Reaktion #43995

Reaktionsgleichung

carbon dioxide

1-Methoxy-2-naphthaldehyde

n-butyl lithium

carbon dioxide

hydrochloric acid

n-Butyl lithium

N,N,N′-Trimethylethylene diamine

→

3-hydroxy-4-methoxynaphtho[2,3-c]furan-1(3H)-one

Ausbeute 3.7%

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   workup.STIRRINGthe reaction stirred at 25° C. for 3 h
3. 3
   workup.STIRRINGStirring
4. 4
   ExtraktionThe mixture was extracted with dichloromethane (50 ml, ×3)
5. 5
   TrocknenThe combined extracts were dried (MgSO4)
6. 6
   Sonstigethe solvent evaporated under vacuum
7. 7
   SonstigeThe oily residue was preabsorbed onto silica
8. 8
   Sonstigepurified by SPE (silica, 10 g)
9. 9
   Wascheneluting with an ethyl acetate/cyclohexane gradient

Vorschrift

N,N,N′-Trimethylethylene diamine (0.82 ml, 6.3 mmol) was dissolved in tetrahydrofuran (16 ml) and cooled to −20° C. n-Butyl lithium (1.6M in hexanes, 3.9 ml, 6.24 mmol) was added and the reaction stirred at −20° C. for 15 min. 1-Methoxy-2-naphthaldehyde (0.96 g, 5.9 mmol) was added followed by n-butyl lithium (1.6M in hexanes, 11.25 ml, 18 mmol) and the reaction stirred at 25° C. for 3 h. Solid carbon dioxide was added and the reaction left until the excess carbon dioxide had sublimed. Stirring continued for 15 min before addition of hydrochloric acid (2N, 50 ml). The mixture was extracted with dichloromethane (50 ml, ×3). The combined extracts were dried (MgSO4) and the solvent evaporated under vacuum. The oily residue was preabsorbed onto silica and purified by SPE (silica, 10 g) eluting with an ethyl acetate/cyclohexane gradient to give 3-hydroxy-4-methoxynaphtho[2,3-c]furan-1(3H)-one (50 mg, 3.7%).

Quelle