反应详情

4.04 g of 2-(3,4-difluoro-6-methoxyphenyl)acetic acid (D3) are dissolved in 34 ml of methanol. 1.54 ml of H2SO4 (95-98%, extra pure) are subsequently added, and the reaction solution is heated under reflux for 3 h. For work-up, the mixture is diluted with 100 ml of water and extracted twice with 150 ml of ethyl acetate each time. The combined organic phases are washed with 50 ml of saturated NaHCO3 solution, dried over Na2SO4, filtered off with suction and evaporated to dryness in vacuo. The residue is recrystallised from cyclohexane, giving 4.0 g of the title compound as a colourless solid having a melting point of 48.3° C.; MS: 216.1 (M+); TLC: Rf=0.60 (cyclohexane/diethyl ether 1:1 parts by volume).

1. temperaturethe reaction solution is heated
2. temperatureunder reflux for 3 h
3. extractionextracted twice with 150 ml of ethyl acetate each time
4. washThe combined organic phases are washed with 50 ml of saturated NaHCO3 solution
5. dry with materialdried over Na2SO4
6. filtrationfiltered off with suction
7. customevaporated to dryness in vacuo
8. customThe residue is recrystallised from cyclohexane