[NH2:1][C:2]1[CH:7]=[C:6]([Cl:8])[N:5]=[C:4]([C:9]([O:11][CH3:12])=[O:10])[C:3]=1[O:13][CH3:14].S(Cl)([Cl:18])(=O)=O.C(=O)(O)[O-].[Na+].[Na+].[Cl-]>CC#N.CCOC(C)=O>[NH2:1][C:2]1[C:7]([Cl:18])=[C:6]([Cl:8])[N:5]=[C:4]([C:9]([O:11][CH3:12])=[O:10])[C:3]=1[O:13][CH3:14]Methyl 4-amino-6-chloro-3-methoxypicolinate (260 mg, 1.2 mmol) was dissolved in dry CH3CN (7 mL), treated with sulfuryl chloride (120 μL, 1.5 mmol) and stirred for 30 min The solution was stirred with satd aq sodium bicarbonate (NaHCO3; 10 mL) for 20 min and then mixed with EtOAc (20 mL) and satd aq NaCl (10 mL). The aqueous phase was extracted with EtOAc (15 mL), and the combined organic phases were washed with satd aq NaCl (10 mL), dried (Na2SO4) and evaporated to give the title compound as a white solid (240 mg, 80%): mp 119-121° C.; 1H NMR (400 MHz, CDCl3) δ 5.04 (s, 2H), 3.97 (s, 3H), 3.93 (s, 3H); EIMS m/z 250.
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