反应详情

26.6 g of finely pulverised aluminium chloride are suspended in 60 ml of methylene chloride. While stirring and while cooling slightly, 9.61 g of 5-methoxybenzocyclobutene-1-carboxylic acid methyl ester, dissolved in a small amount of methylene chloride, are added dropwise at room temperature. After stirring for 30 minutes at room temperature, 15.85 g of o-fluorobenzoyl chloride are added dropwise thereto and the resulting reaction mixture is heated at reflux for 4 hours. After cooling, the reaction mixture is poured onto ice and extracted thoroughly with methylene chloride. The combined organic phases are washed with water, dried over magnesium sulphate and concentrated by evaporation. The yellow oily residue (20 g) is chromatographed over 400 g of silica gel with methylene chloride. Fractions 7-16 (50 ml fractions) are combined and concentrated. The residue is crystallised from ether/petroleum ether. 4-(o-fluorobenzoyl)-5-hydroxybenzocyclobutene-1-carboxylic acid methyl ester is obtained in the form of yellow crystals having a melting point of 59°-61°.

1. temperaturewhile cooling slightly
2. additionare added dropwise at room temperature
3. stirringAfter stirring for 30 minutes at room temperature
4. customthe resulting reaction mixture
5. temperatureis heated
6. temperatureat reflux for 4 hours
7. temperatureAfter cooling
8. additionthe reaction mixture is poured onto ice
9. extractionextracted thoroughly with methylene chloride
10. washThe combined organic phases are washed with water
11. dry with materialdried over magnesium sulphate
12. concentrationconcentrated by evaporation
13. customThe yellow oily residue (20 g) is chromatographed over 400 g of silica gel with methylene chloride
14. concentrationconcentrated
15. customThe residue is crystallised from ether/petroleum ether