反应详情

Methanol (5 ml) was maintained at 0° C., and thionyl chloride (2.4 ml) was added dropwise under an argon atmosphere. To this solution was added 5-hydroxy-L-tryptophan (2.0 g), and the mixture was gradually warmed from 0° C. to room temperature, and stirred at room temperature overnight. The reaction mixture was concentrated under reduced pressure, and the residue was crystallized from a mixed solvent of ethanol and ether to give 5-hydroxy-L-tryptophan methyl ester hydrochloride (1.8 g, yield 74%) as crystals.

1. temperaturethe mixture was gradually warmed from 0° C. to room temperature
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. customthe residue was crystallized from a mixed solvent of ethanol and ether