反应详情

温度

5 °C

626.65 g of (Z)-2-hydroxyimino-3-oxo-butyric acid tert.butyl ester are dissolved in 2.86 l of acetone. The solution is cooled to 5° C. and treated portionwise with 703.5 g of potassium carbonate. 322 ml of dimethyl sulphate are then added dropwise to the yellow suspension without cooling during 1 hour, whereby the temperature of the mixture should not rise above 25° C. The light beige suspension is stirred at 20°-25° C. for about 4 hours until starting material can no longer be detected by thin-layer chromatography. Thereafter, the mixture is poured into 7 l of water and extracted 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, dried over sodium sulphate and evaporated in vacuo at 40° C. The residual yellow oil is dried for a further 6 hours in a high vacuum at 40° C. and subsequently distilled. There is obtained (Z)-2methoxyimino-3-oxo-butyric acid tert.butyl ester as a yellow oil with a boiling point of 57° C. at 0.02 mmHg.

1. temperaturewithout cooling during 1 hour
2. customrise above 25° C
3. extractionextracted three times with 1 l of ethyl acetate each time
4. washThe combined ethyl acetate extracts are washed three times with 1 l of water each time
5. dry with materialdried over sodium sulphate
6. customevaporated in vacuo at 40° C
7. customThe residual yellow oil is dried for a further 6 hours in a high vacuum at 40° C.
8. distillationsubsequently distilled