反应详情

温度

-30 °C

In 15 ml of acetonitrile was dissolved 1.07 g of tert-butyl 2-hydroxyimino-3-oxobutyrate, followed by addition of 2.8 ml of triethylamine. Then, 2.5 ml of chlorotrimethylsilane was added dropwise with ice-cooling and the mixture was stirred at 20°-25° C. for 1.5 hours, after which it was concentrated under reduced pressure. The residue was suspended in 15 ml of tetrahydrofuran and the suspension was filtered in a nitrogen gas stream to remove insolubles. This filtrate containing tert-butyl 2-trimethylsilyloxyimino-3-trimethylsilyloxy-3-butenoate was cooled to -30° C. and 0.46 ml of sulfuryl chloride was added dropwise. After the temperature of the system was increased to 20° C., the reaction mixture was concentrated under reduced pressure. The concentrate was chromatographed on a silica gel column and elution was carried out with 100 ml of hexane-ether (1:1, v/v). The eluate was concentrated under reduced pressure to give 1.08 g of tert-butyl 4-chloro-2-hydroxyimino-3-oxobutyrate. Yield 85.2%.

1. temperaturecooling
2. concentrationafter which it was concentrated under reduced pressure
3. filtrationthe suspension was filtered in a nitrogen gas stream
4. customto remove insolubles
5. additionThis filtrate containing tert-butyl 2-trimethylsilyloxyimino-3-trimethylsilyloxy-3-butenoate
6. addition0.46 ml of sulfuryl chloride was added dropwise
7. temperatureAfter the temperature of the system was increased to 20° C.
8. concentrationthe reaction mixture was concentrated under reduced pressure
9. customThe concentrate was chromatographed on a silica gel column and elution
10. concentrationThe eluate was concentrated under reduced pressure