4-Methylmorpholine → 2-(4-methoxybenzylthio)-pentanoyl-(L)-homophenylalanyl-(L)-phenylalanine t-butyl ester

Participants

Reaction Steps

Combine 2-(4-methoxybenzylthio)-pentanoyl-(L)-homophenylalanine (0.14 g, 0.34 mmol), (L)-phenylalanine t-butyl ester hydrochloride salt (0.174 g, 68 mmol), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.13 g, 0.67 mmol) in dichloromethane (5 mL). Add N-methylmorpholine (0.1 mL, 1.01 mmol) and hydroxybenzotriazole (0.091 g, 0.67 mmol). After 3 hours, after 1 hour, partition the reaction mixture between methyl t-butyl ether and an aqueous 5% sulfuric acid solution. Separate the layers, extract the organic layer with a saturated sodium bicarbonate solution and then brine. Dry over Na2SO4, filter, and evaporate in vacuo to give a residue. Chromatograph the residue on silica gel eluting sequentially with 3/1 hexane/ethyl acetate and then 1/1 hexane/ethyl acetate to give the title compound: Rf=0.45 (silica gel, 1/1 ethyl acetate/hexane).

Provenance & Evidence