Cesium carbonate → 2-Methyl-5-(pyridin-3-ylamino)-thiazole-4-carboxylic acid ethyl ester

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Reaction Steps

A Schlenck flask was charged with 5-amino-2-methyl-thiazole-4-carboxylic acid ethyl ester (0.33 g, 1.80 mmol), 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (Xantphos) (0.15 g, 0.26 mmol) and palladium dibenzylideneacetone (Pd2dba3)-chloroform complex (0.08 g, 0.08 mmol). Degassed dioxane (6.00 ml) was added, followed by 3-bromopyridine (0.23 g, 1.50 mmol). The flask was subjected to 5 cycles of evacuation and backfiring with argon. The reaction mixture was then transferred under argon to a microwave vial containing cesium carbonate (0.84 g, 2.60 mmol). The vial was then irradiated in a microwave oven at 150° C. for 10 min. The mixture was diluted with THF and the solids filtered, washing with THF. The filtrate was evaporated and the residue purified by flash chromatography (ethyl acetate/methanol) to yield 2-methyl-5-(pyridin-3-ylamino)-thiazole-4-carboxylic acid ethyl ester (0.25 g, 65%) as a light yellow solid, MS (ISP): m/e=264.1 (M+H+).

Provenance & Evidence