反应详情

A mixture of 5B (2.38 g) and methanol (20 ml) was added to a stirred solution of sodium hydroxide (1.68 g) in water (20 ml). The reaction mixture was heated at reflux for 3 hours. The reaction mixture was cooled to room temperature and concentrated in vacuo. The concentrate was cooled to 5° C. and acidified with concentrated HCI (3.5 ml). The resulting suspension was stirred at 5° C. for 30 minutes. The solid was collected by filtration, washed with water, then dried in vacuo at 35-40° C. to give the free acid (1.45 g, 65 %).

1. temperatureThe reaction mixture was heated
2. temperatureat reflux for 3 hours
3. concentrationconcentrated in vacuo
4. temperatureThe concentrate was cooled to 5° C.
5. filtrationThe solid was collected by filtration
6. washwashed with water
7. customdried in vacuo at 35-40° C.