Hydrochloric Acid → 5,6,7,8-Tetrahydroquinoline-8-carbothioamide

HRID 1974027Notes

Reaction equation

HRID 1974027 reaction equation
C(NC(C)C)(C)C.C([Li])CCC.CCCCCC.[N:19]1[C:28]2[CH2:27][CH2:26][CH2:25][CH2:24][C:23]=2[CH:22]=[CH:21][CH:20]=1.C[Si]([N:33]=[C:34]=[S:35])(C)C.Cl>C1C=CC=CC=1.O>[N:19]1[C:28]2[CH:27]([C:34](=[S:35])[NH2:33])[CH2:26][CH2:25][CH2:24][C:23]=2[CH:22]=[CH:21][CH:20]=1

Participants

9

Reactant 6

HCID 313Hydrochloric AcidHCID 7912DiisopropylamineHCID 8058HexaneHCID 663355,6,7,8-TetrahydroquinolineHCID 75297IsothiocyanatotrimethylsilaneHCID 178418339Butyllithium

Product 1

HCID 122782125,6,7,8-Tetrahydroquinoline-8-carbothioamideYield 30%

Reagents, catalysts & solvents 2

HCID 241BenzeneSolventHCID 962WaterSolvent

Procedure

A solution of di-isopropylamine (33.3g, 0.33 mol) in benzene (150 ml) was cooled in ice and treated with 9% w/v butyl-lithium in hexane (237 ml, 0.33 mol). After 45 minutes the solution was treated with 5,6,7,8-tetrahydroquinoline (39.9 g, 0.3 mol) dropwise with stirring. After 1.5 hours trimethylsilyl-isothiocyanate (43.2 ml. 0.3 mol) was added and the resulting solution was allowed to stand at 0° C for 0.5 hours and at room temperature for 1 hour. Water (50 ml.) was added and the resulting mixture acidified with 2N HCl. The acid solution was separated, washed with ethyl acetate and the pH was adjusted to 9 with solid sodium carbonate. Extraction with chloroform followed by drying of the extract over MgSO4, filtration and evaporation gave a thick gum which crystallised on trituration with n-hexane. Recrystallisation from methanol gave 5,6,7,8-tetrahydroquinoline-8-thiocarboxamide (16g, 30%) m.p. 160°. The hydrochloride was prepared by dissolution of the free base in hot iso-propyl alcohol adding ethereal HCl solution and allowing to crystallise. m.p. 263-4°.

Workup

  1. customThe acid solution was separated
  2. washwashed with ethyl acetate
  3. extractionExtraction with chloroform
  4. customby drying of the
  5. extractionextract over MgSO4, filtration and evaporation
  6. customgave a thick gum which
  7. customcrystallised on trituration with n-hexane
  8. customRecrystallisation from methanol

Sources & evidence

ORD record
ord-174e30f911de49879310813d029894bf
Source dataset
uspto-grants-1976_12
Patent number
US04000142

Reaction notes

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