisms of Neu5Gc 2 uptake [5]. TGN: trans-G...
Scheme 5: Labelling of alkynylated neuraminic acid by azido-fluorescein.
Figure 1: Top left: HEp-2 cells incorporated with Ac4GlcNAz 16, labelled with alkynylated TAMRA at 580 nm. Bo...
Graphical Abstract
Figure 1: Structures of the naturally occurring TN and TF antigens and the targeted Fmoc-β3hThr analogues.
Scheme 1: Synthesis of Fmoc-β3hThr antigen conjugates by Arndt–Eistert homologation.
Scheme 2: Solid-phase synthesis of the tumour-associated MUC1 α/β-hybrid glycopeptide analogue 8 carrying the...
Graphical Abstract
Figure 1: Aminoethyl glycosides (1–9) which were synthesised in this study.
Scheme 1: General reaction scheme for generation of aminoethyl glycosides. X = OAc, Br or Cl.
Scheme 2: Deprotection protocols.
Graphical Abstract
Figure 1: The H. influenzae outer core target structure.
Scheme 1: i. BH3, Bu2BOTf, THF/CH2Cl2, 85%; ii. TBDMSCl, pyridine, CH2Cl2, 90%; iii. TBDMSCl, pyridine, 92%; ...
Scheme 2: i. PhCH(OMe)2, CSA; ii. NaBH3CN, HCl/Et2O, THF, 80%; iii. NIS/AgOTf, CH2Cl2, 83%; iv. a) NaOMe, MeO...
Scheme 3: i. NIS/AgOTf, CH2Cl2, 77%; ii. a) H2S, pyridine, Et3N; b) CbzCl, pyridine, CH2Cl2, 91%; iii. TBAF, ...
Scheme 4: i. NaOMe, MeOH; ii. H2, Pd/C, MeOH/H2O; iii. 21, PivCl, pyridine, MeCN; iv. I2, H2O, pyridine; v. D...
Graphical Abstract
Figure 1: a) Connolly surface of FimH in complex with FimC [8]. The CRD known from X-ray structures at the tip o...
Figure 2: The bivalent glycopeptide 1 is the target molecule to test the hypothesis of two carbohydrate bindi...
Scheme 1: Synthesis of the eastern part of target molecule 1.
Scheme 2: Synthesis of the western part of target molecule 1.
Scheme 3: Synthesis of the target molecule 1 employing squaric acid diethylester (DES).
Graphical Abstract
Figure 1: The photoaffinity technique allows the identification of ligand binding sites of a receptor protein...
Figure 2: a) Three known photolabile α-D-mannosides that differ in the nature of the photoactive functional g...
Scheme 1: Synthesis of photoactive glycoamino acids 11 and 12. i) Fmoc-Asp-OtBu (for 7), Fmoc-Asp(OtBu)-OH (f...
Scheme 2: Photo-crosslinking experiments with the model peptide angiotensin II and the photoactive mannosides ...
Figure 3: Affino dot–blot with FimHtr and photoactive mannosides applied to nitrocellulose disks. It was irra...
Figure 4: MS/MS spectra of angiotensin II (a) and of angiotensin II, photo-crosslinked with diazirine 2 (b), ...
Graphical Abstract
Figure 1: spatial representation of structure 1.
Figure 2: structures of compounds 2–9.
Figure 3: ORTEP drawing for the 1·Ag(I) cation complex (ellipsoids are drawn at the 50% probability level and...