Acetic Acid → 2-Fluoro-4-iodobenzoic acid

Participants

Reaction Conditions

Reaction Steps

A round bottom (RB) flask containing a solution of 8.0 g (27.0 mmol) of sodium dichromate in 44 mL of glacial acetic acid was placed in an external water bath (21° C.) and left exposed to air. To the resultant orange slurry was added 3.2 g (13.6 mmol) of 2-fluoro-4-iodotoluene followed by the dropwise addition of 22 mL of c. sulfuric acid via syringe (caution: if added too quickly there is a tendency for the mixture to erupt). After the addition of approximately 8 mL of sulfuric acid, a green solid precipitated and the water bath temperature had risen (25° C.). The green reaction mixture was heated in an oil bath (90° C.) for one hour, allowed to cool to ambient temperature, diluted with 1 N NaOH solution (aq.) and ethyl acetate (500 mL) and then quenched with sat. NaHCO3 (aq.) solution. The organic phase was separated and washed with water and brine, dried over MgSO4, filtered and concentrated in vacuo to an orange oil. Residual acetic acid was removed by further extraction between ethyl acetate and sat. NaHCO3 (aq.) solution and washing of the organic phase with water and brine. The organic phase was dried over MgSO4, filtered and concentrated in vacuo to give the title compound as an orange solid. PMR (DMSO—d6): δ 7.61 (1 H, t, J=8.0 Hz, J (C—F)=8.0 Hz), 7.67 (1 H, dd, J=1.5, 8.2 Hz), 7.78 (1 H, dd, J=1.5 Hz, J (C—F)=8.9 Hz).

Provenance & Evidence