Dimethyl Sulfate → 5-Methoxy-1,1,4,4,7-pentamethyl-1,2,3,4-tetrahydronaphthalene

HRID 364759

Reaction equation

HRID 364759 reaction equation
[OH-].[Na+].[OH:3][C:4]1[C:13]2[C:12]([CH3:15])([CH3:14])[CH2:11][CH2:10][C:9]([CH3:17])([CH3:16])[C:8]=2[CH:7]=[C:6]([CH3:18])[CH:5]=1.S(OC)(O[CH3:23])(=O)=O>O.CCCCCCCC[N+](CCCCCCCC)(CCCCCCCC)C.[Cl-].C(Cl)Cl>[CH3:23][O:3][C:4]1[C:13]2[C:12]([CH3:14])([CH3:15])[CH2:11][CH2:10][C:9]([CH3:17])([CH3:16])[C:8]=2[CH:7]=[C:6]([CH3:18])[CH:5]=1

Participants

7

Reactant 3

HCID 6497Dimethyl SulfateHCID 14798Sodium HydroxideHCID 216784833,5,5,8,8-Pentamethyl-5,6,7,8-tetrahydronaphthalen-1-ol

Product 1

HCID 2267025-Methoxy-1,1,4,4,7-pentamethyl-1,2,3,4-tetrahydronaphthaleneYield 81.8%

Reagents, catalysts & solvents 3

HCID 21218Trioctylmethylammonium chlorideCatalystHCID 962WaterSolventHCID 6344DichloromethaneSolvent

Procedure

Methylation. A solution of sodium hydroxide (38 g, 0.95 mol) in water (1 L) was added to a mixture of 1-hydroxy-3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene (109 g, 0.5 mol), dimethyl sulfate (126 g, 1 mol) and Adogen 464* (21.6 g) in methylene dichloride (2 L). The reaction mixture was stirred vigorously at 25°-28° C. for 1 h, after which the organic layer was separated, combined with ammonium hydroxide solution (500 mL, 10%), and stirred vigorously at 20°-25° C. for 0.5 h. The organic layer was then separated and the washing procedure repeated, after which the organic layer was separated, washed with water (2×100 mL), then with brine (50 mL), and dried (Na2SO4). The solvent was removed by distillation and the residue was crystallized from hexane yielding 1-methoxy-3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene (95 g), mp 49°-50° C., GLC purity 99 %+. 1H-NMR (CDCl3) δ6.89 (1H, d, J=1.4 Hz), 6.63 (1H, d, J=1.4 Hz), 3.89 (3H, s), 2.41 (3H, s), 1.74 (4H, m), 1.48 (6H, s), 1.38 (6H, s). IR (KBr) 1273, 1257 cm-1, MS (m/e) 232 (M+, 16.9), 217 (100.0), 175.3 (19.6), 218.6 (16.0).

Workup

  1. customafter which the organic layer was separated
  2. stirringstirred vigorously at 20°-25° C. for 0.5 h
  3. customThe organic layer was then separated
  4. customafter which the organic layer was separated
  5. washwashed with water (2×100 mL)
  6. dry with materialwith brine (50 mL), and dried (Na2SO4)
  7. customThe solvent was removed by distillation
  8. customthe residue was crystallized from hexane

Sources & evidence

ORD record
ord-30af7a4d09b14545bf4097e51149e9a9
Source dataset
uspto-grants-1986_08
Patent number
US04605778

Linked notes

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