- Acetobromomaltose, a new source of carbohydrate radicals. EPR characterisation of maltosyl and 2-deoxymaltos-2-yl radicals and syntheses of tetrasaccharide-like mimics, maltal, 3-α-maltosyl propiononitrile, 1,5-anhydromaltitol and 2-deoxymaltopyranoside
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The acetoxy-protected maltosyl radical 1, obtained through bromine abstraction from acetobromomaltose (ABM), was studied by means of EPR spectroscopy. At room temperature, only the spectrum of 1 was observed, but at higher temperatures a second radical, t
- Alberti, Angelo,Bertini, Sabrina,Comoli, Maura,Guerrini, Marco,Mele, Andrea,Vismara, Elena
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- Iterative synthesis of Leishmania phosphoglycans by solution, solid-phase, and polycondensation approaches without involving any glycosylation
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A general strategy (solution, solid-phase, and polycondensation) for the synthesis of antigenic phosphoglycans (PG) of the protozoan parasite Leishmania is presented. Phosphoglycans constitute the variable structural and functional domain of major cell-su
- Ruhela, Dipali,Vishwakarma, Ram A.
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- Synthesis of C-Oligosaccharides through Versatile C(sp3)?H Glycosylation of Glycosides
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C-oligosaccharides are pharmacologically relevant because they are more hydrolysis-resistant than O-oligosaccharides. Despite indisputable advances, C-oligosaccharides continue to be underdeveloped, likely due to a lack of efficient and selective strategies for the assembly of the interglycosidic C?C linkages. In contrast, we, herein, report a versatile and robust strategy for the synthesis of structurally complex C-oligosaccharides via catalyzed C(sp3)?H activations. Thus, a wealth of complex interglycosidic (2→1)- and (1→1)-C-oligosaccharides becomes readily available by palladium-catalyzed C(sp3)?H glycoside glycosylation. The isolation of key palladacycle intermediates and experiments with isotopically-labeled compounds identified a trans-stereoselectivity for the C(sp3)?H glycosylation. The glycoside C(sp3)?H activation manifold was likewise exploited for the diversification of furanoses, pyranoses and disaccharides.
- Ackermann, Lutz,Kopp, Adelina,Wu, Jun
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- 2-nitroglycal and efficient synthesis method thereof
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The invention discloses an efficient synthesis method of 2-nitroglycal, and belongs to the technical field of synthesis of sugar. The structure of the 2-nitroglycal is shown in the specification. Secondly, the invention also provides a preparation method of the 2-nitro saccharide alkene, and the preparation method provided by the invention can be used for efficiently preparing the 2-nitroglycal through one-step synthesis.
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Paragraph 0075; 0077; 0080-0081
(2021/08/06)
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- From 1,4-Disaccharide to 1,3-Glycosyl Carbasugar: Synthesis of a Bespoke Inhibitor of Family GH99 Endo-α-mannosidase
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Understanding the enzyme reaction mechanism can lead to the design of enzyme inhibitors. A Claisen rearrangement was used to allow conversion of an α-1,4-disaccharide into an α-1,3-linked glycosyl carbasugar to target the endo-α-mannosidase from the GH99 glycosidase family, which, unusually, is believed to act through a 1,2-anhydrosugar "epoxide" intermediate. Using NMR and X-ray crystallography, it is shown that glucosyl carbasugar α-aziridines can act as reasonably potent endo-α-mannosidase inhibitors, likely by virtue of their shape mimicry and the interactions of the aziridine nitrogen with the conserved catalytic acid/base of the enzyme active site.
- Lu, Dan,Zhu, Sha,Sobala, Lukasz F.,Bernardo-Seisdedos, Ganeko,Millet, Oscar,Zhang, Yongmin,Jiménez-Barbero, Jesus,Davies, Gideon J.,Sollogoub, Matthieu
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supporting information
p. 7488 - 7492
(2019/01/03)
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- Direct C-H Trifluoromethylation of Glycals by Photoredox Catalysis
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A mild, efficient, and practical transformation for the direct C-H trifluoromethylation of glycals under visible light has been reported for the first time. This reaction employed fac-Ir3+(ppy)3 as the photocatalyst, Umemoto's reagent as the CF3 source, and a household blue LED or sunlight as the light source. Glycals bearing both electron-withdrawing and -donating protective groups performed this reaction smoothly. This visible light-mediated trifluoromethylation reaction was highlighted by the trifluoromethylation of the biologically important Neu2en moiety.
- Wang, Bang,Xiong, De-Cai,Ye, Xin-Shan
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supporting information
p. 5698 - 5701
(2015/12/01)
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- Synthesis of 2-deoxy-2,2-difluoro-α-maltosyl fluoride and its X-ray structure in complex with Streptomyces coelicolor GlgEI-V279S
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Streptomyces coelicolor (Sco) GlgEI is a glycoside hydrolase involved in α-glucan biosynthesis and can be used as a model enzyme for structure-based inhibitor design targeting Mycobacterium tuberculosis (Mtb) GlgE. The latter is a genetically validated drug target for the development of anti-Tuberculosis (TB) treatments. Inhibition of Mtb GlgE results in a lethal buildup of the GlgE substrate maltose-1-phosphate (M1P). However, Mtb GlgE is difficult to crystallize and affords lower resolution X-ray structures. Sco GlgEI-V279S on the other hand crystallizes readily, produces high resolution X-ray data, and has active site topology identical to Mtb GlgE. We report the X-ray structure of Sco GlgEI-V279S in complex with 2-deoxy-2,2-difluoro-α-maltosyl fluoride (α-MTF, 5) at 2.3 ? resolution. α-MTF was designed as a non-hydrolysable mimic of M1P to probe the active site of GlgE1 prior to covalent bond formation without disruption of catalytic residues. The α-MTF complex revealed hydrogen bonding between Glu423 and the C1F which provides evidence that Glu423 functions as proton donor during catalysis. Further, hydrogen bonding between Arg392 and the axial C2 difluoromethylene moiety of α-MTF was observed suggesting that the C2 position tolerates substitution with hydrogen bond acceptors. The key step in the synthesis of α-MDF was transformation of peracetylated 2-fluoro-maltal 1 into peracetylated 2,2-difluoro-α-maltosyl fluoride 2 in a single step via the use of Selectfluor.
- Thanna, Sandeep,Lindenberger, Jared J.,Gaitonde, Vishwanath V.,Ronning, Donald R.,Sucheck, Steven J.
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p. 7542 - 7550
(2015/07/15)
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- Synthesis of 2-deoxy-2,2-difluoro-α-maltosyl fluoride and its X-ray structure in complex with Streptomyces coelicolor GlgEI-V279S
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Streptomyces coelicolor (Sco) GlgEI is a glycoside hydrolase involved in α-glucan biosynthesis and can be used as a model enzyme for structure-based inhibitor design targeting Mycobacterium tuberculosis (Mtb) GlgE. The latter is a genetically validated drug target for the development of anti-Tuberculosis (TB) treatments. Inhibition of Mtb GlgE results in a lethal buildup of the GlgE substrate maltose-1-phosphate (M1P). However, Mtb GlgE is difficult to crystallize and affords lower resolution X-ray structures. Sco GlgEI-V279S on the other hand crystallizes readily, produces high resolution X-ray data, and has active site topology identical to Mtb GlgE. We report the X-ray structure of Sco GlgEI-V279S in complex with 2-deoxy-2,2-difluoro-α-maltosyl fluoride (α-MTF, 5) at 2.3 ? resolution. α-MTF was designed as a non-hydrolysable mimic of M1P to probe the active site of GlgE1 prior to covalent bond formation without disruption of catalytic residues. The α-MTF complex revealed hydrogen bonding between Glu423 and the C1F which provides evidence that Glu423 functions as proton donor during catalysis. Further, hydrogen bonding between Arg392 and the axial C2 difluoromethylene moiety of α-MTF was observed suggesting that the C2 position tolerates substitution with hydrogen bond acceptors. The key step in the synthesis of α-MDF was transformation of peracetylated 2-fluoro-maltal 1 into peracetylated 2,2-difluoro-α-maltosyl fluoride 2 in a single step via the use of Selectfluor.
- Thanna, Sandeep,Lindenberger, Jared J.,Gaitonde, Vishwanath V.,Ronning, Donald R.,Sucheck, Steven J.
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p. 7542 - 7550
(2015/11/27)
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- A facile synthesis of sialylated oligolactosamine glycans from lactose via the Lafont intermediate
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The 2-aminophosphonium iodide lactosamine glycoside (Lafont intermediate) readily obtained from lactose has been previously shown not to be amenable to derivatization for oligosaccharide synthesis, but has now been successfully converted via the salicylaldehyde imine into suitably protected lactosamine building blocks (13-16) for glycosylation. The titled strategy has enabled us to rapidly synthesize the Neu5Ac-α-2,3LacNAc-β-1,3LacNAc pentasaccharide and Neu5Ac-α-2,3LacNAc-β-1,3LacNAc-β-1,3LacNAc heptasaccharide. Furthermore, this strategy has been adopted for the synthesis of other 2-amino sugars (e.g., 23-27), which provides a useful method for the preparation of 2-amino sugar building blocks.
- Peng, Peng,Liu, Han,Gong, Jianzhi,Nicholls, John M.,Li, Xuechen
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p. 3634 - 3639
(2014/08/18)
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- A convenient and efficient synthesis of glycals by zinc nanoparticles
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A simple and efficient method for the synthesis of pyranoid glycals utilizing the reductive elimination of glycopyranosyl bromides by zinc nanoparticles in an acetate buffer is described. A variety of pyranoid glycals derivatives were obtained, especially for the synthesis of 6-deoxy-4,6-O-benzylidene and disaccharide glycals with good yields.
- Xu, Yun,Wang, Wenjun,Cai, Yu,Yang, Xia,Wang, Peng George,Zhao, Wei
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p. 46662 - 46665
(2014/12/10)
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- Polymethylhydrosiloxane (PMHS): A convenient option for synthetic applications of the iodine/silane combined reagent - Straightforward entries to 2-hydroxyglycals and useful building-blocks of glucuronic acid and glucosamine
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Polymethylhydrosiloxane (PMHS) proved to be a practically convenient alternative to triethylsilane in a large set of synthetic elaborations entailing the quick generation of glycosyl iodides with a iodine/silane combined reagent. In addition, the scope of this combined reagent was expanded to the especially fast generation of 2-acetoxyglycals, and the rapid synthesis of useful building-blocks of D-glucuronic acids and D-glucosamine. All the synthetic targets were obtained in especially short times either via one-pot procedures or through experimental sequences devoid of laborious chromatographical purifications of intermediates. Polymethylhydrosiloxane (PMHS) is a practically convenient alternative to triethylsilane in a large set of synthetic elaborations entailing the quick generation of glycosyl iodides with a iodine/silane combined reagent. Copyright
- Giordano, Maddalena,Iadonisi, Alfonso
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p. 125 - 131
(2013/02/25)
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- Synthesis of multivalent N-acetyl lactosamine modified quantum dots for the study of carbohydrate and galectin-3 interactions
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Ternary core/shell CdSeS/ZnS-QDs coated with N-acetyl lactosamine was prepared as a fluorescent probe to study the interactions of N-acetyl lactosamine and galectin-3. The synthesis of N-acetyl lactosamine was achieved through the 'azidoiodoglycosylation'
- Yang, Yang,Xue, Xiao-Chao,Jin, Xiao-Feng,Wang, Li-Jun,Sha, Yin-Lin,Li, Zhong-Jun
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experimental part
p. 7148 - 7154
(2012/09/07)
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- Synthesis of fluorinated maltose derivatives for monitoring protein interaction by 19F NMR
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A novel reporter system, which is applicable to the 19F NMR investigation of protein interactions, is presented. This approach uses 2-F-labeled maltose as a spy ligand to indirectly probe protein-ligand or protein-protein interactions of proteins fused or tagged to the maltose-binding protein (MBP). The key feature is the simultaneous NMR observation of both 19F NMR signals of gluco/ manno-type-2-F-maltose-isomers; one isomer (α-gluco-type) binds to MBP and senses the protein interaction, and the nonbinding isomers (β-gluco- and/or α/β-manno-type) are utilized as internal references. Moreover, this reporter system was used for relative affinity studies of fluorinated and nonfluorinated carbohydrates to the maltose-binding protein, which were found to be in perfect agreement with published X-ray data. The results of the NMR competition experiments together with the established correlation between 19F chemical shift data and molecular interaction patterns, suggest valuable applications for studies of protein-ligand interaction interfaces.
- Braitsch, Michaela,Kaehlig, Hanspeter,Kontaxis, Georg,Fischer, Michael,Kawada, Toshinari,Konrat, Robert,Schmid, Walther
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p. 448 - 455
(2012/06/30)
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- A rapid synthesis of pyranoid glycals promoted by β-cyclodextrin and ultrasound
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A convenient and environmentally benign procedure for the synthesis of glycals from glycosyl bromides with very low zinc dust loading (1.5 equiv.) is described. The process is activated by β-cyclodextrin and ultrasound. Based on 19 samples, this method has been demonstrated to be highly effective for a broad range of glycosyl bromides, including acid- or base-sensitive and disaccharide glycosyl bromides. A yield of 85%-96% of glycals was obtained. Copyright
- Zhao, Jinzhong,Shao, Huawu,Wu, Xin,Shi, Shaojing
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experimental part
p. 1434 - 1440
(2011/11/05)
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- Synthesis and galectin-binding activities of mercaptododecyl glycosides containing a terminal β-galactosyl group
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Mercaptododecyl glycosides containing a terminal β-galactosyl group were prepared from d-galactose or from d-lactose via hexa-O-acetyl-lactal (10) as a key intermediate. Interactions of these glycolipids (5 kinds) and galectins (β-galactoside binding lectins, 6 species) were evaluated by surface plasmon resonance (SPR) method. High binding responses were observed for the lactoside, 2-deoxy-lactoside, and lactosaminide with some galectins (Gal-3, -4, -8), whereas the galactoside and 2,3-dideoxy-lactoside showed low binding activities.
- Murakami, Teiichi,Yoshioka, Kyoko,Sato, Yukari,Tanaka, Mutsuo,Niwa, Osamu,Yabuki, Soichi
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scheme or table
p. 1265 - 1269
(2011/04/16)
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- Synthesis of benzaldehyde-functionalized glycans: A novel approach towards glyco-SAMs as a tool for surface plasmon resonance studies
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In recent years the interest in tools for investigating carbohydrateprotein (CPI) and carbohydrate-carbohydrate interactions (CCI) has increased significantly. For the investigation of CPI and CCI, several techniques employing different linking methods are available. Surface plasmon resonance (SPR) imaging is a most appropriate tool for analyzing the formation of self-assembled monolayers (SAM) of carbohydrate derivatives, which can mimic the glycocalyx. In contrast to the SPR imaging methods used previously to analyze CPI and CCI, the novel approach reported herein allows a facile and rapid synthesis of linker spacers and carbohydrate derivatives and enhances the binding event by controlling the amount and orientation of ligand. For immobilization on biorepulsive amino-functionalized SPR chips by reductive amination, diverse aldehyde-functionalized glycan structures (glucose, galactose, mannose, glucosamine, cellobiose, lactose, and lactosamine) have been synthesized in several facile steps that include olefin metathesis. Effective immobilization and the first binding studies are presented for the lectin concanavalin A.
- Kopitzki, Sebastian,Jensen, Knud J.,Thiem, Joachim
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supporting information; experimental part
p. 7017 - 7029
(2010/09/10)
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- A mild and environmentally benign method for the synthesis of glycals in PEG-600/H2O
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Glycals were synthesized via a simple, mild, convenient and environmentally benign procedure, in which protected glycosyl bromides undergo the reductive elimination in the presence of zinc in PEG-600/H2O at room temperature. The glycals were obtained in 75-92% isolated yields.
- Zhao, Jinzhong,Wei, Shanqiao,Ma, Xiaofeng,Shao, Huawu
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experimental part
p. 1124 - 1127
(2010/05/02)
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- Versatile and mild synthesis of Di- and trisaccharidic 2-enopyranosyl cyanides by cyanation of per-O-acetylglycals with trimethylsilyl cyanide catalyzed by palladium(II) acetate
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A catalytic amount (1-2 mol%) of palladium(II) acetate was found to work as a catalyst for the cyanation of di- and trisaccharidic per-O-acetylglycals with trimethylsilyl cyanide to afford di- and trisaccharidic 2-enopyranosyl cyanides in high yields and in moderate stereoselectivities. Georg Thieme Verlag Stuttgart.
- Xu, Xiaoyong,Tan, Qitao,Hayashi, Masahiko
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p. 770 - 776
(2008/09/21)
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- Efficient and direct synthesis of saccharidic 1,2-ethylidenes, orthoesters, and glycals from peracetylated sugars via the in situ generation of glycosyl iodides with I2/Et3SiH
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Peracetylated sugars can be efficiently converted into the corresponding 1,2-ethylidenes, -orthoesters, and -glycals via the in situ generation of glycosyl iodides promoted by I2/Et3SiH. The approach is straightforward and avoids isolation of the sensitive iodinated intermediates.
- Adinolfi, Matteo,Iadonisi, Alfonso,Ravidà, Alessandra,Schiattarella, Marialuisa
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p. 7863 - 7866
(2007/10/03)
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- Mild synthesis of disaccharidic 2,3-enopyranosyl cyanides and 2-C-2-deoxy pyranosyl cyanides with Hg(CN)2/HgBr2/TMSCN
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Lewis acid-catalyzed dimerization of mono- and disaccharidic per-O-acetylated glycals gave di- and tetrasaccharidic O-acetylated C-glycosides, respectively. 2,3-Enopyranosyl cyanides were obtained from per-O-acetylated glycals by a new, mild anomeric SN′-acetoxy displacement with Hg(CN)2/HgBr2/TMSCN. Per-O-acetylated 2-C-2-deoxy-pyranoses were converted into pyranosyl cyanides by the same reagent. An unprecedented acetic acid elimination from dimers with D-galacto- and L-fuco-configurations accompanied the SN-displacement under those conditions. A new set of 1H NMR coupling constants for 2,3-enopyranosyl systems was used for configurational assignment of complicated tetrasaccharide mimics.
- Franz, Andreas H.,Wei, YiQiu,Samoshin, Vyacheslav V.,Gross, Paul H.
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p. 7662 - 7669
(2007/10/03)
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- A new catalyst for the reductive elimination of acylated glycosyl bromides to form glycals
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Ethylene-N,N′-bis(salicylideneiminato(IV)) {VO(salen)} was developed as a catalyst for the reductive elimination of acylated glycosyl bromides to form glycals. VO(salen) to be an effective catalyst for the preparation of glycals on a multi-gram scale. The catalyst was green in colour and changed to brown as the reaction progress.
- Stick, Robert V.,Stubbs, Keith A.,Tilbrook, D. Matthew G.,Watts, Andrew G.
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- Synthesis of the tetrasaccharide cap domain of the antigenic lipophosphoglycan of Leishmania donovani parasite
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In this paper we report a new synthesis of the immunologically important tetrasaccharide terminal cap domain [Galp(1-4)-β-[Manp-(1-2)-α-Manp-(1-2)-α]-Manp] of lipophosphoglycan (LPG); the major cell surface GPI molecule and key virulence factor of the protozoan parasite Leishmania donovani. The synthetic approach provided a short convergent route for the LPG cap motif from lactose and mannose starting materials. The synthesis was then applied for the preparation of a radiolabelled cap epitope for macrophage receptor binding and immunological studies. (C) 2000 Elsevier Science Ltd.
- Upreti,Ruhela,Vishwakarma
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p. 6577 - 6584
(2007/10/03)
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- Glycosylated analogs of fusidic acid
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Novel analogs of fusidic acid are described with one or more carbohydrate units attached. Certain glycosylated analogs of fusidic acid have enhanced solubility properties in diluents or excipient of choice as compared to unmodified fusidic acid. Certain glycosylated analogs may be employed as chemotherapeutic agents and particular analogs may be useful for fighting anti-microbial infections.
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- Development of a catalytic cycle for the generation of C1-glycosyl carbanions with Cp2TiCl2: Application to glycal synthesis
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A catalytic cycle has been developed for the conversion of glycosyl halides to their corresponding glycals using Cp2TiCl2. This process can be effectively used with only 30% of the in situ generated single electron reducing agent in contrast to the 2 equivalents normally employed. (C) 2000 Published by Elsevier Science Ltd.
- Hansen,Daasbjerg,Skrydstrup
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p. 8645 - 8649
(2007/10/03)
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- Synthesis of the phosphodisaccharide repeat of antigenic lipophosphoglycan of Leishmania donovani parasite
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Synthesis of the immunologically important and structurally unusual phosphodisaccharide repeat unit (Galp1,4β-Manp-1α-phosphate) of the lipophosphoglycan cell surface GPI molecule of the protozoan parasite Leishmania donovani has been carried out using la
- Upreti, Mani,Vishwakarma, Ram A.
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p. 2619 - 2622
(2007/10/03)
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- A convenient synthesis of glycals employing in-situ generated Cp2TiCl
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Reductive elimination of acetylated glycosyl bromides to the corresponding glycal is easily achieved by mixing the bromide with Cp2TiCl2 and Mn in THF, and hence does not require the separate preparation of Cp2TiCl using glove-box techniques.
- Hansen, Thomas,Krintel, Sussie L.,Daasbjerg, Kim,Skrydstrup, Troels
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p. 6087 - 6090
(2007/10/03)
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- A convenient, highly efficient one-pot preparation of peracetylated glycals from reducing sugars
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A convenient, highly efficient, one-pot, three-step procedure has been developed for the synthesis of peracetylated glycal derivatives from various reducing sugars including D-glucose, D-galactose, L-rhamnose, L-arabinose, D-maltose, D-lactose, and maltotriose. This procedure involves peracetylation of the reducing sugars with acetic anhydride and HBr/acetic acid followed by the transformation of the anomeric acetates to the corresponding bromides with additional HBr/acetic acid and finally reductive elimination of the 1-bromo and 2-acetoxy groups with Zn/CuSC4·5H2O in acetic acid/water containing sodium acetate. The overall yields of purified peracetylated glycals from the corresponding sugars range from 50 - 98%.
- Shull, Brian K.,Wu, Zhijun,Koreeda, Masato
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p. 955 - 964
(2007/10/03)
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- SmI2-promoted chemistry at the anomeric center of carbohydrates. Reductive formation and reaction of glycosyl samarium (III) reagents
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Reaction of 3,4,6-tri-O-benzyl-2-deoxy-α-D-arabino-hexopyranosyl chloride at room temperature with the efficient single electron transfer system of SmI2-THF-HMPA, in the presence of cyclopentanone (Barbier conditions) gave selectively the corresponding α-C-glycoside in 70percent yield.It is postulated that the reactive transient intermediate is a chiral anomeric organosamarium (III) species.Lower yields were obtained in the presence of aldehydes, such as n-butanal or isobutanal.It is also demonstrated that glycosyl phenyl sulfones undergo reductive samariation. 2,3,4,6-Tetra-O-benzyl-β-D-glucopyranosyl phenyl sulfone reacted with cyclopentanone, in the presence of SmI2-THF-HMPA, to give the corresponding β-C-glycoside selectively in 25percent yield, together with the elimination product (40percent).When the protecting group at C-2 was an acetate, a very fast β-elimination of the organosamarium intermediate occurred to give a practically quantitative yield of a substituted glycal.This work constitutes the first application of samarium(II) iodide to the reductive metallation of the anomeric center of carbohydrates.Key words: samarium diiodide / sulfones / carbohydrates / glycals / C-glycosides
- Pouilly, P. de,Chenede, A.,Mallet, J.-M.,Sinay, P.
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p. 256 - 265
(2007/10/02)
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- Reductive elimination of glycosyl phenyl sulfones by SmI2-HMPA: A convenient synthesis of substituted pyranoid glycals
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A series of substituted glycosyl phenyl sulfones was converted into glycals after reductive samariation with SmI2 in the presence of hexamethylphosphoric triamide, followed by elimination of the substituent at C-2. Practically quantitative yields were obtained when the leaving group was an acetate, as illustrated here with seven substrates.
- De Pouilly, Pierre,Chenede, Alain,Mallet, Jean-Maurice,Sinay, Pierre
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p. 8065 - 8068
(2007/10/02)
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