Sulfuric Acid → 4-(3,4-Dimethoxyphenyl)-6-methyl-1,2,3,4-tetrahydroisoquinoline

HRID 54671Notes

Reaction equation

HRID 54671 reaction equation
[CH3:1][C:2]1[CH:22]=[CH:21][C:5]([CH2:6][NH:7][CH2:8][CH:9](O)[C:10]2[CH:15]=[CH:14][C:13]([O:16][CH3:17])=[C:12]([O:18][CH3:19])[CH:11]=2)=[CH:4][CH:3]=1.S(=O)(=O)(O)O>FC(F)(F)C(O)=O>[CH3:19][O:18][C:12]1[CH:11]=[C:10]([CH:9]2[C:21]3[C:5](=[CH:4][CH:3]=[C:2]([CH3:1])[CH:22]=3)[CH2:6][NH:7][CH2:8]2)[CH:15]=[CH:14][C:13]=1[O:16][CH3:17]

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 10590414alpha-[[(4-Methylbenzyl)amino]methyl]-3,4-dimethoxybenzyl alcohol

Product 1

HCID 106843994-(3,4-Dimethoxyphenyl)-6-methyl-1,2,3,4-tetrahydroisoquinolineYield 98.3%

Reagents, catalysts & solvents 1

HCID 6422Trifluoroacetic acidSolvent

Procedure

530 mg of α-[[(4-methylbenzyl)amino]methyl]-3,4-dimethoxybenzyl alcohol was dissolved in 4 ml of trifluoroacetic acid, and after adding thereto 0.12 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 chloroform, the mixture was basified by addition of 28% aqueous ammonia, by a separating procedure, the chloroform layer was collected, was washed with water once, and dried over anhydrous sodium sulfate. The solvent was distilled off, and the residue was recrystallized from ethyl acetate-n-hexane, giving 490 mg of 4-(3,4-dimethoxyphenyl)-6-methyl-1,2,3,4-tetrahydroisoquinoline (melting point: 94°-96° 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 chloroform
  6. additionthe mixture was basified by addition of 28% aqueous ammonia, by a separating procedure
  7. customthe chloroform layer was collected
  8. washwas washed with water once
  9. dry with materialdried over anhydrous sodium sulfate
  10. distillationThe solvent was distilled off
  11. customthe residue was recrystallized from ethyl acetate-n-hexane

Sources & evidence

ORD record
ord-1bbacb1e5f6b4899821a09d9062d8b4b
Source dataset
uspto-grants-1997_04
Patent number
US05623074

Reaction notes

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