2-Amino-6-methylpyridine → 6-Chloro-4-(6-methyl-pyridin-2-ylamino)-pyridazine-3-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

4,6-Dichloro-pyridazine-3-carboxylic acid ethyl ester (300 mg, 1.36 mmol) and 6-methylpyridin-2-amine (176 mg, 1.63 mmol) were dissolved in acetonitrile (4.1 mL), then heated at 140° C. for 16 h. A second portion of 6-methylpyridin-2-amine (73 mg, 0.67 mmol) was added. After a further 2 d at 140° C. the reaction mixture was cooled and concentrated in vacuo. Purification by chromatography (silica, 5 to 40% ethyl acetate in hexanes) gave 6-chloro-4-(6-methyl-pyridin-2-ylamino)-pyridazine-3-carboxylic acid ethyl ester (146 mg, 36%) as a light yellow oil. 1H NMR (300 MHz, CHLOROFORM-d) δ ppm 10.68 (br. s., 1H) 9.21 (s, 1H) 7.59 (t, J=7.7 Hz, 1H) 6.90 (d, J=7.6 Hz, 1H) 6.76 (d, J=7.9 Hz, 1H) 4.57 (q, J=7.2 Hz, 2H) 2.57 (s, 3H) 1.51 (t, J=7.0 Hz, 3H); LCMS (EI/CI) m/z: 315 [M+Na].

Provenance & Evidence