Hydrochloric Acid → 4-Bromo-2,6-diethylphenylboronic acid

HRID 341700

Reaktionsgleichung

Reaktionsgleichung von HRID 341700
[Br:1][C:2]1[CH:7]=[C:6]([CH2:8][CH3:9])[C:5](I)=[C:4]([CH2:11][CH3:12])[CH:3]=1.C([Li])CCC.[B:18](OC)([O:21]C)[O:19]C.Cl>O1CCCC1>[Br:1][C:2]1[CH:7]=[C:6]([CH2:8][CH3:9])[C:5]([B:18]([OH:21])[OH:19])=[C:4]([CH2:11][CH3:12])[CH:3]=1

Komponenten

6

Edukt 4

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 448911015-Bromo-1,3-diethyl-2-iodobenzeneHCID 178418339Butyllithium

Produkt 1

HCID 595626634-Bromo-2,6-diethylphenylboronic acidAusbeute 67,1 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 8028TetrahydrofuranLösungsmittel

Reaktionsbedingungen

Temperatur
-75 °C

Versuchsvorschrift

To a solution of 4-bromo-2,6-diethyl-1-iodobenzene (10 g, 0.029 mol) in tetrahydrofuran (100 ml) at −75° C. is added n-butyl lithium (1.6 M in hexanes, 22.2 ml, 0.035 mol) dropwise maintaining the temperature of the reaction mixture below −70° C. When the addition is complete the mixture is stirred at −75° C. for an additional 30 minutes and then trimethyl borate (17.98 g, 0.17 mol) is added dropwise. After the addition is complete the reaction is stirred at −75° C. for 1 hour, then allowed to come to room temperature and stirred for 2 hours, followed by cooling in an ice bath and acidification with 0.5 N aqueous hydrochloric acid. The mixture is extracted with ethyl acetate (3×300 ml) and the organic fractions are combined, washed with brine, dried over anhydrous sodium sulphate. The mixture is filtered and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-bromo-2,6-diethylphenylboronic acid (5 g) as a white solid.

Aufarbeitung

  1. temperaturedropwise maintaining the temperature of the reaction mixture below −70° C
  2. additionWhen the addition
  3. additionAfter the addition
  4. stirringis stirred at −75° C. for 1 hour
  5. customto come to room temperature
  6. stirringstirred for 2 hours
  7. temperatureby cooling in an ice bath
  8. extractionThe mixture is extracted with ethyl acetate (3×300 ml)
  9. washwashed with brine
  10. dry with materialdried over anhydrous sodium sulphate
  11. filtrationThe mixture is filtered
  12. customthe filtrate is evaporated under reduced pressure
  13. customThe residue is purified by column chromatography on silica gel

Quellen und Nachweise

ORD-Eintrag
ord-fe41789ee4ec4ab390ca352e62ff41a8
Quelldatensatz
uspto-grants-2014_11
Patentnummer
US08895761B2

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