Trimethyl borate → [6-(4-Fluorophenyl)-1,3-benzodioxol-5-yl]boronic acid

HRID 1598845Notes

Reaction equation

HRID 1598845 reaction equation
[Li]CCCC.Br[C:7]1[C:15]([C:16]2[CH:21]=[CH:20][C:19]([F:22])=[CH:18][CH:17]=2)=[CH:14][C:10]2[O:11][CH2:12][O:13][C:9]=2[CH:8]=1.C[O:24][B:25](OC)[O:26]C.[OH-].[Na+]>C1COCC1>[F:22][C:19]1[CH:20]=[CH:21][C:16]([C:15]2[C:7]([B:25]([OH:26])[OH:24])=[CH:8][C:9]3[O:13][CH2:12][O:11][C:10]=3[CH:14]=2)=[CH:17][CH:18]=1

Participants

6

Reactant 4

HCID 8470Trimethyl borateHCID 14798Sodium HydroxideHCID 234510685-Bromo-6-(4-fluorophenyl)-1,3-benzodioxoleHCID 178418339Butyllithium

Product 1

HCID 23451199[6-(4-Fluorophenyl)-1,3-benzodioxol-5-yl]boronic acidYield 50%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Under nitrogen, 6.3 mL (15.8 mmol) of n-BuLi (2.5M in hexanes) was added to a stirred solution of 3.9 g (13.2 mmol) of 5-bromo-6-(4-fluorophenyl)-1,3-benzodioxole (Step 1) in 30 mL of anhydrous THF at -78° C. After 30 minutes, 4.5 mL (39.4 mmol) of trimethylborate was added. The reaction was warmed to ambient temperature and stirred for 3 hours prior to the addition of 60 mL of 5% NaOH. The reaction was stirred for an additional 60 minutes, the THF removed in vacuo, and the pH adjusted to ca. 4. The residue was dissolved in ethyl acetate; the resulting solution was dried over Na2S04 and concentrated in vacuo to give 1.7 g (50%) of [6 (4-fluorophenyl)-1,3-benzodioxol-5-yl] boronic acid as a pale yellow solid: NMR (CDCl3) δ 4.00 (br s, 2H), 6.06 (s, 2H), 6.75 (s, 1H), 7.08-7.17 (m, 2H), 7.26 (s, 1H), 7.31-7.39 (m, 2H).

Workup

  1. stirringThe reaction was stirred for an additional 60 minutes
  2. customthe THF removed in vacuo
  3. dissolutionThe residue was dissolved in ethyl acetate
  4. customthe resulting solution was dried over Na2S04
  5. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-3c89c5b136084f87820630f7ac0e21ad
Source dataset
uspto-grants-1998_04
Patent number
US05739166

Reaction notes

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