Hydrochloric Acid → 8-Cyano-3-methyl-5,6,7,8-tetrahydroquinoline

HRID 1974022Notes

Reaction equation

HRID 1974022 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.CCCCCC.C[Si]([N:27]=[C:28]=S)(C)C.Cl>C1C=CC=CC=1.O>[C:28]([CH:6]1[C:5]2[N:4]=[CH:3][C:2]([CH3:1])=[CH:11][C:10]=2[CH2:9][CH2:8][CH2:7]1)#[N:27]

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 8058HexaneHCID 75297IsothiocyanatotrimethylsilaneHCID 1200283-Methyl-5,6,7,8-tetrahydroquinolineHCID 178418339Butyllithium

Product 1

HCID 122782108-Cyano-3-methyl-5,6,7,8-tetrahydroquinolineYield 35%

Reagents, catalysts & solvents 2

HCID 241BenzeneSolvent2×HCID 962WaterSolvent

Procedure

A solution of 3-methyl-5,6,7,8-tetrahydroquinoline (29 g., 0.2 mol) in benzene (200 ml.) was cooled to 0° C and treated dropwise with a 15% w/w solution of n-butyl lithium in hexane (88 ml., 0.2 mol) under nitrogen. After 1 hour at 0° C the reaction mixture was added portionwise to a solution of trimethylsilylisothiocyanate (112 ml., 0.8 mol.) in benzene (200 ml.) at 0° C and under nitrogen. After 21/2 hours at room temperature the reaction mixture was treated with water (100 ml.) and with 2N HCl to pH 2.0. The aqueous layer was separated, washed with ethyl acetate (1 × 50 ml.) and the pH adjusted to 9.0 with sodium carbonate and extracted with chloroform (3 × 100 ml.) The combined chloroform extracts were dried (MgSO4) and the solvent removed in vacuo to give a red oil which was distilled first at 0.25 mmHg to give recovered 3-methyl-5,6,7,8-tetrahydroquinoline (17 g., 59%) b.p. 54-7° and then at 0.05 mmHg to give the title compound as a pale red oil (12 g. 35%) b.p. 115- 20° RT = 4.1/4 min. (3% SE30, 200° C) identical to authentic material.

Workup

  1. customThe aqueous layer was separated
  2. washwashed with ethyl acetate (1 × 50 ml.)
  3. extractionextracted with chloroform (3 × 100 ml.) The combined chloroform extracts
  4. dry with materialwere dried (MgSO4)
  5. customthe solvent removed in vacuo
  6. customto give a red oil which
  7. distillationwas distilled first at 0.25 mmHg
  8. customto give
  9. customrecovered 3-methyl-5,6,7,8-tetrahydroquinoline (17 g., 59%) b.p. 54-7°

Sources & evidence

ORD record
ord-6684713e70e2422e94d54527a87362b5
Source dataset
uspto-grants-1976_12
Patent number
US04000142

Reaction notes

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