反应详情

A mixture of 9-hydroxy-1-oxo-1H-naphtho[2,1-b]pyran-2-carboxaldehyde acetate (10.0 g, 0.0354 m) and malonic acid (4.0 g, 0.0354 m) in pyridine (100 ml) is refluxed for 45 minutes. Additional malonic acid (1.0 g, 0.00885 m, 0.25 eq.) is added and the reaction refluxed for 30 minutes. The solvent is removed under reduced pressure to give a sludge from which product crystallizes on the addition of acetone. After filtering the product, recrystallization from DMF gives cocoa crystals (2.75 g, 24%), m.p. dec>290° C.

1. temperatureis refluxed for 45 minutes
2. temperaturethe reaction refluxed for 30 minutes
3. customThe solvent is removed under reduced pressure
4. customto give a sludge from which product
5. customcrystallizes on the addition of acetone
6. filtrationAfter filtering
7. customthe product, recrystallization from DMF