Isothiocyanatotrimethylsilane → 5,6,7,8-Tetrahydro-3-methyl-8-quinolinecarbothioamide

HRID 2083221Notes

Reaction equation

HRID 2083221 reaction equation
[CH3:1][C:2]1[CH:3]=[N:4][C:5]2[CH2:6][CH2:7][CH2:8][CH2:9][C:10]=2[CH:11]=1.C([Mg]Br)(C)C.C[Si]([N:21]=[C:22]=[S:23])(C)C>C1(C)C=CC=CC=1.O>[CH3:1][C:2]1[CH:3]=[N:4][C:5]2[CH:6]([C:22](=[S:23])[NH2:21])[CH2:7][CH2:8][CH2:9][C:10]=2[CH:11]=1

Participants

6

Reactant 3

HCID 75297IsothiocyanatotrimethylsilaneHCID 1200283-Methyl-5,6,7,8-tetrahydroquinolineHCID 178418365HCID 178418365, compound

Product 1

HCID 30039215,6,7,8-Tetrahydro-3-methyl-8-quinolinecarbothioamide

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 1140TolueneSolvent

Procedure

3-Methyl-5,6,7,8-tetrahydroquinoline (7.3 g, 0.05 mol.) was added to a solution of isopropylmagnesium bromide [prepared from isopropylbromide (6.15 g, 0.05 mol), magnesium (1.44 g, 0.06 mol) in ether (10 ml.)] and the solution heated at 60° to remove the ether by distillation. Toluene (5 ml.) was added and the reaction mixture was heated at 120° for 2 hours, cooled, diluted with toluene (30 ml) and this solution was added to a solution of trimethylsilyl isothiocyanate (7.85 g, 0.06 mol) in toluene (50 ml.) at 0° C. The reaction mixture was stirred at room temperature for 12 hours. The solution of 3-methyl-5,6,7,8-tetrahydroquinoline-8-(N-bromomagnesio-N-trimethylsilyl)thiocarboxamide was diluted with water (15 ml.) causing hydrolysis to 3-methyl-5,6,7,8-tetrahydroquinoline-8-(N-trimethylsilyl) thiocarboxamide and subsequent hydrolysis to the title compound and the pH adjusted to 2.0 with Conc. HCl. The aqueous solution was extracted with ether and the extracts discarded. The aqueous solution was adjusted to pH 9.0 with Na2CO3 and extracted with chloroform (3 × 50 ml.). The combined extracts were washed with brine, dried and the solvent removed to give a mixture of 3-methyl-5,6,7,8-tetrahydroquinoline and the title compound (5%) which was isolated by chromatography and identified by comparison with authentic material.

Workup

  1. temperaturethe solution heated at 60°
  2. customto remove the ether
  3. distillationby distillation
  4. additionToluene (5 ml.) was added
  5. temperaturethe reaction mixture was heated at 120° for 2 hours
  6. temperaturecooled
  7. additiondiluted with toluene (30 ml)
  8. customhydrolysis

Sources & evidence

ORD record
ord-385f628c6771411e9b627e486083e0e7
Source dataset
uspto-grants-1978_04
Patent number
US04085108

Reaction notes

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