Sodium Carbonate → N,N'-Bis{[(9H-fluoren-9-yl)methoxy]carbonyl}-L-cystine

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Reaction Conditions

Reaction Steps

Fmoc-protected cysteine (FIG. 3, structure B) was synthesized in a two step sequence from L-cystine as outlined in FIG. 4. Sodium carbonate (4.6 g, 43.6 mmol) and L-cystine (5.0 g, 20.8 mmol) were dissolved in water (200 mL). The resulting solution was cooled to 10° C. FmocCl (11.85 g, 45.8 mmol) was dissolved in dioxane (80 mL), and the resulting solution was added dropwise to the aqueous solution of L-cystine. The solution was stirred for 2 h at 10° C. and allowed to gradually warm to room temperature. A thick white precipitate was obtained that was filtered onto a sintered glass funnel. The product was triturated with diethyl ether (50 mL) and dried in vacuuo for 2 d. N,N′-Bis(Fmoc)-L-cystine (14.0 g, 98% yield) was obtained as a white powder.

Provenance & Evidence