- Crystal and molecular structure of methyl L-glycero-α-D-manno- heptopyranoside, and synthesis of 1→7 linked L-glycero-D-manno-heptobiose and its methyl α-glycoside
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Methyl L-glycero-α-D-manno-heptopyranoside was synthesized in good yield by a Fischer-type glycosylation of the heptopyranose with methanol in the presence of cation-exchange resin under reflux and microwave conditions, respectively. The compound crystallized from 2-propanol in an orthorhombic lattice of space group P21212 showing a comparatively porous structure with a 2-dimensional O-H···O hydrogen bond network. As model compounds for the side chain domains of the inner core structure of bacterial lipopolysaccharide, L-glycero-α-D-manno-heptopyranosyl-(1→7)-L- glycero-D-manno-heptopyranose and the corresponding disaccharide methyl α-glycoside were prepared. The former compound was generated via glycosylation of a benzyl 5,6-dideoxy-hept-5-enofuranoside intermediate followed by catalytic osmylation and deprotection. The latter disaccharide was efficiently synthesized in good yield by a straightforward coupling of an acetylated N-phenyltrifluoroacetimidate heptopyranosyl donor to a methyl 2,3,4,6-tetra-O-acetyl heptopyranoside acceptor derivative followed by Zemplen deacetylation.
- Artner, Daniel,Stanetty, Christian,Mereiter, Kurt,Zamyatina, Alla,Kosma, Paul
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experimental part
p. 1739 - 1746
(2011/12/02)
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- Five monophosphates of methyl L-glycero-α-D-manno-heptopyranoside: Synthesis, hydrolysis and migrations
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From suitably protected methyl α-D-mannopyranosides five methyl L- glycero-α-D-manno-heptopyranosides were synthesized by the one-carbon-atom chain elongation at C-6 and converted to five monophosphates (1-5) having the PO(OH)2 group at O-2, -3, -4, -6 and -7. Compounds 1-5 were exposed to acidic and basic hydrolytic conditions used in lipopolysaccharide analysis and the products and their proportion were determined. Under acidic conditions, besides hydrolysis of the glycoside, migrations and hydrolytic cleavage of the phosphate residue were found. Under basic conditions the phosphates were stable.
- Grzeszczyk, Barbara,Holst, Otto,Mueller-Loennies, Sven,Zamojski, Aleksander
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- SYNTHESIS OF L-glycero-D-manno-HEPTOSE
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The easily accessible benzyl 2,3,4-tri-O-benzyl-α-D-manno-hexodialdo-1,5-pyranoside (2) can be converted, in a highly stereoselective manner, by the two-step Tamao method to benzyl 2,3,4-tri-O-benzyl-β-L-glycero-α-D-manno-heptopyranoside (4a).
- Boons, G. J. P. H.,Klein, P. A. M. van der,Marel, G. A. van der,Boom, J. H. van
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p. 507 - 508
(2007/10/02)
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- NEW SYNTHESES OF D- AND L-GLYCERO-D-MANNO-HEPTOSES
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Three methods for the synthesis of the title compounds starting from benzyl 2,3,4-tri-O-benzyl-α-D-manno-hexodialdo-1,5-pyranoside (7) have been elaborated.Conversion of 7 into the cyanohydrin followed by reduction to give the amine and then deamination gave a derivative of L-glycero-D-manno-heptose in low yield.Condensation of 7 with 2-methylfuran gave two stereoisomeric 6-C-(2-methyl-5-furyl) derivatives.The preponderant stereoisomer was ozonised and then reduced to give a derivative of D-glycero-D-manno-heptose.Condensation of 7 with allyloxymethylmagnesium chloride gave derivatives of both heptoses in good yield and with an L-glycero-D-glycero ratio of 3.2:1.Deprotection of these derivatives gave the heptoses in high yield.
- Dziewiszek, Krzysztof,Zamoiski, Aleksander
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p. 163 - 172
(2007/10/02)
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- Branched and Chain-extended Sugars, XXX.- Diastereoselective Synthesis of L-glycero-D-manno-Heptose, a Constituent of the Inner Core Region of Lipopolysaccharides
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Reaction of 2,3;5,6-di-O-isopropylidene-D-mannofuranose (1) with 2-lithio-1,3-dithiane affords diastereoselectively the 3,4;6,7-di-O-isopropylidene-D-glycero-D-galacto-heptose trimethylene dithioacetal (3).Conversion of compound 3 by a sequence of steps gives the tri-O-isopropylidene-D-glycero-D-galacto-heptit 16 which is oxidized with 1,1'-(azodicarbonyl)-dipiperidine to give the tri-O-isopropylidene-L-glycero-D-manno-heptose 17.Finally, compound 17 is transferred via the acetate 19 into the L-glycero-D-manno-heptopyranose 18.
- Paulsen, Hans,Schueller, Matthias,Heitmann, Axel,Nashed, Mina A.,Redlich, Hartmut
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p. 675 - 686
(2007/10/02)
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- SYNTHESE DER L-GLYCERO-D-MANNO-HEPTOSE
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Chain extension of 2,3:5,6-di-O-isopropylidene-D-manno-furanose 2 with 2-lithio-1,3-dithiane gives stereoselectively a derivative of D-glycero-D-galacto-heptose 3.Conversion of the heptose 2 by reduction of the aldehydo function and oxidation of the 7-OH group yields the D-glycero-D-manno-heptose 18.
- Paulsen, Hans,Schueller, Matthias,Nashed, Mina A.,Heitmann, Axel,Redlich, Hartmut
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p. 3689 - 3692
(2007/10/02)
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