| 摘要 |
NEW MATERIAL:The 2,4-dideoxysialic acid derivative of formula I [R1 and R2 are independent H or O-acetyl (R1 and R2 are not H at the same time); R3 is carboxyl or methoxycarbonyl; all R4 groups are same and are hydroxymethyl or O-acetyl]. EXAMPLE:Methyl 2-deoxy-2,3-dehydro-4,7,8,9-tetra-O-acetyl-N-acetyl-neuraminate. USE:A medicinal drug capable of activating suppressor T-cell and having immune regulating action to suppress the immunoglobulin production of B-cell. PREPARATION:The compound of formula III is produced by reacting the com pound of formula II with acetic anhydride in the presence of a relatively small amount of concentrated sulfuric acid at about 20-25 deg.C, or the compound of formula IV is obtained by reacting the above components in the presence of a relatively large amount of concentrated sulfuric acid at about 80-90 deg.C.
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