4-(1H-Pyrazol-4-yl)-7-((2-(trimethylsilyl)ethoxy)methyl)-7H-pyrrolo[2,3-d]pyrimidine

4-(1H-Pyrazol-4-yl)-7-[[2-(trimethylsilyl)ethoxy]methyl]-7H-pyrrolo[2,3-d]pyrimidine is an important intermediate in the preparation of the janus kinase inhibitor INCB018424.

To a flask equipped was added 4-chloro-7-(2-trimethylsilanylethoxymethyl)-7H-pyrrolo[2,3-d]pyrimidine and dioxane and then added 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole followed by a solution of potassium carbonate in water. The solution was degassed by passing a stream of nitrogen through the solution for 15 minutes before being treated with tetrakis(triphenylphosphine)palladium(0), and the resulting reaction mixture was heated at reflux (about 90° C) for 2 hours. When the reaction was complete, the mixture was cooled to room temperature and diluted with ethyl acetate and water. The two layers were separated, and the aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with water and brine, dried over sodium sulfate (Na2SO4), and concentrated under reduced pressure. The residue was suspended in toluene, and the solvent was removed under reduced pressure. The residue was finally triturated with methyl tert-butyl ether, and the solid was collected by filtration and washed with MTBE to afford 4-(1H-pyrazol-4-yl)-7-(2-trimethylsilanyl-ethoxymethyl)-7H-pyrrolo[2,3-d]pyrimidine (yield 64%) as white crystalline solids.