反应详情

7-(1,1-Dimethylethyl-2-(trifluoromethyl)-2H-1-benzopyran-3-carboxylic acid (Example 12) (0.6 g, 2 mmol), chloroform (50 mL), iron filings (0.01 g, 0.2 mmol), and bromine (0.48 g, 3.00 mmol) were stirred at reflux for 16 h. The mixture was allowed to cool and was washed with brine (2×50 mL). After drying over MgSO4, the mixture was filtered, concentrated in vacuo, and the residue crystallized from ether-hexanes yielding the title compound as a white solid (0.5 g, 66%): mp 198.6-199.9° C. 1H NMR (acetone-d6/300 MHz) 7.85 (s, 1H), 7.72 (s, 1H), 7.13 (s, 1H), 5.83 (q, 1H, J=7.2 Hz), 1.5 (s, 9H). Anal. Calc'd for C15H14O3F3Br: C, 47.52; H, 3.72; N, 21.07. Found: C, 47.42; H, 3.68; N, 21.15.

1. temperatureat reflux for 16 h
2. temperatureto cool
3. washwas washed with brine (2×50 mL)
4. dry with materialAfter drying over MgSO4
5. filtrationthe mixture was filtered
6. concentrationconcentrated in vacuo
7. customthe residue crystallized from ether-hexanes yielding the title compound as a white solid (0.5 g, 66%)