Background and overview[1]
3-Nitrophenylboronic acid pinacol ester can be used as a pharmaceutical synthesis intermediate. If you inhale 3-nitrobenzene borate pinacol ester, please move the patient to fresh air; if there is skin contact, take off contaminated clothing, rinse the skin thoroughly with soap and water, and seek medical treatment if you feel unwell; if In case of eye contact, separate eyelids, rinse with running water or saline, and seek medical attention immediately; if ingested, rinse mouth immediately, do not induce vomiting, and seek medical attention immediately. Borates are typically prepared by condensation reactions between organomagnesium or organolithium compounds and trialkylborates. This reaction requires specific conditions, especially low temperature, which are not trivial and often expensive, making it difficult to implement on an industrial scale.
Structure
Preparation [1]
3-Nitrophenylboronic acid pinacol ester was prepared as follows: in a dry tubular reactor under argon, 3-nitrobenzene diazotetrafluoroborate (1 mmol) and ferrocene ( 10 μmol, 1.8 mg) was dissolved in 2 mL anhydrous CH3CN. Then diisopropylaminoborane (2 mmol, 22 6 mg imported from Germany) was added to the solution, and the mixture was stirred at room temperature for 2 hours and 30 minutes. The reaction mixture (2 mL) was quenched by slowly adding anhydrous MeOH at 0 °C and stirred at room temperature for an additional 1 h. After removing all volatiles, 1.3 equiv of pinacol was added in Et2O (2 mL) and the mixture was stirred at room temperature for 4 h. Wash the crude mixture with 50 g/L CuCl2 solution (2 × 5 mL). The organic layer was separated, dried over Na2SO4, filtered and concentrated to dryness. The resulting oil was dissolved with CHCl and filtered through a silica gel pad, eluted with CHCl to obtain the corresponding borate ester 3-nitrobenzene borate pinacol ester.
Main reference materials
[1] EP2684887 New process for preparing arylboranes by arylation of organoboron compounds
