1,2-Dibromoethane → 6-Methyl-2,3-dihydro-1,4-benzodioxine

Participants

Reaction Steps

A mixture of 4-methylbenzene-1,2-diol (10.0 g, 80.5 mmol) and potassium carbonate (111.3 g, 805.0 mmol) in acetone (300 mL) was stirred at room temperature for 1 h. After this time, 1,2-dibromoethane (27.7 mL, 322.0 mmol) was added and the reaction stirred at reflux for 5 d. After this time, the solvents were removed under reduced pressure and the solids redissolved in water (500 mL). The aqueous layer was then extracted three times with ethyl acetate (200 mL). The combined organic extracts were then dried over magnesium sulfate, filtered, and concentrated under reduced pressure. Purification by flash chromatography (silica, 1:20 ethyl acetate/hexanes) afforded 6-methyl-2,3-dihydrobenzo[b][1,4]dioxine (6.4 g, 54%) as a green oil: 1H NMR (500 MHz, CDCl3) δ 6.74 (d, J=8.5 Hz, 1H), 6.67 (d, J=2.0 Hz, 1H), 6.63 (dd, J 2.0, 8.0 Hz, 1H), 4.22 (m, 4H), 2.24 (s, 3H).

Provenance & Evidence