Hydrochloric Acid → Tavaborole

Temperature

-78 °C

Dissolve 1-bromo-2-(1-ethoxy-ethoxymethyl)-4-fluoro-benzene(5.4 g, 19.5 mmol) in dry THF (100 mL) and cool to −78° C. under nitrogen. Add butyl lithium (2.5M in Hexanes, 10.2 mL, 25.4 mmol) dropwise at −78° C. Upon complete addition, stir the reaction at −78° C. for 10 minutes and then add trimethyl borate (4.4 mL, 39 mmol) and warm the reaction to room temperature. Pour the reaction into 1N HCl (100 mL) and stir for 1 hour. Extract the biphasic mixture with ether three times. Dry the combined organic layers with sodium sulfate, filter and concentrate in vacuo. Triturate the oily residue with cold hexanes to yield 2.1 g (70%) of the title compound as a white solid. 1H NMR (d6-DMSO) 9.18 (s, 1H), 7.70 (dd, J=8.2, 5.8 Hz, 1H), 7.20 (dd, J=9.5, 2.7 Hz, 1H), 7.11 (m, 1H), 4.92 (s, 1H).

1. customdropwise at −78° C
2. additionUpon complete addition
3. customthe reaction at −78° C. for 10 minutes
4. customthe reaction to room temperature
5. additionPour
6. stirringstir for 1 hour
7. extractionExtract the biphasic mixture with ether three times
8. dry with materialDry the combined organic layers with sodium sulfate
9. filtrationfilter
10. concentrationconcentrate in vacuo
11. customTriturate the oily residue with cold hexanes

ORD record

ord-21cad861b4734380b9b2bed4a5e5e3d1

Source dataset

uspto-grants-2007_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07271264B2