反应详情

温度

0 °C

To a stirred and cooled mixture of 32 ml of sulfuric acid and 14 ml of water there were added 17 g of 2,3-dihydro-5-chlorobenzofuran, while keeping the temperature at 25° C. After cooling to 0° C. there were added dropwise 14 ml of nitric acid. Stirring and cooling at 0° C. was continued for 44 hours. The reaction mixture was diluted with water (temp. <10° C.) and stirred for 15 min. The precipitate was filtered off, washed with water and recrystallized from a mixture of ethyl acetate and hexane (30:70), yielding 8.9 g (40.5%) of 5-chloro-2,3-dihydro-7-nitrobenzofuran (interm. 3).

1. temperaturecooled
2. customat 25° C
3. stirringStirring
4. temperaturecooling at 0° C.
5. stirringstirred for 15 min
6. filtrationThe precipitate was filtered off
7. washwashed with water
8. customrecrystallized from a mixture of ethyl acetate and hexane (30:70)