Potassium Carbonate → Fmoc-Hyp(OEt)-OH

Participants

Reaction Steps

(S)-2-(Ethylamino)-3-phenylpropanoic acid (Compound SP442) (4.00 g, 20.7 mmol) was dissolved in a mixture of 1,4-dioxane (100 ml) and water (100 ml), potassium carbonate (8.69 g, 62.9 mmol) and (9H-fluoren-9-yl)methyl (2,5-dioxopyrrolidin-1-yl) carbonate (6.98 g, 20.7 mol) were added, and the mixture was stirred at room temperature for 8 hours. The aqueous layer was adjusted to pH 4 with a aqueous potassium bisulfate solution, and 1,4-dioxane was evaporated under reduced pressure. The resulting aqueous solution was extracted with ethyl acetate, and the resulting organic extract was washed with brine, dried over sodium sulfate and then concentrated under reduced pressure. The resulting residue was purified by column chromatography (ethyl acetate:petroleum ether=1:1) to afford (2S,4R)-1-(((9H-fluoren-9-yl)methoxy)carbonyl)-4-ethoxypyrrolidine-2-carboxylic acid (Compound SP443) (3.2 g, 37%).

Provenance & Evidence