| 摘要 |
The invention relates to a new process for the preparation of 3-(3-carboxypropyl)-5-methoxyindole-2-carboxylic acid (I), characterized in that 6-carboethoxy-6-p-methoxyphenylhydrazonohexanoic acid (II) is cyclized using a carboxylic acid which contains 1-3 carbon atoms, the resulting mixture comprising I, the two I monoethyl esters and I diethyl ester is treated with a strong inorganic base, and the resulting salt is converted into the free acid I by treatment with a strong acid.
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