- Straightforward glycosylation of alcohols and amino acids mediated by ionic liquid
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Green glycosylation of functionalized alcohols and α-amino acids, using an ionic liquid as a recyclable solvent, was performed in one step directly from the unprotected monosaccharide under scandium triflate or ferric chloride catalysis. Pure α- and β-glycosides could be obtained after specific enzymatic hydrolysis.
- Monasson, Olivier,Sizun-Thomé, Gwena?lle,Lubin-Germain, Nadège,Uziel, Jacques,Augé, Jacques
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scheme or table
p. 202 - 205
(2012/06/30)
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- Ionic liquid promoted atom economic glycosylation under Lewis acid catalysis
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Straightforward glycosylation of various alcohols with unprotected and non-activated monosaccharides were performed under scandium triflate catalysis. Rate and yield of glycosylation were highly improved when using 1-butyl-3-methylimidazolium trifluoromethanesulfonate as a green solvent. This ionic liquid was allowed to be recycled at least three times without loss of activity. The possibility of drastically reducing the amounts of catalyst (down to 1 mol%) and aglycone (down to 1 equiv) when performing the reaction in ionic liquid opens new perspectives in O-glycosylation, as a direct coupling between an aglycone and free sugars.
- Auge, Jacques,Sizun, Gwenaelle
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scheme or table
p. 1179 - 1183
(2010/05/02)
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- Protecting group free glycosidations using p-toluenesulfonohydrazide donors
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(Figure Presented) N-Glycopyranosylsulfonohydrazides are introduced as glycosyl donors for protecting group free synthesis of O-glycosides, glycosyl azides, and oxazolines. Mono- and disaccharides containing a reducing terminal N-acelylglucosamine residue were condensed with p-toluenesulfonylhydrazide to give the desired β-D-pyranose donors. These donors can be activated with NBS and then glycosidated with the desired alcohol or transformed to the oxazoline or glycosyl azide.
- Gudmundsdottir, Anna V.,Nitz, Mark
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supporting information; scheme or table
p. 3461 - 3463
(2009/04/16)
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- Facile approach to 2-acetamido-2-deoxy-β-D-glucopyranosides via a furanosyl oxazoline
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(Chemical Equation Presented) A concise and convenient route that may be easily scaled is reported for the preparation of unprotected β-glucopyranosides of N-acetyl-D-glucosamine. Reaction of a wide variety of alcohols with a reactive, readily prepared furanosyl oxazoline under acidic conditions affords the corresponding β-D-glucopyranosides in good to high yields. Primary alcohols gave only β-D-glucopyranosides. A mechanism is proposed for this transformation.
- Cai, Ye,Ling, Chang-Chun,Bundle, David R.
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p. 4021 - 4024
(2007/10/03)
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- N-ACETYLGLUCOSAMINE DERIVATIVES AND USE THEREOF
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The present invention relates to An N-acetylglucosamine derivative represented by the following formula (1), and a hyaluronic acid production promoting agent containing the same and a skin external preparation containing the same: wherein R1 is a hydrogen atom or an alkyl group having 2 to 18 carbon atoms; R2, R3, and R4 are hydrogen atoms or acyl groups having 2 to 18 carbon atoms and may be all the same or different from others; the steric structure at position 1 may be α or β; provided that R1, R2, R3, and R4 must not be all hydrogen atoms. It is intended to provide an easily available hyaluronic acid production promoting agent and a skin external preparation whereby the production of hyaluronic acid can be promoted in the skin and thus the skin can be maintained in a vital and moist state so that it is expected that the human skin can be prevented from age.
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Page/Page column 12
(2010/02/12)
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- N-Acetylmuramyl-L-Alanyl-D-Isoglutamine Glycosides: Effect of Glycoside Bond Configuration and Aglycone on Biological Activity
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Hexyl, octyl, and cyclohexyl β-glycosides and heptyl and cyclohexyl α-glycosides of muramyl dipeptide (MDP) were synthesized. Tests in vitro and in vivo revealed lower immunostimulating activities of MDP α-glycosides in comparison with the corresponding β-glycosides and MDP itself. In the case of alkyl β-glycosides, differences in hydrocarbon chain lengths (C4-C8) and in aglycone (aliphatic chain and aliphatic or aromatic ring) exerted no substantial effect on the immunostimulating activity.
- Zemlyakov,Tsikalov,Kalyuzhin,Kur'yanov,Chirva
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p. 286 - 292
(2007/10/03)
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- Pseudosugars, 40: Synthesis of ether- and imino-linked octyl N-acetyl- 5a'-carba-β-lactosaminides and -isolactosaminides: Acceptor substrates for α-(1→3/4)-fucosyltransferase, and enzymatic synthesis of 5a'- carbatrisaccharides
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Synthesis of ether-linked octyl 5a'-carba-β-lactosaminide 3 and - isolactosaminide 5 was carried out in seven steps, starting from the coupling products of 1,2-anhydro-5a-carba-β-D-mannopyranose derivative 7, and the oxide anions generated from the octyl N-acetyl-β-D-glucosaminide derivatives 13 and 16, respectively, under basic conditions. The 5a-carba-α-D- mannopyranose residues of the coupling products 17 and 26 were transformed into the β-D-gluco configuration through epimerization of the respective 2'- oxo derivatives 19 and 28, and selective reduction, and then into the β-D- galacto configuration by direct nucleophilic substitution of their 4',6'- dimesylates 23 and 31 with an acetate ion. Biological assay has shown that 3 is an acceptor substrate for human-milk α-(1→3/4)-fucosyltransferase and, interestingly, 5 is not. In addition, the imino-linked congeners 4 and 6 have been synthesized by coupling of the 4-amino-4-deoxy- and 3-amino-3-deoxy derivatives 37 and 41 of octyl N-acetyl-β-D-glucosaminide, and the carba- sugar epoxide 8, respectively, and subsequent deprotection. Compound 4 is a substrate while 6 is neither a substrate nor an inhibitor for fucosyltransferase. Small-scale enzymatic synthesis was carried out by treatment of 3 and 4 with GDP-fucose and milk fucosyltransferase, which resulted in conversion into the corresponding trisaccharides 47 and 48, respectively.
- Ogawa, Seiichiro,Matsunaga, Naoki,Li, Hong,Palcic, Monica M.
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p. 631 - 642
(2007/10/03)
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- Alkylating agents from sugars. Cyclophosphamides derived from 2-amino- 2-deoxy-D-allose
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Cyclophosphamides derived from alkyl 2-amino-4,6-O-benzylidene-2-deoxy- β-D-allopyranosides have been synthesized with good yield by treatment of the corresponding 2-amino-2-deoxy-D-allose derivatives with bis(2- chloroethyl)phosphoramide dichloride. The ring-forming reaction took place with very high diastereoselectivity. Subsequent hydrogenolysis gave excellent yields of cyclophosphamides derived from alkyl 2-amino-2-deoxy-β-D- allopyranosides, with hydrophilicity greater than that of the precursors. The starting material was easily available from 2-acetamido-2-deoxy-D-glucose.
- Iglesias-Guerra, Fernando,Romero, Isidora,Alcudia, Felipe,Vega-Perez, Jose M.
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- A new synthesis of O-glycosides from totally O-unprotected glycosyl donors
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O-Glycosidation of the totally O-unprotected aldoses (D-glucose, D-galactose and D-mannose) and D-fructose in THF or 1,4-dioxane using anhydrous FeCl3 as promoter afforded either aldofuranosides 1, 3, 4 in good overall yields or exclusively β-D-fructopyranosides 7. Conversely α-D-aldopyranosides 2, 5 and 6 were obtained respectively from D-glucose, D-mannose and N-acetyl-D-glucosamine when the reactions were performed in the presence of BF3.OEt2 under ultrasonication.
- Ferrieres, Vincent
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p. 2749 - 2752
(2007/10/02)
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- Synthesis and surface-active properties of some alkyl 2-amino-2-deoxy-β-D-glucopyranosides
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Several alkyl 2-acetamido-2-deoxy-β-D-glucopyranosides were synthesized using either the oxazoline or the N-allyloxycarbonyl procedure.The latter procedure gave better yields with fatty alcohols and cholesterol.The derivatives thus prepared were partly of fully deprotected and their surface-active properties assessed.Keywords: 2-Amino-2-deoxy-D-glucose; Amphiphiles; Surfactant; 14C-labelled
- Boullanger, Paul,Chevalier, Yves,Croizier, Marie-Christine,Lafont, Dominique,Sancho, Marie-Rose
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