反应详情

To a 0° C. solution of ethyl 2-(N-methyl-3-phenylprop-2-ynoylamino)acetate (prepared according to the procedure described for Intermediate A, 20 g, 82 mmol) in THF (100 mL) was added a solution of Li(SiMe3)2 (1M in THF, 82 mL, 82 mmol). The resulting mixture was stirred for 2 h, then was slowly treated with water (20 mL) and diluted with CH2Cl2 (200 mL). The organic layer was washed with water (150 mL), a 1N HCl solution (150 mL) and water (150 mL), dried (Na2SO4) and concentrated under reduced pressure. The crude product was purified by flash chromatography (gradient from 0% to 50% EtOAc/hex) to give racemic ethyl 1-methyl-5-oxo-3-phenyl-3-pyrroline-2-carboxylate (14 g, 70%) as a brown oil: TLC (40% EtOAc/hex) Rf 0.13; 1H NMR (CDCl3) δ 1.10 (t, J=7.4 Hz, 3H), 3.03 (s, 3H), 4.12 (m, 2H), 5.13 (s, 1H), 6.46 (s, 1H), 7.39-7.41 (m, 3H), 7.53-7.60 (m, 2H); HPLC ES-MS m/z (rel abundance) 246 (MH+, 100%).

1. washThe organic layer was washed with water (150 mL)
2. dry with materiala 1N HCl solution (150 mL) and water (150 mL), dried (Na2SO4)
3. concentrationconcentrated under reduced pressure
4. customThe crude product was purified by flash chromatography (gradient from 0% to 50% EtOAc/hex)