Diisopropylethylamine → ethyl 6-chloro-4-(6,7-dihydro-5H-cyclopenta[b]pyridin-2-ylamino)pyridazine-3-carboxylate

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Reaction Conditions

Reaction Steps

A heavy walled resealable tube was charged with ethyl 4,6-dichloropyridazine-3-carboxylate (1.5 g, 6.79 mmol), 6,7-dihydro-5H-cyclopenta[b]pyridin-2-amine (1.09 g, 8.14 mmol), acetonitrile (10 mL) and Hunig's base (877 mg, 1.19 mL, 6.79 mmol). The mixture was heated at 80° C. with stirring for 3d, after cooling to room temperature, the solvents were distilled off and the crude residue obtained was purified by chromatography (80 g column, 50 μM from Thomson, 0 to 10% acetone in dichloromethane, 20 min) to give ethyl 6-chloro-4-(6,7-dihydro-5H-cyclopenta[b]pyridin-2-ylamino)pyridazine-3-carboxylate (554 mg, 26%) as a light brown solid. 1H NMR (CHLOROFORM-d) δ: 10.51 (s, 1H), 8.94 (s, 1H), 7.41 (d, J=8.3 Hz, 1H), 6.60 (d, J=8.3 Hz, 1H), 4.46 (q, J=7.2 Hz, 2H), 2.92 (t, J=7.7 Hz, 2H), 2.83 (t, J=7.4 Hz, 2H), 1.87-2.24 (m, 2H), 1.42 (t, J=7.2 Hz, 3H); LC-MS 319.0 [M+H]+.

Provenance & Evidence