反应详情

To the tert-butyl 2-hydroxyimino-3-oxobutyrate was added water [6], to which was added 30% sodium hydroxide [800 ml] at 28° C. while stirring to render the pH to 9.0. To the resultant solution was added dimethyl sulfate [1324 g] at 28° to 30° C. in the course of 20 minutes, which was stirred for 4 hours while adding thereto at 25° to 30° C. a 30% aqueous solution of sodium hydroxide [500 ml] to adjust the pH within the range of 8.7 to 9.0. After completion of the reaction, extraction was conducted with methylene chloride [4 l], and the aqueous layer was subjected to further extraction with methylene chloride [2 l]. The methylene chloride layers were combined and washed with a 1N aqueous solution of sodium hydroxide, 1N HCl, a 5% aqueous solution of sodium hydrogencarbonate and water, each one litre portion, successively. The resultant solution was dried over anhydrous sodium sulfate [700 g], followed by concentration under reduced pressure to obtain tert-butyl 2-methoxyimino-3-oxobutyrate [1878 g] as an oily product. The yield was 93.3%. NMR(CDCl3): δ4.08 (3H,s), 2.36(3H,s), 1.53(9H,s)ppm .

1. stirringwas stirred for 4 hours
2. additionwhile adding
3. customat 25° to 30° C.
4. customAfter completion of the reaction, extraction
5. extractionthe aqueous layer was subjected to further extraction with methylene chloride [2 l]
6. washwashed with a 1N aqueous solution of sodium hydroxide, 1N HCl
7. dry with materialThe resultant solution was dried over anhydrous sodium sulfate [700 g]
8. concentrationfollowed by concentration under reduced pressure