反应详情

p-Toluenesulfonic acid (6.1 g, 31.9 mmoi) was added to a solution of N-ethyl-4-hydroxy-4-(3-(1-methylethoxy)phenyl)piperidine (Preparation 43, 4.2 g, 16.0 mmol) in toluene (50 ml), and the reaction mixture was heated under reflux for 3 h. The reaction mixture was allowed to cool to room temperature, water (20 ml) was added, and the resultant biphasic system was stirred vigorously for several minutes. The aqueous layer was basified with 2N aqueous sodium hydroxide solution (10 ml) and the two phases were separated. The aqueous layer was then further extracted with ether (3×10 ml) and the combined extracts were dried (MgSO4), filtered and concentrated to give a crude oil which was purified by silica column chromatography eluting with ethyl acetate:methanol: 0.880 ammonia (96:3:1) to give the title compound as an oil (2.1 g, 54%).

1. temperaturethe reaction mixture was heated
2. temperatureunder reflux for 3 h
3. customthe two phases were separated
4. extractionThe aqueous layer was then further extracted with ether (3×10 ml)
5. dry with materialthe combined extracts were dried (MgSO4)
6. filtrationfiltered
7. concentrationconcentrated
8. customto give a crude oil which
9. customwas purified by silica column chromatography
10. washeluting with ethyl acetate