Acetic Anhydride → Ethyl 4-(acetyloxy)-2-ethyl-1-benzofuran-6-carboxylate

Reaktionsgleichung

[CH2:1]([O:3][C:4]([CH:6]([CH:10]=[CH:11][C:12]1[O:13][C:14]([CH2:17][CH3:18])=[CH:15][CH:16]=1)C(O)=O)=O)[CH3:2].C([O-])(=[O:21])C.[Na+].[C:24]([O:27][C:28](=O)[CH3:29])(=[O:26])C>>[C:1]([O:3][C:4]1[C:16]2[CH:15]=[C:14]([CH2:17][CH3:18])[O:13][C:12]=2[CH:11]=[C:10]([C:24]([O:27][CH2:28][CH3:29])=[O:26])[CH:6]=1)(=[O:21])[CH3:2]

Komponenten

Edukt 3

HCID 7918Acetic Anhydride

HCID 517045Sodium Acetate

HCID 66755689(Ethoxycarbonyl)-4-(5-ethyl-2-furyl)but-3-enoic acid

Produkt 1

HCID 59559992Ethyl 4-(acetyloxy)-2-ethyl-1-benzofuran-6-carboxylateAusbeute 28 %

Versuchsvorschrift

A mixture of (ethoxycarbonyl)-4-(5-ethyl-2-furyl)but-3-enoic acid (45.4 g, 0.18 mol) and sodium acetate (59.0, 0.72 mol) in acetic anhydride (450 mL) was heated to reflux for 5 hours. TLC (petroleum ether/EtOAc 4:1) indicated complete consumption of the starting material. The reaction mixture was concentrated and the residue was poured into 15% aq. Na2CO3 (500 mL), and extracted with EtOAc (500 mL×3). The combined organic layers was washed with brine (200 mL), dried over Na2SO4, and concentrated. The product was purified via silica gel column chromatography using petroleum ether/EtOAc (70:1) to afford the desired compound (13.0 g, 28%) as a yellow solid.