反应详情

A sample of 8-(4-chloro-3-methoxyphenyl)-1,4-dioxa-8-azaspiro[4.5]decane (1.1 g, 2.89 mmol) was treated with 6 M HCl (15 mL) and heated at reflux for 3 h. The mixture was cooled to RT and made basic with 2 M NaOH. The basic mixture was extracted with EtOAc. The extract was dried (Na2SO4) and concentrated on a rotary evaporator to give the crude product. The crude product was purified by flash chromatography (40 g silica gel cartridge and gradient elution from 10 to 40% EtOAc/hexanes) to give 1-(4-chloro-3-methoxyphenyl)piperidin-4-one (690 mg, 2.88 mmol, 51.5% yield) as a yellow oil. 1H-NMR (400 MHz, CDCl3) δ ppm 7.21 (1 H, d, J=8.57 Hz), 6.52 (1 H, d, J=2.64 Hz), 6.47 (1 H, dd, J=8.68, 2.75 Hz), 3.88 (3 H, s), 3.57 (4 H, t, J=6.04 Hz), 2.55 (4 H, t, J=6.04 Hz).

1. temperatureheated
2. temperatureat reflux for 3 h
3. extractionThe basic mixture was extracted with EtOAc
4. dry with materialThe extract was dried (Na2SO4)
5. concentrationconcentrated on a rotary evaporator
6. customto give the crude product
7. customThe crude product was purified by flash chromatography (40 g silica gel cartridge and gradient elution from 10 to 40% EtOAc/hexanes)