反应详情

温度

-6.5 °C

0.388 mol (25.9 g) hydroxy urea were dissolved in 195 ml 2 M HCl, 80 ml of methanol were added and 0.388 mol (56.7 g) of 1,1-dimethoxypentane-3-on (62% content in product mixture) were added dropwise under cooling with the internal temperature being maintained at −6 to −7° C. The solution was thawed to room temperature in an ice bath and stirred for 1 h, then evaporated until dryness. The residue was suspended with 100 ml of acetone, the mixture was cooled to below 0° C. in an ice/ethanol bath, the solid filtered off and washed with little ice-cold acetone. After drying 32.6 g crude product were obtained. The crude product was heated until boiling with 200 ml ethanol, hot filtered and slowly cooled to −18° C. The precipitated solid was filtered off, washed with a little amount of ethanol and dried. 11.7 g of the title compound were obtained.

1. temperatureunder cooling with the internal temperature
2. customThe solution was thawed to room temperature in an ice bath
3. customevaporated until dryness
4. temperaturethe mixture was cooled to below 0° C. in an ice/ethanol bath
5. filtrationthe solid filtered off
6. washwashed with little ice-cold acetone
7. dry with materialAfter drying 32.6 g crude product
8. customwere obtained
9. filtrationhot filtered
10. temperatureslowly cooled to −18° C
11. filtrationThe precipitated solid was filtered off
12. washwashed with a little amount of ethanol
13. customdried