Ethylene Glycol → 2-(5-Bromo-2,4-dimethoxyphenyl)-1,3-dioxolane

Participants

Reaction Steps

Ex-46A: 5-Bromo-2,4-dimethoxybenzaldehyde (4.92 g, 20.1 mmol) was dissolved in benzene (41 mL). Ethylene glycol (3 mL, 54 mmol) and p-toluenesulfonic acid (25 mg, 0.13 mmol) were added and the solution was refluxed with a Dean-Stark trap attached. After 6 h, the reaction was cooled and washed with water (1×20 mL), saturated, aqueous NaHCO3 (1×20 mL), and water (1×20 mL). The organic phase was dried over sodium sulfate, filtered, concentrated, and dried to provide 5.32 g of 2-(5-bromo-2,4-dimethoxy-phenyl)-[1,3]dioxolane as a faint yellow oil which solidified upon standing (92% yield). 1H-NMR (CDCl3) δ 7.67 (s, 1H), 6.47 (s, 1H), 6.06 (s, 1H), 4.11–4.13 (m, 2H), 3.98–4.03 (m, 2H), 3.91 (s, 3H), 3.87 (s, 3H). HRMS (ES+) Calcd. for C11H13BrO4: 289.0075. Found: 289.0077.

Provenance & Evidence