| 摘要 |
PURPOSE:To obtain the titled substance as a carcinometastasis-inhibitor with high safety, by reacting methyl chloro-tetraacetyl-beta-D-N-acetylneuraminate with fluoroisopropylideneuridine in the presence of silver trifluoro methanesulfonate. CONSTITUTION:Methyl 2-chloro-4,7,8,9-tetra-O-acetyl-beta-D-N-acetylneuraminate expressed by formula I is reacted with 5-fluoro-2',3'-isopropylidene uridine, preferably at 1:1.5-3.0 molar ratio, in the presence of silver trifluoromethanesulfonate, preferably at room temperature - -50 deg.C for 5-50min to obtain the aimed N-acetylneuraminic acid derivative expressed by formulae III and IV (R<1> represents acetyl; R<2> prepresents methoxycarbonyl; R<3> represents formula V). |
