Trimethyl borate → 4-(Methylthio)phenylboronic acid

HRID 1839919Notes

Reaction equation

HRID 1839919 reaction equation
[Li]CCCC.Br[C:7]1[CH:12]=[CH:11][C:10]([S:13][CH3:14])=[CH:9][CH:8]=1.C[O:16][B:17](OC)[O:18]C.[OH-].[Na+]>O1CCCC1>[CH3:14][S:13][C:10]1[CH:11]=[CH:12][C:7]([B:17]([OH:18])[OH:16])=[CH:8][CH:9]=1

Participants

6

Reactant 4

HCID 8470Trimethyl borateHCID 14798Sodium HydroxideHCID 660374-BromothioanisoleHCID 178418339Butyllithium

Product 1

HCID 27339594-(Methylthio)phenylboronic acidYield 83.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Under nitrogen, 113 mL (181 mmol) of n-BuLi (1.6 M in hexanes) was added to a stirred solution of 30 g (150 mmol) of 4-bromothioanisole (Lancaster) in 1,500 mL of anhydrous tetrahydrofuran (THF) at −78° C. After 30 minutes, 51 mL (450 mmol) of trimethylborate was added. The reaction was warmed to ambient temperature and stirred overnight. The resulting solution was treated with 300 mL of 10% NaOH and stirred vigorously for 1 hour. The THF was removed in vacuo, the pH adjusted to 4-5 and the solid collected by filtration. The solid was washed repeatedly with water and hexane. Drying in vacuo gave 21 g (83%) of 4-methylthiophenylboronic acid as a colorless solid: NMR (DMSO-d6) δ 2.47 (s, 3H), 7.20 (d, J=8 Hz, 2H), 7.71 (d, J=8 Hz, 2H), 7.96 (s, 2H).

Workup

  1. stirringstirred vigorously for 1 hour
  2. customThe THF was removed in vacuo
  3. filtrationthe solid collected by filtration
  4. washThe solid was washed repeatedly with water and hexane
  5. customDrying in vacuo

Sources & evidence

ORD record
ord-088d50a028f94efb921a63af5a853798
Source dataset
uspto-grants-2004_01
Patent number
US06677488B2

Reaction notes

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