[Br:1][C:2]1[CH:3]=[C:4]([CH:7]=[C:8]([Br:10])[CH:9]=1)[CH:5]=[O:6].[CH2:11](O)[CH2:12][OH:13]>C1(C)C=CC=CC=1.C(OCC)(=O)C.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>[Br:1][C:2]1[CH:3]=[C:4]([CH:5]2[O:13][CH2:12][CH2:11][O:6]2)[CH:7]=[C:8]([Br:10])[CH:9]=1A mixture of 3,5-dibromobenzaldehyde (5.37 g, 20.37 mmol), ethylene glycol (3.40 mL, 61.10 mmol) and p-toluenesulfonic acid monohydrate (78 mg, 0.41 mmol) in anhydrous toluene (30 mL) was heated at reflux under Dean-Stark conditions for 5 h. The reaction mixture was cooled to room temperature and diluted with ethyl acetate (25 mL). The ethyl acetate layer was washed with a saturated NaHCO3 solution (25 mL). The organic layer was removed and washed with water (1×25 mL) and dried with anhydrous MgSO4, filtered and evaporated in vacuo to give a colorless viscous liquid (6.27 g). GC-MS (Cl/methane) analysis of the liquid shows the desired product's mass: m/z 306 (79Br,79BrM+), m/z 308 (79Br,81BrM+), and m/z 310 (81Br,81BrM+); Calcd for C9H8Br2O2: 307.96. 1H NMR (400 MHz, CDl3): δ 3.97-4.10 (M, 4H, 2×—CH2—O—), 5.74 (s, 1H, O—CH-0), 7.53 (d, J=1.80 Hz, 2H), 7.63 (appt, J=1.80 Hz, 1H). 1H NMR spectrum of the liquid was consistent with the suggested structure of the product.
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