反应详情

温度

50 °C

The product of Example I (5 g.) was heated under reflux with methanol (50 ml.) and concentrated sulphuric acid (1 ml.) for 4 hours. The product was poured into water, extracted with ether, the ether extracts dried and evaporated to give methyl 2-(2-fluoro-4-biphenylyl)-2-hydroxypropionate, m.p. 59°-61° C. This ester (1 g.) was dissolved in thionyl chloride (5 ml.) and heated on a water bath at 50° C. for two hours. Thionyl chloride was removed and the product was applied to preparative thin layer chromatography plates, eluted with an ether/petroleum (b.p. 62°-68° C.) mixture (5% 95%) and methyl 2-chloro-2-(2-fluoro-4-biphenylyl)propionate recovered. This was dissolved in ethyl acetate (5 ml.) and hydrogenated at room temperature using a 10% palladium/charcoal catalyst (73 mg.) for 16 hours. The solution was filtered and evaporated to give methyl 2-(2-fluoro-4-biphenylyl)propionate, whose structure was confirmed by n.m.r. This was hydrolysed by heating under reflux with aqueous ethanolic potassium hydroxide. The solution was acidified, extracted with ether and then aqueous potassium carbonate (10%) and this extract acidified and the precipitate collected to give 2-(2-fluoro-4-biphenylyl)propionic acid (m.p t. 105°-106° C.).

1. customThionyl chloride was removed
2. washeluted with an ether/petroleum (b.p. 62°-68° C.) mixture (5% 95%) and methyl 2-chloro-2-(2-fluoro-4-biphenylyl)propionate
3. customrecovered
4. dissolutionThis was dissolved in ethyl acetate (5 ml.) and hydrogenated at room temperature
5. customfor 16 hours
6. filtrationThe solution was filtered
7. customevaporated