Triphenylphosphine → 2,6-Difluoro-3-(2-(2-methoxyethoxy)ethoxy)benzoic acid

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Reaction Conditions

Reaction Steps

A mixture of methyl 2,6-difluoro-3-hydroxybenzoate (500 mg, 2.66 mmol), diethyleneglycol-monomethyl ether (479 mg, 3.99 mmol) and PPh3 (1046 mg, 3.99 mmol) in THF (12.0 mL) was purged with nitrogen, cooled to −78° C. and then DIAD (753 μl, 3.99 mmol) added over 5 min. The reaction mixture was warmed to RT and after 1 hr an aq solution of NaOH (2M, 10 mL) and water (10 mL) were added and the mixture was stirred rapidly at RT for 1 hr. The resulting mixture was extracted with ether (50 mL) and the organic layer was back-extracted with aq NaOH (1M, 20 mL). The combined (basic) aqueous phases were extracted twice with ether and then acidified to pH 1 by the addition of conc. hydrochloric acid and the mixture extracted three times with ether. The combined ether extracts were dried (MgSO4) and evaporated in vacuo to afford the title compound as a white solid (0.51 g, 65%); Rt 1.81 min, (Method 1, basic); m/z 275 (M−H)− (ES−).

Provenance & Evidence