Sulfuric Acid → 7,8-Dimethoxy-4-(3,4-dimethoxyphenyl)-1,2,3,4-tetrahydroisoquinoline

HRID 486372Notes

Reaction equation

HRID 486372 reaction equation
[CH3:1][O:2][C:3]1[C:23]([O:24][CH3:25])=[CH:22][CH:21]=[CH:20][C:4]=1[CH2:5][NH:6][CH2:7][CH:8](O)[C:9]1[CH:14]=[CH:13][C:12]([O:15][CH3:16])=[C:11]([O:17][CH3:18])[CH:10]=1.S(=O)(=O)(O)O>FC(F)(F)C(O)=O>[CH3:25][O:24][C:23]1[C:3]([O:2][CH3:1])=[C:4]2[C:20]([CH:8]([C:9]3[CH:14]=[CH:13][C:12]([O:15][CH3:16])=[C:11]([O:17][CH3:18])[CH:10]=3)[CH2:7][NH:6][CH2:5]2)=[CH:21][CH:22]=1

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 14719553alpha-[[(2,3-Dimethoxybenzyl)amino]methyl]-3,4-dimethoxybenzyl alcohol

Product 1

HCID 147195577,8-Dimethoxy-4-(3,4-dimethoxyphenyl)-1,2,3,4-tetrahydroisoquinolineYield 84%

Reagents, catalysts & solvents 1

HCID 6422Trifluoroacetic acidSolvent

Procedure

α-[[(2,3-Dimethoxybenzyl)amino]methyl]-3,4-dimethoxybenzyl alcohol 6.56 g, 18.9 mmol) was dissolved in trifluoroacetic acid (50 ml). Concentrated sulfuric acid was added to the solution under stirring and under cooling with ice and the reaction was conducted under these conditions for 40 minutes. The reaction solution was concentrated. Water was added to the residue and then it was made basic with aqueous ammonia under stirring and under cooling with ice. After extraction with dichloromethane, the dichloromethane layer was washed with a saturated sodium chloride aqueous solution and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the resultant crystals were washed with isopropyl ether to obtain 5.23 g of 7,8-dimethoxy-4-(3,4-dimethoxyphenyl)-1,2,3,4-tetrahydroisoquinoline.

Workup

  1. temperatureunder cooling with ice
  2. concentrationThe reaction solution was concentrated
  3. additionWater was added to the residue
  4. stirringunder stirring
  5. temperatureunder cooling with ice
  6. extractionAfter extraction with dichloromethane
  7. washthe dichloromethane layer was washed with a saturated sodium chloride aqueous solution
  8. dry with materialdried over anhydrous magnesium sulfate
  9. distillationThe solvent was distilled off under reduced pressure
  10. washthe resultant crystals were washed with isopropyl ether

Sources & evidence

ORD record
ord-ce673e785c57416fbcae6b3b94c4ca69
Source dataset
uspto-grants-1994_03
Patent number
US05292521

Reaction notes

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