反应详情

温度

-10 °C

Cyclohexylmagnesium bromide (240 ml of a 2M solution in ether, 0.48 mol) in ether (200 ml) was added dropwise to a solution of 2-methyl-4H-3,1-benzoxazin-4-one (100 g, 0.62 mol) in ether (1100ml) at -10° C. over 2 h. The mixture was stirred at this temperature for 2 h, then at ambient temperature for 30 min. After cooling to -10° C. the suspension was treated with 2M HCl (600 ml), keeping the temperature below 0° C. After stirring for 15 min the layers were separated, and the ethereal layer washed sequentially with water (500 ml), 5% sodium hydroxide solution (2×500 ml) and finally water (2×500 ml). The organic layer was separated, dried (MgSO4), evaporated in vacuo and chromatographed on silica using petrol:ethyl acetate (2:1). to give (2-acetamidophenyl) cyclohexyl methanone (28 g, 24%) as a pale yellow solid. mp 66° C. 1H NMR (CDCL3, 360 MHz)-- 1.25-1.89 (10H, m), 2.23 (3H, s), 3.33 (1H, m), 7.13 (1H, dt, J=6 and 1 Hz), 7.53 (1H, dt, J=6 and 1 Hz), 7.92 (1H, d, J=6 Hz), 8.76 (1H, d, J=6 Hz), 11.73 (1H, brs).

1. waitat ambient temperature for 30 min
2. customthe temperature below 0° C
3. stirringAfter stirring for 15 min the layers
4. customwere separated
5. washthe ethereal layer washed sequentially with water (500 ml), 5% sodium hydroxide solution (2×500 ml) and finally water (2×500 ml)
6. customThe organic layer was separated
7. dry with materialdried (MgSO4)
8. customevaporated in vacuo
9. customchromatographed on silica