Chlorotrimethylsilane → 1-Bromo-2,4,5-trifluoro-3-(trimethylsilyl)benzene

HRID 279485

Reaktionsgleichung

Reaktionsgleichung von HRID 279485
C([Li])CCC.C(NC(C)C)(C)C.[Br:13][C:14]1[CH:19]=[C:18]([F:20])[C:17]([F:21])=[CH:16][C:15]=1[F:22].C([N-]C(C)C)(C)C.[Li+].[CH3:31][Si:32](Cl)([CH3:34])[CH3:33].FC(F)(F)S(OC)(=O)=O>O1CCCC1.CCOCC>[Br:13][C:14]1[CH:19]=[C:18]([F:20])[C:17]([F:21])=[C:16]([Si:32]([CH3:34])([CH3:33])[CH3:31])[C:15]=1[F:22]

Komponenten

9

Edukt 6

HCID 6397ChlorotrimethylsilaneHCID 7912DiisopropylamineHCID 9526Methyl triflateHCID 675971-Bromo-2,4,5-trifluorobenzeneHCID 2724682Lithium diisopropylamide2×HCID 178418339Butyllithium2×

Produkt 1

HCID 148965881-Bromo-2,4,5-trifluoro-3-(trimethylsilyl)benzeneAusbeute 88 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 3283Diethyl EtherLösungsmittelHCID 8028TetrahydrofuranLösungsmittel

Versuchsvorschrift

This preparation route is very expensive. The first and the second synthesis step each involve reaction with butyllithium and diisopropylamine in tetrahydrofuran at −78° C., and the third synthesis step involves reaction with butyllithium in ether, likewise at −78° C. In the first step, 1-bromo-2,4,5-trifluorobenzene is reacted first with lithium diisopropylamide and then with trimethylsilyl chloride, the resulting 1-bromo-2,4,5-trifluoro-3-(trimethylsilyl)benzene (88% yield) is once more reacted with lithium diisopropylamide and subsequently with methyl trifluoromethanesulfonate, the resulting 1-bromo-2,4,5-trifluoro-6-methyl-3-(trimethylsilyl)benzene (75% yield) is reacted with butyllithium and subsequently with CO2 in the form of dry ice, and the resulting 2,4,5-trifluoro-6-methyl-3-(trimethylsilyl)- benzoic acid (62% yield) is reacted with cesium fluoride in acetonitrile to give 6-methyl-2,4,5-trifluorobenzoic acid (89% yield).

Aufarbeitung

  1. customThe first and the second synthesis step
  2. customthe third synthesis step
  3. customlikewise at −78° C

Quellen und Nachweise

ORD-Eintrag
ord-8831a9dd4b444a58ab4d19325cb20e76
Quelldatensatz
uspto-grants-2002_03
Patentnummer
US06362365B1

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