反应详情

To a mixture of 3,5-dimethoxy-4-hydroxybenzoic acid (3.00 g) and acetic anhydride (30 ml) was dropwise added pyridine (15 ml) with ice-cooling over a 5 minutes period. After stirring at room temperature for 30 minutes, the reaction mixture was poured into water and stirred at room temperature for 30 minutes followed by extracting thrice with ethyl acetate. The combined extract was washed with 10% hydrochloric acid, dried and concentrated. The residue was recrystallized from a mixture of methylene chloride and hexane to afford the title compound (3.13 g), melting at 192°-194° C.

1. temperaturecooling over a 5 minutes period
2. stirringstirred at room temperature for 30 minutes
3. extractionby extracting thrice with ethyl acetate
4. extractionThe combined extract
5. washwas washed with 10% hydrochloric acid
6. customdried
7. concentrationconcentrated
8. customThe residue was recrystallized from a mixture of methylene chloride and hexane