Potassium carbonate (54 mg, 2 eq) and a solution of dibutylamine (30 mg, 1.2 eq) in acetonitrile (2 ml) are added successively to a solution of 6-chloro-3-nitro-N-(3-piperidin-1-ylpropyl)pyridin-2-amine (59 mg, 1 eq) in acetonitrile (3 ml). The mixture is heated to reflux for 15 hours then cooled down to ambient temperature and concentrated under reduced pressure at 40° C. The residue is taken up in dichloromethane (200 ml) and water (90 ml). After decantation and extractions, the combined organic phases are washed with salt water, dried over Na2SO4 then concentrated under reduced pressure at 40° C. Purification of the residue obtained, by flash chromatography on silica gel (eluent: heptane/ethyl acetate 1:1 to 100% ethyl acetate), produces the expected compound (73 mg; 95% yield).
