反应详情

Under general experimental conditions reported by Kelper, JOC, 52, 453-55 (1987), a slurry of Ba(OH)2 (46.0 mg, 266 μmol) in water (480 μL) was added to a mixture of N-ethylurethane (2.04 mL, 17.1 mmol) and a 37% aqueous solution of formalin (1.28 mL, 17.1 mmol) in one portion with stirring. The mixture became cool and gradually formed a cloudy solution. The mixture was stirred at room temperature and the disappearance of N-ethylurethane monitored by TLC analysis. After 2 h, the reaction was quenched by adding solid CO2, stirred for 30 minutes and filtered to remove the precipitated barium carbonate. The solvent was removed under vacuum to provide an oily residue. The trace amounts of water were removed by azeotropic distillation with benzene (3×100 mL) to provide 56 as a clear oil (2.50 g, quant.): 1H NMR (400 MHz, CDCl3) δ 4.88 (d, J=7.6 Hz, 1H), 4.79 (d, J=7.6 Hz, 2H), 4.18 (q, J=7.6 Hz, 2H), 3.40 (q, J=6.4 Hz, 2H), 1.30 (t, J=7.6 Hz, 3H), 1.19 (t, J=7.6 Hz, 3H).

1. temperatureThe mixture became cool
2. customgradually formed a cloudy solution
3. customthe reaction was quenched
4. additionby adding solid CO2
5. stirringstirred for 30 minutes
6. filtrationfiltered
7. customto remove the precipitated barium carbonate
8. customThe solvent was removed under vacuum
9. customto provide an oily residue
10. customThe trace amounts of water were removed by azeotropic distillation with benzene (3×100 mL)