Diethylamine → (R)-4-(9H-Fluoren-9-ylmethoxycarbonylamino)-4-{(S)-1-[1-(1-hydroxy-2-methoxycarbonyl-ethyl)-cyclopropylcarbamoyl]-2-tritylsulfanyl-ethylcarbamoyl}-butyric acid tert-butyl ester

참여 물질

반응 단계

To 4 (908 mg, 1.28 mmol) in MeCN (10 mL) was added diethylamine (1 mL, 10% v/v), and the reaction mixture was stirred for 2 h. The mixture was then concentrated in vacuo, MeCN (3×20 mL) was added, then removed in vacuo, and the crude amine was placed under high vacuum for 2 h. Subsequently, to a solution of PyBOP (705 mg, 1.35 mmol) and Fmoc-D-Glu(OtBu)-OH (577.8 mg, 1.36 mmol) in CH2Cl2 (15 mL) at 0° C. was added diisopropylethylamine (0.70 mL, 4.02 mmol) under Ar(g) and the mixture was stirred for 2 min. A solution of the crude amine derivative of 4 in MeCN (15 mL) was added, and the mixture was stirred at rt for 16 h, and the solvent was then removed in vacuo. Purification by flash column chromatography on silica (eluant 4:6-6:4 EtOAc/Hexane) gave 5 (1.099 g, 1.20 mmol, 94%) as a white solid: Rf 0.54 EtOAc/Hexane (6:4), and as a mixture of diastereoisomers not resolved by 1H NMR.

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