Cesium carbonate → 3-(4-Aminophenyl)-5-{1-[(2S)-1,4-dioxan-2-ylmethyl]-1H-pyrazol-4-yl}pyridin-2-amine

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Reaction Steps

4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (10.0 g) was added to a suspension of cesium carbonate (75.6 g) in 1,4-dioxane (200 ml), followed by stirring. (2R)-1,4-Dioxan-2-ylmethyl methanesulfonate (12.1 g) and tetra-n-butylammonium iodide (0.95 g) were then added, and the mixture was stirred at 100° C. for six hours. After cooling the reaction solution to room temperature, 3-(4-aminophenyl)-5-bromopyridin-2-amine (10.9 g) and [1,1′-bis(diphenylphosphino)ferrocene]palladium(II) dichloride-dichloromethane adduct (2.1 g) were added, and the mixture was stirred at 100° C. for one hour. The reaction solution was returned to room temperature, ethyl acetate was added, and the insoluble matter was then removed by filtration. The resulting organic layer was sequentially washed with water and brine and then dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography [chloroform:methanol=99:1->19:1 (v/v)] to give 10.3 g of the title compound as a solid.

Provenance & Evidence