Reaktion #1771996

Reaktionsgleichung

dichloroacetic acid

Boc-norvalinol

toluene

EDC

→

Boc-norvalinal

Lösungsmittel

dimethylsulfoxide

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONAfter addition
2. 2
   Temperaturto warm to room temperature over a period of 2 h
3. 3
   EinengenThe reaction mixture was concentrated
4. 4
   Sonstigeto remove the toluene
5. 5
   workup.DISSOLUTIONdissolved in ethyl acetate
6. 6
   WaschenThe solution was washed successively with 1N sodium bisulfate, saturated sodium bicarbonate and brine
7. 7
   Trocknendried over sodium sulfate
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated

Vorschrift

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).

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