76-09-5

1238702-56-1

1238702-58-3

The general procedure for the synthesis of 1-phenyl-pyrazole-5-boronic acid pinacol ester from pinacol and the compound (CAS: 1238702-56-1) is as follows: with reference to Example 132, a mixture of 1-phenyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole and 1-phenyl-1H-pyrazole-5-boronic acid was room temperature was dissolved in toluene (86 mL). Subsequently, pinacol (5.39 g, 45.6 mmol) and boric acid (8.57 g, 45.6 mmol) were added. The reaction mixture was heated to 40 °C and the reaction was stirred at this temperature for 2 days. After completion of the reaction, the mixture was concentrated under reduced pressure and the residue was ground with hexane to afford pinacol ester of 1-phenyl-pyrazole-5-boronic acid (7.93 g, 64% yield) as a light yellow solid. The product was characterized by 1H NMR (DMSO-d6, 300 MHz): δ 1.23 (12H, s), 6.84 (1H, s), 7.34-7.59 (5H, m), 7.75 (1H, d, J = 1.9 Hz).