反应详情

(E)-1-chloro-2-fluoro-4-(2-nitrovinyl)benzene (4.2 g, 20.84 mmol), 2-(methylamino)acetic acid (4.64 g, 52.1 mmol), paraformaldehyde (3.75 g, 125 mmol) were mixed in dry toluene (104 mL). The reaction mixture was heated at reflux using Dean-stark overnight. The reaction mixture was partitioned between EtOAc and water. The organic was washed by sat. NaCl, dried over Na2SO4 and concentrated. The crude material was purified by flash chromatography to yield (+/−)-(3R,4S)-3-(4-chloro-3-fluorophenyl)-1-methyl-4-nitropyrrolidine in 45% yield. LCMS (m/z): 259.2 (MH+), 0.52 min; 1H NMR (400 MHz, CDCl3) δ ppm 7.37 (t, J=8.0 Hz, 1H), 7.15 (dd, J=2.0, 10.2 Hz, 1H), 7.09-7.01 (m, 1H), 4.91-4.82 (m, 1H), 3.98 (d, J=5.1 Hz, 1H), 3.34 (dd, J=4.1, 10.8 Hz, 1H), 3.23 (t, J=8.6 Hz, 1H), 3.10 (dd, J=7.8, 10.6 Hz, 1H), 2.63 (dd, J=7.0, 9.4 Hz, 1H), 2.44 (s, 3H).

1. temperatureThe reaction mixture was heated
2. temperatureat reflux
3. customThe reaction mixture was partitioned between EtOAc and water
4. washThe organic was washed by sat. NaCl
5. dry with materialdried over Na2SO4
6. concentrationconcentrated
7. customThe crude material was purified by flash chromatography