Hydrochloric Acid → 6-Methoxy-1-methyl-1,2,3,4-tetrahydroisoquinoline hydrochloride

HRID 35237Notes

Reaction equation

HRID 35237 reaction equation
[ClH:1].[CH3:2][O:3][C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[C:10]([CH3:14])=[N:9][CH2:8][CH2:7]2.[OH-].[Na+].[BH4-].[Na+].Cl>CO>[ClH:1].[CH3:2][O:3][C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[CH:10]([CH3:14])[NH:9][CH2:8][CH2:7]2

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 4311764Sodium borohydride2×HCID 212958233,4-Dihydro-6-methoxy-1-methylisoquinoline hydrochloride

Product 1

HCID 142302826-Methoxy-1-methyl-1,2,3,4-tetrahydroisoquinoline hydrochlorideYield 80.5%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a stirred solution of 3,4-dihydro-6-methoxy-1-methylisoquinoline hydrochloride (19.2 g, 0.09 m) and NaOH (2.0 g, 0.05 m) in absolute methanol (600 ml) was added NaBH4 (14.0 g, 0.37 m) and the mixture was stirred for 2 hours. Another 4 g (0.11 m) of NaBH4 was added, and after 4 hours the reaction was added slowly to 150 ml of 20% aq HCl. The mixture was brought to gentle reflux for 2 hours and then the reaction was filtered, and the filtrate was concentrated on a rotating evaporator. The residue was added to 400 ml water and basified with 20% NaOH to a pH of 11-12. The mixture was extracted with methylene chloride (3×200 ml), dried over MgSO4, then concentrated to an oil (21 g). The oil was dissolved in ether (1 liter), and the solution was acidified with HCl gas. The resultant solid was filtered off and dried, giving 15.6 g of 1,2,3,4-tetrahydro-6-methoxy-1-methylisoquinoline hydrochloride, m.p. 218°-219°. (Yield 73%)

Workup

  1. temperatureto gentle reflux for 2 hours
  2. filtrationthe reaction was filtered
  3. concentrationthe filtrate was concentrated on a rotating evaporator
  4. additionThe residue was added to 400 ml water and basified with 20% NaOH to a pH of 11-12
  5. extractionThe mixture was extracted with methylene chloride (3×200 ml)
  6. dry with materialdried over MgSO4
  7. concentrationconcentrated to an oil (21 g)
  8. dissolutionThe oil was dissolved in ether (1 liter)
  9. filtrationThe resultant solid was filtered off
  10. customdried

Sources & evidence

ORD record
ord-f45ef367abd440c28eee6b132dc80e13
Source dataset
uspto-grants-1988_08
Patent number
US04766131

Reaction notes

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