A mixture of 0.43 g (0.89 mmol) of 4-(6-bromohexyl)-3-(3-ethoxy-3-oxopropyl)-δ-oxobenzenepentanoic acid ethyl ester from the preceding example, 0.188 g (0.91 mmol) of 2,3-dihydro-7-hydroxy-8-propyl-4H-1-benzopyran-4-one and 0.398 g (2.88 mmol) of anhydrous granular potassium carbonate in 10 mL of 2-butanone was stirred and heated at 89° C. for 19.3 hr. The mixture was filtered with suction and the solid was washed with ether and ethyl acetate. The filtrate was concentrated in vacuo and the crude product was flash chromatographed on 80 g of silica gel, eluting with hexane-ethyl acetate (5:2). There was obtained 0.496 g (91.5%) of the title compound as a colorless oil.
