反应详情

A mixture of 87.6 g (0.38 mole) of 95% pure 4-fluoro-3-bromo-benzoic acid, 200 ml of methanol and 3 ml of sulphuric acid was boiled under for 18 hours. The excess methanol was then distilled off in vacuo, 300 ml of toluene were added and the solution was shaken first with 50 ml of water, then with 50 ml of saturated sodium bicarbonate solution and subsequently with 50 ml of water again. Thereafter, the solvent was distilled off in vacuo and the residue was distilled in vacuo. 86 g (97% of theory) of 4-fluoro-3-bromo-benzoic acid methyl ester were obtained in this manner in the form of a colorless oil which solidified as crystals when cold and had a boiling point of 64° C./0.1 mm Hg.

1. customwas boiled under for 18 hours
2. distillationThe excess methanol was then distilled off in vacuo, 300 ml of toluene
3. additionwere added
4. distillationThereafter, the solvent was distilled off in vacuo
5. distillationthe residue was distilled in vacuo