Trifluoroacetic acid → 4-propoxy-1H-indazol-5-ol

Participants

Reaction Steps

Under a nitrogen atmosphere, trifluoroacetic acid (5.5 ml) was added to a solution of 4-propoxy-1-tetrahydro-2H-pyran-2-yl-5-(tetrahydro-2H-pyran-2-yloxy)-1H-indazole (852.6 mg) in dichloromethane (16.5 ml) at room temperature. After 2.5 hours, the reaction solution was poured onto ice, adjusted to pH 7 with an aqueous sodium hydroxide solution, and then extracted with ethyl acetate. The extract solution was concentrated under reduced pressure and the resulting residue was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate). The residue purified was concentrated under reduced pressure and the resulting residue was washed with diethyl ether/hexane by repulping to obtain 4-propoxy-1H-indazol-5-ol (338.2 g, 80%, two steps).

Provenance & Evidence