反应详情

(4R)-4-(4-Chlorophenyl)pyrrolidin-2-one (44 g, 225.6 mmol) was treated with conc. sulfuric acid (220 mL). This solution was cooled in ice. Guanidine nitrate (27.5 g, 225.6 mmol) was added in portions. The reaction mixture was warmed to room temperature and stirred for 1 h. The mixture was then poured into ice. The product crashed out as a pale yellow solid and was filtered, washed with hexane, and dried to give the title compound (51 g, 95% yield). 1H-NMR (400 MHz, CD3OD): δ7.12 d, J=8.4 Hz, 1H), 6.73-6.74 (d, J=4.0 Hz, 1H), 6.52-6.55 (m, 1H), 3.70-3.74 (m, 1H), 3.54-3.62 (m, 1H), 3.32-3.46 (m, 1H), 2.63-2.69 (dd, J=16.4, 8.8 Hz, 1H), 2.37-2.43 (dd, J=16.8, 8.8 Hz, 1H); MS (ESI) m/z 241.05 (M+H)+.

1. temperatureThis solution was cooled in ice
2. additionThe mixture was then poured into ice
3. filtrationwas filtered
4. washwashed with hexane
5. customdried