3,4-bis(Benzyloxy)-6-{2-[5-(trifluoromethyl)pyridin-3-yl]ethynyl}pyridazine → 3,4-Bis(benzyloxy)-6-(2-(5-(trifluoromethyl)pyridin-3-yl)ethyl)pyridazine

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Reaction Steps

To a solution of 3,4-bis(benzyloxy)-6-{2-[5-(trifluoromethyl)pyridin-3-yl]ethynyl}pyridazine (Intermediate 16, 1.5 g) in methanol (10 ml) was added 10% palladium on carbon (0.04 g) slowly under nitrogen and the reaction mixture was stirred for 30 minutes at room temperature under a hydrogen atmosphere. The resulting mixture was filtered through a “Celite” (trade mark) diatomaceous earth bed under nitrogen atmosphere and washed with methanol before the filtrate was concentrated under vacuum to afford crude 3,4-bis(benzyloxy)-6-(2-(5-(trifluoromethyl)pyridin-3-yl)ethyl)pyridazine (0.4 g, 0.86 mmol). This was taken up in methanol (10 ml) at room temperature and 10% palladium on carbon (0.04 g) was added slowly under nitrogen atmosphere. The mixture was then stirred under hydrogen (200 psi) at room temperature overnight before being filtered through a bed of “Celite” diatomaceous earth under nitrogen and washed with methanol. The organic layer was concentrated in vacuo to afford the crude product (0.2 g) which was purified by the preparative HPLC to afford homogeneous 4-hydroxy-6-{2-[5-(trifluoromethyl)pyridin-3-yl]ethyl})pyridazin-3(2H)-one (0.03 g, 81.6% yield).

Provenance & Evidence