反应详情

温度

2 °C

0.10 mol (7.61 g) hydroxy urea were dissolved in 150 ml of 1 M HCl and 0.11 mol (16.15 g, techn. 90%) of 4,4,-dimethoxy-2-butanone was added dropwise under ice cooling whereby the internal temperature was maintained at 1-3° C. The solution was thawed in an ice bath to room temperature and stirred over night, then filtered and evaporated to dryness. The residue was suspended with 100 ml of acetone, the mixture was cooled to −18° C., the solid filtered off and washed with a little ice-cold acetone. After drying, 10.7 g or crude product were obtained. The crude product was recrystallized with 1750 ml ethanol from the boiling heat, cooled in an ice/ethanol bath, filtered off, washed with a little ethanol and dried (fraction 1). The mother liquor was concentrated on a rotary evaporator until again product started to precipitate, cool stored and a second fraction isolated. After drying, 6.15 g (1. fraction) and 1.86 g (2. fraction) product was obtained. Both fractions were combined and recrystallized from the boiling heat with 230 ml 90% ethanol (10 (D/0 water) similarly. After drying, 3.75 g (3. fraction) and 2.36 g (4. fraction) of the title compound were obtained.

1. customThe solution was thawed in an ice bath to room temperature
2. filtrationfiltered
3. customevaporated to dryness
4. temperaturethe mixture was cooled to −18° C.
5. filtrationthe solid filtered off
6. washwashed with a little ice-cold acetone
7. customAfter drying
8. custom10.7 g or crude product were obtained
9. customThe crude product was recrystallized with 1750 ml ethanol from the
10. temperatureboiling heat
11. temperaturecooled in an ice/ethanol bath
12. filtrationfiltered off
13. washwashed with a little ethanol
14. customdried (fraction 1)
15. concentrationThe mother liquor was concentrated on a rotary evaporator until again product
16. customto precipitate
17. temperaturecool
18. customa second fraction isolated
19. customAfter drying
20. custom6.15 g (1. fraction) and 1.86 g (2. fraction) product was obtained
21. customrecrystallized from the
22. temperatureboiling heat with 230 ml 90% ethanol (10 (D/0 water) similarly
23. customAfter drying