Hydrochloric Acid → 3,5-Dimethylphenylboronic acid

Mg turnings (1.44 g, 59.43 mmol) were covered with dry THF (18.8 ml) in a dried, N2 filled flask fitted with an addition funnel and reflux condenser. To this was added 5-bromo-m-xylene (10 g, 54.03 mmol) in THF (15 ml) after initiation of the Grignard reaction. The addition was carried out over several minutes and the reaction mixture was heated at reflux for 1-2 h until most of the Mg had reacted. The reaction mixture was then cooled and transferred to an addition funnel fitted to a N2 filled flask containing triisopropyl borate (24.9 ml) at -70° C. The dropwise addition was carried out over several minutes and the mixture warmed to room temperature and stirred overnight. The grey solution was poured onto 2M HCl and immediately turned yellow. The solution was extracted into Et2O and the Et2O fractions were combined, dried over MgSO4 and the solvent was removed in vacuo to yield 2.41 g (29.7%). mp 249-251° C.; 1H NMR (CDCl3) 2.44 (6 H, s), 7.23 (1 H, s), 7.84 (2 H, s); 13C NMR (CD3OD) 21.36, 133.28, 134.39, 137.48.

1. customfitted with an addition funnel
2. temperaturereflux condenser
3. customafter initiation of the Grignard reaction
4. additionThe addition
5. waitwas carried out over several minutes
6. temperaturethe reaction mixture was heated
7. customhad reacted
8. temperatureThe reaction mixture was then cooled
9. customtransferred to an addition funnel
10. customfitted to a N2 filled flask
11. additionThe dropwise addition
12. waitwas carried out over several minutes
13. extractionThe solution was extracted into Et2O
14. dry with materialdried over MgSO4
15. customthe solvent was removed in vacuo
16. customto yield 2.41 g (29.7%)

ORD record

ord-c3df1a0fa4e444c6a7e340f3be7ebe3e

Source dataset

uspto-grants-1998_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05834434