Diethyl Ether → 1-Ethyl-5-methoxynaphthalene

HRID 1713714Notes

Reaction equation

HRID 1713714 reaction equation
OC1[C:11]2[C:6](=[C:7]3[CH:15]=[CH:14][CH:13]=[C:12]([CH3:16])[C:8]3=[CH:9][CH:10]=2)[O:5][C:4](=O)C=1.[CH2:18](OCC)C>COCCOCCOCCOC.[Pd]>[CH3:4][O:5][C:6]1[C:7]2[C:8](=[C:12]([CH2:16][CH3:18])[CH:13]=[CH:14][CH:15]=2)[CH:9]=[CH:10][CH:11]=1

Participants

5

Reactant 2

HCID 3283Diethyl EtherHCID 547180894-Hydroxy-7-methyl-benzo[h]chromen-2-one

Product 1

HCID 123363811-Ethyl-5-methoxynaphthaleneYield 50%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 8189TriglymeSolvent

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. temperaturethe mixture was heated
  2. temperatureto reflux for 3 days
  3. temperatureAfter cooling
  4. filtrationwas filtered on Celite
  5. washwashed with diethyl ether

Sources & evidence

ORD record
ord-f146fd9e3f5746e99b0a4977b0c3f020
Source dataset
uspto-grants-2010_09
Patent number
US07795299B2

Reaction notes

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