反应详情

温度

135 °C

A mixture of 2.88 g (0.02 mol) of 3,4-difluorobenzaldehyde, 3.24 g (0.025 mol) of propionic anhydride and 0.92 g (0.02 mol) of sodium propionate under nitrogen is heated at 135° C. with a magnetic stirrer for 20 hours. The reaction mixture is poured onto 50 ml of water. A solid precipitates that dissolves when 50 ml of saturated K2CO3 is added with stirring. The basic solution is extracted with ether (2×100 ml). The aqueous phase is then 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.

1. customA solid precipitates
2. dissolutionthat dissolves when 50 ml of saturated K2CO3
3. additionis added
4. extractionThe basic solution is extracted with ether (2×100 ml)
5. additionThe aqueous phase is then poured into an excess of concentrated HCl and ice
6. filtrationThe precipitated white solid is filtered
7. customdried