General procedure for the synthesis of 1-methylpyrazole-3-boronic acid pinacol ester from 3-bromo-1-methylpyrrole and bis(pinacolato)diboronic acid: firstly, compound 701 (3-bromo-1-methylpyrrole, 0.2 g, 1.24 mmol) was dissolved in 5 mL of 1,4-dioxane. Subsequently, bis(pinacolato)diboron (0.378 g, 1.49 mmol), potassium acetate (0.365 g, 3.72 mmol), and [1,1-bis(diphenylphosphino)ferrocene]palladium chloride dichloromethane complex (0.11 g, 0.124 mmol) were added to this solution. The reaction mixture was heated to 95 °C under nitrogen protection and kept at this temperature for 5 hours of reaction. After completion of the reaction, the mixture was cooled to room temperature. To the reaction mixture was added 15 mL of water, stirred for 1 hour and filtered to give 0.114 g of solid product, 1-methylpyrazole-3-boronic acid pinacol ester. The yield was 44.19%.
