Reaction Steps
A solution of 3-aminoisoxazole (0.070 ml, 0.954 mmol) and 1-(3-cyclopropyl-3′,5′-difluoro-[1,1′-biphenyl]-4-yl)-2-oxo-1,2-dihydroquinoline-6-sulfonyl chloride (0.150 g, 0.318 mmol) in 3 mL THF was cooled to 0° C. and was treated with LiHMDS 1N in THF (0.636 ml, 0.636 mmol). The cooling bath was removed and the reaction mixture was allowed to stir for one hour. TFA (0.122 ml, 1.589 mmol) was then added, and the reaction mixture was concentrated. Purification of the crude residue by reverse phase column chromatography [Puriflash C18, 10-100% (0.1% NH4OH in MeOH)/(0.1% NH4OH in water)] gave 1-(3-cyclopropyl-3′,5′-difluoro-[1,1′-biphenyl]-4-yl)-N-(isoxazol-3-yl)-2-oxo-1,2-dihydroquinoline-6-sulfonamide (0.06, 0.115 mmol, 36.3% yield). m/z (ESI) 520.1 (M+H)+. The atropisomers were separated using supercritical fluid chromatography (SFC). The column used was Chiralpak OJ-H. The mobile phase was run under isocratic conditions; CO2 with 25% Methanol to afford product as an off-white solid. First atropisomer (peak 1): (M)-1-(3-cyclopropyl-3′,5′-difluoro-[1,1′-biphenyl]-4-yl)-N-(isoxazol-3-yl)-2-oxo-1,2-dihydroquinoline-6-sulfonamide (0.015 g, 0.029 mmol, 9.08% yield). NMR (ACETONITRILE-d3) □: 8.22 (d, J=2.1 Hz, 1H), 8.17 (d, J=1.8 Hz, 1H), 8.01 (d, J=9.6 Hz, 1H), 7.80 (dd, J=8.9, 2.1 Hz, 1H), 7.65 (dd, J=8.2, 2.2 Hz, 1H), 7.35-7.42 (m, 3H), 7.30 (d, J=8.2 Hz, 1H), 6.95-7.04 (m, 1H), 6.76 (d, J=9.6 Hz, 1H), 6.66 (d, J=8.9 Hz, 1H), 6.30 (d, J=1.8 Hz, 1H), 1.42-1.53 (m, 1H), 0.69-0.88 (m, 2H), 0.51-0.65 (m, 2H). m/z (ESI) 472.0 (M+H)+. Second atropisomer (peak 2): (P)-1-(3-cyclopropyl-3′,5′-difluoro-[1,1′-biphenyl]-4-yl)-N-(isoxazol-3-yl)-2-oxo-1,2-dihydroquinoline-6-sulfonamide (0.016 g, 0.031 mmol, 9.69% yield). NMR (ACETONITRILE-d3) □: 8.22 (d, J=2.1 Hz, 1H), 8.17 (d, J=1.8 Hz, 1H), 8.01 (d, J=9.6 Hz, 1H), 7.80 (dd, J=8.9, 2.1 Hz, 1H), 7.65 (dd, J=8.2, 2.2 Hz, 1H), 7.35-7.42 (m, 3H), 7.30 (d, J=8.2 Hz, 1H), 6.95-7.04 (m, 1H), 6.76 (d, J=9.6 Hz, 1H), 6.66 (d, J=8.9 Hz, 1H), 6.30 (d, J=1.8 Hz, 1H), 1.42-1.53 (m, 1H), 0.69-0.88 (m, 2H), 0.51-0.65 (m, 2H). m/z (ESI) 520.2 (M+H)+.
