Ethyl Acetate → N-tert-butoxycarbonyl-L-phenylalanyl-L-phenylalanyl-L-histidine methyl ester

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Reaction Steps

L-Phenylalanyl-L-histidine methyl ester dihydrobromide(1.75 g) is dissolved in a mixture of dimethylformamide (10 ml) and triethylamine(1.4 ml), and N-tert-butoxycarbonyl-L-phenylalanine succinimido ester (1.34 g) is added thereto. The mixture is stirred at room temperature overnight. Ethyl acetate is added to the mixture, and insoluble materials are filtered off. The filtrate is washed with an aqueous sodium bicarbonate solution, and an aqueous sodium chloride solution is added thereto. The precipitated crystals are washed with ethyl acetate and water and then dried to give N-tert-butoxycarbonyl-L-phenylalanyl-L-phenylalanyl-L-histidine methyl ester(1.5 g) as colorless crystals. Yield: 71.8%

Provenance & Evidence