Tetrahydrofuran → 2-{6,6-dimethyl-1-[2-(trimethylsilyl)ethoxymethyl]-4,5,6,7-tetrahydro-1H-indazol-3-yl}-1-[2-(trimethylsilyl)ethoxymethyl]-1H-indole-6-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 2-{6,6-dimethyl-1-[2-(trimethylsilyl)ethoxymethyl]-4,5,6,7-tetrahydro-1H-indazol-3-yl}-1-[2-(trimethylsilyl)ethoxymethyl]-1H-indole-6-carboxylate (33 g, 57 mmol) in a mixed solvent of tetrahydrofuran (165 ml) and methanol (165 ml) was added 4 N aqueous sodium hydroxide solution (71 ml, 284 mmol), and the mixture was heated at 60° C. for 2 hr. After cooling, the reaction mixture was concentrated, 10% aqueous citric acid solution was added to the residue to adjust the pH to 5, and the mixture was extracted with ethyl acetate. Then, the organic layer was washed with saturated brine, and dried over sodium sulfate. Sodium sulfate was removed by filtration, and the filtrate was concentrated under reduced pressure to give the title compound (31 g, yield 97%).

Provenance & Evidence