Dimethyl Sulfate → 5-Methoxy-1,4-dihydronaphthalene

HRID 1013092

Reaction equation

HRID 1013092 reaction equation
[C:1](=O)([O-])[O-].[K+].[K+].[C:7]1([OH:17])[C:16]2[CH2:15][CH:14]=[CH:13][CH2:12][C:11]=2[CH:10]=[CH:9][CH:8]=1.S(OC)(OC)(=O)=O>C(O)C>[CH3:1][O:17][C:7]1[CH:8]=[CH:9][CH:10]=[C:11]2[C:16]=1[CH2:15][CH:14]=[CH:13][CH2:12]2

Participants

5

Reactant 3

HCID 6497Dimethyl SulfateHCID 11430Potassium CarbonateHCID 974665,8-Dihydro-1-naphthol

Product 1

HCID 151310665-Methoxy-1,4-dihydronaphthaleneYield 92.5%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Conditions

Temperature
40 °C

Procedure

Add powdered potassium carbonate (193.1 g, 1.397 mol) to a solution of commercially available 5,8-dihydronaphthalen-1-ol [68.08 g, 90% potency based on 1H-NMR, 0.4657 mol, from Societa Italiana Medicinala Scandicci, s.r.l., Reggello (Firenze), Italy] in ethanol (700 mL). Cool the solution to 0° C. with ice water and add dimethyl sulfate (88.1 g, 66.1 mL, 0.699 mol) dropwise, maintaining the temperature between 5° C. and 10° C. Heat the reaction mixture to 40° C. until TLC shows the absence of starting material (about 2 hr). Filter off the solids by vacuum filtration and concentrate. Dilute the residual brown oil with diethyl ether (500 mL), wash with 10% aqueous ammonium hydroxide (500 mL), water (500 mL), brine (500 mL), dry (sodium sulfate) and concentrate to give the crude product as a brown oil (73 g). Purify the crude product by short path distillation under vacuum (bp 120-130° C./5 Torr) to give the title compound as a clear oil (69.0 g, 92.5% potency corrected) (contains some 1,2,3,4-tetrahydro-5-methoxynaphthalene as an impurity).

Workup

  1. temperaturemaintaining the temperature between 5° C. and 10° C
  2. customthe absence of starting material (about 2 hr)
  3. filtrationFilter off the solids
  4. filtrationby vacuum filtration
  5. concentrationconcentrate
  6. additionDilute the residual brown oil with diethyl ether (500 mL)
  7. washwash with 10% aqueous ammonium hydroxide (500 mL), water (500 mL), brine (500 mL)
  8. dry with materialdry (sodium sulfate)
  9. concentrationconcentrate
  10. customto give the crude product as a brown oil (73 g)
  11. customPurify the crude product
  12. distillationby short path distillation under vacuum (bp 120-130° C./5 Torr)

Sources & evidence

ORD record
ord-452ab81680f64905869b3220362db98d
Source dataset
uspto-grants-2011_07
Patent number
US07981882B2

Linked notes

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