Potassium Carbonate → N-(tert-butoxycarbonyl)-3,4-bis(2,6-dichlorobenzyloxy)-L-phenylalanine methyl ester

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Reaction Steps

2,6-Dichlorobenzyl chloride (1.73 g) was added to a suspension of N-(tert-butoxycarbonyl)-3,4-dihydroxy-L-phenylalanine methyl ester (2.5 g), K2CO3 (2.22 g), and n-Bu4NI (0.297 g) in DMF (15 mL) at room temperature. The mixture was stirred overnight at room temperature, diluted with water and extracted with ether. The extract was dried (MgSO4) and evaporated. The residue was purified by column chromatography (silica gel; eluent: hexanes/CH2Cl2/EtOAc, 5:5:1) to yield N-(tert-butoxycarbonyl)-3,4-bis(2,6-dichlorobenzyloxy)-L-phenylalanine methyl ester (2.0 g), ESMS: m/z 630 (MH+), N-(tert-butoxycarbonyl)-3-(2,6-dichlorobenzyloxy)-4-hydroxy-L-phenylalanine methyl ester (0.39 g), ESMS: m/z 470(MH+), and N-(tert-butoxycarbonyl)-4-(2,6-dichlorobenzyloxy)-3-hydroxy-L-phenylalanine methyl ester (0.45 g), ESMS: m/z 470 (MH+), respectively.

Provenance & Evidence