反应详情

289.0 g (1.19 mol) of N-phenylethyl-3-fluorobenzamide were dissolved in 1000 ml of xylene and admixed at 90° C. in portions with 202.7 g (1.43 mol, 1.2 eq.) of phosphorus pentoxide. Subsequently, 326.8 ml (3.57 mol, 3.0 eq.) of phosphorus oxychloride were added dropwise. The mixture was heated under reflux for 4 h. The reaction solution was subsequently poured while hot onto ice and adjusted cautiously to pH=12 with solid NaOH with ice cooling. The precipitate was extracted three times with 500 ml of toluene, dried over MgSO4 and concentrated under reduced pressure to a highly viscous oil which later crystallizes. 267.41 g are obtained with a purity of approx. 99%, corresponding to 99.8% of theory.

1. temperatureThe mixture was heated
2. temperatureunder reflux for 4 h
3. additionThe reaction solution was subsequently poured while hot onto ice
4. extractionThe precipitate was extracted three times with 500 ml of toluene
5. dry with materialdried over MgSO4
6. concentrationconcentrated under reduced pressure to a highly viscous oil which
7. customlater crystallizes
8. custom267.41 g are obtained with a purity of approx. 99%, corresponding to 99.8% of theory