Trimethyl borate → (2,4,6-trimethylpyridin-3-yl)boronic Acid

Temperature

-78 °C

3-bromo-2,4,6-trimethylpyridine (CAS No. 23079-73-4; Prasenjit Mal etc., Journal of Organic Chemistry, 68(9), pp. 3446-3453) (1 g) was added to THF (20 mL). The solution was cooled to −78° C., and n-butyllithium (1.63 M solution in n-hexane, 3.37 mL) was added, followed by stirring at the same temperature for 30 minutes. Trimethyl borate (0.78 mL) was added to the reaction mixture, and the mixture was stirred at −78° C. for 10 minutes and at room temperature for 50 minutes. A saturated aqueous ammonium chloride solution was added to the reaction mixture, and the reaction mixture was concentrated under reduced pressure. The resulting residue was partitioned between oil and water by adding water and DCM. The aqueous layer was concentrated under reduced pressure. DCM and ethanol were added to the resulting residue. The insoluble matter was filtered, and the filtrate was concentrated under reduced pressure to give the title compound (242 mg). 1H-NMR (400 MHz, DMSO-d6) δ (ppm): 2.50 (s, 3H), 2.63 (s, 3H), 2.67 (s, 3H), 7.52 (s, 1H).

1. stirringthe mixture was stirred at −78° C. for 10 minutes and at room temperature for 50 minutes
2. concentrationthe reaction mixture was concentrated under reduced pressure
3. customThe resulting residue was partitioned between oil and water
4. additionby adding water and DCM
5. concentrationThe aqueous layer was concentrated under reduced pressure
6. additionDCM and ethanol were added to the resulting residue
7. filtrationThe insoluble matter was filtered
8. concentrationthe filtrate was concentrated under reduced pressure

ORD record

ord-276439c7ae794a47957a65ba3a346632

Source dataset

uspto-grants-2013_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08563565B2