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

HRID 1089798Notes

Reaction equation

HRID 1089798 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 79.1%

Reagents, catalysts & solvents 1

HCID 6422Trifluoroacetic acidSolvent

Procedure

1.0 g of α-[[(2,3-dimethoxybenzyl)amino]methyl]-3,4-dimethoxybenzyl alcohol was dissolved in 7.5 ml of trifluoroacetic acid, and after adding thereto 0.23 ml of conc. sulfuric acid under ice cooling, the mixture was allowed to react for 30 minutes. The reaction solution was concentrated, and subjected to azeotropic distillation with toluene 2 times. After adding to the mixture chloroform, the mixture was basified by addition of 28% aqueous ammonia under ice cooling. After a separating procedure, the chloroform layer was collected, washed with water, and dried over anhydrous magnesium sulfate. The solvent was distilled off, and the residue thus obtained was recrystallized from chloroform-n-hexane, affording 750 mg of 7,8-dimethoxy-4-(3,4-dimethoxyphenyl)-1,2,3,4-tetrahydroisoquinoline (m.p. 109°-110° C.).

Workup

  1. additionafter adding
  2. customto react for 30 minutes
  3. concentrationThe reaction solution was concentrated
  4. distillationsubjected to azeotropic distillation with toluene 2 times
  5. additionAfter adding to the mixture chloroform
  6. additionthe mixture was basified by addition of 28% aqueous ammonia under ice cooling
  7. customAfter a separating procedure, the chloroform layer was collected
  8. washwashed with water
  9. dry with materialdried over anhydrous magnesium sulfate
  10. distillationThe solvent was distilled off
  11. customthe residue thus obtained
  12. customwas recrystallized from chloroform-n-hexane

Sources & evidence

ORD record
ord-7908571185614160a71dbffd5787d798
Source dataset
uspto-grants-1992_01
Patent number
US05079256

Reaction notes

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