Reaktion #451940

Reaktionsgleichung

2,5-Dimethyl-2,5-dichlorohexane

m-cresol

→

1-hydroxy-3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene

Ausbeute 78.3%

Lösungsmittel

ethylene dichloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added in one direction
2. 2
   TemperaturAfter 1 h the mixture was cooled to 20° C.
3. 3
   ExtraktionThe mixture was then extracted with toluene (500 mL)
4. 4
   SonstigeThe organic layer was separated
5. 5
   Waschenwashed with brine (3×50 mL)
6. 6
   Trocknendried (Na2SO4)
7. 7
   SonstigeThe solvent was removed by distillation
8. 8
   Sonstigethe residue was crystallized from a hexane/benzene solvent mixture

Vorschrift

2,5-Dimethyl-2,5-dichlorohexane (183 g, 1 mol) was stirred with m-cresol (129.6 g, 1.2 mol) and aluminum chloride (4 g) was added in one direction. The mixture was heated at 95° C., with stirring for 1.5 h, after which ethylene dichloride (100 mL) was added and then the heating was continued. After 1 h the mixture was cooled to 20° C. and poured onto an ice-water/hydrochloric acid mixture (150 mL, 10% HCl solution). The mixture was then extracted with toluene (500 mL). The organic layer was separated, washed with brine (3×50 mL) and dried (Na2SO4). The solvent was removed by distillation and the residue was crystallized from a hexane/benzene solvent mixture to give 1-hydroxy-3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene (171 g), mp 133°-134° C., GLC purity 99%+. 1H-NMR (CDCl3) δ 6.82 (1H, broad s), 6.35 (1 H, d, J=1.4 Hz), 4.72 (1H, s), 2.30 (3H, s), 1.71 (4H, m), 1.49 (6H, s), 1.34 (6H, s). 13C-NMR (CDCl3) δ 154.2 (1C, s), 147.8 (1C, s), 135.7 (1C, s), 128.0 (1C, s), 120.2 (1C, d), 114.6 (1C, d), 37.9 (1C, t), 35.2 (1C, t), 34.6 (1C, s), 33.7 (1C, s), 32.0 (2C, q), 28.5 (2C, q), 20.8 (1C, q). IR (KBr) 3,503 cm-1, MS (m/e) 218 (M+, 24.7), 203 (100.0), 161 (55.1), 147 (23.9), 57 (10.9).

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