Isopropyl 4-amino-6-chloro-5-fluoropicolinate → Methyl 4-amino-6-chloro-5-fluoropicolinate

Beteiligte Stoffe

Reaktionsschritte

Isopropyl 4-amino-6-chloro-5-fluoropicolinate (1.35 g, 5.80 mmol) was dissolved in anhydrous CH3OH (50 mL), treated with titanium(IV) isopropoxide (300 mg, 2.2 mmol), and heated at reflux for 4 h. After cooling, the volatiles were removed under vacuum, and the residue was taken up in EtOAc (30 mL). This solution was stirred with H2O (1 mL) for 20 min and then filtered through diatomaceous earth. The filtrate was washed with satd aq NaCl (10 mL), dried (Na2SO4), and evaporated to give the title compound (1.2 g, 97%): mp 180-183° C.; 1H NMR (400 MHz, DMSO-d6) δ 7.45 (d, J=6.0 Hz, 1H), 6.93 (s, 2H), 3.83 (s, 3H); 19F NMR (376 MHz, DMSO-d6) δ −131.36, −131.42, −135.47, −135.53; EIMS m/z 204.

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