Potassium Carbonate → Ethyl 6-chloro-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylate

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Reaction Conditions

Reaction Steps

The 2-amino-5-chlorobenzaldehyde from Step 1 (15.0 g, 96 mmol), anhydrous potassium carbonate (27.6 g, 200 mmol), and ethyl 4,4,4-trifluorocrotonate (34 mL, 200 mmol) were mixed in anhydrous dimethyformamide (60 mL) and heated at 100° C. for 7 hours. The contents were allowed to cool and partitioned between ethyl acetate (200 mL) and water (200 mL). The aqueous layer was extracted with ethyl acetate (1×100 mL). The ethyl acetate extracts were combined and washed with brine (1×200 mL), dried over MgSO4, and concentrated in vacuo leaving a dark oil which solidified upon standing. The solid was purified by flash chromatography (silica gel; ethyl acetate-hexanes, 1:9). Fractions containing the desired product were combined, concentrated in vacuo and the residue recrystallized from ethyl acetate-hexanes to afford the ethyl 6-chloro-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylate as a yellow solid (16.36 g, 56%): mp 132.6-134.2° C. 1H NMR (CDCl, 300 MHz) 7.61 (s, 1H), 7.10 (m, 2H), 6.55 (d, 1H, J=8.0 Hz), 5.10 (q, 1H, J=6.0 Hz), 4.55 (brs, 1H), 4.23 (m, 2H), 1.32 (t, 3H, J=7.0 Hz). FABHRMS m/z 306.0468 (M+H+, Calc'd 306.0509). Anal. Calc'd for C13H11NO2F3Cl: C, 51.08; H, 3.63; N, 4.58. Found: C, 50.81; H, 3.49; N, 4.72.

Provenance & Evidence