Ethylene Glycol → HCID 19701587, compound

Participants

Reaction Steps

3-Bromo-4-hydroxybenzaldehyde (2a, 10.0 g, 49.8 mmol) was heated at reflux with 1,2-dihydroxyethane (25 g, 0.4 mol) in toluene (150 mL) in the presence of p-toluenesulfonic acid (950 mg) for 48 h in an apparatus fitted with a Dean-Stark trap. The reaction mixture was concentrated by reduced pressure evaporation, washed with aqueous sodium hydrogen carbonate, water, brine, dried over Na2SO4, evaporated to dryness and then passed through a short silica gel column using a hexanes-ethyl acetate mixture (5:1) with a few drops of triethylamine as eluent to afford the protected product 3a (11.0 g, 95%) as a crystalline solid. Rf=0.38 (25% EtOAc-hexanes): mp 76-78° C. IR (neat) 3351, 2954, 2891, 1608, 1499, 1431, 1284, 1100 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.57 (d, J=1.8 Hz, 1H), 7.28 (dd, J=8.4, 2.4 Hz, 1H), 6.96 (d, J=8.7 Hz, 1H), 5.69 (s, 1H), 4.03 (m, 4H); 13C NMR (75 MHz, CDCl3) δ 152.9, 131.5, 130.2, 127.5, 115.8, 110.0, 102.7, 65.2; CIMS (m/z, rel intensity) 247 (MH++2, 7), 245 (MH+, 7), 203 (100), 201 (100), 175 (4), 173(5), 94 (1).

Provenance & Evidence