3,5-bis(methoxycarbonyl)phenylboronic acid pinacol ester is an organic intermediate that can be used in the Suzuki coupling reaction. It can be used to prepare rigid aromatic tricarboxylic acid ligands such as 5-[4-(1-carboxynaphthyl)]-isophthalic acid. Rigid aromatic tricarboxylic acid ligands are widely used in the construction of MOF materials. These materials typically possess excellent pore structures and large specific surface areas, making them potential applications in various fields such as energy gas storage and separation, catalysis, chemical sensing, and drug delivery.
General procedure for the synthesis of 3,5-dimethoxycarbonylphenylboronic acid pinacol ester from dimethyl 5-bromoisophthalate and pinacol ester of bisboronic acid: dimethyl 5-bromo-1,3-benzenedicarboxylate (5.4 g, 19.8 mmol) and pinacol ester of boronic acid (6.0 g, 29.4 mmol) were added into a 250 mL three-necked flask and anhydrous 1,4-dioxane (50 mL) was added As a solvent, Pd(dppf)2Cl2 (0.2 g, 0.27 mmol) was added under nitrogen protection. The reaction mixture was heated to 100 °C and kept for 12 hours. Upon completion of the reaction, it was cooled to room temperature and the excess 1,4-dioxane was removed by distillation. Water (20 mL) was added and extracted with ethyl acetate (30 mL x 3), the organic phases were combined and dried with anhydrous Na2SO4. After filtration, the filtrate was evaporated to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate=94/6) to afford 3,5-dimethoxycarbonylphenylboronic acid pinacol ester (4.59 g, 72% yield) in white powder form.
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