Hydrochloric Acid → 6-Trifluoromethyl-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylic acid

Beteiligte Stoffe

Reaktionsschritte

Ethyl 6-trifluoromethyl-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylate from Step 3 (45 mg, 0.13 mmol) was suspended in methanol-tetrahydrofuran-water (10 mL, 7:2:1). Lithium hydroxide (24 mg, 0.52 mmol) was added, and the mixture was gently heated to reflux for two hours. The reaction was cooled to room temperature and 1 N HCl added until pH=1. The organic solvent was removed in vacuo to afford a suspension of a crude yellow solid. Diethyl ether (20 mL) was added, and the solution was washed with water (2×20 mL), saturated ammonium sulfate (2×20 mL), dried over sodium sulfate and filtered. The filtrate was concentrated in vacuo to yield 6-trifluoromethyl-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylic acid as a yellow solid, (0.041 g, 0.132 mmol, 99%): mp 150–156° C. 1H NMR (CD3OD/300 MHz) 7.78 (s, 1H), 7.48 (s, 1H), 7.40 (m, 1H), 6.81 (m, 1H), 5.17 (m, 1H). ESHRMS m/z 310.0307 (M−H, Calc'd 310.0303).

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