反应详情

To a solution of (L) N-Cbz-glutamic acid (5.62 g; 20 mmol) in dry DMF (100 mL) was added HATU (8.36 g; 22 mmol) and DMAP (0.56 g) followed by the dropwise addition of TEA (6 mL; 44 mmol). The reaction mixture was stirred at room temperature for 1 h (solution A). In the meantime, to a solution of (L) cyclohexylalanine-OMe(HCl) (5.32 g; 24 mmol) in dry DMF (30 mL) was added DIEA (9.28 g; 72 mmol) and the reaction mixture was stirred for 15 min (solution B). Solution B was mixed with solution A and stirred overnight at room temperature. The solvent was removed on the rotary evaporator and the residue was taken up in ethyl acetate (300 mL). The organic layer was washed sequentially with saturated sodium bicarbonate (2×100 mL), 5% HCl (2×100 mL) and brine (100 mL). The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated, yielding a crude product which was purified by flash chromatography (silica gel; hexane/ethyl acetate 75:25) to give 1 as a white solid (2.15 g; 32% yield). 1H NMR (CDCl3): δ 8.0 (s, 1H), 7.32 (m, 5H), 5.04 (m, 2H), 4.62 (m, 1H), 4.0 (m 1H), 3.73 (s, 3H), 2.3 (m, 2H), 2.0 (m, 2H), 1.65 (m, 6H), 1.46 (m, 1H), 1.18 (m, 4H), 0.89 (m, 2H).

1. customThe solvent was removed on the rotary evaporator
2. washThe organic layer was washed sequentially with saturated sodium bicarbonate (2×100 mL), 5% HCl (2×100 mL) and brine (100 mL)
3. dry with materialThe organic layer was dried over anhydrous sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated
6. customyielding a crude product which
7. customwas purified by flash chromatography (silica gel; hexane/ethyl acetate 75:25)