Triisopropyl borate → HCID 66717113, compound

Temperature

-70 °C

A stirred mixture of 3-bromo-2-methoxy-5-methylthiophene (Step B, 296 mg, 1.43 mmol) and triisopropyl borate (396 μL, 2.15 mmol) in toluene/THF (2.3/0.6 mL) was cooled to −70° C. under an atmosphere of N2. n-Butyl lithium (2.0M in pentane, 1.07 mL, 2.15 mmol) was added dropwise via a syringe pump over 1 h. The reaction stirred at −70° C. for 40 min more and was quenched with 2N HCl (2 mL) at −20° C. The reaction was partitioned between EtOAc (15 mL) and H2O (15 mL). The aqueous layer was extracted with EtOAc (10 mL); the combined organic layers were washed with brine (15 mL), dried (Na2SO4), filtered, and concentrated in vacuo to afford (2-methoxy-5-methyl-3-thienyl)boronic acid as a yellow oil. This material was used without further purification.

1. customwas quenched with 2N HCl (2 mL) at −20° C
2. customThe reaction was partitioned between EtOAc (15 mL) and H2O (15 mL)
3. extractionThe aqueous layer was extracted with EtOAc (10 mL)
4. washthe combined organic layers were washed with brine (15 mL)
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated in vacuo

ORD record

ord-cef2f46090854192946a642229a0d1c4

Source dataset

uspto-grants-2014_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08735435B2