Dimethyl Sulfate → Tert-butyl 2-methoxyimino-3-oxobutyrate

Participants

Reaction Steps

In 31.6 g of glacial acetic acid was dissolved 31.6 g (0.2 mole) of tert-butyl acetoacetate, and a solution of 15.2 g (0.22 mole) of sodium nitrite in 30 ml of water was added dropwise at 0° to 5° C. over a period of 2 hours and stirred at room temperature for 1 hour. After completion of the reaction, 100 ml of water and 100 ml of dichloromethane were added and then stirred, and the resulting mixture was allowed to stand to be separated and the aqueous layer was removed. To the thus obtained solution of tert-butyl 2-hydroxyimino-3-oxobutyrate in dichloromethane was added 41.5 g (0.3 mole) of potassium carbonate with cooling, after which 27.8 g (0.22 mole) of dimethyl sulfate was added dropwise at 20° C. over a period of 2 hours and stirred at 20° C. for another 1 hour. After completion of the reaction, the reaction solution was washed with 150 ml of water and dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure to obtain 38.0 g (yield 95%) of tert-butyl 2-methoxyimino-3-oxobutyrate as a light-yellow, oily substance.

Provenance & Evidence