Methanol → Methyl 2-(3,5-difluorophenyl)-2-hydroxyacetate
Reaktionsgleichung
[F:1][C:2]1[CH:3]=[C:4]([CH:9]([OH:13])[C:10]([OH:12])=[O:11])[CH:5]=[C:6]([F:8])[CH:7]=1.B(O)(O)O.[CH3:18]O>>[F:1][C:2]1[CH:3]=[C:4]([CH:9]([OH:13])[C:10]([O:12][CH3:18])=[O:11])[CH:5]=[C:6]([F:8])[CH:7]=1Komponenten
4
Versuchsvorschrift
25.0 g of 3,5-difluorophenylhydroxyacetic acid (D2) are dissolved in 325 ml of methanol. 3.9 g of boric acid are subsequently added, and the reaction mixture is stirred at room temperature for 18 hours. The resultant solution is then evaporated to dryness. The residue is extracted using 100 ml of ethyl acetate and 100 ml of water. The aqueous phase is subsequently extracted twice with 50 ml of ethyl acetate each time. The combined organic phases are dried over sodium sulfate and filtered. The filtrate is evaporated to dryness in vacuo, giving 25.5 g of the title compound as crude product. Recrystallisation from 17 ml of ethyl acetate and 170 ml of cyclohexane give 23.5 g of the pure compound C2 having a melting point of 61.8° C. (MS 201.9 (M+)).