Methyl 3,4-dihydro-7-hydroxy-8-propyl-2H-1-benzopyran-2-carboxylate (10 g, 40 mmol), 1-bromo-3-chloropropane (75 g, 48 mmol), and potassium carbonate (828 g, 60 mmol) were added to 100 ml of methyl ethyl ketone, and the reaction mixture was heated to reflux and stirred overnight. The reaction mixture was diluted with ethyl acetate and washed with water. The organic layer was dried over magnesium sulfate, concentrated, and the crude product was chromatographed on silica gel using 20% ethyl acetate/80% hexane as eluant to give the product.
