4,5-DIFLUORO-2-METHOXYPHENYLACETIC ACID synthesis

Yield:1227845-66-0 93%

Reaction Conditions:

with sulfuric acid for 3 h;Reflux;

Steps:

Methyl 2-(3,4-difluoro-6-methoxyphenyl)acetate (C3)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: R_f=0.60 (cyclohexane/diethyl ether 1:1 parts by volume).

References:

US2011/224302,2011,A1 Location in patent:Page/Page column 12; 14