Acetonitrile → Methyl 4-amino-3-chloro-6-(2,5-difluoro-4-(trimethylsilyl)phenyl)picolinate

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Reaction Conditions

Reaction Steps

In a microwave vessel, a suspension of (2,5-difluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)trimethylsilane (see, e.g., WO 2013003740 A1) (0.6 g, 1.922 mmol), methyl 4-amino-3,6-dichloropicolinate (Head A) (0.354 g, 1.601 mmol), bis(triphenyl phosphine)palladium(II) chloride (0.112 g, 0.160 mmol) and sodium carbonate (0.204 g, 1.922 mmol) in a 3:1 mixture of acetonitrile (4.00 mL) and water (1.334 mL) was stirred under microwave irradiation (120° C., 20 min). The reaction mixture was poured into an half saturated brine solution and was extracted with EtOAc (3×). The combined organic layers were dried over Na2SO4, filtered and concentrated. The residue was purified by preparative reverse phase HPLC (water/acetonitrile gradient) to afford the title compound as a white solid (0.234 g, 0.631 mmol, 39.4%): 1H NMR (400 MHz, CDCl3) δ 7.66 (dd, J=8.7, 5.8 Hz, 1H), 7.25 (d, J=1.2 Hz, 1H), 7.09 (dd, J=10.8, 4.1 Hz, 1H), 4.84 (s, 2H), 4.00 (s, 3H), 0.32 (d, J=0.7 Hz, 9H); 19F NMR (376 MHz, CDCl3) δ −106.56, −106.61, −124.00-124.06; ESIMS m/z 371 ([M+H]+).

Provenance & Evidence