反应详情

38 ml of acetic anhydride and 11 ml of ethyl orthoformate were added to the whole of the ethyl 3-difluoromethoxy-2,4,5-trifluoro-6-nitrobenzoylacetate [(XV), R1 =--OCHF2, R3' =NO2, R17 =C2H5, X=X'=F] prepared as described in step (b) above, and then the mixture was heated under reflux for 3 hours; the excess acetic anhydride and ethyl orthoformate were then removed by evaporation under reduced pressure, to give 20.6 g of ethyl 2-(3-difluoromethoxy-2,4,5-trifluoro-6-nitrobenzoyl)-3-ethoxyacrylate as a red liquid.

1. custom' =NO2, R17 =C2H5, X=X'=F] prepared
2. temperaturewas heated
3. temperatureunder reflux for 3 hours
4. customthe excess acetic anhydride and ethyl orthoformate were then removed by evaporation under reduced pressure