反应详情

温度

100 °C

Methanesulfonylacetone (12.6 g, 92.9 mmol) was dissolved in N,N-dimethylformamide (200 mL) and cooled in ice under nitrogen. Then potassium tert.butylate (11.7 g, 102 mmol) was added (exothermic 20° C.) and stirring without cooling continued for 15 min. Cooled in ice again, then 6-bromo-2-methyl-4H-3,1-benzoxazin-4-one (example B.1) (22.3 g, 92.9 mmol) was added and then stirred without cooling for 4 h. Cooled in ice again, then potassium tert.butylate (11.7 g, 102 mmol) was added, and the resulting red solution was stirred at 20° C. for 15 min and then heated at 100° C. for 30 min. After cooling, 4 M HCl (30 mL) was added, and the mixture was evaporated thoroughly at 0.1 mbar/50° C. The residue was suspended in water (200 mL) and stirred vigorously for 30 min which led to the formation of a filterable precipitate. This solid was filtered off and washed with water (50 mL). One obtained 14.25 g (48.5%) of white crystals. MS: m/z=315/317 (M+H).

1. temperaturecooled in ice under nitrogen
2. temperaturewithout cooling
3. temperatureCooled in ice again
4. stirringstirred
5. temperaturewithout cooling for 4 h
6. temperatureCooled in ice again
7. stirringthe resulting red solution was stirred at 20° C. for 15 min
8. temperatureAfter cooling
9. customthe mixture was evaporated thoroughly at 0.1 mbar/50° C
10. stirringstirred vigorously for 30 min which
11. filtrationThis solid was filtered off
12. washwashed with water (50 mL)