| 摘要 |
A method for preparing compounds of formula (I), wherein X, i, j, R1, R2, R3 and R4 are as defined in claim 1, by (i) reacting a derivative of formula (II) with an acrylonitrile derivative of formula (III) in a polar medium consisting of a first organic solvent (1) forming an azeotrope with water or a lower alcohol, and a second polar organic solvent (2), and in the presence of a quaternary ammonium hydroxide catalyst, the boiling point of the second solvent (2) being lower than the boiling point of the first solvent (1); (ii) removing the second solvent (2) by distillation; (iii) adding a sufficient amount of water and/or a lower alcohol to the reaction medium to distil all of the first solvent (1) azeotropically without leaving the reaction medium completely dry and then distilling all of said solvent (1); and (iv) hydrolysing the resulting suspension by adding a strong base or a strong acid to the reaction medium, and optionally converting the resulting carboxylate salt of formula (I) into the corresponding carboxylic acid, is disclosed.
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