反应详情

To a stirred solution of methyl-lithium in ether (120 ml., 1.9 M solution) at room temperature was added over 0.5 hours finely powdered 3,4-dihydro-7-hydroxy-4-(1-napthyl) coumarin (14.5 g, 0.05 moles). After refluxing for 1 hour a purple solid precipitated out of solution and the reaction mixture was allowed to cool, acidified with dilute hydrochloric acid and extracted with ether (3×). The combined ether extracts were dried and removal of solvent gave a dark coloured oil which was refluxed overnight in glacial acetic acid. The glacial acetic acid was removed in vacuo and the residue dissolved in ether, washed with water, saturated sodium bicarbonate solution and dried. Removal of solvent gave an extremely viscous oil, column chromatography of which on silica, eluting with 40°-60° petrol: ether (gradually increasing concentration of ether) gave the required chroman as a low melting pale yellow solid (9.4 g., 76%).

1. temperatureAfter refluxing for 1 hour a purple solid
2. customprecipitated out of solution
3. temperatureto cool
4. extractionextracted with ether (3×)
5. dry with materialThe combined ether extracts were dried
6. customremoval of solvent
7. customgave a dark coloured oil which
8. customThe glacial acetic acid was removed in vacuo
9. dissolutionthe residue dissolved in ether
10. washwashed with water, saturated sodium bicarbonate solution
11. customdried
12. customRemoval of solvent
13. customgave an extremely viscous oil, column chromatography of which on silica
14. washeluting with 40°-60° petrol
15. temperatureether (gradually increasing concentration of ether)