Methanol → 2,6-Dimethyl-6-(3-methyl-but-2-enyl)-cyclo-hex-2-enone

HRID 1793226Notes

Reaction equation

HRID 1793226 reaction equation
[H-].[Na+].[CH3:3][C:4]1[CH:9]=[CH:8][CH:7]=[C:6]([CH3:10])[C:5]=1[OH:11].C(Cl)[CH:13]=[C:14]([CH3:16])[CH3:15].[CH3:18]O>C1(C)C=CC=CC=1.[Pd]>[CH3:3][C:4]1[C:5](=[O:11])[C:6]([CH3:18])([CH2:10][CH:13]=[C:14]([CH3:16])[CH3:15])[CH2:7][CH2:8][CH:9]=1

Participants

7

Reactant 4

HCID 887MethanolHCID 104291-Chloro-3-methyl-2-buteneHCID 113352,6-DimethylphenolHCID 24758Sodium hydride

Product 1

HCID 115792582,6-Dimethyl-6-(3-methyl-but-2-enyl)-cyclo-hex-2-enone

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 1140TolueneSolvent

Conditions

Temperature
50 °C

Procedure

Sodium hydride (60%, 85 g, 2.13 mol) was added portionwise to a solution of 2,6-dimethylphenol (250 g, 2.05 mol) in 2 L of toluene at 10-15° C. The resulting suspension was stirred for 45 min. The mixture was cooled to 50° C., and prenyl chloride (262 g, 2.13 mol, 85%) was added during 1.5 h keeping the temperature at 50° C. The mixture was then stirred for further 2 h at 10-15° C. Methanol (1 L) and palladium (2.5 g, 10% on charcoal) was added and the grey suspension was hydrogenated at 0.3 bar overpressure, keeping the temperature at 20-22° C. (ice bath). The suspension was then filtered through a pad of celite. The yellow filtrate was washed with water (0.5 L), aqueous sodium hydroxide (0.5 L) and brine (0.5 L), dried (MgSO4) and concentrated in vacuo. The residue was distilled over a 5 cm Vigreux column to yield 318 g (81%, bp 78-82° C./0.05 Torr) of a colorless oil. 1H-NMR (400 MHz, CDCl3): 6.62 (bs, 1H, 3-H), 5.06-5.11 (m, 1H, 2′-H), 2.34-2.28 (m, 2H, 4-H), 2.25-2.14 (m, 2H, 1′H), 1.91 (dt, J5a,5b=13.6 Hz, J5a,4=6.1 Hz, 1H, 5a-H), 1.76 (s, 3H, 2-CH3), 1.77-1.70 (m, 1H, 5b-H), 1.70 (s, 3H, 4′-H), 1.59 (s, 3H, 3′-CH3), 1.05 (s, 3H, 6-CH3) ppm. GC/MS (EI): 192 (M+, 16), 124 (100), 109 (74), 82 (31), 69 (40), 41 (57). IR (ATR): 2965s, 2922s, 1667vs, 1449m, 1376m, 1033m cm−1.

Workup

  1. customat 50° C
  2. stirringThe mixture was then stirred for further 2 h at 10-15° C
  3. customat 20-22° C.
  4. filtrationThe suspension was then filtered through a pad of celite
  5. washThe yellow filtrate was washed with water (0.5 L), aqueous sodium hydroxide (0.5 L) and brine (0.5 L)
  6. dry with materialdried (MgSO4)
  7. concentrationconcentrated in vacuo
  8. distillationThe residue was distilled over a 5 cm Vigreux column
  9. customto yield 318 g (81%, bp 78-82° C./0.05 Torr) of a colorless oil

Sources & evidence

ORD record
ord-b6db5d76b7944ff18a499f9e72331b8a
Source dataset
uspto-grants-2006_07
Patent number
US07078570B2

Reaction notes

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