反应详情

A portion (4.25 g) of the compound obtained in Example 1 was dissolved in ethanol (40 ml). To the solution was added conc. hydrochloric acid (40 ml) and the resulting mixture was heated to reflux for 2 hours. After allowing to cool, the mixture was diluted with water, adjusted to pH 9 with potassium carbonate and extracted three times with ethyl acetate. The organic layers were combined, washed with saturated aqueous solution of sodium chloride and dried over anhydrous sodium sulfate. Then, the solvent was distilled off under reduced pressure and the residue was crystallized from an ether/hexane mixed solvent to yield 3.33 g (92%) of the titled compound as crystals.

1. temperaturethe resulting mixture was heated
2. temperatureto reflux for 2 hours
3. temperatureto cool
4. extractionextracted three times with ethyl acetate
5. washwashed with saturated aqueous solution of sodium chloride
6. dry with materialdried over anhydrous sodium sulfate
7. distillationThen, the solvent was distilled off under reduced pressure
8. customthe residue was crystallized from an ether/hexane mixed solvent