4-Hydroxy-7-trifluoromethyl-quinoline-3-carboxylic acid ethyl ester (0.86 g, 3.02 mmol) was dissolved in DMF (10 mL). Cs2CO3 (0.98 g, 3.02 mmol) was added at RT and the mixture was stirred for 10 min. A solution of 5-(5-bromo-pentyloxy)-2-hydroxymethyl-pyran-4-one 10 (0.86 g, 3.02 mmol) in DMF (5 mL) was added via syringe. This mixture was stirred at 50° C. for 22 h. Water (10 mL) was added and the mixture extracted with EtOAc (2×50 mL), washed with water (3×50 mL), brine (3×50 mL) dried over MgSO4, filtered and evaporated. The crude product was purified by column chromatography on silica using as eluent (CH2Cl2:MeOH)=90:10. 4-[5-(6-Hydroxymethyl-4-oxo-4H-pyran-3-yloxy)-pentyloxy]-7-trifluoromethyl-quinoline-3-carboxylic acid ethyl ester 13 was obtained (0.43 g, 31% yield) as a pale yellow foam.
