Reaktion #216719

Reaktionsgleichung

dimethylaminopyridine

1-(3-dimethylaminopropyl)-3-ethyl carbodiimide

tetronic acid

triethylamine

4-cyclohexyl butyric acid

→

3-(4-cyclohexyl-1-oxobutyl)-4-hydroxy-2(5H)-furanone

Lösungsmittel

N,N-dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITAfter 10 minutes
2. 2
   Sonstigethe ice bath is removed
3. 3
   workup.STIRRINGto stir overnight
4. 4
   SonstigeThe reaction mixture is quenched with 1N HCl
5. 5
   Waschenthe solution is washed three times with hexanes
6. 6
   WaschenThe combined organic layers are washed with water
7. 7
   Trocknendried over magnesium sulfate
8. 8
   Sonstigeevaporated
9. 9
   Sonstigechromatographed on silica gel using 5% methanol/ethyl acetate with 2 mL of acetic acid/liter
10. 10
    Sonstigeto give an orange solid

Vorschrift

To a solution of 1.0 g (10.0 mmol) of tetronic acid in 30 mL of dry N,N-dimethylformamide at 0° C. is added 1.5 mL (11 mmol) of triethylamine followed by 0.37 g (30 mmol) of 4 dimethylaminopyridine. After stirring at 0° C. for 5 minutes, 2.0 g (11.7 mmol) of 4-cyclohexyl butyric acid is added, followed by 2.25 g (11.7 mmol) of 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide. After 10 minutes, the ice bath is removed and the reaction mixture is allowed to stir overnight. The reaction mixture is quenched with 1N HCl and the solution is washed three times with hexanes. The combined organic layers are washed with water, dried over magnesium sulfate and evaporated. The residue is flash chromatographed on silica gel using 5% methanol/ethyl acetate with 2 mL of acetic acid/liter to give an orange solid: m.p. 38-42° C.; IR (film) 2920, 2840, 1770, 1690, 1660, 1600 cm-1 ; NMR (CDCl3) δ 0.9 (m, 2H), 1.2 (m, 6H), 1.7 (m, 6H), 2.9 (q, J=7 Hz, 2H), 4.6 and 4.7 (s, 2H), 12.1 (bs, 1H); MS (EI): M+ 252.

Quelle