4-Nitrophenol → Z-Phe-ONp

Participants

Reaction Steps

N-Benzyloxycarbonyl-L-phenylalanine (2.99 g) and p-nitrophenol (1.39 g) are dissolved in tetrahydrofuran (30 ml), and dicyclohexylcarbodiimide (2.1 g) is added thereto under ice-cooling. The mixture is stirred at room temperature for four hours and insoluble materials are filtered off. Ethyl acetate is added to the filtrate and the mixture is washed with an aqueous sodium bicarbonate solution and an aqueous sodium chloride solution, dried, and then concentrated to remove solvent. Hexane is added to the residue to give N-benzyloxycarbonyl-L-phenylalanine-p-nitrophenyl ester as crystals. The product is dissolved in tetrahydrofuran (20 ml), and a solution(15 ml) of L-histidine methyl ester dihydrochloride (2.4 g) and triethylamine (2.8 ml) in water is added thereto under ice-cooling, and the mixture is stirred at room temperature overnight. The reaction mixture is concentrated under reduced pressure to remove solvent. The residue is purified by silica gel column chromatography (solvent; chloroform:methanol=15:1) and crystallized with ethyl acetate to give N-benzyloxycarbonyl-L-phenylalanyl-L-histidine methyl ester (2.8 g) as colorless crystals. Yield ; 64.1%

Provenance & Evidence