(RS)-3-(1-cyclopropyl-prop-2-ynyloxy)-4,5-dimethoxy-benzaldehyde → 2-cyclopropyl-7,8-dimethoxy-2H-chromene-5-carbaldehyde
Reaktionsgleichung
[CH:1]1([CH:4]([O:7][C:8]2[CH:9]=[C:10]([CH:13]=[C:14]([O:18][CH3:19])[C:15]=2[O:16][CH3:17])[CH:11]=[O:12])[C:5]#[CH:6])[CH2:3][CH2:2]1>C(N(CC)C1C=CC=CC=1)C>[CH:1]1([CH:4]2[CH:5]=[CH:6][C:9]3=[C:10]([CH:11]=[O:12])[CH:13]=[C:14]([O:18][CH3:19])[C:15]([O:16][CH3:17])=[C:8]3[O:7]2)[CH2:3][CH2:2]1Komponenten
3
Edukt 1
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Reaktionsbedingungen
- Temperatur
- 200 °C
Versuchsvorschrift
2.4 g of (RS)-3-(1-cyclopropyl-prop-2-ynyloxy)-4,5-dimethoxy-benzaldehyde were dissolved in 20 ml of N,N-diethyl-aniline, heated to 200° C. under argon and stirred at 200° C. for a further 1 hr. The solvent was distilled off at 90° C./1 mbar and the residue was extracted: 2×100 ml of diethyl ether, 2×100 ml of 1N HCl, 2×100 ml of saturated NaCl. The crude product was purified by two-fold silica gel chromatography with dichloromethane and, respectively, ethyl acetate/hexane 5:1. (RS)-2-Cyclopropyl-7,8-dimethoxy-2H-1-benzopyran-5-carbaldehyde was obtained as a brown oil (HPLC 96%).