Trifluoroacetic acid → Methyl D-Tryptophanate

To 4.92 g (16.2 mmol) of N-α-t-BOC-D-tryptophan in 100 mL of DMF was added 2.46 g (17.8 mmol) of potassium carbonate followed by 2.41 g (17.0 mmol) of iodomethane, and the mixture was stirred overnight at 24° C. under an atmosphere of nitrogen. The reaction mixture was diluted with water, and extracted three times with ethyl acetate. The combined organics were washed five times with 500 mL of water and once with brine, dried over MgSO4 and concentrated to give 4.67 g of a white solid. To the crude (R)-2-tert-butoxycarbonylamino-3-(1H-indol-3-yl)-propionic acid methyl ester was added 15 mL of cold trifluoroacetic acid at about 0° C. and the mixture was stirred for about 2 h. The mixture was concentrated and the residue was diluted with 1N NaOH and extracted three times with ethyl acetate. The combined organic extracts were washed with brine and dried over Na2SO4 to give (R)-2-amino-3-(1H-indol-3-yl)-propionic acid methyl ester as an orange oil in quantitative yield.

1. concentrationThe mixture was concentrated
2. additionthe residue was diluted with 1N NaOH
3. extractionextracted three times with ethyl acetate
4. washThe combined organic extracts were washed with brine
5. dry with materialdried over Na2SO4

ORD record

ord-13523729c5ef47e9b9048be9e734e2e6

Source dataset

uspto-grants-2003_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06630487B2