| 摘要 |
A process for the preparation of highly pure (E)-N,N-diethyl-2-cyano-3-(3,4-dihydroxy-5-nitrophenyl)acrylamide (Entacapone). It comprises condensing 3,4-dihydroxy-5-nitro benzaldehyde with N,N-diethyl cyano acetamide in an organic solvent in the presence of an organic base and an acid under reflux conditions followed by distilling off the solvent under vacuum and treating the residue with a lower aliphatic carboxylic acid at 40-8O0 C. The resulting residue is extracted with a chlorinated solvent and the solvent is distilled off under vacuum. The resulting residue is extracted with an organic solvent to obtain crude N,N-diethyl-2-cyano-3-3,4-dihydroxy-5-nitrophenyl)acrylamide. The crude product N,N-diethyl-2-cyano-3-(3,4-dihydroxy-5-nitrophenyl) acrylamide formed is treated with a mixture of organic alcohol and organic acid in the molar ratio of the crude product to organic alcohol 1:5 to 15 and crude product to organic acid 1:1 to 3 under reflux conditions.
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