反应详情

2-Fluoro-5-formylbenzonitrile (250 mg, 1.68 mmol), 2,2-diethyl-1,3-propanediol (776 mg, 5.87 mmol) and a catalytic amount of p-toluenesulfonic acid monohydrate were refluxed in toluene (25 mL) overnight in a Dean-Stark apparatus. The reaction mixture was then concentrated and the residue dissolved in chloroform (50 mL) and washed with saturated sodium bicarbonate solution (2×25 mL) then brine (1×25 mL). The organic phase was dried (Na2SO4) and evaporated to give an oil. The oil was then chromatographed on silica gel (4:1 hexane/ethyl acetate) to give 5-(5,5-diethyl-1,3-dioxan-2-yl)-2-fluorobenzenecarbonitrile (43) as a light yellow oil (401 mg, 91%). 1H NMR (MeOD, 300 MHz): δ 0.90, t (7.7 Hz), CH2CH3; 0.97, t (7.5 Hz), CH2CH3; 1.25, q (7.6 Hz), CH2CH3; 1.86, q (7.6 Hz), CH2CH3; 3.72, d (11.5 Hz), CH2O; 4.02, d (11.4 Hz), CH2O; 5.52, s, H2; 7.42, t (9.3 Hz), H3; 7.86, m, H4,6. ESI (+ve) MS: m/z 264 (M+H, 11%).

1. concentrationThe reaction mixture was then concentrated
2. dissolutionthe residue dissolved in chloroform (50 mL)
3. washwashed with saturated sodium bicarbonate solution (2×25 mL)
4. dry with materialThe organic phase was dried (Na2SO4)
5. customevaporated
6. customto give an oil
7. customThe oil was then chromatographed on silica gel (4:1 hexane/ethyl acetate)