反应详情

341.5 g (1.16 moles) of 4-chloro-4'-methanesulfonylbenzophenone, prepared in example 2, 310 ml (1.85 moles) of ethyl succinate and 195.5 g (1.74 moles) of potassium t-butoxide are successively added to 2.5 liters of t-butanol. The temperature rises to 40°-45° C., the mixture is stirred for 7 hours at room temperature after this exothermic reaction and is then poured into iced water. After acidification to pH 3 with hydrochloric acid, the mixture is extracted with diethyl ether. The organic phase is washed with water, dried over magnesium sulfate and evaporated in vacuo. The oil obtained is dissolved in diethyl ether and then left overnight at room temperature. The crystals formed are filtered off and dried to provide 102 g of (Z)-3-ethoxycarbonyl-4-(4-chlorophenyl)-4-(4-methanesulfonylphenyl)but-3-enoic acid as crystals with a melting point of 184°-186° C. after recrystallization from isopropanol. The evaporation of the filtrate allows the recovery of 219 g of a mixture consisting of 82% of the (E)-isomer and 18% of the (Z)-isomer.

1. customrises to 40°-45° C.
2. customafter this exothermic reaction
3. extractionAfter acidification to pH 3 with hydrochloric acid, the mixture is extracted with diethyl ether
4. washThe organic phase is washed with water
5. dry with materialdried over magnesium sulfate
6. customevaporated in vacuo
7. customThe oil obtained
8. waitleft overnight at room temperature
9. customThe crystals formed
10. filtrationare filtered off
11. customdried