A mixture of ethyl 6-chloro-7-fluoro-2-(trifluoromethyl)-2H-chromene-3-carboxylate (Example 7a, Step 2) (0.5 g, 1.54 mmole) and isopentylamine (0.18 mL, 1.54 mmole) was dissolved in anhydrous DMF (5 mL), warmed to 90° C. and treated with K2CO3 (0.25 g, 1.84 mmole). The mixture was maintained at 90° C. for 24 hrs, cooled to room temperature, filtered through celite and condensed to a viscous oil. The oil was purified by flash chromatography (silica gel) with 40% methylene chloride in hexane to give light yellow solid (0.49 g, 82%): GCMS m/z 393.00 (M+). 1H NMR (CDCl3/400 MHz) 7.58 (s, 1H), 7.09 (s, 1H), 6.31 (s, 1H), 5.64 (q, 1H, J=7.0 Hz), 4.27 (m, 2H), 3.19 (m, 2H), 1.71 (m, 1H), 1.57 (m, 2H), 1.31 (m, 3H), 0.96 (m, 6H).
