Diisopropylethylamine → ethyl 6-chloro-4-(1-methyl-1H-benzo[d]imidazol-4-ylamino)pyridazine-3-carboxylate

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Reaction Steps

A heavy walled resealable tube, was charged with ethyl 4,6-dichloropyridazine-3-carboxylate (500 mg, 2.26 mmol) and 1-methyl-1H-benzo[d]imidazol-4-amine dihydrochloride (498 mg, 2.26 mmol) in acetonitrile (3.5 mL) with stirring. DIPEA (877 mg, 1.19 mL, 6.79 mmol) was added and the tube was heated with stirring in an oil bath at 80° C. for 24 h. Solvents evaporated and crude purified by flash chromatography (silica 20-45 μM, 80 g, Thomson, 0 to 20% acetone in dichloromethane, 20 min) to give ethyl 6-chloro-4-(1-methyl-1H-benzo[d]imidazol-4-ylamino)pyridazine-3-carboxylate (461 mg, 1.39 mmol, 61%) as a light yellow solid. 1H NMR (CHLOROFORM-d) δ: 10.42 (s, 1H), 7.92 (s, 1H), 7.30-7.45 (m, 2H), 7.23-7.28 (m, 1H), 7.20 (s, 1H), 4.59 (q, J=7.1 Hz, 2H), 3.91 (s, 3H), 1.51 (t, J=7.2 Hz, 3H); LC-MS 332.0 [M+H]+.

Provenance & Evidence