The general procedure for the synthesis of (4-(1H-pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidin-7-yl)methyl pivalate from 4-pyrazole boronic acid pinacol ester and (4-chloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)methyl tertiarylate was performed as follows: in a reaction vessel, add (4-chloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl) methyl 2,2-dimethylpropionate (10 g), water (50 mL) and potassium carbonate (15.5 g) and stirred at room temperature. Subsequently, 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (8.7 g), 1,4-dioxane (100 mL) and tetrakis(triphenylphosphine)palladium(0) (0.08 g) were added. The reaction mixture was heated to 80°C to 85°C and stirred at this temperature for 14 hours. The reaction process was monitored by thin layer chromatography. Upon completion of the reaction, ethyl acetate (100 mL) was added to the mixture and stirring was continued for 1 hour. It was then filtered through Hyflo and washed with ethyl acetate (40 mL). The organic layer was separated and concentrated under reduced pressure to afford the target product [4-(1H-pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidin-7-yl]methyl pivalate in 82.27% yield.