Hydrochloric Acid → 3,5-Dimethylphenylboronic acid

HRID 1739141Notes

Reaction equation

HRID 1739141 reaction equation
N#N.Br[C:4]1[CH:5]=[C:6]([CH3:11])[CH:7]=[C:8]([CH3:10])[CH:9]=1.[B:12](OC(C)C)([O:17]C(C)C)[O:13]C(C)C.Cl>C1COCC1>[CH3:10][C:8]1[CH:9]=[C:4]([B:12]([OH:17])[OH:13])[CH:5]=[C:6]([CH3:11])[CH:7]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 947NitrogenHCID 21531Triisopropyl borateHCID 136357Benzene, 1-bromo-3,5-dimethyl-

Product 1

HCID 27343493,5-Dimethylphenylboronic acid

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

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 2 M 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 (6H, s), 7.23 (1H, s), 7.84 (2H, s); 13C NMR (CD3OD) 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 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%)

Sources & evidence

ORD record
ord-d496859f02a54a9cb4160aad46c579e9
Source dataset
uspto-grants-1999_10
Patent number
US05965539

Reaction notes

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