反应详情

温度

-10 °C

To a cooled solution (-78° C.) of lithium diisopropylamide in 8 mL of tetrahydrofuran was added acetaldehyde N-tert-butylimine (0.4 mL, 3.0 mmol) and the mixture was stirred for 30 minutes. Diethyl chlorophosphate (518 mg, 3.0 mmol) was added and the solution was stirred at -78° C. for 2 hours, allowed to warm to -10° C. over a period of 3 hours, and recooled to -78° C. 2,4-dimethoxybenzaldehyde (232 mg, 2.0 mmol) was added to the yellow solution and the mixture was stirred for 30 minutes and allowed to warm to ambient temperature overnight. The mixture was then treated with oxalic acid (6 mmol in 20 mL of water) and then 20 mL of benzene was added. The two phase system was stirred overnight at room temperature and the layers separated. The aqueous layer was extracted with ether and the organic layers were combined and washed successively with 5% oxalic acid, 15% sodium bicarbonate, and brine. Drying (potassium carbonate) and concentration of the organic phase followed by purification of the residue (distillation or preparative TLC, silica gel, 30 ethyl acetate-hexane) gave 261 mg of 2,4-dimethoxycinnamaldehyde (yield 68%). ##STR18##

1. stirringthe solution was stirred at -78° C. for 2 hours
2. customrecooled to -78° C
3. stirringthe mixture was stirred for 30 minutes
4. temperatureto warm to ambient temperature overnight
5. stirringThe two phase system was stirred overnight at room temperature
6. customthe layers separated
7. extractionThe aqueous layer was extracted with ether
8. washwashed successively with 5% oxalic acid, 15% sodium bicarbonate, and brine
9. dry with materialDrying (potassium carbonate) and concentration of the organic phase
10. distillationfollowed by purification of the residue (distillation or preparative TLC, silica gel, 30 ethyl acetate-hexane)