反应详情

In the manner described in Example 99, 3,3-bis(3-fluorophenyl)-2-propen al (17.8 g) was reacted with (carbethoxymethylene)triphenylphosphine (26.2 g) in carbon tetrachloride (200 mL) at room temperature overnight. The crude product (23 g) obtained from the usual work up was Predominantly (E)-5,5-bis(3-fluorophenyl)-2,4-pentadienoic acid ethyl ester. A stirred solution of the above material (23 g) in hot methanol (200 mL) was treated in one portion with 2N sodium hydroxide solution (75 mL). After 10 minutes at reflux, the reaction had become homogeneous and most of the methanol was distilled off. The cooled solution was diluted with water (300 mL), then was extracted with dichloromethane (3×200 mL). The organic extracts were discarded and the aqueous phase was added in a fine stream to a stirred mixture of 2N hydrochloric : acid (20mL) and ice (300 g). The resulting precipitate was filtered off then washed with water and dried. Triturating of the crude acid with hot hexane (150 mL) furnished 18.2 g of (E)-5,5-bis(3-fluorophenyl)-2,4-pentadienoic acid mp 162°-164° C. The analytical sample was obtained from 2-propanol. mp 163.5°-165° C.- Anal Calculated for C17H12F2O2 : C, 71.32; H, 4.22; F. 13.27 Found: C, 71.17; H. 4.23; F, 13.37.

1. customThe crude product (23 g) obtained from the usual work
2. temperatureAfter 10 minutes at reflux
3. distillationwas distilled off
4. additionThe cooled solution was diluted with water (300 mL)
5. extractionwas extracted with dichloromethane (3×200 mL)
6. additionthe aqueous phase was added in a fine stream to a stirred mixture of 2N hydrochloric
7. filtrationThe resulting precipitate was filtered off
8. washthen washed with water
9. customdried
10. customTriturating of the crude acid with hot hexane (150 mL)