[OH:1][C:2]1[CH:11]=[CH:10][C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[C:3]=1C=O.[F:14][C:15]([F:24])([F:23])/[CH:16]=[CH:17]/[C:18]([O:20][CH2:21][CH3:22])=[O:19].[C:25]([O-])([O-])=O.[K+].[K+]>CN(C)C=O.O>[F:14][C:15]([F:23])([F:24])[C:16]1[CH2:25][O:1][C:2]2[CH:11]=[CH:10][C:9]3[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=3)[C:3]=2[C:17]=1[C:18]([O:20][CH2:21][CH3:22])=[O:19]A mixture of 2-hydroxy-1-naphthaldehyde (8.6 g, 0.050 mol) and ethyl 4,4,4-trifluorocrotonate (9.2 g, 0.055 mol) dissolved in anhydrous dimethylformamide (DMF) and treated with anhydrous K2CO3 (13.8 g, 0.100 mol). The solution was maintained at room temperature for 50 hours and diluted with water. The solution was extracted with ethyl acetate, and the combined extracts were washed with brine, dried over anhydrous MgSO4, filtered and concentrated in vacuo to afford 4.8 g of an oil. The oil was purified by HPLC, eluting with hexanes:ethyl acetate (30:1). The appropriate fractions were concentrated to afford 1.6 g (10%) of the napthopyran ester as a yellow solid.
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