Hydrochloric Acid → 2-Chloro-4-ethoxyphenylboronic Acid (contains varying amounts of Anhydride)

HRID 1764898Notes

Reaction equation

HRID 1764898 reaction equation
C([Li])CCC.Br[C:7]1[CH:12]=[CH:11][C:10]([O:13][CH2:14][CH3:15])=[CH:9][C:8]=1[Cl:16].C[O:18][B:19](OC)[O:20]C.Cl>C1COCC1>[Cl:16][C:8]1[CH:9]=[C:10]([O:13][CH2:14][CH3:15])[CH:11]=[CH:12][C:7]=1[B:19]([OH:20])[OH:18]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 227356231-Bromo-2-chloro-4-ethoxybenzeneHCID 178418339Butyllithium

Product 1

HCID 35397162-Chloro-4-ethoxyphenylboronic Acid (contains varying amounts of Anhydride)

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

n-Butyllithium (1.6 M solution in hexanes, 23.5 mmol, 14.7 mL) was added to 1-bromo-2-chloro-4-ethoxybenzene (19.5 mmol, 4.59 g) in THF (120 mL) at −78° C. under an atmosphere of nitrogen. After stirring for thirty minutes the trimethylborate (76.6 mmol, 8.7 mL) was added over twenty minutes. The reaction was allowed to warm to room temperature overnight while stirring. The solution was then acidified with HCl (3 M, 200 mL), and extracted into EtOAc. The EtOAc was then extracted with NaOH (1 N, 4×100 mL), which was subsequently acidified with concentrated HCl forming a white precipitate. The white precipitate (2.25 g, 58%) was filtered and dried to afford (2-Chloro-4-ethoxyphenyl)boronic acid. 1H NMR (CDCl3, 300 MHz): 7.87 (1H, d, J8.4 Hz), 6.88 (1H, d, J 2.5 Hz), 6.84 (1H, dd, J 8.4 and 2.5 Hz), 5.53 (2H, br. s), 4.06 (2H, q, J 7.07 Hz), 1.42 (3H, t, J 7.0 Hz.)

Workup

  1. additionwas added over twenty minutes
  2. extractionextracted into EtOAc
  3. extractionThe EtOAc was then extracted with NaOH (1 N, 4×100 mL), which
  4. filtrationThe white precipitate (2.25 g, 58%) was filtered
  5. customdried

Sources & evidence

ORD record
ord-5e6cf159072c402d932adc6cd711ccc6
Source dataset
uspto-grants-2007_06
Patent number
USRE039679E1

Reaction notes

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