Benzyloxycarbonyl-L-phenylalanine → N-benzyloxycarbonylphenylalanine methyl ester

Participants

Reaction Conditions

Reaction Steps

After 1.80 g of Z-Phe was dissolved in 20 mL of MeOH, 73 mg of DMAP, 1.38 g of WSCD HCl were added at 0° C., followed by stirring at 4° C. for 12 hours. The solvent was concentrated and the concentrate was dissolved in AcOEt, followed by washing with 1N HCl aq., satd. NaHCO3 aq., and satd. NaCl aq. After drying over Na2SO4, the solvent was concentrated to give Z-Phe-OMe as oil. After dissolving in 20 mL of dry THF, 196 mg of LiBH4 was added thereto and the mixture was stirred at room temperature for 15 hours. The solvent was concentrated and the concentrate was dissolved in AcOEt and the residue was washed with 1N HCl aq., satd. NaHCO3 aq., and satd. NaCl aq. After drying over Na2SO4, the solvent was concentrated and ether-petroleum ether was added to give 1.45 g (yield 85%) of Z-Phe-ol as precipitates. After 60 mg of 60% NaH was suspended in 10 mL of dry THF, 285 mg of Z-Phe-ol, 264 mg of 18-crown-6 and 1.48 mL of tert-butyl bromoacetate were added at 0° C. While returning to room temperature, the mixture was stirred for 15 hours.

Provenance & Evidence