反应详情

To a mixture of sodium hydride (0.84 g: 55% dispersion in mineral oil) and tetrahydrofuran (40 ml) was dropwise added a solution of ethyl diethylphosphonoacetate (4.33 g) in tetrahydrofuran (20 ml) with ice-cooling of 6° to 12° C. over a 12 minutes period. After stirring at room temperature for 30 minutes, to the mixture thus obtained was dropwise added a solution of 3,5-dichlorobenzaldehyde (3.07 g) in tetrahydrofuran (20 ml) with ice-cooling of 8° to 11° C. over a 10 minutes period. After stirring at room temperature for 4 hours, the reaction mixture was poured into water and extracted twice with ethyl acetate. The combined extract was washed with water, dried and concentrated. The residue was purified by flash column chromatography through silica gel (100 g). Fractions eluted with a 99:1 mixture of hexane and ethyl acetate were collected and worked up to afford the title compound (3.33 g), melting at 71°-73° C.

1. temperaturecooling of 6° to 12° C. over a 12 minutes period
2. customthus obtained
3. temperaturecooling of 8° to 11° C. over a 10 minutes period
4. stirringAfter stirring at room temperature for 4 hours
5. extractionextracted twice with ethyl acetate
6. extractionThe combined extract
7. washwas washed with water
8. customdried
9. concentrationconcentrated
10. customThe residue was purified by flash column chromatography through silica gel (100 g)
11. washFractions eluted with a 99:1 mixture of hexane and ethyl acetate
12. customwere collected