In a 100 mL round bottom flask, open to the atmosphere was added the crude product Benzene, 1,3-dimethoxy-5-propyl (0.736 g, 4.08 mmol, 1.0 equiv.) and a 1:1 mixture of glacial acetic acid (20 mL, 349.7 mmol, 17.4 M) and hydrobromic acid (48% in H2O, 20 mL, 368.3 mmol, 18.4 M). The reaction mixture was refluxed at 125 °C for 3 hours while stirring, or until the starting material was consumed via TLC analysis. At this point, the reaction was allowed to cool to room temperature and quenched by the addition of DI H2O. The biphasic solution was added to a separatory funnel, wherein the organic portion was extracted Et2O (ca. 3x 20 mL). The organic layers were then combined, neutralized with a concentrated sodium bicarbonate solution (ca. 30 mL), washed with a saturated brine solution (ca. 50 mL), dried over MgSO4, filtered, and concentrated in vacuo to afford the final product without 5-Propyl-1,3-benzenediol (5-propylbenzene-1,3-diol) (0.609 g, 99% yield) as a pale yellow oil.
