Triphenylphosphine → 6-[4-[4-[2-(1-methyl-1H-pyrazol-5-yl)ethoxy]phenyl]piperazin-1-yl]-3-(trifluoromethyl)[1,2,4]triazolo[4,3-b]pyridazine

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Reaction Steps

DIAD (20.73 mL, 105.27 mmol) was added dropwise to 4-[4-[3-(trifluoromethyl)[1,2,4]triazolo[4,3-b]pyridazin-6-yl]piperazin-1-yl]phenol (32.0 g, 87.72 mmol), 2-(1-methyl-1H-pyrazol-5-yl)ethanol (prepared as described in Example 513, preparation of starting materials) (16.6 g, 131.58 mmol) and triphenylphosphine (34.5 g, 131.58 mmol) in THF (320 mL) at 0° C. under nitrogen. The resulting solution was stirred at ambient temperature for 3 days. The reaction mixture was evaporated to dryness and re-dissolved in DCM (700 mL), and the solution was washed sequentially with 2M NaOH (200 mL×2) and saturated brine (200 mL). The organic layer was dried over MgSO4, filtered and evaporated to afford crude product. The crude product was purified by flash silica chromatography, eluting with a gradient of 80 to 100% EtOAc in isohexane followed by EtOAc, then a gradient of 0 to 3% MeOH in DCM. Pure fractions were evaporated to dryness to afford 6-[4-[4-[2-(1-methyl-1H-pyrazol-5-yl)ethoxy]phenyl]piperazin-1-yl]-3-(trifluoromethyl)[1,2,4]triazolo[4,3-b]pyridazine (28.7 g, 69.3%) as a solid.

Provenance & Evidence