Dimethyl Sulfoxide → tert-Butyl 2-methyl-3-oxopiperidine-1-carboxylate

Temperatur

-78 °C

A solution of oxalyl chloride (4.06 mL, 46.5 mmol) in 50 mL of dichloromethane was cooled to −78° C. and 4.95 mL (69.8 mmol) of dimethyl sulfoxide was added slowly and the mixture was stirred at −78° C. for 10 min. Then a solution of 5.00 g (23.3 mmol) of tert-butyl 3-hydroxy-2-methylpiperidine-1-carboxylate (Step B) in 5 mL of dichloromethane was added dropwise to above mixture. The mixture was stirred at −78° C. for 20 min, then 40.5 mL (232 mmol) of N,N-diisopropylethylamine was added to the mixture. The reaction was warmed to ambient temperature and continued to stir at ambient temperature for 1 h. The mixture was partitioned between dichloromethane and water. The aqueous phase was extracted with three potions of dichloromethane. The combined organic layers were washed with brine, dried over magnesium sulfate, and concentrated. Purification by flash chromatography on a Biotage®D system (silica gel, eluting with 10% ethyl acetate/hexane to 30% ethyl acetate/hexane) gave the title compound. LC/MS 214 (M+1).

1. stirringThe mixture was stirred at −78° C. for 20 min
2. temperatureThe reaction was warmed to ambient temperature
3. stirringto stir at ambient temperature for 1 h
4. customThe mixture was partitioned between dichloromethane and water
5. extractionThe aqueous phase was extracted with three potions of dichloromethane
6. washThe combined organic layers were washed with brine
7. dry with materialdried over magnesium sulfate
8. concentrationconcentrated
9. customPurification by flash chromatography
10. washon a Biotage®D system (silica gel, eluting with 10% ethyl acetate/hexane to 30% ethyl acetate/hexane)

ORD-Eintrag

ord-a80bde083e5b43ffb2d375488b7a319f

Quelldatensatz

uspto-grants-2008_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07388019B2