Ethyl 4-chloro-6,7-difluoroquinoline-3-carboxylate → HCID 178515220, compound

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Reaction Steps

1.05 equiv. of methyl 3-hydrazinylthiophene-2-carboxylate was added to a solution of 3c in ethanol. After 1.5 hr of stirring at room temperature, the solution was concentrated in vacuo and residue was dissolved in chloroform and washed with aq. Sodium bicarbonate solution, dried and concentrated in vacuo. The resulting solid was suspended in ethanol and stirred with 1N sodium hydroxide solution for 30 minutes, acidified with acetic acid and concentrated in vacuo. The solid was filtered, washed with water, dried and suspended in ethanol. 1N sodium hydroxide was added and the reaction mixture was refluxed for 1 hr, acidified with acetic acid and the crystals were collected by filtration. The yellow solid was combined with copper powder and quinoline and stirred at 190° C. for 1 hour. The copper was removed by filtration and the filtrate was mixed with 1N sodium hydroxide solution, followed by extraction with ether. The separated aqueous layer was treated with active charcoal, acidified with acetic acid to yield compound 4l as yellow solid. 1H-NMR (DMSO-d6) δ (ppm): 7.58 (1H, dd, J=5.22, 3.30 Hz), 7.69 (1H, dd, J=11.26, 7.14 Hz), 7.74 (1H, dd, J=5.22, 1.38 Hz), 7.80 (1H, m), 8.15 (1H, dd, J=10.7, 8.2 Hz), 8.77 (1H, d, J=6.2 Hz). m/z 304.2 (MH+).

Provenance & Evidence