Reaction Steps
Methyl 2″-({(4S,5R)-5-[3,5-bis(trifluoromethyl)phenyl]-4-methyl-2-oxo-1,3-oxazolidin-3-yl}methyl)-4′-chloro-2-methyl-4″-(trifluoromethyl)-1,1′:3′,1″-terphenyl-4-carboxylate (25 mg, 0.034 mmol), aqueous potassium hydroxide (300 μL, 3M, 0.90 mmol) and ethanol (2 mL) were stirred at 20° C. overnight. Volatiles were removed under reduced pressure. The resulting residue was treated with brine followed by extraction with ethyl acetate. The combined extracts were dried over Na2SO4 followed by filtration and concentration in vacuo to afford an oil. This oil was purified by preparative TLC on SiO2 (eluted with 50% EtOAc in hexanes) to afford a clear glass. The glass was further purified by reverse phase preparative HPLC (Kromasil 100-5C18, 100×21.1 mm) eluting by a MeCN (0.1% TFA, v/v)/H2O (0.1% TFA, v/v) gradient mixture affording 2″-({(4S,5R)-5-[3,5-bis(trifluoromethyl)phenyl]-4-methyl-2-oxo-1,3-oxazolidin-3-yl}methyl)-4′-chloro-2-methyl-4″-(trifluoromethyl)-1,1′:3′,1″-terphenyl-4-carboxylic acid. LCMS calc.=715.12; found=716.12 (M+1)+. 1H NMR signals are doubled because of atropisomerism 1H NMR (CDCl3, 500 MHz) δ 7.99 (d, J=8.0 Hz, 1H), 7.92 (d, J=8.5 Hz, 1H), 7.85 (d, J=5 Hz, 1H), 7.72-7.68 (m, 1.5H), 7.67-7.60 (m, 2.5H), 7.47-7.36 (m, 2H), 7.32 (d, J=8.0 Hz, 0.5H), 7.28 (d, J=8.0 Hz, 0.5H), 7.15 (s, 1H), 7.08 (dd, J=8.5, 7.0 Hz, 1H), 5.58 (d, J=8.0 Hz, 0.5H), 5.29 (d, J=6.5 Hz, 0.5H), 4.97 (d, J=15.5 Hz, 0.5H), 4.94 (d, J=14 Hz, 0.5H), 4.16 (d, J=16 Hz, 0.5H), 3.96 (d, J=15.5 Hz, 0.5H), 3.87 (s, 3H), 3.83-3.74 (m, 1H), 2.38, 2.33 (s, 3H), 0.55 (d, J=6.5 Hz, 1.5H), 0.42 (d, J=7 Hz, 1.5H).
