1-Methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-benzimidazole

Synthesis

To a solution of 5-bromo-1-methyl-1H-benzo[d]imidazole (1.0 g, 4.74 mmol) in dioxane (10 mL) were added pinacol ester of bisboronic acid (1.5 g, 5.68 mmol), sodium 2-ethylhexanoate (1.968 g, 11.86 mmol), and Pd(dppf)Cl2-DCM (247 mg, 0.474 mmol ). The mixture was stirred at 110 °C for 4 h under nitrogen protection. After completion of the reaction, the mixture was poured into water (60 mL) and extracted with ethyl acetate (50 mL x 2). The organic layers were combined, dried with anhydrous Na2SO4, filtered and concentrated in vacuum. Purification by silica gel column chromatography (petroleum ether/ethyl acetate = 1/1) afforded 1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-benzo[d]imidazole (1.0 g, 82%) as a yellow solid. lc-MS m/z: 259.1 [M + H]+. tR = 1.67 min.

References

[1] Patent: WO2017/176960, 2017, A1. Location in patent: Paragraph 00745
[2] Patent: US2013/225548, 2013, A1. Location in patent: Paragraph 0561
[3] Patent: WO2013/148603, 2013, A1. Location in patent: Paragraph 0219-0220