反应详情

A solution of ethyl 2-chloroacetoacetate (8.25 g) in dry dimethylformamide was treated with sodium hydride (1.3 g and stirred at ambient temperature for 0.5 h. A solution of 4-(bromomethyl)phenylpropan-2-one, ethylene ketal (12.0 g) in dry dimethylformamide (20 ml) was then added and the mixture was heated at 70° C. for 4 h. The reaction mixture was cooled, poured into ice/water, acidified with 2N-hydrochloric acid, extracted with ethyl acetate (4×50 ml) and the combined organic extracts dried (magnesium sulphate), filtered and evaporated in vacuo. The residue was dissolved in ethanol and treated at 0°-5° C. with barium hydroxide hydrate (7.7 g). The mixture was stirred for 0.5 h, poured into ice/water, extracted with ethyl acetate (3×50 ml) and the combined organic extracts dried (magnesium sulphate), filtered and evaporated in vacuo to leave a red oil, which was purified by column chromatography on silica using diethyl ether: petroleum ether (60°-80°) (30:70) as eluent to give ethyl 3-(4-acetonylphenyl)-2-chloropropionate, ethylene ketal, (6.0 g).

1. temperaturethe mixture was heated at 70° C. for 4 h
2. temperatureThe reaction mixture was cooled
3. extractionextracted with ethyl acetate (4×50 ml)
4. dry with materialthe combined organic extracts dried (magnesium sulphate)
5. filtrationfiltered
6. customevaporated in vacuo
7. dissolutionThe residue was dissolved in ethanol
8. additiontreated at 0°-5° C. with barium hydroxide hydrate (7.7 g)
9. stirringThe mixture was stirred for 0.5 h
10. additionpoured into ice/water
11. extractionextracted with ethyl acetate (3×50 ml)
12. dry with materialthe combined organic extracts dried (magnesium sulphate)
13. filtrationfiltered
14. customevaporated in vacuo
15. customto leave a red oil, which
16. customwas purified by column chromatography on silica