Cesium carbonate → Tert-butyl 2-(pyridin-3-yl)-[1,2,4]triazolo[1,5-a]pyridin-6-ylcarbamate

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Reaction Steps

A mixture of 6-bromo-2-(pyridin-3-yl)-[1,2,4]triazolo[1,5-a]pyridine (1.65 g, 6.00 mmol), tert-butyl carbamate (843 mg, 7.2 mmol) and cesium carbonate (2.74 g, 8.4 mmol) in 1,4-dioxane (37.8 ml) was purged with argon. Then tris(dibenzylideneacetone)dipalladium(0) (330 mg, 360 μmol) and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (416 mg, 720 μmol) were added and the purging was repeated. The mixture was heated to reflux and stirred for 18 hours under argon atmosphere. After evaporation to dryness under reduced pressure, the crude material was purified by flash chromatography (50 g silicagel column using heptane/ethyl acetate 20-100% as eluent). Final evaporation of the solvents afforded (2-pyridin-3-yl-[1,2,4]triazolo[1,5-a]pyridin-6-yl)-carbamic acid tert-butyl ester (1.35 g, 72.5%) as yellow solid. Mp.: 296° C. MS: m/z=312.3 (M+H+).

Provenance & Evidence