7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline--hydrogen chloride (1/1) → 7,8-Dichloro-3,4-dihydroisoquinoline

HRID 2058428Notes

Reaction equation

HRID 2058428 reaction equation
N(S([O-])(=O)=O)(S([O-])(=O)=O)[O].[K+].[K+].Cl.[Cl:14][C:15]1[C:24]([Cl:25])=[C:23]2[C:18]([CH2:19][CH2:20][NH:21][CH2:22]2)=[CH:17][CH:16]=1>C(=O)([O-])[O-].[Na+].[Na+]>[Cl:14][C:15]1[C:24]([Cl:25])=[C:23]2[C:18]([CH2:19][CH2:20][N:21]=[CH:22]2)=[CH:17][CH:16]=1

Participants

4

Reactant 2

HCID 1239197,8-Dichloro-1,2,3,4-tetrahydroisoquinoline--hydrogen chloride (1/1)HCID 3032624Potassium nitrosodisulfonate

Product 1

HCID 128184197,8-Dichloro-3,4-dihydroisoquinoline

Reagents, catalysts & solvents 1

HCID 10340Sodium CarbonateSolvent2×

Procedure

To a mixture of 1 liter 5 percent aqueous sodium carbonate and 62.6 g. (0.233 mole) potassium nitrosodisulfonate was added 21.9 g. (0.092 mole) 7,8-dichloro-1,2,3,4-tetrahydroisoquinoline hydrochloride and then 0.1 liter 5 percent aqueous sodium carbonate. The reaction mixture was stirred at room temperature for 23 hours. The reaction mixture was then extracted with methylene chloride (3×250 ml.). The combined extract was washed with saturated sodium chloride solution, dried over anhydrous magnesium sulfate and filtered. The filtrate was concentrated to dryness under reduced pressure to afford a crude intermediate. The crude intermediate was recrystallized from ethyl acetate to yield 7,8-dichloro-3,4-dihydroisoquinoline as a yellow solid with a melting point of 56°-60° C. 7,8-Dichloro-3,4-dihydro isoquinoline was converted to the desired 7,8-dichloro-1-isopropyl-1,2,3,4-tetrahydroisoquinoline via a Grignard reaction with isopropylmagnesium iodide. 7,8-Dichloro-1-isopropyl-1,2,3,4-tetrahydroisoquinoline hydrochloride has a melting point of 196°-200° C.

Workup

  1. extractionThe reaction mixture was then extracted with methylene chloride (3×250 ml.)
  2. extractionThe combined extract
  3. washwas washed with saturated sodium chloride solution
  4. dry with materialdried over anhydrous magnesium sulfate
  5. filtrationfiltered
  6. concentrationThe filtrate was concentrated to dryness under reduced pressure
  7. customto afford a crude intermediate
  8. customThe crude intermediate was recrystallized from ethyl acetate

Sources & evidence

ORD record
ord-834bd13d095941d1afc95ab219d50cde
Source dataset
uspto-grants-1982_03
Patent number
US04317826

Reaction notes

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