Hydrochloric Acid → (2,6-Dimethoxyphenyl)boronic acid

HRID 1272568Notes

Reaction equation

HRID 1272568 reaction equation
ClC1CCCCC1.[CH3:8][O:9][C:10]1[CH:17]=[CH:16][CH:15]=[C:12]([O:13][CH3:14])[CH:11]=1.[Li].[B:19](OC)([O:22]C)[O:20]C.Cl>C1COCC1.C1CCCCC1.O>[CH3:8][O:9][C:10]1[CH:17]=[CH:16][CH:15]=[C:12]([O:13][CH3:14])[C:11]=1[B:19]([OH:22])[OH:20]

Participants

9

Reactant 5

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 90251,3-DimethoxybenzeneHCID 10952Chlorocyclohexane2×HCID 3028194Lithium

Product 1

HCID 2734343(2,6-Dimethoxyphenyl)boronic acidYield 91.3%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent2×HCID 8078CyclohexaneSolvent

Conditions

Temperature
-50 °C

Procedure

A mixture of 20.88 g of chlorocyclohexane (0.176 mol) and 22.1 g of resorcinol dimethyl ether (0.16 mol) is added dropwise to a suspension of 2.35 g of lithium granules (0.34 mol) in 300 g of THF at −50° C., with an addition time of 2 hours being selected. After a conversion of the chlorocyclohexane of >97% determined by GC (total of 9 h), 16.6 g of trimethyl borate (0.16 mol) are added dropwise at the same temperature over a period of 15 minutes. After stirring for another 30 minutes at −50° C., the reaction mixture is poured into 120 g of water, the pH is adjusted to 6.3 by means of 37% HCl, and THF and cyclohexane are distilled off at 35° C. under reduced pressure. 25 ml of methylcyclohexane are added to the product suspension, the colorless product is filtered off with suction and is washed once with 25 ml of cold methylcyclohexane and once with 25 ml of cold water. After drying, 26.5 g of 2,6-dimethoxyphenylboronic acid (0.146 mol, 91%, melting point: 104–107° C.) are obtained in the form of colorless crystals, HPLC purity >99% a/a.

Workup

  1. additionare added dropwise at the same temperature over a period of 15 minutes
  2. distillationare distilled off at 35° C. under reduced pressure
  3. addition25 ml of methylcyclohexane are added to the product suspension
  4. filtrationthe colorless product is filtered off with suction
  5. washis washed once with 25 ml of cold methylcyclohexane and once with 25 ml of cold water
  6. customAfter drying

Sources & evidence

ORD record
ord-d2759f8de1bb4e6e8f45cc39cc20044c
Source dataset
uspto-grants-2007_04
Patent number
US07208614B2

Reaction notes

Loading…