5-Methoxytetralone → 5-Methylnaphthalen-1-ol

HRID 1713713Notes

Reaction equation

HRID 1713713 reaction equation
CO[C:3]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:4]=1[CH2:5][CH2:6][CH2:7][C:8]2=[O:13].[CH2:14]([Mg]Br)C>C(OCC)C>[CH3:14][C:3]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:4]=1[CH:5]=[CH:6][CH:7]=[C:8]2[OH:13]

Participants

4

Reactant 2

HCID 366205-MethoxytetraloneHCID 178418443HCID 178418443, compound

Product 1

HCID 113556405-Methylnaphthalen-1-ol

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Conditions

Temperature
0 °C

Procedure

5-Methoxy-1-tetralone (5) (4 g, 22.6 mmol) was dissolved in 50 mL anhydrous diethyl ether, stirred, and cooled down on ice to 0° C. Ethylmagnesium bromide (19 mL, 56.8 mmol) was added dropwise to the solution, producing copious precipitation. The mixture was then heated to reflux and stirred for 10 h. After cooling, cold water was added slowly to the reaction mixture, which was then extracted with diethyl ether three times. The organic layer was evaporated to afford crude product 6. Without purification, zinc chloride (15 g, 114 mmol) was added to a solution of 6 in benzene (35 mL), then concentrated hydrochloride acid (12 mL) was added to the solution at room temperature. The reaction mixture was heated to reflux for 5 h, cooled, extracted with diethyl ether three times, and the organic layer was evaporated to afford crude product. Purification by column chromatography gave 7 (2 g). To a solution of 7 (2 g) in triglyme (15 mL) was added 10% Pd/C (2 g) and the mixture was heated to reflux for 3 days. After cooling, diethyl ether was added to the mixture and it was filtered on Celite, then washed with diethyl ether to provide compound 8. 50% yield; 1H NMR δ 1.37 (3H, t, J=7.8 Hz, CH3CH2—), 3.10 (2H, q, J=7.8 Hz, CH3CH2—), 4.01 (3H, s, OCH3), 6.82 (1H, d, J=7.8 Hz, H-2), 7.36-7.44 (3H, m, H-3, 6, 7), 7.64 (1H, d, J=8.7 Hz, H-4), 815 (1H, d, J=8.4 Hz, H-8).

Workup

  1. customproducing copious
  2. customprecipitation
  3. temperatureThe mixture was then heated
  4. temperatureto reflux
  5. stirringstirred for 10 h
  6. temperatureAfter cooling
  7. additioncold water was added slowly to the reaction mixture, which
  8. extractionwas then extracted with diethyl ether three times
  9. customThe organic layer was evaporated

Sources & evidence

ORD record
ord-af0945ff4d524e1b88503d5687bfa884
Source dataset
uspto-grants-2010_09
Patent number
US07795299B2

Reaction notes

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