1,2-Dichloroethane → tert-butyl N-((2S)-1-oxopentan-2-yl)carbamate

Temperatur

0 °C

To Boc-norvalinol (7.77 g, 38 mmol), in anhydrous dimethylsulfoxide (153 mL) and toluene (153 mL) was added EDC (73.32 g, 382 mmol). After the solution was cooled to 0° C., dichloroacetic acid (15.8 mL, 191 mmol) was added dropwise. After addition was complete, the reaction was stirred for 15 min. The solution was allowed to warm to room temperature over a period of 2 h. The reaction mixture was concentrated to remove the toluene, then dissolved in ethyl acetate. The solution was washed successively with 1N sodium bisulfate, saturated sodium bicarbonate and brine, dried over sodium sulfate, filtered and concentrated to afford crude Boc-norvalinal which was used directly in the next step. TLC Rf=0.84 (40% ethyl acetate/hexanes).

1. additionAfter addition
2. temperatureto warm to room temperature over a period of 2 h
3. concentrationThe reaction mixture was concentrated
4. customto remove the toluene
5. dissolutiondissolved in ethyl acetate
6. washThe solution was washed successively with 1N sodium bisulfate, saturated sodium bicarbonate and brine
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated

ORD-Eintrag

ord-35d18a1a962e4b69bdc1de88b9381d92

Quelldatensatz

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

USRE043298E1