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

HRID 2083223Notes

Reaction equation

HRID 2083223 reaction equation
C(NC(C)C)(C)C.C([Li])CCC.CCCCCC.[CH3:19][C:20]1[CH:21]=[N:22][C:23]2[CH2:24][CH2:25][CH2:26][CH2:27][C:28]=2[CH:29]=1.C[Si]([N:34]=[C:35]=[S:36])(C)C>C1C=CC=CC=1.O>[CH3:19][C:20]1[CH:21]=[N:22][C:23]2[CH:24]([C:35](=[S:36])[NH2:34])[CH2:25][CH2:26][CH2:27][C:28]=2[CH:29]=1

Participants

8

Reactant 5

HCID 7912DiisopropylamineHCID 8058HexaneHCID 75297IsothiocyanatotrimethylsilaneHCID 1200283-Methyl-5,6,7,8-tetrahydroquinolineHCID 178418339Butyllithium

Product 1

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

Reagents, catalysts & solvents 2

HCID 241BenzeneSolventHCID 962WaterSolvent

Procedure

A solution of di-isopropylamine [11.11 g., 0.11 mol.) in benzene (50 ml.) was cooled to 0° C and treated portionwise with a 9% w/v solution of butyl lithium in hexane (79 ml., 0.11 mol.). After 45 minutes at 0° C the solution was treated dropwise with 3-methyl-5,6,7,8-tetrahydroquinoline (14.7 g., 0.10 mol.) with rapid stirring and under an atmosphere of nitrogen. After 11/2 hours at 0° C the red suspension was treated portionwise over 2 minutes with trimethylsilylisothiocyanate (14.7 ml., 0.11 mol.) and the reaction mixture stirred at 0° C for 1/2 hour and at room temperature for 1 hour. The solution of 3-methyl-5,6,7,8-tetrahydroquinoline-8-(N-lithio-N-trimethylsilyl)thiocarboxamide was diluted with water (25 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 2N HCl. The mixture was extracted with ethylacetate (3 × 25 ml.) and the combined extracts discarded. The aqueous solution was adjusted to pH 10.0 with sodium carbonate and extracted with chloroform (3 × 50 ml.). The combined extracts were washed with saturated brine (1 × 50 ml.), dried (MgSO4) and the solvent removed in vacuo. The residual oily solid was triturated with n-hexane (100 ml.) and the solid filtered and recrystallised from isopropanol to give the title compound as pale yellow needles (8.9 g., 43%) m.p. 153° C identical in all respects to authentic material. The filtrate was analysed by g.l.c. (10% SE30, T=160° C and identified as a mixture of 8-cyano-3-methyl-5,6,7,8-tetrahydroquinoline (1 g., 6% yield based on starting material) and recovered 3-methyl-5,6,7,8-tetrahydroquinoline (7.17 g., 48% yield based on starting material)

Workup

  1. stirringthe reaction mixture stirred at 0° C for 1/2 hour and at room temperature for 1 hour
  2. customhydrolysis

Sources & evidence

ORD record
ord-fd8199cb98d94689ac3a0e3c088ec900
Source dataset
uspto-grants-1978_04
Patent number
US04085108

Reaction notes

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