Ethyl 5-[4-(methylsulfonyl)phenoxy]-7-(tetrahydro-2H-pyran-4-ylmethoxy)-1H-indole-2-carboxylate → 5-[4-(Methylsulfonyl)phenoxy]-7-(tetrahydro-2H-pyran-4-ylmethoxy)-1H-indole-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Ethyl 5-[4-(methylsulfonyl)phenoxy]-7-(tetrahydro-2H-pyran-4-ylmethoxy)-1H-indole-2-carboxylate (3.5 g) was dissolved in a mixed solvent of tetrahydrofuran (30 mL)-ethanol (30 mL), 1M aqueous sodium hydroxide solution (15 mL) was added, and the mixture was stirred at 50° C. for 1 hr. The reaction solution was allowed to cool to room temperature, and concentrated under reduced pressure. Water was added to the residue, and the mixture was neutralized with 1M hydrochloric acid, and subjected to extraction with ethyl acetate. The organic layer was washed with saturated brine, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The obtained crude product was crystallized from a mixed solvent of ethanol-hexane-diethyl ether. The obtained colorless crystals were recrystallized from acetone-hexane to give the title compound (1.1 g) as colorless crystals. melting point 256-258° C. (decomposition).

Provenance & Evidence