反应详情

A solution of 200 mg (0.888 mmol) (2E)-2-[(3-methyl-1H-indazol-5-yl)methylidene]-3-oxobutanenitrile (Example 2A), 353 mg (0.888 mmol, approx. 50% purity) tert-butyl 4-hydroxy-2-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate [W.-R. Li et al., J. Org. Chem. 2002, 67, 4702-4706] and 102 mg (1.332 mmol) ammonium acetate in acetic acid (4 ml) was stirred at 100° C. for 45 min. The reaction mixture was concentrated under reduced pressure, and the residue was purified first by flash chromatography (silica gel; dichloromethane/methanol gradient, final mixture 10:1 v/v) and then by preparative RP-HPLC (acetonitrile/water+0.1% TFA gradient) to give 31 mg (11% of th.) of the title compound.

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. customthe residue was purified first by flash chromatography (silica gel; dichloromethane/methanol gradient, final mixture 10:1 v/v)