反应详情

23 mg (0.36 mmol) of copper powder were added to 3.31 g (7.16 mmol) of the compound from Example 21A in 13 ml of pyridine and 3 ml of ethanol. The reaction mixture was heated under reflux for 4 h and then the pyridine was removed in vacuo. The residue was taken up in ethyl acetate, silica gel was added, and the mixture was concentrated. The crude product-silica gel mixture was initially prepurified by flash chromatography (mobile phase: cyclohexane/ethyl acetate 5/1→3/1), and the product was again purified by preparative HPLC (acetonitrile/water gradient). 2.38 g (82% of theory) of the title compound were obtained.

1. temperatureThe reaction mixture was heated
2. temperatureunder reflux for 4 h
3. customthe pyridine was removed in vacuo
4. additionsilica gel was added
5. concentrationthe mixture was concentrated
6. customthe product was again purified by preparative HPLC (acetonitrile/water gradient)