Triisopropyl borate → (5-Cyano-2-methylphenyl)boronic acid

HRID 2096652Notes

Reaction equation

HRID 2096652 reaction equation
Br[C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][C:9]=1[CH3:10])[C:5]#[N:6].[Li]CCCC.[B:16](OC(C)C)([O:21]C(C)C)[O:17]C(C)C>C1COCC1>[C:5]([C:4]1[CH:7]=[CH:8][C:9]([CH3:10])=[C:2]([B:16]([OH:21])[OH:17])[CH:3]=1)#[N:6]

Participants

5

Reactant 3

HCID 21531Triisopropyl borateHCID 140048403-Bromo-4-methylbenzonitrileHCID 178418339Butyllithium

Product 1

HCID 53216743(5-Cyano-2-methylphenyl)boronic acidYield 27.8%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A stirred solution of 3-bromo-4-methylbenzonitrile (3.5 g, 17.86 mmol) in dry THF was added n-BuLi (10.71 mL) slution dropwise at −78° C., and the mixture was stirred for 15 minutes, followed by the addition of triisopropyl borate (6.71 g, 35.71 mmol) in one portion. The reaction flask was kept in a cooling bath for 30 min., and room temperature for 3 hours. The solvent was removed, and the residue was dissolved in ether. The solution was washed with 1N HCl solution and water, dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by recrystallyzation from the mixture of CH2Cl2 and hexane to give 5-cyano-2-methylphenylboronic acid (800 mg, 20%). 1H-NMR (CDCl3 400 MHz): δ7.50-7.78 (m, 2H), 7.30 (d, 1H), 2.42 (d, 3H).

Workup

  1. waitThe reaction flask was kept in a cooling bath for 30 min.
  2. waitroom temperature for 3 hours
  3. customThe solvent was removed
  4. dissolutionthe residue was dissolved in ether
  5. washThe solution was washed with 1N HCl solution and water
  6. dry with materialdried over Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo
  9. customThe residue was purified by recrystallyzation from the mixture of CH2Cl2 and hexane

Sources & evidence

ORD record
ord-a0906f0842064cabbfeed715965f4c80
Source dataset
uspto-grants-2013_05
Patent number
US08450308B2

Reaction notes

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