Hydrochloric Acid → tert-Butyl 4-(6-(6-Chloro-3-oxo-2,3-dihydropyridazin-4-ylamino)pyridin-3-yl)-3-oxopiperazine-1-carboxylate

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Reaction Conditions

Reaction Steps

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and reflux condenser was charged with 2d (558 mg, 1.91 mmol), 4-bromo-6-chloropyridazin-3(2H)-one (400 mg, 1.91 mmol), cesium carbonate (1.37 g, 4.20 mmol), dioxane (25 mL) and DMF (25 mL). After bubbling nitrogen through the resulting solution for 30 min, Xantphos (94 mg, 0.162 mmol) and tris(dibenzylidene acetone)dipalladium(0) (87 mg, 0.096 mmol) were added and the reaction mixture was heated at 125° C. for 18 h. Water (75 mL) was added after the reaction mixture was cooled to room temperature and the pH adjusted to 6.5 with 2N hydrochloric acid. The resulting precipitate was collected by vacuum filtration, absorbed on silica gel and purified by column chromatography to afford a 37% yield (300 mg) of 2f as a tan foam: 1H NMR (300 MHz, DMSO-d6) δ13.15 (s, 1H), 9.71 (s, 1H), 8.37 (4, 1H, J=2.7 Hz), 8.29 (s, 1H), 7.76 (dd, 1H, J=9.0, 2.7 Hz), 7.55 (d, 1H, J=9.0 Hz), 4.09 (s, 2H), 3.72 (m, 4H), 1.45 (s, 9H); MS (ESI+) m/z 420.1 (M+H).

Provenance & Evidence