反应详情

温度

20 °C

592.1 g of acetoacetic acid tert.butyl ester are dissolved in 560 ml of glacial acetic acid. To this solution is added dropwise at 5°-10° C. during 21/2 hours a solution of 290.6 g of sodium nitrite in 655 ml of water. The resulting yellow suspension is stirred for 30 minutes at 20° C., treated with 940 ml of water and stirred for a further 2 hours. The mixture is treated with 900 ml of water and 900 g of ice and extracted in the stirring vessel three times with 1 l of ethyl acetate each time. The combined ethyl acetate extracts are washed three times with 1 l of water each time, then treated with 5 l of water and the pH-value is adjusted to 6.8 with sodium hydrogen carbonate. After separating the aqueous phase, the organic phase is washed once with water. Thereafter, the ethyl acetate solution is dried over sodium sulphate and evaporated in vacuo at 40° C. There is obtained (Z)-2-hydroxyimino-3-oxo-butyric acid tert-butyl ester as a yellow oil which is dried for a further 9 hours in a high vacuum at 40° C.

1. stirringstirred for a further 2 hours
2. extractionextracted in the stirring vessel three times with 1 l of ethyl acetate each time
3. washThe combined ethyl acetate extracts are washed three times with 1 l of water each time
4. additiontreated with 5 l of water
5. customAfter separating the aqueous phase
6. washthe organic phase is washed once with water
7. dry with materialThereafter, the ethyl acetate solution is dried over sodium sulphate
8. customevaporated in vacuo at 40° C