| 摘要 |
The present invention relates to a novel, optimized process for the preparation of cyclohexanedionecarboxylic acid derivatives of formula I which can be carried out in a single vessel affording a very good yield, which process comprises heating a reactive carboxylic acid derivative of formula III <IMAGE> (III) wherein X is a halide, an alkylsulfonic or arylsulfonic acid radical or the molecular radical <IMAGE> which is necessary to form an anhydride and R1 is alkyl or cycloalkyl, with an alkali metal cyanide or copper cyanide, in an inert organic solvent, to give a mixture, then adding in succession to said mixture, at a temperature in the range from 0 DEG C. to room temperature, zinc chloride, an equimolar amount, with respect to the carboxylic acid derivative of formula III, of a 3,5-cyclohexanedione-1-carboxylic acid derivative of formula II <IMAGE> (II) wherein A is an ester or amide radical, and, dropwise, an amine, and, after acidifying the reaction mixture with an aqueous acid, isolating the resultant 4-acyl-3,5-cyclohexanedione-1-carboxylic acid derivative of formula I <IMAGE> (I) <IMAGE> +TR <IMAGE> by extraction. Said cyclohexanedionecarboxylic acid derivatives have herbicidal and plant growth regulating properties.
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