| 摘要 |
A process for the industrial synthesis of tetraesters of 5-[bis(carboxymethyl)amino]-3-carboxymethyl-4-cyano-2-thiophenecarboxylic acid of formula (I) and the application thereof in the industrial production of bivalent salts of ranelic acid and their hydrates is disclosed, wherein: R and R' which are the same or different, each represent linear or branched (C1-C6)alkyl; wherein a compound of formula (III) wherein: R is as defined hereinbefore, is reacted with a compound of formula (IV) wherein: R' is as defined hereinbefore, in the presence of a catalytic amount of a C8-C10-type quaternary ammonium compound, and in the presence of potassium carbonate, at the reflux of an organic solvent; the reaction mixture is subsequently filtered; the mixture is then concentrated by distillation; a co-solvent is then added, and the reaction mixture is cooled and filtered to yield, after drying of the powder, the compound of formula (I) is obtained.
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