Ethylene Glycol → 2-(4-Bromothiophen-2-yl)-1,3-dioxolane

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Reaction Steps

4-Bromo-thiophene-2-carbaldehyde (9.24 g, 48.4 mmol), ethane-1,2-diol (13.5 mL, 242 mmol), toluene-4-sulfonic acid monohydrate (416 mg, 2.42 mmol) were dissolved in toluene (100 mL), and the solution was stirred for 1.5 hours under reflux. An aqueous solution of saturated sodium bicarbonate was added to the reaction solution at 0° C., which was then extracted with ethyl acetate, the organic layer was washed with brine and dried over anhydrous magnesium sulfate. The solvent was evaporated in vacuo, the residue was purified by NH silica gel column chromatography (hexane:ethyl acetate=20:1), and the title compound (11.8 g, quantitatively) was obtained as a white solid.

Provenance & Evidence