Potassium Carbonate → 4'-[(4-hydroxytetrahydro-2H-thiopyran-4-yl)methoxy]-2',6'-dimethylbiphenyl-3-carbaldehyde

To a solution of 1-oxa-6-thiaspiro[2.5]octane (6.33 g, 48.6 mmol) and 4′-hydroxy-2′,6′-dimethylbiphenyl-3-carbaldehyde (10.0 g, 44.2 mmol) in N,N-dimethylformamide (150 mL) was added potassium carbonate (6.11 g, 44.2 mmol) under stirring at room temperature, and the mixture was stirred at 100° C. stirred for 12 hr. The reaction mixture was concentrated under reduced pressure, and the residue was neutralized with 1 M hydrochloric acid. The mixture was extracted with ethyl acetate, and the extract was dried over anhydrous sodium sulfate and concentrated under reduced pressure. Diisopropyl ether was added to the obtained oil to allow crystallization and the crystals were collected by filtration to give the title compound (12.3 g yield 78%) as colorless crystals.