反应详情

The ester from Step 2 (1.7 g, 5.6 mmol) and 2.5 N sodium hydroxide (4.4 mL, 11 mmol) were mixed in tetrahydrofuran (25 mL), methanol (10 mL), and water (25 mL). After stirring overnight, contents were concentrated in vacuo to remove the THF and methanol. The aqueous solution remaining was extracted with diethyl ether (2×100 mL). The resulting aqueous layer was acidified with 2 N HCl causing the precipitation of an oil. The oil was purified by flash chromatography on silica gel, eluting with ethyl acetate-hexanes (1:1). Fractions containing the desired product were combined, and concentrated in vacuo. The residue was triturated with dichloromethane, and filtered to afford the 6-chloro-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylic acid as a yellow solid (0.645 g, 41%): mp 187.8-188.8° C. 1H NMR (acetone-d6, 300 MHz) 7.69 (s, 1H), 7.36 (s, 1H), 7.15 (d, 1H, J=8.0 Hz), 6.83 (d, 1H, J=8.0 Hz), 6.60 (brs, 1H), 5.20 (m, 1H). ESHRMS m/z 276.0040 (M−H, Calc'd 276.0039). Anal. Calc'd for C11H7NO2F3Cl+2.6% H2O: C, 46.39; H, 2.98; N, 4.92. Found: C, 45.99; H, 2.54; N, 4.85.

1. concentrationcontents were concentrated in vacuo
2. customto remove the THF and methanol
3. extractionThe aqueous solution remaining was extracted with diethyl ether (2×100 mL)
4. customthe precipitation of an oil
5. customThe oil was purified by flash chromatography on silica gel
6. washeluting with ethyl acetate-hexanes (1:1)
7. additionFractions containing the desired product
8. concentrationconcentrated in vacuo
9. customThe residue was triturated with dichloromethane
10. filtrationfiltered