Hydrochloric Acid → 4-Fluoro-2-hydroxybenzaldehyde

Participants

Reaction Steps

To the mixture of 3-fluorophenol (10 mL, 102 mmol), anhydrous magnesium chloride (28.2g, 744.6 mmol) in 500 mL of anhydrous acetonitrile was added anhydrous triethylamine (67 mL, 382.5 mmol) and paraformaldehyde (22.3g, 744.6 mmol). The mixture was then heated to reflux for five hrs. After cooling to room temperature, 500 mL of 5% aqueous hydrochloric acid was added. The product was extracted with ethyl acetate. The combined organic extracts were washed three times with 5% hydrochloric acid, brine, and dried over anhydrous magnesium sulfate. After removing the volatiles, the product was obtained as a light pink solid; 11 g, yield=72%. A small fraction was further purified on silica gel column with EtOAc/hexane mixture for further analytical characterization, it gave a white solid. M.P.=67.5-69.0° C. 1H NMR (CDCl3/300 MHz) 11.40(s, 1H), 9.86(s, 1H), 7.62-7.57(m, 1H ), 6.79-6.67(m, 2H). 13C(CDCl3/30OMH) 195.4, 168.3(d, J=258 Hz), 164.4(d, J=14.9 Hz), 136.3(d, J=12.6 Hz), 118.2(d, J=2.0 Hz), 108.5(d, J=23.3 Hz), 104.9(d, J=24.4 Hz). 19F (CDCl3/400 MHz) −97.9(m). LC-MS couldn't observe the desired peak. HRMS (ES−) m/z calcd for (C7H5FO2) 139.0201 (M−H), found 139.0211(M−H).

Provenance & Evidence