Dimethyl Sulfoxide → tert-butyl N-(2-methyl-4-oxobutan-2-yl)carbamate

Temperature

-78 °C

At −78° C. DMSO (1.22 ml, 17.2 mmol) was added to a solution of oxalyl chloride (1.1 ml, 12.9 mmol) in dichloromethane (15 ml). The mixture was stirred for 15 min at −78° C. A solution of 3-hydroxy-1,1-dimethylpropylcarbamic acid tert-butyl ester (1.75 g, 8.6 mmol) in dichloromethane (10 ml) was added dropwise over a period of 15 min. The solution was stirred at −78° C. for another 15 min. Triethylamine (6.0 ml, 43 mmol) was added. The solution was stirred at −78° C. for 5 min and then warmed to room temp. The solution was diluted with dichloromethane (100 ml) and extracted with 1N hydrochloric acid (100 ml). The aqueous phase was extracted with dichloromethane (50 ml). The combined organic layers were washed with a saturated solution of sodium hydrogencarbonate (100 ml) and dried over magnesium sulfate. The solvent was removed in vacuo. The crude product was purified by column chromatography on silica (140 g) with ethyl acetate/heptane (1:3) to give 1.10 g of 3-(tert-butoxycarbonylamino)-3-methylbutanal.

1. customAt −78° C
2. stirringThe solution was stirred at −78° C. for another 15 min
3. stirringThe solution was stirred at −78° C. for 5 min
4. temperaturewarmed to room temp
5. extractionextracted with 1N hydrochloric acid (100 ml)
6. extractionThe aqueous phase was extracted with dichloromethane (50 ml)
7. washThe combined organic layers were washed with a saturated solution of sodium hydrogencarbonate (100 ml)
8. dry with materialdried over magnesium sulfate
9. customThe solvent was removed in vacuo
10. customThe crude product was purified by column chromatography on silica (140 g) with ethyl acetate/heptane (1:3)

ORD record

ord-1b27be89f0834535b96c43e34fd52733

Source dataset

uspto-grants-2002_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06350767B1