Cesium carbonate → (S)-tert-Butyl 4-(6-(6-Chloro-2-methyl-3-oxo-2,3-dihydropyridazin-4-ylamino)pyridin-3-yl)-3-methylpiperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with (S)-tert-butyl 4-(6-aminopyridin-3-yl)-3-methylpiperazine-1-carboxylate 105b (2.5 g, 8.5 mmol), 4-bromo-6-chloro-2-methylpyridazin-3(2H)-one (2.2 g, 10.0 mmol), XantPhos (240 mg, 0.40 mmol), tris(dibenzylideneacetone)dipalladium(0) (360 mg, 0.40 mmol), Cs2CO3 (5.5 g, 17 mmol), and 1,4-dioxane (100 mL). After three cycles of vacuum/argon flush, the mixture was heated at 100° C. for 2.5 h. It was then cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the resulting residue was purified by silica-gel column chromatography eluting with dichloromethane/methanol (40:1 to 30:1) to afford 117a as a pale yellow solid (3.2 g, 86%). MS-ESI: [M+H]+ 435.1.

Provenance & Evidence