Methyl iodide → Boc-D-Trp(Me)-OH

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Reaction Steps

N-tert-Butoxycarbonyl-D-tryptophan (3.0 g) was dissolved in N,N-dimethylformaldehyde (30 mL) under argon, and potassium tert-butoxide (as 12% tetrahydrofuran solution) (17.7 g) was added dropwise thereto under cooling on ice, followed by stirring for 15 minutes. A solution of iodomethane (2.1 g) in N,N-dimethylformaldehyde (3.0 mL) was added to the mixture, and stirring was performed for 10 minutes. The resultant mixture was partitioned between 30% aqueous citric acid solution and ethyl acetate, and the organic layer was sequentially washed with 30% aqueous citric acid solution and saturated aqueous sodium chloride solution, followed by drying over sodium sulfate. The solvent was evaporated under reduced pressure, and diisopropyl ether was added to the thus-recovered residue. The precipitates were recovered through filtration, washed with diisopropyl ether, and dried under reduced pressure, whereby the title compound (1.89 g) was yielded.

Provenance & Evidence