Hydrochloric Acid → 6-Chloro-1,2-dihydro-1-methyl-2-(trifluoromethyl)-3-quinoline-carboxylic acid

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Reaction Steps

Ethyl 6-chloro-1,2-dihydro-1-methyl-2-(trifluoro-methyl)-3-quinolinecarboxylate (1.21 g, 3.78 mmol) was suspended in methanol-tetrahydrofuran-water (20 mL, 7:2:1). Lithium hydroxide (0.262 g, 6.24 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 vauco to afford a suspension of crude yellow solid. Diethyl ether (20 mL) was added, and the resulting solution was washed with water (2×20 mL), saturated ammonium chloride (2×20 mL), dried over sodium sulfate and filtered. The filtrate was concentrated in vacuo to afford the product as a yellow solid, 6-chloro-1,2-dihydro-1-methyl-2-(trifluoromethyl)-3-quinoline-carboxylic acid. (1.08 g, 98% yield): mp 208-209° C. 1H NMR (CD3OD/300 MHz) 7.69 (d, 1H, J=2.5 Hz), 7.28-7.24 (m, 2H), 6.73 (dd, 1H, J=9.5, 2.5 Hz), 5.13 (q, 1H, J=7.0), 3.16 (s, 3H). Anal. Calc'd for C12H9F3NO2Cl: C, 49.42; H, 3.11; N, 4.80; Cl, 12.16. Found: C, 49.88; H, 3.29; N, 4.59; Cl, 12;42.

Provenance & Evidence