Diethylamine → 9H-fluoren-9-ylmethyl N-ethylcarbamate;methyl 2-[[1-[[(2S)-2-formamido-3-tritylsulfanylpropanoyl]amino]cyclopropanecarbonyl]amino]acetate

Participants

Reaction Steps

To a solution of 1 (310.5 mg, 0.420 mmol) in MeCN/CH2Cl2 (10 mL/19 mL) under Ar(g) was added diethylamine (2.9 mL, 10% v/v) and the reaction mixture stirred at rt for 1 h 50 min. The solvent was removed in vacuo, the crude mixture treated with MeCN (3×20 mL) and the solvent was removed under reduced pressure. The crude amine was then dried under high vacuum for 1 h. Then to a solution of PyBOP (234.9 mg, 0.451 mmol) and FmocGly-OH (133.86 mg, 0.450 mmol) in CH2Cl2 (20 mL) was added diisopropylethylamine (0.25 mL, 1.44 mmol) under Ar(g) with stirring for 3 min. A solution of the resultant deprotected amine of 1 in MeCN (20 mL) was added, and the resulting mixture was allowed to stir at rt for 16 h. The solvent was then removed in vacuo. Purification by flash column chromatography on silica (eluant 1:99-3:97-5:95 MeOH/CH2Cl2) gave a white solid. The material was washed with 1M HCl (aq), dried (MgSO4) and concentrated in vacuo to give 2 (228.6 mg, 0.289 mmol, 68%) as a white solid.

Provenance & Evidence