反应详情

A mixture of 1-methyl-1H-indazol-4-ol (0.130 g, 0.88 mmol), ethyl-2-butynoate (0.59 g, 5.26 mmol), a catalytic amount of 4-dimethylaminopyridine, and potassium carbonate (0.120 g, 0.88 mmol) in tetrahydrofuran (10 mL) in a sealed tube was heated at 80° C. for 14 h. The reaction mixture was then filtered. The solids were washed with a small amount of tetrahydrofuran and the combined filtrate was concentrated in vacuo. The residue was purified by flash column chromatography (silica gel 0% to 40% ethyl acetate/hexanes) which afforded (E)-3-(1-methyl-1H-indazol-4-yloxy)-but-2-enoic acid ethyl ester (0.170 g, 74%) as a viscous tan oil.

1. filtrationThe reaction mixture was then filtered
2. washThe solids were washed with a small amount of tetrahydrofuran
3. concentrationthe combined filtrate was concentrated in vacuo
4. customThe residue was purified by flash column chromatography (silica gel 0% to 40% ethyl acetate/hexanes) which