反应详情

Methyl-2-ethylacetoacetate (100 mL) was taken up in toluene (250 mL). Ethylene glycol (46.9 mL, 1.35 equiv.) and a catalytic amount of p-TsOH.H2O were added, and the mixture was refluxed overnight under Dean-Stark conditions. After cooling to ambient temperature, the mixture was washed with 5% aqueous NaHCO3 and saturated aqueous NaCl, the organic phase was dried over Na2SO4 and evaporated under reduced pressure. The residue was purified by repeated vacuum distillation (118-128° C., 15 mbar), yielding 85.5 g of product. 1H NMR (400 MHz, CDCl3) δ 0.90 (t, J=7 Hz, 3H), 1.28 (t, J=7 Hz, 3H), 1.40 (s, 3H), 1.59-1.83 (m, 2H), 2.56 (dd, J=11.5 and 4 Hz, 1H), 3.90-4.06 (m, 4H), 4.18 (m, 2H).

1. temperaturethe mixture was refluxed overnight under Dean-Stark conditions
2. washthe mixture was washed with 5% aqueous NaHCO3 and saturated aqueous NaCl
3. dry with materialthe organic phase was dried over Na2SO4
4. customevaporated under reduced pressure
5. distillationThe residue was purified by repeated vacuum distillation (118-128° C., 15 mbar)