Sulfuric Acid → Ethyl 4-hydroxy-7-methoxy-2-oxo-2',3',5',6'-tetrahydro-spiro[naphthalene-1,4'-pyran]-3-carboxylate
Reaktionsgleichung
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([C:9]2([C:15]([CH:17]([C:23]([O:25][CH2:26][CH3:27])=[O:24])[C:18]([O:20]CC)=O)=[O:16])[CH2:14][CH2:13][O:12][CH2:11][CH2:10]2)[CH:6]=[CH:7][CH:8]=1.OS(O)(=O)=O>>[OH:20][C:18]1[C:6]2[C:5](=[CH:4][C:3]([O:2][CH3:1])=[CH:8][CH:7]=2)[C:9]2([CH2:14][CH2:13][O:12][CH2:11][CH2:10]2)[C:15](=[O:16])[C:17]=1[C:23]([O:25][CH2:26][CH3:27])=[O:24]Komponenten
3
Reaktionsbedingungen
- Temperatur
- 0 °C
Versuchsvorschrift
Diethyl 2-(4-(3-methoxyphenyl)-tetrahydro-2H-pyran-4-carbonyl)malonate (2.1 g, see Example 18) was added to 5 mL H2SO4 stirred at 0° C. The mixture was stirred at room temperature for 1 hour, M+1=379. The mixture was then poured into 100 g crushed ice and extracted with EtOAc (3×50 mL). The combined organic layers were washed with H2O (20 mL) and brine (20 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The crude product was purified by column chromatography eluting with 20% EtOAc/hexane to give 0.55 g of the title compound. MS (m/z)=379 (M+H)+.