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

Temperature

-78 °C

##STR105## Dimethylsufoxide (1.22 ml, 17.2 mmol) was added to a solution of oxalyl chloride (1.1 ml, 12.9 mmol) at -78° C. 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 temperature. 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 saturated sodium hydrogen carbonate solution (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. stirringThe solution was stirred at -78° C. for another 15 min
2. stirringThe solution was stirred at -78° C. for 5 min
3. temperaturewarmed to room temperature
4. extractionextracted with 1N hydrochloric acid (100 ml)
5. extractionThe aqueous phase was extracted with dichloromethane (50 ml)
6. washThe combined organic layers were washed with saturated sodium hydrogen carbonate solution (100 ml)
7. dry with materialdried over magnesium sulfate
8. customThe solvent was removed in vacuo
9. customThe crude product was purified by column chromatography on silica (140 g) with ethyl acetate/heptane (1:3)

ORD record

ord-278bc25d3f3449f3b531457dfc8fb6c1

Source dataset

uspto-grants-1999_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05922770