Hydrochloric Acid → Trans-4-Acetyl-3,5,5-Trimethylcyclohexene

HRID 2057491Notes

Reaction equation

HRID 2057491 reaction equation
[Cl-].[Al+3].[Cl-].[Cl-].[O:5]=[C:6]([CH:8]=[C:9]([CH3:11])[CH3:10])[CH3:7].C=[CH:13][CH:14]=[CH:15][CH3:16].Cl.Cl[CH2:19]Cl>>[C:6]([C@@H:8]1[C:15]([CH3:16])([CH3:19])[CH2:14][CH:13]=[CH:10][C@H:9]1[CH3:11])(=[O:5])[CH3:7]

Participants

6

Reactant 5

HCID 313Hydrochloric AcidHCID 6344Dichloromethane3×HCID 8858Mesityl oxideHCID 15301Penta-1,3-dieneHCID 6451240Aluminum(III) Chloride

Product 1

HCID 54437493Trans-4-Acetyl-3,5,5-Trimethylcyclohexene

Procedure

To powdered anhydrous aluminum chloride (13.7 g, 0.10 mol) under nitrogen is added dry dichloromethane (30 ml). Mesityl oxide (20.0 g, 0.20 mol) in dichloromethane (75 ml) is then added with stirring over 30 minutes and the mixture is heated under reflux for 1 hour. Penta-1,3-diene (mixture of isomers) (70.0 g, 1.03 mol) in dichloromethane (300 ml) is added dropwise over 6 hours. The mixture is then stirred overnight at room temperature. Liquid paraffin (100 ml) and 10% hydrochloric acid (200 ml) is added and the mixture is steam distilled for 3 hours. The steam distillate is extracted with ether (5×75 ml) and the product worked up as usual. The residue is distilled to give a liquid, b.p. 52°-54° at 1 mm Hg (15.0 g, 0.09 mol, 45%), shown by GLC [column (A), 120° C.] to consist of two components in the proportions ca. 13:87 in order of increasing retention time. These were separated by preparative GLC [column (B), 130° C.]: trans-4-acetyl-3,5,5-trimethylcyclohexene (6) (Found: C, 79.6; H, 10.75. C11H18O requires C, 79.5; H, 10.85%); m/e 166 (M+, 33%), 123 (100), 109 (39), 107 (33), 81 (39), 69 (33), 67 (27), 55 (27), 43 (82) and 41 (50); τ9.17-8.86 (9H, 4 overlapping lines, 3- and 5-Me), 8.60-8.04 (2H, m, 6-H2), 7.87 (3H, s, Ac), 7.90-7.30 (2H, m with br s overlapping, 3- and 4-H), and 4.54 br (2H, s, 1- and 2-H); νmax. (film) 1 710 (Ac) and 695 cm-1 (cis--CH=CH); cis-4-acetyl-3,5,5-trimethylcyclohexene (5) (Found: C, 79.55; H, 10.8%); m/e 166 (M+, 4%), 138 (39), 123 (95), 109 (11), 107 (23), 81 (12), 69 (8), 67 (9), 55 (12), 53 (11), 43 (100) and 41 (23); τ9.18-8.89 (9H, 3 overlapping lines, 3- and 5-Me), 8.68-8.18 (2H, m, 6-H2), 7.97 (3H, s, Ac), 7.70-7.30 (2H, m, 4- and 3-H), and 4.86-4.16 (2H, m, 1- and 2-H); νmax. (film) 1 710 (Ac), and 1 692 and 710 cm-1 (cis-CH=CH).

Workup

  1. temperaturethe mixture is heated
  2. temperatureunder reflux for 1 hour
  3. stirringThe mixture is then stirred overnight at room temperature
  4. distillationdistilled for 3 hours
  5. extractionThe steam distillate is extracted with ether (5×75 ml)
  6. distillationThe residue is distilled
  7. customto give a liquid, b.p. 52°-54° at 1 mm Hg (15.0 g, 0.09 mol, 45%)
  8. temperatureof increasing retention time
  9. customThese were separated by preparative GLC [column (B), 130° C.]

Sources & evidence

ORD record
ord-d71ed315bd4a4e3bb7b2b0933c38e3c1
Source dataset
uspto-grants-1980_07
Patent number
US04211242

Reaction notes

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