Hydrochloric Acid → 5,6,7,8-Tetrahydro-3-methyl-8-quinolinecarbothioamide

HRID 1974020Notes

Reaction equation

HRID 1974020 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([Li])CCC.C[Si]([N:21]=[C:22]=[S:23])(C)C.Cl>CCCCCC.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

7

Reactant 4

HCID 313Hydrochloric AcidHCID 75297IsothiocyanatotrimethylsilaneHCID 1200283-Methyl-5,6,7,8-tetrahydroquinolineHCID 178418339Butyllithium

Product 1

HCID 30039215,6,7,8-Tetrahydro-3-methyl-8-quinolinecarbothioamideYield 39%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8058HexaneSolvent3×

Conditions

Temperature
0 °C

Procedure

A solution of 3-methyl-5,6,7,8-tetrahydroquinoline (7.3 g., 0.05 mol.) in hexane (50 ml.) was cooled to 0° C and treated dropwise with stirring with a 15% w/w solution of butyl lithium in hexane (26 ml., 0.06 mol.) in an atmosphere of nitrogen. The reaction mixture was stirred at 0° C for an additional 1 hour and was added portionwise to a solution of trimethylsilylisothiocyanate (13.1 g., 0.1 mol.) in hexane (50 ml.) and under nitrogen keeping the internal temperature at -20° C. The reaction mixture was stirred for an additional 30 minutes at -20° C, allowed to warm to room temperature and diluted with water (50 ml.). The pH was adjusted to 2.0 with conc. HCl and the hexane layer separated and discarded. The aqueous solution was adjusted to pH 10.0 with sodium carbonate and extracted with ethyl acetate (3 × 50 ml.). The combined extracts were dried (MgSO4) and the solvent removed in vacuo. The residue was triturated with n-hexane and solid filtered and recrystallised from benzene to give the title compound as colourless needles (3.5 g., 39%) m.p. 153° identical in all respects to authentic material. (Found: C, 64.6; H, 7.0; N, 13.9%. C11H14N2S Requires: C, 64.1; H, 6.8; N, 13.6%). The hexane soluble material was distilled to give recovered 3-methyl-5,6,7,8-tetrahydroquinoline (3.5 g., 50%) b.p. 120°/15 mm.

Workup

  1. additiontreated dropwise
  2. stirringThe reaction mixture was stirred for an additional 30 minutes at -20° C
  3. temperatureto warm to room temperature
  4. customthe hexane layer separated
  5. extractionextracted with ethyl acetate (3 × 50 ml.)
  6. dry with materialThe combined extracts were dried (MgSO4)
  7. customthe solvent removed in vacuo
  8. customThe residue was triturated with n-hexane and solid
  9. filtrationfiltered
  10. customrecrystallised from benzene

Sources & evidence

ORD record
ord-c284d97d1b8e47d3b3a16a56c34724df
Source dataset
uspto-grants-1976_12
Patent number
US04000142

Reaction notes

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