[F:1][C:2]1[N:10]=[C:9]([F:11])[CH:8]=[CH:7][C:3]=1[C:4](O)=[O:5].O=S(Cl)Cl.[NH3:16]>ClCCCl.CN(C=O)C>[F:1][C:2]1[N:10]=[C:9]([F:11])[CH:8]=[CH:7][C:3]=1[C:4]([NH2:16])=[O:5]A solution 2,6-difluoronicotinic acid (7.4 g, 0.046 mmol) and SOCl2 (20 mL) in 1,2-dichloroethane (60 mL) containing DMF (1 drop) is heated under reflux for 4 h, then concentrated to dryness under reduced pressure. The residue is dissolved in Et2O (100 mL), cooled to 0° C., and treated dropwise with concentrated ammonia (10.0 mL, 0.17 mmol). After 10 min the solution is washed with aqueous NaHCO3 and worked up to give 2,6-difluoronicotinamide (5.61 g, 76%). 1H NMR (CDCl3) δ 8.70 (1H, dd, J=9.6, 8.3 Hz), 7.00 (1H, ddd, J=8.3, 2.9, 1.1 Hz), 6.71, 6.55 (1H, 1H, 2 brs).
Wird geladen…
