p-Toluenesulfonic acid → 2-(Chloromethyl)-2,3-dihydrothieno[3,4-b][1,4]dioxine

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Reaction Steps

Under a nitrogen atmosphere in a 500 mL round bottom flask equipped with a reflux condenser, 20.0 g (0.139 mol) dimethoxythiophene, 17.8 g (0.161 mol) 3-chloro-1,2-propanediol, and 5 g p-toluenesulfonic acid was dissolved in 350 mL toluene. The reaction was then heated to ˜90 C overnight. At this time TLC indicated consumption of starting material. After cooling the reaction mixture was concentrated to ˜100 mL and poured into saturated potassium carbonate solution. The mixture was extracted with DCM and the combined extracts were dried with magnesium sulfate. Solvent removal gave a dark oil that was purified by column chromatography using 3:1 hexanes/DCM. Solvent removal gave the product as a white solid. Structure and purity were confirmed by 1H/13C NMR and LC-MS.

Provenance & Evidence