[F:1][C:2]([F:16])([F:15])[C:3]1[CH:8]=[CH:7][N:6]=[C:5]([O:9][CH:10]([CH3:14])[C:11]([OH:13])=[O:12])[CH:4]=1.[CH3:17][Si](C=[N+]=[N-])(C)C>C(Cl)Cl.CO>[F:16][C:2]([F:15])([F:1])[C:3]1[CH:8]=[CH:7][N:6]=[C:5]([O:9][CH:10]([CH3:14])[C:11]([O:13][CH3:17])=[O:12])[CH:4]=1To a solution of 2-(4-trifluoromethyl-2-pyridyloxy)propionic acid (Step A, 15 g, 55 mol) in 100 mL of methylene chloride and 100 mL of methanol at 0° C. was added trimethylsilyldiazomethane (2 M solution in hexane) until a yellow color persisted. After stirring at room temperature for 15 min, the reaction mixture was concentrated to dryness, and the residue was purified by flash chromatography on silica gel eluted with 0 to 10% ethyl acetate in hexane to give methyl 2-(4-trifluoromethyl-2-pyridyloxy)propionate, which was used immediately for methylation following the procedure described in Reference Example 13, Step B substituting ethyl iodide with methyl iodide. 1H NMR (500 MHz, CD3OD): δ 8.25 (d, 1H), 7.18 (d, 1H), 7.15 (s, 1H), 3.65 (s, 3H), 1.65 (s, 6H).
Wird geladen…