To a stirred solution of Fmoc-Lys(MMT) (9.7336 g) in 100 ml of mixture of methylene chloride and acetonitrile (1:1) at room temperature was added diethylamine (100 ml). The mixture was stirred at room temperature for 1.5 hrs. After removal of solvent, the residue was flushed with acetonitrile at 60° C. (90 ml×2), washed with acetonitrile (20 ml×3) and ether (20 ml×3). The solid was then dissolved as far as possible in 1:1 CH2Cl2/CH3OH (200 ml) and some solid byproduct was removed by filtering through filter paper. After removal of solvent and being dried in vacuo, 4.7707 g (82.2%, based on Fmoc-Lys) of pale yellow foam was obtained. ES(+)-MS: 147(Lys+1), 273(MMT).
