2,4-Difluoroaniline → Pyridine-3-carboxamide, 4-chloro-N-(2,4-difluorophenyl)-

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Reaction Steps

To a mixture of 4-chloronicotinic acid (Lancaster Synthesis, 0.31 g, 2.0 mmol) and 2,4-difluoroaniline (Aldrich, 0.20 mL, 2.0 mmol) in anhydrous dichloromethane (5 mL) was added bromo-tris-pyrrolidino-phosphonium hexafluorophosphate (PyBroP®, Novabiochem, 1.4 g, 3.0 mmol) followed by diisopropylethylamine (1.1 mL, 6.4 mmol). Anhydrous DMF (2 mL) was added to the mixture and the reaction stirred at ambient temperature. After 255 hours, the reaction mixture was partitioned between chloroform and 10% LiCl (aq). The organic layer was washed three times with 10% LiCl (aq), dried over anhydrous MgSO4, then concentrated in vacuo. Purification of the residue by flash column chromatography (SiO2, eluting with 1:1 hexane/EtOAc) afforded the desired compound (0.23 g, 42%). 1H NMR (DMSO-d6) δ 10.58 (s, 1H), 8.78 (s, 1H), 8.66 (d, 1H, J=5.4 Hz), 7.82-7.88 (m, 1H), 7.71 (d, 1H, J=5.4 Hz), 7.37-7.43 (m, 1H), 7.14-7.19 (m, 1H);

Provenance & Evidence