C([O:8][C:9]1[C:18]([Br:19])=[CH:17][CH:16]=[C:15]2[C:10]=1[C:11]([C:24]([F:27])([F:26])[F:25])=[CH:12][C:13]([O:20][CH:21]([CH3:23])[CH3:22])=[N:14]2)C1C=CC=CC=1.C([O-])([O-])=O.[K+].[K+]>CS(O)(=O)=O.C(O)(=O)C.O>[Br:19][C:18]1[C:9]([OH:8])=[C:10]2[C:15](=[CH:16][CH:17]=1)[N:14]=[C:13]([O:20][CH:21]([CH3:23])[CH3:22])[CH:12]=[C:11]2[C:24]([F:27])([F:26])[F:25]
A solution of 5-benzyloxy-6-bromo-2-isopropoxy-4-(trifluoromethyl)quinoline (13.5 g, 30.8 mmol) in 31 mL methanesulfonic acid and 31 mL acetic acid was stirred at rt for 10 h, whereupon it was poured in water (500 mL), neutralized with K2CO3 (ca. 75 g) and extracted with EtOAc (3×200 mL). The combined organic layers were washed with brine (200 mL), dried over MgSO4, filtered and concentrated. Flash chromatography (2%–5% EtOAc:hexanes, gradient elution) afforded 9.9 g (92%) of 6-bromo-5-hydroxy-2-isopropoxy-4-(trifluoromethyl)quinoline, a yellow-brown oil. 1H NMR (400 MHz, CDCl3) δ 7.71 (d, 1H, J=9.1), 7.38 (d, 1H, J=9.1), 6.23 (s, 1H), 5.53 (sept, 1H, J=6.2), 1.41 (d, 6H, J=6.2).
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