反应详情

温度

200 °C

A solution of sodium hydroxide (175 g) in water (800 ml) was added to a solution of diethyl (4-bromophenyl)methylmalonate (150 g) in ethanol (850 ml) and the mixture was heated under reflux for 9 hours. Volatile material was removed by evaporation and the residue was dissolved in a solution of sodium hydroxide (130 g) in water (250 ml). The solution was heated under reflux for 2.5 hours, filtered through a bed of diatomaceous earth and the filtrate was acidified with 6M sulphuric acid. The mixture was extracted with ether (4×500 ml) and the extracts were dried (MgSO4). The solution was concentrated and the residue was heated at 200° C. until evolution of carbon dioxide ceased. The residue was dissolved in 1M sodium hydroxide solution (500 ml) and the solution was acidified with 6M sulphuric acid. The mixture was extracted with ether (4×500 ml) and the extracts were dried (MgSO4). The solvent material was removed by evaporation to give 3-(4-bromophenyl)-2-methylpropionic acid (91 g), m.p. 72-73 ° C.; 1H NMR (d6-DMSO): 1.0 (d, 3H), 2.05-2.15 (m, 2H), 2.85-2.9 (m, 1H), 7.1 (d, 2H), 7.4 (d, 2H).

1. temperaturethe mixture was heated
2. temperatureunder reflux for 9 hours
3. customVolatile material was removed by evaporation
4. dissolutionthe residue was dissolved in a solution of sodium hydroxide (130 g) in water (250 ml)
5. temperatureThe solution was heated
6. temperatureunder reflux for 2.5 hours
7. filtrationfiltered through a bed of diatomaceous earth
8. extractionThe mixture was extracted with ether (4×500 ml)
9. dry with materialthe extracts were dried (MgSO4)
10. concentrationThe solution was concentrated
11. dissolutionThe residue was dissolved in 1M sodium hydroxide solution (500 ml)
12. extractionThe mixture was extracted with ether (4×500 ml)
13. dry with materialthe extracts were dried (MgSO4)
14. customThe solvent material was removed by evaporation