2,4,6-Trimethylphenol → 3,4,5-Tribromo-2,4,6-trimethyl-2,5-cyclohexadienone

HRID 649694

Reaktionsgleichung

Reaktionsgleichung von HRID 649694
Br[CH2:2][C:3]1[C:8]([Br:9])=[C:7]([CH3:10])[C:6]([OH:11])=[C:5]([CH3:12])[C:4]=1[Br:13].CC1C=C(C)C=C(C)C=1O.BrBr.[Br:26]C1C(C)=C(O)C(C)=C(Br)C=1C>C(O)(=O)C.C([O-])(=O)C.[Na+].C(O)(=O)C.O>[Br:13][C:4]1[C:3]([Br:26])([CH3:2])[C:8]([Br:9])=[C:7]([CH3:10])[C:6](=[O:11])[C:5]=1[CH3:12]

Komponenten

8

Edukt 4

HCID 106982,4,6-TrimethylphenolHCID 24408BromineHCID 131086813,5-Dibromo-2,4,6-trimethylphenol2×HCID 139546603,5-Dibromo-4-(bromomethyl)-2,6-dimethylphenol

Produkt 1

HCID 201420513,4,5-Tribromo-2,4,6-trimethyl-2,5-cyclohexadienone

Reagenzien, Katalysatoren, Lösungsmittel 3

HCID 176Acetic AcidLösungsmittelHCID 962WaterLösungsmittelHCID 23662384Sodium DiacetateLösungsmittel

Versuchsvorschrift

The preparation of a halogenated phenol such as 4-bromomethyl-3,5-dibromo-2,6-dimethylphenol (tribromomesitol) can involve the following sequence: bromination of 2,4,6-trimethylphenol (mesitol) with 2 moles of bromine in acetic acid to prepare 3,5-dibromo-2,4,6-trimethylphenol (dibromometisol) which is isolated by precipitation with water. K. Auwers & F. Rapp, Ann., 302, 153-71 (1898) and O. Jacobsen, Ann., 195, 265-92 (1879); the dibromomesitol is brominated in acetic acid sodium acetate buffer at low temperatures to afford an intermediate, 3,4,5-tribromo-2,4,6-trimethyl-2,5-cyclohexadienone, which is isolated by fast precipitation with water and filtration; this solid slowly rearranges to tribromomesitol at room temperature, more quickly at higher temperatures. K. Fries & E. Brandes, Ann., 542, 48-77 (1939). This procedure to prepare tribromomesitol is complex and not industrially viable.

Quellen und Nachweise

ORD-Eintrag
ord-8c3c9c6ff7fa470bab4e3dcb32e8886c
Quelldatensatz
uspto-grants-1988_04
Patentnummer
US04740636

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