Acetic Acid → 2-(3,4-Difluoro-5-methoxyphenyl)acetic acid

Participants

Reaction Conditions

Reaction Steps

1.59 g of 5-allyl-1,2-difluoro-3-methoxybenzene (C2) are dissolved in 5.25 ml of ethyl acetate and 19.75 ml of glacial acetic acid and cooled to 0° C. in an ice bath. The solution is subsequently treated with ozone for 15 min (ozone generator: oxygen flow rate 40 l/h—corresponds to 5 g/h of O3). The mixture is subsequently diluted with 12 ml of water and warmed at 50° C. for a further 15 min. The reaction solution is then evaporated in vacuo, and the residue remaining is dissolved in 50 ml of tetrahydrofuran. 420 μl of H2O2 (30% solution) and 163 mg of phenylselenic acid are added. The reaction solution is subsequently heated under reflux for 2 h and, when the reaction is complete, evaporated to dryness in vacuo. The residue is purified by flash column chromatography on silica gel (solvent gradient: dichloromethane/0-40% by vol. of methanol), giving 806 mg of the title compound as a colourless oil; MS: 203.1 (MH+); TLC: Rf=0.40 (cyclohexane/ethyl acetate 9:1).

Provenance & Evidence