Trifluoroacetic acid → 6-((3R,4R)-3-aminotetrahydro-2H-pyran-4-ylamino)-4-(5,6-dimethylpyridin-2-ylamino)pyridazine-3-carboxamide

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Reaction Steps

6-Chloro-4-(5,6-dimethylpyridin-2-ylamino)pyridazine-3-carboxamide (120 mg, 432 mmol) and tert-butyl (3R,4R)-4-aminotetrahydro-2H-pyran-3-ylcarbamate (187 mg, 864 μmol) in N-methyl-2-pyrrolidinone (6 mL) was heated at 150° C. for 1.5 d. After solvent evaporation, the residue was dissolved in dichloromethane (2 mL) and TFA (370 mg, 250 μL, 3.24 mmol). The mixture was stirred at room temperature for 3 h, then the solvent was evaporated and the residue was purified by chromatography (spherical silica, 20-45 μm, 11 g, Versaflash from Supelco, 97:2.75:0.15 to 87:12.35:0.65 dichloromethane:MeOH:NH4OH, 20 min) to afford a brown solid. The brown solid was dissolved in dichloromethane and 10 mL of cyclohexane was added. After standing, a solid precipitate formed. The supernatant was decanted and the solid residue was dried under vacuum to give 6-((3R,4R)-3-aminotetrahydro-2H-pyran-4-ylamino)-4-(5,6-dimethylpyridin-2-ylamino)pyridazine-3-carboxamide (18 mg, 12% over two steps) as a brown solid. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 11.23 (br. s., 1H) 8.29 (s, 1H) 8.03 (br. s., 1H) 7.36 (d, J=8.08 Hz, 1H) 6.67 (d, J=8.08 Hz, 1H) 5.68-5.79 (m, 1H) 5.39 (br. s., 1H) 4.02 (d, J=7.33 Hz, 1H) 3.88 (d, J=11.12 Hz, 1H) 3.69 (d, J=11.62 Hz, 1H) 3.55 (t, J=11.49 Hz, 1H) 3.10 (br. s., 1H) 2.49 (s, 3H) 2.25 (s, 3H) 2.02 (d, J=12.38 Hz, 1H) 1.42-1.84 (m, 3H); LCMS (EI/CI) m/z: 358 [M+H].

Provenance & Evidence