3-Pyridinylboronic acid → Carbamic acid, N-[2-(3-pyridinyl)[1,2,4]triazolo[1,5-a]pyridin-7-yl]-, 1,1-dimethylethyl ester

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Reaction Steps

Nitrogen is bubbled for 10 minutes through a mixture of tert-butyl 2-bromo-[1,2,4]triazolo[1,5-a]pyridin-7-ylcarbamate (1.39 g, 4.44 mmol) and pyridin-3-ylboronic acid (818 mg, 6.66 mmol) in dioxane (23.8 ml) and sat. aqueous sodium carbonate sol. (5.94 ml), then 1,1′-bis(diphenylphosphino)ferrocene palladium (II) chloride (181 mg, 222 μmol) is added and the resulting mixture is fluxed for 18 hours under nitrogen atmosphere. The residue is diluted with dichloromethane and washed with water; the organic layer is separated, dried with magnesium sulfate and the solvent is removed under reduced pressure. The residue is loaded on silicagel and purified by chromatography on a 50 g silica column using heptane/ethyl acetate 50-100% as eluent affording tert-butyl 2-(pyridin-3-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-ylcarbamate (762 mg, 55.1%) as a light brown foam. MS: m/z=312.4 (M+H+).

Provenance & Evidence