反应详情

A mixture of 23 g. of α-[(5-acetylamino-4-chloro-2-methoxycarbonylphenyl)oxy]-γ-butyrolactone, 46 ml. of triethylamine and 230 ml. of acetic anhydride was heated at 120° C. for 5 hours. The solvents were evaporated off under reduced pressure, then the residue was poured into ice-water. The precipitating crystals were collected by filtration, washed with water and dried, followed by recrystallization from ethyl acetate to give 6-diacetylamino-5-chloro-4',5'-dihydrospiro[benzo[b]furan-2(3H), 3'(2'H)-furan]-2',3-dione melting at 181°-185° C. Yield 6.8 g.

1. additionA mixture of 23 g
2. customThe solvents were evaporated off under reduced pressure
3. additionthe residue was poured into ice-water
4. filtrationThe precipitating crystals were collected by filtration
5. washwashed with water
6. customdried
7. customfollowed by recrystallization from ethyl acetate