Methanol → 4-(2,4-Dimethoxy-6-methyl-phenyl)-4-oxo-butyric acid methyl ester
Reaktionsgleichung
[CH3:1][O:2][C:3]1[CH:8]=[C:7]([O:9][CH3:10])[CH:6]=[C:5]([CH3:11])[C:4]=1[C:12](=[O:18])[CH2:13][CH2:14][C:15]([OH:17])=[O:16].OS(O)(=O)=O.[CH3:24]O>>[CH3:24][O:16][C:15](=[O:17])[CH2:14][CH2:13][C:12]([C:4]1[C:5]([CH3:11])=[CH:6][C:7]([O:9][CH3:10])=[CH:8][C:3]=1[O:2][CH3:1])=[O:18]Komponenten
4
Reaktionsbedingungen
- Temperatur
- 75 °C
Versuchsvorschrift
A mixture of 4-(2,4-dimethoxy-6-methyl-phenyl)-4-oxo-butyric acid (3.70 g, 14.68 mmol) and concentrated H2SO4 (0.2 mL) in MeOH (50 mL) was heated at 75° C. for 1 hour and concentrated in vacuo. The residue was purified by silica gel flash column chromatography to give 4-(2,4-dimethoxy-6-methyl-phenyl)-4-oxo-butyric acid methyl ester (3.86 g, quant.). 1H NMR (400 MHz, CDCl3) δ 6.70 (s, 1H), 6.50 (s, 1H), 3.90 (s, 3H), 3.85 (s, 3H), 3.65 (s, 3H), 3.10 (t, J=8.1 Hz, 2H), 2.65 (t, J=8.1 Hz, 2H), 2.20 (s, 3H).