Hydrochloric Acid → 7-fluorobenzo[c][1,2]oxaborole-1,5(3H)-diol

To a solution of 2-(4-bromo-3-fluoro-5-((tetrahydro-2H-pyran-2-yloxy)methyl)phenoxy)tetrahydro-2H-pyran (9.13 g, 23.5 mmol) was added n-butyllithium (1.6 M in hexanes, 16 mL, 26 mmol) dropwise at −78° C. After stirring 5 min, triisopropyl borate (8.7 mL, 38 mmol) was added, and the mixture was allowed to warm to room temperature and stirred for 2 h. 6 M HCl (10 mL) was added, and the mixture was stirred for 2 h. Water was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with brine and dried on anhydrous sodium sulfate. The solvent was removed in vacuo, and the residue was purified by silica gel chromatography (1:1 hexane/ethyl acetate) to give 7-fluorobenzo[c][1,2]oxaborole-1,5(3H)-diol (3.54 g, 90%). 1H-NMR (400 MHz, DMSO-d6) δ (ppm) 4.86 (s, 2H), 6.40 (dd, J=9.9, 1.5 Hz, 1H), 6.59 (s, 1H), 8.92 (br s, 1H), 10.2 (s, 1H).

1. stirringstirred for 2 h
2. stirringthe mixture was stirred for 2 h
3. extractionthe mixture was extracted with ethyl acetate
4. washThe organic layer was washed with brine
5. dry with materialdried on anhydrous sodium sulfate
6. customThe solvent was removed in vacuo
7. customthe residue was purified by silica gel chromatography (1:1 hexane/ethyl acetate)

ORD record

ord-20c5f7b8ea044e7cb7813eb6435408e7

Source dataset

uspto-grants-2014_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08716478B2