| 摘要 |
A method for preparing a magnesium salt of dimecrotic acid is provided to obtain dimecrotic acid and the magnesium salt thereof with high yield and high purity, thereby reducing the manufacturing cost. A method for preparing a magnesium salt of dimecrotic acid comprises a step of dissolving dimecrotic acid represented by a formula(2) in absolute ethanol and then adding magnesium ethoxide to the solution of the step(a) to allow reaction, wherein the dimecrotic acid is prepared by a method comprising the steps of: (a) adding 2-5 equivalents of dimethylsulfate regarding 4-methyl-7-hydroxycumarin represented by a formula(4) to the compound of the formula(4) and NaOH in a solvent and allowing the reaction solution to be reacted under pH of more than 10 to prepare 4-methyl-7-methoxycumarin represented by a formula(3); (b) dissolving the compound obtained from the step(a) and NaOH in ethanol; (c) adding dimethylsulfate to the solution prepared by the step(b) and allowing them to react to synthesize crude dimecrotic acid; and (d) recrystallizing the crude dimecrotic acid in ethanol using a strong acid to prepare the dimecrotic acid. Further, the step(a) is performed by adding the dimethylsulfate one time, heating the reaction solution at 40 to 45 °C, and adding residual quantity of the dimethylsulfate.
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