Propionic anhydride → 3-(3,4-Difluorophenyl)-2-methylprop-2-enoic acid

반응식

[F:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][C:9]=1[F:10])[CH:5]=O.[C:11]([O:15]C(=O)CC)(=[O:14])[CH2:12][CH3:13].C([O-])(=O)CC.[Na+]>O>[F:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][C:9]=1[F:10])[CH:5]=[C:12]([CH3:13])[C:11]([OH:15])=[O:14]

참가 물질

반응 조건

온도: 135 °C

실험 절차

A mixture of 3,4-difluorobenzaldehyde (2.88 g, 0.02 mol), propionic anhydride (3.24 g, 0.025 mol) and sodium propionate (0.92 g, 0.02 mol) under nitrogen is heated to 135° C. for 20 hours. The reaction mixture is poured into water (50 ml). A solid precipitates, which dissolves when saturated K2CO3 (50 ml) is added with stirring. The basic solution is washed with ether (2×100 ml). The aqueous phase is poured into an excess of concentrated HCl and ice. The precipitated white solid is filtered and dried to give 3,4-difluoro-α-methylcinnamic acid, m.p. 122-125° C.