Hydrogen Peroxide → 1-t-Butoxycarbonyl-2-methylindole-4-acetic Acid

Participants

Reaction Conditions

Reaction Steps

A solution of cyclohexane (16.1 ml) in tetrahydrofuran (160 ml) was cooled at −10° C., and then to the mixture was added dropwise borane-tetrahydrofuran complex (1M, 80 ml), and the mixture was stirred at 0° C. for 1 hour. To the solution was added dropwise a solution of 1-t-butoxycarbonyl-2-methyl-4-(2-trimethylsilylethynyl)indole (13.1 g; prepared in Reference Example 3) in tetrahydrofuran (60 ml), the mixture was stirred for 1 hour at room temperature. To a reaction solution was added dropwise 3N aqueous solution of sodium hydroxide (40 ml) and 30% hydrogen peroxide (in water, 45 ml), successively, and the mixture was stirred for 12 hours. The reaction mixture was extracted with water-diethyl ether. The aqueous layer was adjusted to acidic condition with hydrochloric acid and then extracted with ethyl acetate. The extraction was washed with water and a saturated aqueous solution of sodium chloride, successively, dried and concentrated under reduced pressure to give the title compound (10.4 g; crude).

Provenance & Evidence