反应详情

Methyl 3-acetyl-4-cinnamoyloxy-benzoate (46.2 g; m.p. 97°-99° C) was dissolved in methyl-ethyl-ketone (350 ml). After addition of anhydrous potassium carbonate (37 g), the mixture was refluxed for 6 hours. After cooling, dilution with petroleum ether (500 ml) and filtration, the collected precipitate was dissolved in water, acidified with acetic acid, extracted with ethylacetate. The organic phase was washed with potassium carbonate 5% and water, then evaporated to dryness. After crystallisation from methanol, (2-hydroxy-5-carbomethoxy-benzoyl)-cinnamoyl-methane (31.2 g; m.p. 138°-140° C) was obtained, which was refluxed for 15 minutes with formic acid 99% (140 ml). After cooling, dilution with water (l. 1) and filtration, the collected precipitate was crystallised from acetone to obtain 6-carbomethoxy-2-(β-phenylvinyl)-chromone (27.8 g; m.p. 175°-177° C) which was hydrolysed with a solution of potassium hydroxide 1% (600 ml) in ethanol 95% at reflux temperature for 45 minutes. After cooling, acidification with acetic acid, concentration under vacuum and dilution with water, the precipitate was collected and washed with water to give, after crystallisation from acetone, 6-carboxy-2-(β-phenyl-vinyl)-chromone (16.1 g; m.p. 273°-275° C).

1. temperaturethe mixture was refluxed for 6 hours
2. temperatureAfter cooling
3. filtrationdilution with petroleum ether (500 ml) and filtration
4. dissolutionthe collected precipitate was dissolved in water
5. extractionextracted with ethylacetate
6. washThe organic phase was washed with potassium carbonate 5% and water
7. customevaporated to dryness
8. customAfter crystallisation from methanol