反应详情

2,3,5,6-Tetrafluorophenyl trifluoroacetate (1.7 g, 6.5 mmol) was added dropwise to a solution of FMOC-alanine (2.0 g, 6.4 mmol) and triethylamine (1.0 ml, 7 mmol) in 20 ml of anhydrous CH2Cl2. After 1 hr., CH2Cl2 was removed by evaporation at reduced pressure using rotary evaporator, redissolved in 30 ml ethylacetate/hexane (1:1). Flash chromatography (4×20 cm, hexane/ethyl acetate, 3:1) afforded rude 4 as a white solid. It was recrystallized from hexane/ethyl acetate to give 4 as a white crystalline solid (2.3 g, 78%): 1H NMR (CDCl3, 200 MHz, ppm) 7.73 (d, 2H, J=7.1 Hz, aromatic protons), 7.75 (d, 2H, J=7.7 Hz, aromatic protons), 7.24-7.42 (m, 411, aromatic protons), 7.01 (m, 1H, C6F4H), 5.21 (br s, 1H, —CONH—), 4.38 (d, 2H, J=7.1 Hz, —CH2OCO—), 4.20 (m, 1H, benzyl proton), 3.58 (m, −2H, NCH 2), 2.93 (t, 2H, J=5.4 Hz, —CH2CO—). Anal. Calcd. for C24H17NO4F4: C, 62.75; H, 3.73; N, 3.05. Found: C, 62.52; H, 3.59; N, 3.01.

1. custom, CH2Cl2 was removed by evaporation at reduced pressure
2. customevaporator
3. dissolutionredissolved in 30 ml ethylacetate/hexane (1:1)