Hydrochloric Acid → 3,5-Dimethylphenylboronic acid

HRID 325206Notes

Reaction equation

HRID 325206 reaction equation
[Mg].Br[C:3]1[CH:4]=[C:5]([CH3:10])[CH:6]=[C:7]([CH3:9])[CH:8]=1.[B:11](OC(C)C)([O:16]C(C)C)[O:12]C(C)C.Cl>C1COCC1>[CH3:9][C:7]1[CH:8]=[C:3]([B:11]([OH:16])[OH:12])[CH:4]=[C:5]([CH3:10])[CH:6]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 21531Triisopropyl borateHCID 136357Benzene, 1-bromo-3,5-dimethyl-HCID 5462224Magnesium2×

Product 1

HCID 27343493,5-Dimethylphenylboronic acid

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

Magnesium turnings (1.44 g, 59.43 mmol) were covered with dry THF (18.8 mL) in a dried, nitrogen 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 mnL) after initiation of the Grignard reaction. The addition was carried out over several minutes and the reacton mixture was heated at reflux for 1-2 hours until most of the magnesium had reacted. The reaction mixture was then cooled and transferred to an addition funnel fitted to an nitrogen 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 2 M HCl and immediately turned yellow. The solution was extracted with Et2O and the Et2O fractions were combined, dried over MgSO4 and the solvent was removed in vacuo to provide the desired product (2.41 g): m.p.249-251° C.; 1H NMR (CDCl3) d 2.44 (6H, s), 7.23 (1H, s), 7.84 (2H, s); 13C NMR (CD3OD) d 21.36, 133.28, 134.39, 137.48.

Workup

  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 reacton mixture was heated
  7. customhad reacted
  8. temperatureThe reaction mixture was then cooled
  9. customtransferred to an addition funnel
  10. customfitted to an nitrogen filled flask
  11. additionThe dropwise addition
  12. waitwas carried out over several minutes
  13. extractionThe solution was extracted with Et2O
  14. dry with materialdried over MgSO4
  15. customthe solvent was removed in vacuo

Sources & evidence

ORD record
ord-3278b1651289414a968067a3f4e16629
Source dataset
uspto-grants-2001_04
Patent number
US06221865B1

Reaction notes

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