反応 #487532

反応方程式

triethylamine

α-hydroxyisovaleric acid

2-bromopropionyl bromide

→

3-Methyl-6-isopropyl-1,4-dioxane-2,5-dione

収率 35.0%

溶媒

acetone

反応条件

後処理

1. 1
   ろ過After filtration of the triethylammonium bromide salts, acetone
2. 2
   workup.DISTILLATIONwas distilled off
3. 3
   workup.DISSOLUTIONthe resulting mixture was dissolved in 500 mL ethyl acetate
4. 4
   ろ過After filtration over silica gel the solvents
5. 5
   workup.DISTILLATIONwere distilled off
6. 6
   その他the remaining crude product was recrystallized from hexane

実験手順

5.1 g α-hydroxyisovaleric acid (43 mmol) and 4.85 mL 2-bromopropionyl bromide (45 mmol) were stirred at 75° C. under nitrogen for 12 h. 300 mL acetone and 12 mL anhydrous triethylamine (86 mmol) were added to the mixture and the solution was stirred for 3 h at 60° C. After filtration of the triethylammonium bromide salts, acetone was distilled off and the resulting mixture was dissolved in 500 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 hexane. 1H NMR (500 MHz, CDCl3): δ 5.0 (q, 1H), 4.76 (d, 1H), 2.5 (m, 1H), 1.66 (d, 3H), 1.16 (d, 3H), 1.06 (d, 3H). 13C NMR (500 MHz, CDCl3): δ 167.59, 166.16, 79.83, 72.10, 29.24, 18.51, 15.86, 15.79. ELEM. ANAL. Calcd. for C8H12O4: C, 55.81; H, 6.98. Found: C, 55.55; H, 6.99. Yield: 35%.

出典