Tributylvinyltin → 6-chloro-1-(tetrahydro-pyran-2-yl)-3-vinyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

To a solution of 6-chloro-3-iodo-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid ethyl ester (5.00 g, 11.48 mmol) in anhydrous tetrahydrofuran (115 ml) was added tributyl(vinyl)stannane (3.52 ml, 12.05 mmol). The mixture was degassed for 15 minutes using argon, dichlorobis(triphenylphosphine)palladium (0.40 g, 0.57 mmol) was then added. The resulting solution was heated at 80° C. overnight under argon, then evaporated under reduced pressure. Ethyl acetate and a 5% aqueous potassium fluoride solution were added to the residue, the resulting precipitate was filtered. The filtrate was recovered and the two layers separated, the organic phase was washed with brine, dried (Na2SO4), filtered and concentrated under vacuum. The crude product was purified on a silica gel column chromatography using a gradient of ethyl acetate (0-10%) in cyclohexane to afford the title compound as a yellow solid (3.24 g, 84%).

Provenance & Evidence