- The reactions of β- and α-pyranose peracetates with PCl5, and utilization of the products to construct sarsasapogenin glycosides
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The reactions of β- and α-pyranose peracetates with PCl5 gave products regioselectively chlorinated. The reactions of 1,2,3,4,6-penta-O-acetyl-β-D-glucopyranose (5) and -β-D-galactopyranose (6) with PCl5 in CCl4 and that of methyl 2,3,4-tri-O-acetyl-β-D-glucuronatopyranose (7) with PCl5 in toluene gave 2-O-trichloroacetyl-β-D-pyranosyl chlorides 4, 12 and 14, respectively, as major products, and α-D-pyranosyl chlorides 11, 13 and 15, respectively, as minor products. On the other hand, the reactions of compounds 8 and 9 which were α-anomers of 5 and 6, respectively, with PCl5 gave as major products transformed acetyl groups at C-6 to -C(Cl) = CCl2 or -C(Cl)2-CCl3 group (16 and 17 from 8 and 18 from 9). The same reaction of 10, which was α-anomer of 7, gave α-chloride 15 as a major product. The glycosidation of sugar derivative 4 with sarsasapogenin 23 gave β-glycoside 24 (29.1%) and α-glycoside 25 (46.9%), and that of 12 with 23 gave β-glycoside 26 (24.0%) and α-glycoside 27 (40.8%). The improvement of the yields of β-glycosides 24 and 26 (66.9 and 62.1% for 24 and 26, respectively) in the glycosidations were accomplished by the employment of α-bromides 28 and 29 obtained from 4 and 6, respectively. The glycosidations of monoglycosides 30 and 31 obtained by the treatment 24 and 26, respectively, with ammonia-saturated ether with sugar acetate bromides 32 and 34 gave diglycoside derivatives 35 and 33, respectively.
- Saito,Ichinose,Sasaki,Sumita
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Read Online
- 2-Trimethylsilylethyl glycosides. Treatment with electrophilic reagents to give trimethylsilyl- and methoxymethyl glucopyranosides and glucopyranosyl chloride
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Treatment of 2-trimethylsilylethyl 2346-tetra-O-acetyl-β-D-glucopy ranoside (-1) with trimethylsilyl trifluoromethanesulfonate trifluoromethanesulfonic acid or borontrifluoride etherate in the presence ofdimethoxymethane gave methoxymethyl 2346-tetra-O-acetyl-β-D-glucopyranoside in 54 62 and 66% yield respectively. In the absence of dimethoxymethane trimethylsilyl 2346-tetra-O-acetyl-β-D-glucopyranoside was formed in 78% yield. Treatment of I with 11-dichloromethylmethyl ether in the presence of zinc chloride gave 2346-tetra-O-acetyl-α-D-glucopyranosyl chloride in 98% yield.
- Jansson, Karl,Magnusson, Goeran
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Read Online
- ON THE REACTION OF 6-GLYCOSYLAMINO-5-NITROSOPYRIMIDINES WITH VILSMEIER-TYPE REAGENTS. SYNTHESIS OF 8-AMINO-9-GLYCOSYLPURINES
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8-amino, 8-(N-methyl)amino and 8-(N,N-dimethyl)amino-9-glucopyranosylpurines have been obtained by reaction of the corresponding 6-glycopyranosyl-5-nitrosopyrimidine with Vilsmeyer-Type reagents (formamide, substituted formamides and phosphorus oxychloride).
- Melguizo, M.,Nogueras, M.,Sanchez, A.,Quijano, L.
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Read Online
- Stereoselective Preparation of C-Aryl Glycosides via Visible-Light-Induced Nickel-Catalyzed Reductive Cross-Coupling of Glycosyl Chlorides and Aryl Bromides
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A nickel-catalyzed cross-coupling reaction of glycosyl chlorides with aryl bromides has been developed. The reaction proceeds smoothly under visible-light irradiation and features the use of bench-stable glycosyl chlorides, allowing the highly stereoselective synthesis of C-aryl glycosides. (Figure presented.).
- Mou, Ze-Dong,Wang, Jia-Xi,Zhang, Xia,Niu, Dawen
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supporting information
p. 3025 - 3029
(2021/05/27)
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- Chemical glucosylation of pyridoxine
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The chemical synthesis of pyridoxine-5′-β-D-glucoside (5′-β-PNG) was investigated using various glucoside donors and promoters. Hereby, the combination of α4,3-O-isopropylidene pyridoxine, glucose vested with different leaving and protecting groups and the application of stoichiometric amounts of different promoters was examined with regards to the preparation of the twofold protected PNG. Best results were obtained with 2,3,4,6-tetra-O-acetyl-D-glucopyranosyl fluoride and boron trifluoride etherate (2.0 eq.) as promoter at 0 °C (59%). The deprotection was accomplished stepwise with potassium/sodium hydroxide in acetonitrile/water followed by acid hydrolysis with formic acid resulting in the chemical synthesis of 5′-β-PNG.
- Bachmann, Thomas,Rychlik, Michael
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- Chemoenzymatic synthesis of arabinomannan (AM) glycoconjugates as potential vaccines for tuberculosis
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Mycobacteria infection resulting in tuberculosis (TB) is one of the top ten leading causes of death worldwide in 2018, and lipoarabinomannan (LAM) has been confirmed to be the most important antigenic polysaccharide on the TB cell surface. In this study, a convenient synthetic method has been developed for synthesizing three branched oligosaccharides derived from LAM, in which a core building block was prepared by enzymatic hydrolysis in flow chemistry with excellent yield. After several steps of glycosylations, the obtained oligosaccharides were conjugated with recombinant human serum albumin (rHSA) and the ex-vivo ELISA tests were performed using serum obtained from several TB-infected patients, in order to evaluate the affinity of the glycoconjugate products for the human LAM-antibodies. The evaluation results are positive, especially compound 21 that exhibited excellent activity which could be considered as a lead compound for the future development of a new glycoconjugated vaccine against TB.
- Li, Zhihao,Bavaro, Teodora,Tengattini, Sara,Bernardini, Roberta,Mattei, Maurizio,Annunziata, Francesca,Cole, Richard B.,Zheng, Changping,Sollogoub, Matthieu,Tamborini, Lucia,Terreni, Marco,Zhang, Yongmin
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supporting information
(2020/07/27)
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- Nonenzymatic synthesis of anomerically pure, mannosylbased molecular probes for scramblase identification studies
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The chemical synthesis of molecular probes to identify and study membrane proteins involved in the biological pathway of protein glycosylation is described. Two short-chain glycolipid analogs that mimic the naturally occurring substrate mannosyl phosphoryl dolichol exhibit either photoreactive and clickable properties or allow the use of a fluorescence readout. Both probes consist of a hydrophilic mannose headgroup that is linked to a citronellol derivative via a phosphodiester bridge. Moreover, a novel phosphoramidite chemistry-based method offers a straightforward approach for the non-enzymatic incorporation of the saccharide moiety in an anomerically pure form.
- Bütikofer, Peter,H?ner, Robert,Khorev, Oleg,Langenegger, Simon M.,Menon, Anant K.,Picca, Giovanni,Probst, Markus
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supporting information
p. 1732 - 1739
(2020/09/15)
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- From Glucose to Polymers: A Continuous Chemoenzymatic Process
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Efforts to synthesize degradable polymers from renewable resources are deterred by technical and economic challenges; especially, the conversion of natural building blocks into polymerizable monomers is inefficient, requiring multistep synthesis and chromatographic purification. Herein we report a chemoenzymatic process to address these challenges. An enzymatic reaction system was designed that allows for regioselective functional group transformation, efficiently converting glucose into a polymerizable monomer in quantitative yield, thus removing the need for chromatographic purification. With this key success, we further designed a continuous, three-step process, which enabled the synthesis of a sugar polymer, sugar poly(orthoester), directly from glucose in high yield (73 % from glucose). This work may provide a proof-of-concept in developing technically and economically viable approaches to address the many issues associated with current petroleum-based polymers.
- Banahene, Nicholas,Bettinger, Reuben,Du, Wenjun,Esser-Kahn, Aaron P.,Liang, Zhijie,Maiti, Sampa,Manna, Saikat,Pham, Lucynda,Wang, Jun,Xu, Yi,Zientko, John
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supporting information
p. 18943 - 18947
(2020/08/25)
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- Method for preparing halogenated sugar under mild conditions
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The invention discloses a method for preparing halogenated sugar under mild conditions. The method comprises the following steps that an easily-prepared thioglycoside donor and a halogen simple substance or halogen intercompound undergo a reaction at room temperature to obtain the halogenated sugar (chlorine, bromine and iodine). The halogen simple substance or the halogen intercompound is commercial easily available iodine elementary substance, iodine bromide and iodine chloride. The method is suitable for various pyranoses and furanoses. The method has no limitation on a protecting group ofthe thioglycoside donor, and the protecting group can be an electron withdrawing group such as acetyl, benzoyl and the like, and can also be an electron donating group such as benzyl, silicon base andthe like. Meanwhile, the reaction can occur in various organic solvents such as dichloromethane, acetonitrile and methylbenzene. The preparation method of the halogenated sugar is simple, reaction conditions are mild, raw materials are easy to obtain, the application range is wide, the halogenated sugar is compatible with acid-labile groups such as isopropylidene ketal and silicon groups, and a pure product can be obtained by removing a solvent from the halogenated sugar which is not stable in the separation process.
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Paragraph 0019-0021; 0055-0060
(2020/07/02)
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- Synthesis of glycosyl chlorides using catalytic Appel conditions
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The stereoselective synthesis of glycosyl chlorides using catalytic Appel conditions is described. Good yields of α-glycosyl chlorides were obtained using a range of glycosyl hemiacetals, oxalyl chloride and 5 mol% Ph3PO. For 2-deoxysugars treatment of the corresponding hemiacetals with oxalyl chloride without phosphine oxide catalyst also gave good yields of glycosyl chloride. The method is operationaly simple and the 5 mol% phosphine oxide by-product can be removed easily. Alternatively a one-pot, multi-catalyst glycosylation can be carried out to transform the glycosyl hemiacetal directly to a glycoside.
- Pongener, Imlirenla,Nikitin, Kirill,McGarrigle, Eoghan M.
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supporting information
p. 7531 - 7535
(2019/08/20)
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- Quinoline-galactose hybrids bind selectively with high affinity to a galectin-8 N-terminal domain
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Quinolines, indolizines, and coumarins are well known structural elements in many biologically active molecules. In this report, we have developed straightforward methods to incorporate quinoline, indolizine, and coumarin structures into galactoside derivatives under robust reaction conditions for the discovery of glycomimetic inhibitors of the galectin family of proteins that are involved in immunological and tumor-promoting biological processes. Evaluation of the quinoline, indolizine and coumarin-derivatised galactosides as inhibitors of the human galectin-1, 2, 3, 4N (N-terminal domain), 4C (C-terminal domain), 7, 8N, 8C, 9N, and 9C revealed quinoline derivatives that selectively bound galectin-8N, a galectin with key roles in lymphangiogenesis, tumor progression, and autophagy, with up to nearly 60-fold affinity improvements relative to methyl β-d-galactopyranoside. Molecular dynamics simulations proposed an interaction mode in which Arg59 had moved 2.5 ? and in which an inhibitor carboxylate and quinoline nitrogen formed structure-stabilizing water-mediated hydrogen bonds. The compounds were demonstrated to be non-toxic in an MTT assay with several breast cancer cell lines and one normal cell line. The improved affinity, selectivity, and low cytotoxicity suggest that the quinoline-galactoside derivatives provide an attractive starting point for the development of galectin-8N inhibitors potentially interfering with pathological lymphangiogenesis, autophagy, and tumor progression.
- Pal, Kumar Bhaskar,Mahanti, Mukul,Huang, Xiaoli,Persson, Stella,Sundin, Anders P.,Zetterberg, Fredrik R.,Oredsson, Stina,Leffler, Hakon,Nilsson, Ulf J.
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p. 6295 - 6305
(2018/09/10)
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- Efficient Synthesis of α-Glycosyl Chlorides Using 2-Chloro-1,3-dimethylimidazolinium Chloride: A Convenient Protocol for Quick One-Pot Glycosylation
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A mild and convenient method for the synthesis of α-glycosyl chlorides in high 80–96 % yields within 15–30 min using 2-chloro-1,3-dimethylimidazolinium chloride (DMC) is disclosed. The method has a wide substrate scope and is compatible with labile OH protecting groups, including benzyl, acetyl, benzoyl, isopropylidene, benzylidene, TBDMS (tert-butyldimethylsilyl), and TBDPS (tert-butyldiphenylsilyl) groups. The excellent α selectivity obtained in this reaction is attributed to in-situ isomerization of β-glycosyl chlorides to the more stable α-glycosyl chlorides, as demonstrated by 1H NMR spectroscopic studies. Disarmed sugars with OBz or OAc groups at C-2 were chlorinated at a faster rate but ismomerized (β→α) at a slower rate than armed sugars with an OBn group at C-2. More importantly, the method enables highly desirable one-pot glycosylation reactions to take place, thus allowing efficient syntheses of disaccharides and simple O-glycosylated sugars in high overall yields without the need for separation or purification of the α-glycosyl chloride donors. This method will be especially useful for direct glycosylation reactions using glycosyl chloride donors that are unstable upon separation and purification.
- Tatina, Madhu Babu,Khong, Duc Thinh,Judeh, Zaher M. A.
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supporting information
p. 2208 - 2213
(2018/06/04)
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- Solvent-free synthesis of glycosyl chlorides based on the triphenyl phosphine/hexachloroacetone system
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Glycosyl chlorides, useful as glycosyl donors in glycoside synthesis and precursors in organic synthesis, can be easily prepared under solvent-free conditions by exposing a sugar hemiacetal to an equimolar mixture of PPh3 and hexachloroacetone
- Traboni, Serena,Liccardo, Federica,Bedini, Emiliano,Giordano, Maddalena,Iadonisi, Alfonso
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p. 1762 - 1764
(2017/04/13)
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- A New Versatile Water-Soluble Iniferter Platform for the Preparation of Molecularly Imprinted Nanoparticles by Photopolymerisation in Aqueous Media
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The multi-step synthesis of a new water-soluble dithiocarbamate iniferter platform for the preparation of nanoparticles and -gels in aqueous solvents by photoinduced living-radical polymerisation is described herein. The water solubility of the dithiocarb
- Bonomi, Paolo,Attieh, Mira Daoud,Gonzato, Carlo,Haupt, Karsten
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supporting information
p. 10150 - 10154
(2016/07/19)
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- ALPHA-D-GALACTOSIDE INHIBITORS OF GALECTINS
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The present invention relates to a compound of the general formula (1). wherein the pyranose ring is a-D-galactopyranose, A is selected from The compound of formula (1) is suitable for use in a method for treating a disorder relating to the binding of a galectin, such as galectin-3 to a ligand in a mammal, such as a human. Furthermore the present invention concerns compounds for use in a method of treatment of a disorder relating to the binding of a galectin, such as galectin-3 to a ligand in a mammal, such as a human.
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Page/Page column 130; 131
(2016/08/23)
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- Analyte detection utilizing polynucleotide sequences, composition, process and kit
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A method of detecting in a sample an analyte (A) having a molecularly recognizable portion thereon, which comprises: providing (B) a molecular bridging entity having thereon: (i) a portion capable of recognizing the molecularly recognizable portion on the analyte; and (ii) a portion comprising a polynucleotide sequence; and (C) a signalling entity having thereon: (i) a polynucleotide portion capable of annealing to the polynucleotide portion of the bridging entity, thereby to form a stable polynucleotide hybrid, and (ii) a signal generating portion; forming a complex comprising: (1) the analyte (A) complexed through its molecularly recognizable portion to (2) the recognizing portion of the entity (B); the entity (B) being complexed through the polynucleotide portion thereon to (3) the polynucleotide portion of the signalling entity; and detecting a signal by means of the signal generating portion present in the complex.
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- Improved synthesis of per-O-acetylated C1 hydroxyglycopyranose and structural study as non-covalent organic framework
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An improved method for the synthesis of per-O-acetylated C-1-hydroxyglycopyranose was developed by hydrolysis of per-O-acetylated glycopyranosyl α-chlorides derived from sugars with C-2 axial acetates for example l-rhamnose and d-mannose. 2,3,4-Tri-O-acetyl-α-l-rhamnopyranose crystallized in tetragonal space group I4, a rare phenomenon in carbohydrate literature. The three dimensional packing of the molecule with the help of regular hydrogen bond and C-H···O interactions resulted in the formation of porous framework showing channels with pore size 7 A?.
- Singhamahapatra, Anadi,Sahoo, Laxminarayan,Paul, Katuri J.V.,Varghese, Babu,Loganathan, Duraikkannu
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p. 6121 - 6124
(2013/10/22)
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- Short synthetic route to benzaldehyde-functionalized idose and talose derivatives by acetoxonium ion rearrangements
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Carbohydrate-carbohydrate interactions (CCI) are mediated by complexation of metal ions. Angyal postulated on the requirements for hydroxy group arrangement in pyranoses to account for metal-ion complexation. These requirements are particularly well fulfilled in α-ido- and α-talopyranosides, whose ring hydroxy groups have all axial and axial-equatorial-axial configurations, respectively. Surface plasmon resonance (SPR) and gold-nanoparticle techniques have proved to be powerful tools to investigate CCIs. Benzaldehyde-functionalized glycans can be used for attachment to both gold nanoparticles and SPR sensor surfaces. Therefore, benzaldehyde-equipped ido- and talopyranosides were synthesized by the almost forgotten Paulsen acetoxonium rearrangement. This approach provides peracetylated idose and talose in only two steps from common glucose and galactose precursors, respectively, in overall yields of up to 41 % and, therefore, avoids long and laborious procedures to obtain these rare carbohydrates. The derivatives are being used in ongoing CCI studies using SPR to test Angyal's postulate about the structural requirements for hydroxy group arrangements. Almost forgotten: The Paulsen acetoxonium rearrangement provides a facile and rapid access to rare carbohydrates. Through a cascade of antimony pentachloride induced acetoxonium rearrangements, ido- and talopyranose derivatives can be synthesized from simple glucose and galactose precursors in a one-pot procedure. Copyright
- Kopitzki, Sebastian,Thiem, Joachim
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p. 4008 - 4016
(2013/07/26)
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- Synthesis, biological evaluation, wac and NMR studies of s-galactosides and non-carbohydrate ligands of cholera toxin based on polyhydroxyalkylfuroate moieties
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The synthesis of several non-carbohydrate ligands of cholera toxin based on polyhydroxyalkylfuroate moieties is reported. Some of them have been linked to D-galactose through a stable and well-tolerated S-glycosidic bond. They represent a novel type of non-hydrolyzable bidentate ligand featuring galactose and polyhydroxyalkylfuroic esters as pharmacophoric residues, thus mimicking the GM1 ganglioside. The affinity of the new compounds towards cholera toxin was measured by weak affinity chromatography (WAC). The interaction of the best candidates with this toxin was also studied by saturation transfer difference NMR experiments, which allowed identification of the binding epitopes of the ligands interacting with the protein. Interestingly, the highest affinity was shown by non-carbohydrate mimics based on a polyhydroxyalkylfuroic ester structure. No carbs here: Saturation transfer difference (STD) NMR studies of bidentate ligands of cholera toxin (see figure, WAC = weak affinity chromatography) show the methylfuran moiety as the main contact point in the interaction with the toxin. Several polyhydroxyalkylfuroate-based structures are synthesized and analyzed and show similar or even better affinity than the bidentate ligands. They constitute the first examples of non-carbohydrate ligands for cholera toxin. Copyright
- Ramos-Soriano, Javier,Niss, Ulf,Angulo, Jesus,Angulo, Manuel,Moreno-Vargas, Antonio J.,Carmona, Ana T.,Ohlson, Sten,Robina, Inmaculada
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supporting information
p. 17989 - 18003
(2014/01/17)
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- Indium(III) triflate-mediated one-step preparation of glycosyl halides from free sugars
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In(OTf)3 has been found to be an efficient catalyst for the direct conversion of reducing sugars to their respective acylated glycosyl halides in good yields under mild conditions. The glycosyl halides so obtained can be converted to alkyl glyc
- Giri, Santosh Kumar,Kartha, K. P. Ravindranathan
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experimental part
p. 3378 - 3383
(2010/12/25)
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- A mild and general method for preparation of α-glycosyl chlorides
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A mild and efficient chlorination method for production of glycosyl chlorides is first described which employs inexpensive trichlorotriazine (TCT) and DMF as a chlorination reagent and is compatible with typical acid-labile hydroxyl protecting functions. The scope and limitations, reaction mechanism and its application in the sequential glycosylations are discussed.
- Chang, Chih-Wei,Chang, Shih-Sheng,Chao, Chin-Sheng,Mong, Kwok-Kong T.
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supporting information; experimental part
p. 4536 - 4540
(2009/12/03)
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- A facile preparation of peracylated α-aldopyranosyl chlorides with thionyl chloride and tin tetrachloride
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Aldopyranose peracetates react with thionyl chloride and tin tetrachloride, producing the corresponding peracylated aldopyranosyl chlorides in very good to excellent yields (88-100%) with exclusive α-anomeric selectivity and short reaction times. The use of peracylated sugars as the substrate in large scale reactions also proceeds in high yield. Crown Copyright
- Wang, Qingbing,Fu, Jie,Zhang, Jianbo
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scheme or table
p. 2989 - 2991
(2009/04/05)
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- 'Click' preparation of carbohydrate 1-benzotriazoles, 1,4-disubstituted, and 1,4,5-trisubstituted triazoles and their utility as glycosyl donors
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Glycosyl triazoles can be prepared from readily available anomeric azides through various 'click' methodologies: thermal Huisgen cycloaddition with alkynes, strain-promoted Huisgen cycloaddition of benzynes, and Cu I-catalyzed azide-alkyne cycloaddition of terminal alkynes (CuAAC reaction). Here we investigate the formation of glycosyl 1-benzotriazoles from anomeric and non-anomeric carbohydrate azides using benzynes derived from substituted anthranilic acids. The reactivity of the resulting anomeric 1-benzotriazoles as glycosyl donors was investigated and compared with 1,4-disubstituted glycosyl triazoles (from the CuAAC reaction) and 1,4,5-trisubstituted glycosyl triazoles (prepared by Huisgen cycloaddition of glycosyl azides and dimethyl acetylene dicarboxylate). The 1,4,5-trisubstituted glycosyl triazoles were activated by Lewis acids and could be converted to O-glycosides, S-glycosides, glycosyl chlorides, and glycosyl azides. By contrast, under all conditions investigated, the 1,4-disubstituted glycosyl triazoles were unreactive as glycosyl donors. Glycosyl 1-benzotriazoles were generally inert as glycosyl donors; however, a tetrafluorobenzotriazole derivative, which bears electron-withdrawing substituents on the benzotriazole group, was a moderate glycosyl donor and could be converted to an S-glycoside by treatment with thiocresol and tin(iv) chloride.
- Watt, Jacinta A.,Gannon, Carlie T.,Loft, Karen J.,Dinev, Zoran,Williams, Spencer J.
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experimental part
p. 837 - 846
(2009/04/11)
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- Efficient synthesis of ω-mercaptoalkyl 1,2-trans-glycosides from sugar peracetates
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Lewis acid-promoted reactions of peracetylated sugars (glucose, galactose, maltose, lactose) with ω-bromo-1-alkanols (C8, C12) were investigated. ZnCl2 was found to promote the 1,2-trans-glycosylation of the alcohols in toluene at about 60 °C in a stereocontrolled manner with better yields than commonly employed promoters such as SnCl4. The ω-bromoalkyl acetylated glycosides were readily converted to ω-mercaptoalkyl glycosides, which are useful for the preparation of glycoclusters.
- Murakami, Teiichi,Hirono, Reiko,Sato, Yukari,Furusawa, Kiyotaka
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p. 1009 - 1020
(2008/02/04)
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- First direct glycosylation of unprotected nonreducing mono- and disaccharides
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The first single-step random-glycosylation methodology for fully unprotected glycosyl acceptors is reported by random glycosylation leading to all possible regioisomers. For such systems conventional glycosylation methods such as Koenigs-Knorr glycosylation, Schmidt's trichloroacetimidate glycosylation and reactions employing glycosyl fluoride donors fail entirely. Starting from unprotected nonreducing saccharides, the glycosylation of β-glucosylated and β-galactosylated monosaccharides (Glc, Gal), symmetric disaccharides (e.g. α,α-trehaloses) as well as unsymmetric disaccharides (e.g. sucrose) were studied. The influence of base type and concentration were examined. Several libraries of di- and trisaccharides were generated. All regioisomers were formed in approximately equal proportions, and their partial separation was achieved by flash column chromatography. Even though it appears that overall yields are lower when comparing to classical protecting-group chemistry, this synthetic effort may be superior especially for access to higher saccharides. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Steinmann, Andreas,Thimm, Julian,Thiem, Joachim
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p. 5506 - 5513
(2008/09/17)
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- Acylation of carbohydrates over Al2O3: Preparation of partially and fully acylated carbohydrate derivatives and acetylated glycosyl chlorides
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Selective and per-O-acylation of carbohydrate derivatives using acyl chlorides and Al2O3, a solid support reagent, is reported. This protocol does not require the addition of any base or activator. This methodology has been further extended to the selective acylation of carbohydrate diols and the one-pot preparation of acetylated glycosyl chlorides direct from free reducing sugars. The yields obtained in most of the cases are excellent.
- Tiwari, Pallavi,Misra, Anup Kumar
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p. 339 - 350
(2007/10/03)
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- Immobilization of glycoconjugate polymers on cellulose membrane for affinity separation
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Membranes with immobilized glycoconjugate polymers were prepared and lectin adsorption was evaluated. Glycoconjugate polymers having the carbohydrates, lactose, and mannose, the amino groups of the reaction point, and a fluorescence label were synthesized, while cellulose membranes were carboxymethylated. The content of the carboxyl group was evaluated by titration. Subsequently, the glycoconjugate polymers were immobilized on the cellulose membranes by amide linkages formed by condensation reaction. Analysis of the luminescence of the fluorescence labels revealed that the glycoconjugate polymers had been immobilized on the cellulose membranes. Examination of lectin adsorption by the glycoconjugate polymer on the membrane revealed that the membrane with the immobilized mannose-having polymer adsorbed 53% of the applied ConA and the membrane with the immobilized lactose-having polymer adsorbed 83% of the applied RCA120. The membrane with immobilized glycoconjugate polymers selectively adsorbed each lectin. In addition, membranes with different types of immobilized glycoconjugate polymers were used in stacks, and in this case, the membranes selectively adsorbed lectin. Thus, membranes with immobilized glycoconjugate polymers efficiently and easily purify lectin.
- Miyagawa, Atsushi,Kasuya, Maria Carmelita Z.,Hatanaka, Kenichi
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p. 348 - 356
(2007/10/03)
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- New glycomimetics: Anomeric sulfonates, sulfenamides, and sulfonamides
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The synthesis of a variety of new 1-thio-D-glucopyranose derivatives oxidized at the sulfur atom is described, including seven 1-C-sulfonic acids, three sulfonate esters, three sulfinate esters, an S,S′-diglycosyl thiolsulfonate and thiolsulfmate, four S-
- Knapp, Spencer,Darout, Etzer,Amorelli, Benjamin
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p. 1380 - 1389
(2007/10/03)
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- Design, development and synthesis of mixed bioconjugates of piperic acid-glycine, curcumin-glycine/alanine and curcumin-glycine-piperic acid and their antibacterial and antifungal properties
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In the present communication different curcumin bioconjugates viz. 4,4′-di-O-glycinoyl-curcumin, 4,4′-di-O-d-alaninoyl-curcumin, 4,4′-di-O-(glycinoyl-di-N-piperoyl)-curcumin, 4,4′-di-O-piperoyl curcumin, curcumin-4,4′-di-O-β-D-glucopyranoside, 4,4′-di-O-acetyl-curcumin along with piperoyl glycine, have been synthesised and characterised by spectra UV, 1H NMR and elemental analysis. All the covalent bonds used are biodegradable. This makes these derivatives as potent prodrugs, which can get hydrolysed at the target sites. These bioconjugates were tested in vitro against different bacteria and fungi. The 4,4′-di-O-(glycinoyl-di-N-piperoyl)-curcumin and 4,4′-di-O- acetyl-curcumin are more effective than Cefepime, an antibacterial drug available in market, at the same concentration. The 4,4′-di-O-(glycinoyl- di-N-piperoyl)-curcumin and 4,4′-di-O-piperoyl curcumin had antifungal activity in vitro almost comparable with fluconazole, the most popular antifungal drug. The enhanced activity of these bioconjugates vis-a-vis the parent molecule that is curcumin may be due to improved cellular uptake or reduced metabolism of these bioconjugates resulting in building up of enough concentration inside the infected cells. It opens a new era for exploring suitably designed curcumin bioconjugates as potential antibacterial/antifungal drugs.
- Mishra, Satyendra,Narain, Upma,Mishra, Roli,Misra, Krishna
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p. 1477 - 1486
(2007/10/03)
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- Design, synthesis, and enzymatic property of a sulfur-substituted analogue of trigalacturonic acid
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A sulfur-substituted analogue of trigalacturonic acid (3) was synthesized. The synthesis features the application of 3-cyano-3-(tert-butyldimethylsilyl) oxypropylthioether (CSP) as a novel protective group for thiols. This analogue was designed with the expectation that it would be a stable analogous substrate for endo-polygalacturonase isolated from Stereum purpureum based on computer modeling experiments. Surface plasmon resonance experiments revealed that 3 forms a stable complex with the target enzyme.
- Yamamoto, Kazunori,Watanabe, Naoki,Matsuda, Hiroko,Oohara, Keiichiro,Araya, Tomoyuki,Hashimoto, Masaru,Miyairi, Kazuo,Okazaki, Isao,Saito, Minoru,Shimizu, Tetsuya,Kato, Hiroaki,Okuno, Toshikatsu
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p. 4932 - 4935
(2007/10/03)
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- Highly stereoselective synthesis of peracylated α-aldopyranosyl chlorides from aldopyranose peracetates and thionyl chloride catalyzed by BiCl3 generated in situ from the procatalyst BiOCl
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Aldopyranose peracetates react with thionyl chloride and BiCl3, generated in situ from a substoichiometric amount of the procatalyst BiOCl, producing the corresponding peracylated aldopyranosyl chlorides in very good to excellent yields (82-97%
- Ghosh, Rina,Chakraborty, Arijit,Maiti, Swarupananda
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p. 9631 - 9634
(2007/10/03)
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- Reaction of 1,2-trans-glycosyl acetates with phosphorus pentachloride: New efficient approach to 1,2-trans-glycosyl chlorides
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Reaction of phosphorus pentachloride with 1,2-trans-glycosyl esters is described. The reaction mechanism presumably involves formation of a tetrachlorophosphonium ion as one of the key reactive intermediates, which can be induced either by Lewis acids or by using acetonitrile as the reaction solvent. Two novel, efficient methods for the synthesis of the thermodynamically unstable glycosyl chlorides were developed based on this reaction.
- Ibatullin, Farid M.,Selivanov, Stanislav I.
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p. 9577 - 9580
(2007/10/03)
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- Towards α- or β-D-C-glycosyl compounds by tin-catalyzed addition of glycosyl radicals to acrylonitrile and vinylphosphonate, and flexible reduction of tetra-O-acetyl-α-D-glucopyranosyl bromide with cyanoborohydride
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Photo-induced radical addition of acetylated α-D-glucopyranosyl bromide (1) to acrylonitrile or diethyl vinylphosphonate, in the presence of catalytic amounts of tri-n-butyltin chloride and sodium (or tetra-n-butylammonium) cyanoborohydride in excess, all
- Praly, Jean-Pierre,Ardakani, Azin Salek,Bruyere, Isabelle,Marie-Luce, Chrystelle,Bing Qin, Bing
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p. 1623 - 1632
(2007/10/03)
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- Synthesis of C7-C16-alkyl glycosides: Part I - Synthesis of alkyl D-glucopyranosides in the presence of tin (IV) chloride as a Lewis acid catalyst
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The Lewis acid catalyzed glycosylation reaction of β-peracetylated sugar derivative (glucose) with fatty alkanols is used in a synthesis of C7-C16-alkyl glucopyranosides. The process occurs under the influence of tin (IV) chloride.
- Konstantinovic,Predojevic,Mojsilovic,Dimitrijevic,Milosevic
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p. 796 - 801
(2007/10/03)
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- An easy access to anomeric glycosyl amides and imines (Schiff bases) via transformation of glycopyranosyl trimethylphosphinimides
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The preparation and application of anomeric glycosyl phosphinimides in preparative synthesis were studied. Starting from the appropriate glycosyl azides and trialkyl or triaryl phosphines, the corresponding phosphinimides were obtained by modified Staudin
- Kovács, László,Osz, Erzsébet,Domokos, Valéria,Holzer, Wolfgang,Gy?rgydeák, Zoltán
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p. 4609 - 4621
(2007/10/03)
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- A convenient preparation of glycosyl chlorides from aryl/alkyl thioglycosides
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(equation presented) Because of the vast structural diversity encountered in the field of glycobiology, versatile methods for orthogonal oligosaccharide assembly are always of interest. Reported herein is the preparation of glycosyl chloride donors obtained by reaction of the corresponding thioglycoside precursors with chlorosulfonium chloride reagent 4. The crude chlorides thus obtained can be used directly in subsequent glycosylation reactions, and examples of the generality of this approach are provided.
- Sugiyama, Shin,Diakur, James M.
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p. 2713 - 2715
(2007/10/03)
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- Dehydroxy substitution reactions of the anomeric hydroxy groups in some protected sugars initiated by anodic oxidation of triphenylphosphine
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The anodic transformation of 2,3:5,6-di-O-isopropylidene-α-D- mannofuranose (4) and 2,3,4,6-tetra-O-benzyl-D-glucopyranose (5) to the corresponding alkoxy phosphonium ions induces dehydroxy substitution of the sugars at the anomeric positions. Their dehyd
- Maeda, Hatsuo,Matsumoto, Sayaka,Koide, Takashi,Ohmori, Hidenobu
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p. 939 - 943
(2007/10/03)
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- A convenient synthesis of peracetylated glycosyl halides using bismuth(III) halides as catalysts
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A new halogenation procedure for peracetylated glycopyranosides is reported, using bismuth(III) halides and halogenosilanes under very mild conditions.
- Montero, Jean-Louis,Winum, Jean-Yves,Leydet, Alain,Kamal, Mehrnaz,Pavia, Andre A.,Roque, Jean-Pierre
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p. 175 - 180
(2007/10/03)
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- Zirconium tetrachloride as a convenient catalyst for the glycosylation of sterols with 2,3,4,6,6'-penta-O-acetyl-5-hydroxymethylgalactosyl fluoride
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Zirconium tetrachloride was found to catalyze glycosylation of various sterols with peracetylated 5-hydroxymethylene galactosyl fluoride.
- Pikul, Stanislaw,Greg Switzer
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p. 1165 - 1168
(2007/10/03)
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- Conversion of p-methoxyphenyl glycosides into the corresponding glycosyl chlorides and bromides, and into thiophenyl glycosides
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p-Methoxyphenyl (pMP) β-D-glycopyranosides (Glc, Gal, GlcNPhth, GalNPhth, GlcNTroc, Galβ4Glc, Galα4Gal) were prepared from the corresponding 1-O-acetyl sugars in 79-90% yield, using boron trifluoride etherate as promoter. Treatment of the pMP glycosides with acyl chlorides or bromides in the presence of various Lewis acids gave the corresponding glycosyl chlorides and bromides in 81-98% yield. Treatment of the acyl-protected pMP glycosides with thiophenol and boron trifluoride etherate gave the corresponding thioglycosides in 80-100% yield and high (> 20:1) β/α selectivity. The stability of pMP glycosides was investigated against a series of reagents.
- Zhang, Zhiyuan,Magnusson, Goeran
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- Process for the preparation of protected mono-sugar and oligo-sugar halides
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The reaction of protected monosaccharides or oligosaccharides or protected monosaccharide and oligosaccharide derivatives containing an anomeric hydroxyl group with secondary α-haloenamines affords high yields of protected glycosyl halides, which are valuable intermediates for the introduction of sugar groups in the synthesis of oligosaccharides, glycolipids or glycopeptides.
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- Free radical-mediated addition of peracetylated 1-bromo-β-D-glucopyranosyl chloride to acrylonitrile
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Dropwise addition of a benzene solution of tri-n-butylstannane to a solution of 2,3,4,6-tetra-O-acetyl-1-bromo-β-D-glucopyranosyl chloride in boiling benzene containing acrylonitrile in excess led predominantly, under photolytic conditions, to a mixture of nonononitriles, either chlorinated or unsaturated. Dropwise addition of a benzene solution of tri-n butylstannane to a solution of 2,3,4,6-tetra-O- acetyl-1-bromo-β-D-glucopyranosyl chloride in boiling benzene containing acrylonitrile in excess led predominantly, under photolytic conditions, to a mixture of nonononitriles, either chlorinated or unsaturated.
- Praly,El Kharraf,Descotes
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p. 117 - 123
(2007/10/02)
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- 2-(Trimethylsilyl)ethyl Glycosides. Transformation into Glycopyranosyl Chlorides
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2-(Trimethylsilyl)ethyl (TMSET) glycosides were transformed in high yields into the corresponding 1-chloro sugars by treatment with 1,1-dichloromethyl methyl ether/zinc chloride.With acetyl, benzoyl, and benzyl protection of the 2-postion, the α-glycopyranosyl chloride was the major product, whereas with the 2-phthalimido sugar 13, the β-chloride 21 was obtained.The fully benzylated TMSET glucopyranoside 1 gave the α-chloro sugar 22 carrying a 6-O-formyl group whereas the partially benzylated sugars 16 and 17 gave the chloro sugars with all protecting groups intact.
- Jansson, Karl,Noori, Ghazi,Magnusson, Goeran
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p. 3181 - 3185
(2007/10/02)
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- A FACILE, ONE-STEP PROCEDURE FOR THE CONVERSION OF 2-(TRIMETHYLSILYL)ETHYL GLYCOSIDES TO THEIR GLYCOSYL CHLORIDES
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Treatment of a variety of protected 2-(trimethylsilyl)ethyl (SE) mono, di and trisaccaride glycosides and hemiacetal sugars with α,α-dichloromethyl methyl ether (DCMME) in the presence of ZnCl2, SnCl4 or FeCl3 in dichloromethane gave their corresponding 1
- Kartha, K.P. Ravindranathan,Jennings, Harold J.
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p. 2537 - 2540
(2007/10/02)
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- Comparative photohalogenation of phenylglucopyranoside and its oxidation derivatives
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The photobrominations of the peracetylated phenyl thio-1-β-D-glucopyranoside and of the corresponding sulphoxides and sulphone have been investigated. The differences observed in both substrate reactivity and substitution regioselectivity indicate an easier homolysis of the anomeric C-H bond in the thioglycoside.
- Praly,Descotes
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p. 1133 - 1136
(2007/10/02)
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- PREPARATION OF GLYCOSYL HALIDES UNDER NEUTRAL CONDITIONS
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The anomeric hydroxyl group of various furanose and pyranose hemiacetals can be replaced by a fluorine, chlorine, bromine or iodine atom under neutral conditions using haloenamines.
- Ernst, Beat.,Winkler, Tammo.
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p. 3081 - 3084
(2007/10/02)
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- DIRECT TRANSFORMATION OF METHYL GLYCOPYRANOSIDES INTO CORRESPONDING GLYCOSYL HALIDES
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Is has been demonstrated that the reaction of methyl hexopyranosides with an excess of acyl halides, carried out in the presence of Lewis acids, leads to corresponding, thermodynamically favored glycosyl halides.
- Grynkiewicz, Grzegorz,Konopka, Miroslawa
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p. 149 - 153
(2007/10/02)
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- STEREOSELECTIVE SYNTHESIS OF 1,2-TRANS-1-THIOGLYCOSES USING ALUMINIUM CHLORIDE: EVIDENCE FOR 1,2-CIS-1-CHLOROGLYCOPYRANOSYLPERACETATES AS THE ACTUAL REACTION INTERMEDIATES
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Synthesis of 1,2-trans-1-thioglycosylacetates has been achieved in excellent yields from corresponding 1,2-trans-glycosylacetates using aluminium chloride via 1,2-cis-1-chloroglycopyranosylacetates with retention of configuration.
- Rajanikanth, B.,Seshadri, R.
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p. 2295 - 2296
(2007/10/02)
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- A GLYCOSYLATION REACTION: CONVERSION OF METHYL GLYCOSIDES TO GLYCOSYL CHLORIDES BY BORON TRICHLORIDE
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Methyl glycosides react readily with boron trichloride in dichloromethane solutions at -78 deg C to give the corresponding glycosyl chlorides for subsequent use in glycosylation reactions.This reaction is compatible with the presence of glycosyl linkages
- Perdomo, Guillermo R.,Krepinsky, Jiri J.
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p. 5595 - 5598
(2007/10/02)
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