197223-39-5

3,5-Di-tert-butylphenylboronic acid is a colorless solid that emits light when heated. It has been used as a fluorescent probe for boronate esters, and can be synthesized by reacting 3,5-di-tert-butylphenol with boric acid. This material has also been used to prepare nanoparticles of various sizes for use in the study of emission. The emission spectrum of 3,5-Di-tert-butylphenylboronic acid is reversible and its temperature range is from -20 to 100 degrees Celsius.

The general procedure for the synthesis of (3,5-di-tert-butylphenyl)boronic acid from trimethyl borate and 3,5-di-tert-butylbromobenzene was as follows: 1-bromo-3,5-di-tert-butylbenzene (1-bromo-3,5-di-tert-butylbenzene) and 40 mL of tetrahydrofuran (THF) were added to a 100 mL glass reactor in a dry ice-heptane bath and Cooled to -70 °C. 16.4 mL (40.9 mmol) of n-butyllithium-hexane solution (2.5 mol/L) was slowly added dropwise and stirred for 30 min at this temperature. Subsequently, 4.25 g (40.9 mmol) of trimethyl borate was added at -78 °C and stirring was continued for 2 hours. The reaction mixture was then warmed to room temperature and stirred for 12 hours. Upon completion of the reaction, 1 M aqueous hydrochloric acid was slowly added to the reaction solution and the pH was adjusted to 3. The reaction solution was transferred to a separatory funnel and extracted three times with tert-butyl methyl ether (MTBE). The organic phases were combined and dried over anhydrous sodium sulfate. The desiccant was removed by filtration and the organic phase was concentrated under reduced pressure to give the crude product. Finally, the crude product was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate=20/1) to afford 8.00 g (91% yield) of 3,5-di-tert-butylphenylboronic acid (3,5-di-tert-butylphenylboronic acid) as a pale yellow solid.

[1] Patent: JP5710035, 2015, B2. Location in patent: Paragraph 0169
[2] Chemical Communications, 2015, vol. 51, # 10, p. 1926 - 1929
[3] Chemistry - A European Journal, 2012, vol. 18, # 14, p. 4174 - 4178
[4] Patent: EP2532687, 2012, A2