Powdered KOH (0.111 g, 1.98 mmol) was added to a solution of (−)-1-cyclopropyl-2,2,2-trifluoro-1-(2-mercapto-1,3-thiazol-5-yl)ethanol (0.507 g, 1.98 mmol) in dry MeOH (2 mL). When a solution was obtained, the reaction mixture was concentrated to dryness. Dry toluene was then added and the mixture was concentrated to dryness again. The residue was dissolved in NMP (2 mL) and 7-bromo-4-pyridin-3-yl-2H-chromen-2-one (0.500 g, 1.65 mmol) was added and the resulting mixture was stirred at 120° C. for 16 h. Once cooled, the mixture was directly applied onto a column of silica gel and chromatographed (acetone/toluene 5:95 to 20:80), affording the title compound. 1H NMR (500 MHz, CDCl3): δ 8.76 (brd, 1H), 8.68 (d, 1H), 7.85 (s, 1H), 7.79 (brd, 1H), 7.50 (m, 2H), 7.31-7.36 (m, 2H), 6.39 (s, 1H), 3.05 (br s, 1H), 1.48 (m, 1H), 0.71 (m, 2H), 0.62 (m, 1H), 0.56 (m, 1H); [α]D=−31.1° (c=1.05, EtOH).
