Abstract
Treatment of the readily available peracetylated N -acetylneuraminic acid glycosyl chloride [methyl 5-acetamido-4,7,8,9-tetra-O -acetyl-2-chloro-2,3,5-trideoxy-β-d -glycero-d -galactononulopyranosonate)] with anhydrous Na2 HPO4 in refluxing MeCN quantitatively affords the peracetylated N -acetylneuraminic acid glycal [methyl 5-acetamido-4,7,8,9-tetra-O -acetyl-3,5-dideoxy-2,6-anhydro-d -glycero-d -galacto-non-2-enonate], which can be isolated from the reaction mixture by simple filtration and subsequent evaporation of the solvent. No glycal formation was detected at room temperature even after prolonged treatment with Na2 HPO4 . The method proposed is experimentally simple and allows ready preparation of substantial amounts of the title compound, which is an important intermediate in sialic acid chemistry.
Key words
carbohydrates - halides - eliminations - alkenes - phosphates
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