- Application of halide molten salts as novel reaction media for O-glycosidic bond formation
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In this study we have explored the application of halide molten salts as reaction media for O-glycosidic bond formation under basic conditions and mild heating. Eighteen different room-temperature ionic liquids and molten salts, representing four different classes of cations (i.e. imidazolium, pyridinium, pyrrolidinium and ammonium), were screened in the glycosidation reaction of p-nitrophenol with aceto-bromo-α-D-galactose. 1-Butyl-4-methylimidazolium chloride (BMIM·Cl) gave the best results and was applied in the reactions of other phenolic substrates to give the products with up to 80% yields. All the reactions were highly selective to give the β-anomers, and the molten salt BMIM·Cl could easily be reused with no apparent loss in activity.
- Kumar, Vineet,Talisman, Ian Jamie,Malhotra, Sanjay V.
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supporting information; experimental part
p. 3377 - 3381
(2010/08/19)
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- STEREOSELECTIVE SYNTHESES OF O- AND S-NITROPHENYL GLYCOSIDES. PART III. SYNTHESES IN THE &α-D-GALACTOPYRANOSE AND &α-MALTOSE SERIES
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The action of p-nitrophenol penta-O-acetyl-β-D-galactopyranose in dichloromethane, in the presence of stannic tetrachloride gave p-nitrophenyl α-D-galactoside in fair yield.This technique failed when o-nitrophenol was used.Tetra-O-acetyl-β-D-galactopyranosyl and hepta-O-acetyl-β-maltosyl chlorides were converted to p- or o-nitrophenyl α-D-glycosides and p-nitrophenyl α-D-1-thioglycosides in good yield using hexamethylphosphoramide as a solvent and the sodium salt of the phenols as nucleophiles.The galactosides have been functionalized for further condensation at the C-4 position by selective benzoylation.
- Apparu, Maecel,Blanc-Muesser, Michele,Defaye, Jacques,Driguez, Hugues
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p. 314 - 320
(2007/10/02)
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