Reaktion #487531

Reaktionsgleichung

triethylamine

α-hydroxyisobutyric acid

2-bromopropionyl chloride

→

3,6,6-Trimethyl-1,4-dioxane-2,5-dione

Ausbeute 46.0%

Lösungsmittel

acetone

Reaktionsbedingungen

Aufarbeitung

1. 1
   FiltrationAfter filtration of the triethylammonium chloride salts, acetone
2. 2
   workup.DISTILLATIONwas distilled off
3. 3
   workup.DISSOLUTIONthe resulting mixture was dissolved in 450 mL ethyl acetate
4. 4
   FiltrationAfter filtration over silica gel the solvents
5. 5
   workup.DISTILLATIONwere distilled off
6. 6
   Sonstigethe remaining crude product was recrystallized from ethyl acetate

Vorschrift

5 g α-hydroxyisobutyric acid (48 mmol) and 5.15 mL 2-bromopropionyl chloride (50 mmol) were stirred at 75° C. under nitrogen for 12 h. 300 mL acetone and 14 mL anhydrous triethylamine (100 mmol) were added to the mixture and the solution was stirred for 3 h at 60° C. After filtration of the triethylammonium chloride salts, acetone was distilled off and the resulting mixture was dissolved in 450 mL ethyl acetate:hexane mixture (1:1). After filtration over silica gel the solvents were distilled off, and the remaining crude product was recrystallized from ethyl acetate:hexane mixture (1:10). 1H NMR (500 MHz, CDCl3): δ 5.1 (q, 1H), 1.705 (s, 6H), 1.69 (d, 3H). 13C NMR (500 MHz, CDCl3): δ 168.58, 166.64, 80.54, 72.90, 26.23, 25.27, 17.41. ELEM. ANAL. Calcd. for C7H10O4: C, 53.16; H, 6.33. Found: C, 52.86; H, 6.39. Yield: 46%.

Quelle