N-bromobutanimide → Tert-butyl 4-methoxy-2-oxobutanoate

A solution of 10.6 g (38.1 mmol) of tert-butyl 2-(2-methoxyethyl)-1,3-dithiane-2-carboxylate in 365 ml of acetone and 18 ml of water was added dropwise to a solution, cooled to −18° C., of 54.2 g (305 mmol) of N-bromosuccinimide in 365 ml of acetone and 18 ml of water such that the internal temperature did not exceed −5° C. After the addition had ended, the mixture was stirred for another 10 min and the reaction was then terminated using 630 ml of sodium sulphite solution (1N). 420 ml of n-heptane were added to the reaction mixture and, after phase separation, the aqueous phase was extracted three times with 315 ml of ethyl acetate. The combined organic phases were dried over sodium sulphate and filtered, and the solvent was removed at 25° C. and 75 mbar. The resulting suspension was stirred with 100 ml of n-hexane and the precipitate was filtered off. The solvent was removed under reduced pressure, giving the target compound. Yield: 5.28 g (59% of theory)

1. customdid not exceed −5° C
2. additionAfter the addition
3. customthe reaction was then terminated
4. addition420 ml of n-heptane were added to the reaction mixture
5. customafter phase separation
6. extractionthe aqueous phase was extracted three times with 315 ml of ethyl acetate
7. dry with materialThe combined organic phases were dried over sodium sulphate
8. filtrationfiltered
9. customthe solvent was removed at 25° C.
10. stirringThe resulting suspension was stirred with 100 ml of n-hexane
11. filtrationthe precipitate was filtered off
12. customThe solvent was removed under reduced pressure
13. customgiving the target compound

ORD record

ord-5c0cf5d86173488daa5374879aacf70e

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09434690B2