反应详情

温度

110 °C

A 22 L flask was charged with the hydrate of (4-bromo-3-fluorophenyl)-2-oxoacetaldehyde (5, 1020 g, 4.41 mol), toluene (7.5 L), triethyl orthoformate (1633 g, 1.8 L, 11.04 mol, 2.5 equiv), para-toluene sulfonic acid (33.5 g, 0.176 mol, 0.4 equiv) at room temperature, and the resulting reaction mixture was heated to 110° C. and stirred at 110° C. for 6 h. When HPLC showed that the reaction was complete, the reaction mixture was cooled down to room temperature before being poured into a 50 L separation funnel along with ethyl acetate (7.5 L) and the saturated aqueous sodium bicarbonate solution (NaHCO3, 3 L). The mixture was stirred and the layers were separated. The aqueous layer was extracted with ethyl acetate (2 L). The combined organic layers were washed with brine (4 L), dried with sodium sulfate (Na2SO4), and concentrated under the reduced pressure to afford crude 1-(4-bromo-3-fluorophenyl)-2,2-diethoxyethanone (6, 1240 g, 1345.7 g theoretical, 92.1% yield) which was used in the subsequent reaction without further purification. For 6: 1H NMR (400 MHz, DMSO-d6) δ ppm 7.94-7.94 (m, 2H), 7.78 (dd, 1H, J=8.51, 2.08 Hz), 5.40 (s, 1H), 3.77-3.60 (m, 4H), 1.16-1.14 (m, 6H).

1. customthe resulting reaction mixture
2. temperaturethe reaction mixture was cooled down to room temperature
3. stirringThe mixture was stirred
4. customthe layers were separated
5. extractionThe aqueous layer was extracted with ethyl acetate (2 L)
6. washThe combined organic layers were washed with brine (4 L)
7. dry with materialdried with sodium sulfate (Na2SO4)
8. concentrationconcentrated under the reduced pressure