3-Chloro-6-methylpyridazine → tert-butyl 2-(6-methylpyridazin-3-yl)-2,4,6,7-tetrahydro-5H-pyrazolo[4,3-c]pyridine-5-carboxylate

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Reaction Conditions

Reaction Steps

A mixture of tert-butyl 1,4,6,7-tetrahydro-5H-pyrazolo[4,3-c]pyridine-5-carboxylate (3.72 g, 16.67 mmol), 3-chloro-6-methylpyridazine (3.2 g, 24.92 mmol), Pd2(dba)3 (760 mg, 0.83 mmol), tBuXPhos (705 mg, 1.66 mmol) and tBuONa (1.99 g, 20.77 mmol) in toluene (90 mL) is degassed by argon and heated at 120° C. in a sealed tube overnight. EtOAc (200 mL) and water (250 mL) are added and the layers are separated. The organic layer is washed with water (200 mL) and then brine (200 mL), dried and evaporated. Purification of the residue by flash column with hexane/EtOAc (2:1) gives a white solid that is a mixture of two regioisomers. Recrystallization of the solid from hexane/EtOAc (1:1) gives the title compound as white needles. MS (M+1): 316.2.

Provenance & Evidence