- Transition-Metal-Free Synthesis of C-Glycosylated Phenanthridines via K2S2O8-Mediated Oxidative Radical Decarboxylation of Uronic Acids
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We have developed an efficient protocol for the synthesis of C-glycosylated phenanthridines. Tetrafuranos-4-yl and pentapyranos-5-yl radicals, generated from K2S2O8-mediated oxidative decarboxylation of furan- and pyranuronic acids, undergo attack to 2-isocyanodiphenyls and ensuing homolytic aromatic substitution to provide diverse C-glycosylated phenanthridines in satisfactory yields without resort to transition metals. This reaction tolerates various functional groups, and enables ready synthesis of complex oligosaccharide-based phenanthridines. The C-glycosylated phenanthridine derived from β-cyclodextrin has been prepared, which might be potential in medicinal and biological chemistry due to its flexible conformation.
- Zhou, Xin,Wang, Peng,Zhang, Li,Chen, Pengwei,Ma, Mingxu,Song, Ni,Ren, Sumei,Li, Ming
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- Synthesis of three different galactose-based methacrylate monomers for the production of sugar-based polymers
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Glycopolymers, synthetic sugar-containing macromolecules, are attracting ever-increasing interest from the chemistry community. Glycidyl methacrylate (GMA) is an important building block for the synthesis of sugar based methacrylate monomers and polymers. Normally, glycidyl methacrylate shows some advantages such as reactivity against nucleophiles or milder synthetic conditions such as other reactive methacrylate monomers. However, condensation reactions of glycidyl methacrylate with for instance protected galactose monomer leads to a mixture of two products due to a strong competition between the two possible pathways: epoxide ring opening or transesterification. In this paper, we propose two alternative routes to synthesize regiospecific galactose-based methacrylate monomers using the epoxy-ring opening reaction. In the first alternative route, the protected galactose is first oxidized to the acid in order to make it more reactive against the epoxide of GMA. In the second route, the protected sugar was first treated with epichlorohydrin followed by the epoxy ring opening reaction with methacrylic acid, to create an identical analogue of the ring-opening product of GMA. These two monomers were polymerized using conventional radical polymerization and were compared to the previously known galactose-methacrylate one. The new polymers show similar thermal stability but lower glass transition temperature (Tg) with respect to the known galactose methacrylate polymer.
- Desport, Jessica S.,Mantione, Daniele,Moreno, Mónica,Sardón, Haritz,Barandiaran, María J.,Mecerreyes, David
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- Glyco- and peptidomimetics from three-component joullie-ugi coupling show selective antiviral activity
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Chlorination-elimination chemistry coupled with three-component Joullie-Ugi reaction and facile deprotection allowed efficient access to an array of polyhydroxylated pyrrolidines through parallel synthesis that may be considered to be a library of imino (
- Chapman, Timothy M.,Davies, Ieuan G.,Gu, Baohua,Block, Timothy M.,Scopes, David I. C.,Hay, Philip A.,Courtney, Stephen M.,McNeill, Luke A.,Schofield, Christopher J.,Davis, Benjamin G.
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- Visible-Light-Mediated, Chemo- and Stereoselective Radical Process for the Synthesis of C-Glycoamino Acids
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An approach for efficient synthesis of C-glycosyl amino acids is described. Different from typical photoredox-catalyzed reactions of imines, the new process follows a pathway in which α-imino esters serve as electrophiles in chemoselective addition reactions with nucleophilic glycosyl radicals. The process is highlighted by the mild nature of the reaction conditions, the highly stereoselectivity attending C-C bond formation, and its applicability to C-glycosylations using both armed and disarmed pentose and hexose derivatives.
- Ji, Peng,Zhang, Yueteng,Wei, Yongyi,Huang, He,Hu, Wenbo,Mariano, Patrick A.,Wang, Wei
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p. 3086 - 3092
(2019/05/01)
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- I2/PPh3-mediated facile synthesis of glycoconjugated N-acylbenzotriazoles
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A well-stabilized method for synthesis of N-acylbenzotriazoles from carboxylic acids using I2/PPh3 in anhydrous dichloromethane has been extended in glycochemistry to synthesize glycoconjugated N-acylbenzotriazoles with high yields at room temperature in 2-hour reaction time.
- Singh, Mala,Agrahari, Anand K.,Mishra, Nidhi,Singh, Anoop S.,Tiwari, Vinod K.
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p. 125 - 132
(2018/09/14)
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- A highly efficient TEMPO mediated oxidation of sugar primary alcohols into uronic acids using 1-chloro-1,2-benziodoxol-3(1H)-one at room temperature
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Oxidation of various sugar primary alcohols into corresponding uronic acids was demonstrated using 1-chloro-1,2-benziodoxol-3(1H)-one and TEMPO. The reaction proceeds at room temperature in good to excellent yields. Primary alcohols get oxidized selective
- Tiwari, Varsha,Badavath, Vishnu Nayak,Singh, Adesh Kumar,Kandasamy, Jeyakumar
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supporting information
p. 2511 - 2514
(2018/05/29)
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- A green and sustainable phosphine-free NHC-ruthenium catalyst for selective oxidation of alcohols to carboxylic acids in water
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In this work, we present a new catalytic system for the selective dehydrogenative oxidation of primary alcohols to carboxylic acids using a phosphine-free NHC-ruthenium catalyst in water under mild reaction conditions. With this catalytic system, a variety of primary alcohols have been converted to carboxylic acids respectively, in aqueous media, without using any additional oxidant; the only side product in this reaction is molecular hydrogen. This novel synthetic protocol is applied for direct oxidation of biologically active monosaccharides and polymers with primary alcohol groups in the side chain. The use of water as a solvent and oxygen donor as well as the absence of any toxic oxidizing agent make this atom economical reaction interesting from an environmental point of view.
- Malineni, Jagadeesh,Keul, Helmut,M?ller, Martin
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supporting information
p. 17409 - 17414
(2015/10/12)
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- Synthesis of novel glycopeptidomimetics via Nβ-protected- amino alkyl isonitrile based Ugi 4C reaction
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The Ugi-4C reaction employing Nβ-protected-amino alkyl isonitrile, amino acid ester, aldehyde, and glycosyl acid has resulted in novel glycosylated peptidomimetics. The extension of MCR products for the synthesis of N,N′-orthogonally protected
- Vasantha, Basavalingappa,Prabhu, Girish,Basavaprabhu, Hosmani,Sureshbabu, Vommina V.
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p. 4409 - 4413
(2013/07/26)
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- Chiral lanthanoid dimers ligated by carbohydrate-based diketonates: Catalytic and luminescent properties
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The reaction of hydrated lanthanoid chlorides (Ln = La, Eu) with chiral, carbohydrate-based diketonate ligands has yielded dimeric species with Ln 2L6 composition as determined by MALDI mass spectrometry and single-crystal X-ray crystallography. The X-ray crystallographic analysis identified a chiral cavity formed by interligand repulsion able to coordinate dimethylformamide, prompting investigation of the catalytic properties of the dimers. Preliminary results indicate that the dimers display catalytic activity in thio-Michael addition reactions as well as metal-based luminescence in the case of europium.
- Gee, William J.,Hierold, Judith,MacLellan, Jonathan G.,Andrews, Philip C.,Lupton, David W.,Junk, Peter C.
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p. 3755 - 3760
(2011/11/14)
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- TPAP-catalyzed direct oxidation of primary alcohols to carboxylic acids through stabilized aldehyde hydrates
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We present a simple, mild, and highly effective method for the direct conversion of primary alcohols to carboxylic acids. TPAP serves as the catalyst, and NMO?H2O plays a dual role, acting as the co-oxidant and as a reagent for aldehyde hydrate stabilization. This previously unknown stabilizing effect of geminal diols by N-oxides is the key for the efficiency of the overall transformation.
- Schmidt, Andrea-Katharina C.,Stark, Christian B. W.
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supporting information; experimental part
p. 4164 - 4167
(2011/10/08)
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- Tempo-mediated oxidation of primary alcohols to carboxylic acids by exploitation of ethers inan aqueous-organicbiphase system
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Expeditious and benign methods for primary alcohol- carboxylicacid conversions with TEMPO were developed in abiphasic system composed of aslightlymiscible ether (THP) and aqueous layer. Easily available co-oxidants such as Py-HBr3, Bu4NBr3, and electrooxidation were successfully applied to generate N-oxoammonium species as a recyclable catalyst.
- Mei, Zhen-Wu,Ma, Li-Jian,Kawafuchi, Hiroyuki,Okihara, Takumi,Inokuchi, Tsutomu
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experimental part
p. 1000 - 1002
(2011/03/22)
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- m-iodosylbenzoic acid as a convenient recyclable reagent for highly efficient RuCl3-catalyzed oxidation of alcohols to carbonyl compounds
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m-Iodosylbenzoic acid selectively oxidizes primary and secondary alcohols to the respective carbonyl compounds in the presence of RuCl3 (0.5 mol%) at room temperature in aqueous acetonitrile. Separation of pure products is conveniently achieved by scavenging any aryl iodide by ion exchange with IRA-900 (hydroxide form) or by simple extraction of the basic aqueous solution with water. The reduced form of the reagent, m-iodobenzoic acid, can be easily recovered from the ion-exchange resin or from the basic aqueous solution by simple acidification with HCl. Georg Thieme Verlag Stuttgart.
- Yusubov, Mekhman S.,Gilmkhanova, Marina P.,Zhdankin, Viktor V.,Kirschning, Andreas
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p. 563 - 566
(2007/10/03)
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- Selective TEMPO-catalyzed chemicals vs. electrochemical oxidation of carbohydrate derivatives
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TEMPO-catalyzed electrochemical oxidation of carbohydrate derivatives was performed and compared with chemical oxidation, which requires the use of co-oxidants. Allyl-protected derivatives could be readily oxidized by both methods. Electrochemical selecti
- Barbier, Maximilien,Breton, Tony,Servat, Karine,Grand, Eric,Kokoh, Boniface,Kovensky, Jose
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p. 253 - 266
(2007/10/03)
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- A facile method for oxidation of primary alcohols to carboxylic acids and its application in glycosaminoglycan syntheses
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A convenient two-step, one-pot procedure was developed for the conversion of primary alcohols to carboxylic acids. The alcohol was first treated with NaOCl and TEMPO under phase-transfer conditions, followed by NaClO2 oxidation in one pot. This reaction is applicable to a wide range of alcohols and the mild reaction conditions are compatible with many sensitive functional groups, including electron-rich aromatic rings, acid-labile isopropylidene ketal and glycosidic linkages, and oxidation-prone thioacetal, p-methoxybenzyl, and allyl moieties. Several glycosaminoglycans such as heparin, chondroitin, and hyaluronic acid oligosaccharides have been synthesized in high yields by using this new oxidation protocol.
- Huang, Lijun,Teumelsan, Nardos,Huang, Xuefei
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p. 5246 - 5252
(2008/02/13)
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- PYRROLIDINE COMPOUNDS
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The present invention relates to a process for the preparation of a pyrrolidone compound of the formula (I): where R1 is substituted or unsubstituted alkyl, alkenyl, or alkynyl, or an aromatic or non-aromatic cyclic or heterocyclic structure, R
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Page/Page column 45-46
(2008/06/13)
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- Synthesis and hydrolysis behavior of side-chain functionalized norbornenes
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The stabilities of various functionalized norbornenes that are monomers for the ring-opening metathesis polymerization (ROMP) in aqueous solution were evaluated toward hydrolysis under a range of temperatures (37, 60, and 80 °C) and pH values (3-9). All monomers contain hydrolyzable linkages to pendant functional groups, and conclusions were drawn relating to how the chemical diversity of these pendant functional groups, in accordance with the pH and temperature variations, affect hydrolysis of the aforementioned linkages. The hydrolysis was monitored by reverse phase HPLC analysis, and/or NMR spectroscopy. As expected, monomers containing ester linkages were fairly labile at higher pH values, while acetal-based linkers were cleaved at lower pH values. β-Amino ester groups experienced a significant increase in hydrolysis rate, while carboxylic acid-containing monomers did not follow any clear trend. Saccharide-containing monomers exhibited unique behaviors for various pH values and temperature ranges.
- Carlise, Joseph R.,Kriegel, Robert M.,Rees Jr., William S.,Weck, Marcus
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p. 5550 - 5560
(2007/10/03)
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- Stereoselective synthesis of C-glycosides via Tebbe methylenation and Claisen rearrangement
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A variety of β-C-glycosides may be readily accessed in a stereoselective fashion from 3-OH glycal esters, via the use of Tebbe methylenation and subsequent thermal Claisen rearrangement. The use of carbohydrate ester substrates allows the formation of β(1
- Godage,Fairbanks
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p. 7589 - 7593
(2007/10/03)
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- Application of stabilized sugar-derived phosphoranes in the synthesis of higher carbon monosaccharides. First synthesis of a C21-dialdose
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C21 Monosaccharide precursors 11 and 12 were synthesized by a coupling of a C12 aldehyde 1 with C9 stabilized phosphoranes 2 and 3 respectively. The 'smaller' C19 sugar 13 was prepared from a C12 alde
- Jarosz, Slawomir,Salanski, Piotr,Mach, Mateusz
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p. 2583 - 2594
(2007/10/03)
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- Synthesis of peptidosialosides and peptidosaccharides
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Synthesis of a sialoside and neutral sugars connected to a galactose uronic acid by a peptide bond is described.
- Sabesan, Subramaniam
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p. 3127 - 3130
(2007/10/03)
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- Stereoselective ring-opening of acetylated pyranose-1,2-(ethyl orthoacetates)
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When acetylated pyranose-1,2-(ethyl orthoacetates) were hydrolyzed in acidic solvents, the ring-opening of the orthoacetate rings was influenced by the axial or equatorial OAc group at C-4 on the pyranoses; on acid-catalyzed hydrolysis, 3,4,6-tri-O-acetyl-α-D-galactopyranose- (8) and methyl 3,4-di-O-acetyl-α-D-galacturonatopyranose-1,2-(ethyl orthoacetate) (16) having an axial OAc group at C-4 on the pyranose rings gave 1,3,4,6-tetra-O-acetyl-α-D-galactopyranose (9) and methyl 1,3,4-tri-O-acetyl-α-D-galacturonatopyranose (23), respectively, whereas 3,4,6-tri-O-acetyl-α-D-glucopyranose- (10) and methyl 3,4-di-O-acetyl-α-D-glucuronatopyranose-1,2-(ethyl orthoacetate) (22) having an equatorial OAc group at C-4 on the pyranose rings gave 2,3,4,6-tetra-O-acetyl-D-glucopyranose (11) and methyl 2,3,4-tri-O-acetyl-D-glucuronatopyranose (24), respectively. On the acid-catalyzed hydrolysis, 3,4-di-O-acetylβ-L-arabinopyranose-1,2-(ethyl orthoacetate) (34) having an axial OAc group at C-4 on the pyranose ring gave a mixture of 1,3,4-tri-O-acetyl-β-L- (35) and 2,3,4-tri-O-acetyl-L-arabinopyranose (36). These selectivities of ring-opening of the 1,2-(orthoacetates) were considered to have resulted from the differences of the conformers of the 1,2-(orthoacids) intermediates derived from the 1,2-(orthoacetates) and the orientation of the acetyl groups at C-4 on the pyranose rings.
- Saito,Sumita,Ichinose,Kanda
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- D-Galacturonic Acid Drivatives, VI. - D-Galacturonic Acid Derivatives with Liquid Crystalline Properties
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Esters, thioesters, and amides of D-galacturonic acid have been synthesized from alcohols, thioalcohols, and amines having long alkyl chains.Key intermediates of the reaction with the different nucleophiles was the 1,2:3,4-di-O-isopropylidene-α-D-galactpy
- Vogel, Christian,Jeschke, Udo,Vill, Volkmar,Fischer, Hartmut
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p. 1171 - 1178
(2007/10/02)
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- Oxidation of partially protected carbohydrates at the nickel hydroxide electrode
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Primary hydroxy groups in pyranoses are oxidized in excellent yields to the corresponding carboxylic acids. In furanose 3 the yield of acid is only moderate. Secondary hydroxy groups are inert, aside from lactols. The different reactivity of secondary and primary hydroxy groups allows the chemoselective oxidation of 8 and 10.
- Schaefer, Hans J.,Schneider, Roy
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p. 715 - 724
(2007/10/02)
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- Galacturonic Acid Derivatives. I. Galacturonates from Acetyl- and Isopropylidene-D-galactopyranoses
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Galacturonic acid derivatives to be employed as glycosyl donors in saccharide synthesis are prepared from galacturonic acid itself or from galactose.Various syntheses of 1,2,3,4-tetra-O-acetyl-D-galactopyranuronic acids (6) with differently protected carb
- Vogel, Chr.,Boye, H.,Kristen, H.
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- A Stereoselective Totally Synthetic Route to Methyl α-Peracetylhikosaminide
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A synthesis of the title system from D-galactose has been achieved.The racemic galactose 1,2,3,4-bisacetonide is expanded to a C7 heptulose, which is then extended to an undecose by a Lewis acid catalyzed cyclocondensation reaction.Racemic galactose was s
- Danishefsky, Samuel J.,Maring, Clarence J.
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p. 2193 - 2204
(2007/10/02)
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- Indirect Electrooxidation of Alkohols and Aldehydes by Using a Double Mediatory System Consisting of RuO4/RuO2 and Cl+/Cl- Redoxes in an Aqueous-Organic Two-Phase System
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A double mediatory system consisting of RuO4/RuO2 and Cl+/Cl- redox couples has been developed for the indirect electrooxidation of alcohols and aldehydes.The reaction proceeds in the following manner: (1) oxidation of the substrate with ruthenium tetraoxide (RuO4) in the organic layer, (2) regeneration of ruthenium tetraoxide from ruthenium dioxide (RuO2) with active chlorine species (Cl2 or +), and (3) oxidation of chloride ion to + on the anode in the aqueous layer.The range of applicability of the present procedure is discussed by oxidations of (1)secondary alcohols to ketones, (2) primary alcohols and aldehydes to carboxylic acid, (3) 1,n-diols to lactones and keto acids, and (4) carbohydrate derivatives.
- Torii, Sigeru,Inokuchi, Tsutomu,Sugiura, Toyoyuki
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p. 155 - 161
(2007/10/02)
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