Hydrochloric Acid → HCID 12310809, compound

Participants

Reaction Steps

Indole (5.86 g) was dissolved in dichloromethane (50 ml) and to the solution was added dropwise 2.89 M solution of methyl magnesium bromide in diethyl ether (40 ml) over a period of 45 minutes at room temperature. After the dropwise addition was completed, the mixture was stirred for 45 minutes at room temperature. Under cooling at −10° C., a solution of ethyl (2RS,3SR)-2,3-epoxybutanoate (6.51 g) in dichloromethane (50 ml) was added dropwise over a period of 20 minutes. The mixture was stirred for 1 hour at −10 ° C. To the mixture was added 1 N aqueous solution of hydrochloric acid (150 ml). The organic layer was removed, and the aqueous layer was extracted with dichloromethane (50 ml). The organic layers were combined, and concentrated under reduced pressure. The residue was dissolved by adding ethanol (56 ml) and water (24 ml). To the solution was added 1 N aqueous solution of sodium hydroxide (50 ml) under ice cooling. The mixture was stirred for 3.5 hours under ice cooling and 12 hours at room temperature. To the mixture was added 1 N aqueous solution of sodium hydroxide (25 ml), and the mixture was stirred for 1 hour at room temperature. The ethanol was distilled off under reduced pressure, and aqueous layer was washed twice with ethyl acetate (70 ml). The aqueous layer was acidified by adding conc. hydrochloric acid (10 ml). The mixture was extracted twice with ethyl acetate (100 ml). The ethyl acetate layers were combined and dried over anhydrous magnesium sulfate. To the ethyl acetate layer was added activated carbon (1 g) and mixture was stirred. After filtration, the filtrate was concentrated under reduced pressure. The residue was recrystallized from water to give (2RS,3SR)-2-hydroxy-3-(indol-3-yl)butyric acid (7.27 g) as pale brown solid.

Provenance & Evidence