Diethylene Glycol → 3-Methyl-5,6,7,8-tetrahydroquinoline

HRID 372682Notes

Reaction equation

HRID 372682 reaction equation
[CH3:1][C:2]1[CH:3]=[N:4][C:5]2[CH2:6][CH2:7][CH2:8][C:9](=O)[C:10]=2[CH:11]=1.O.NN.C(O)COCCO.[OH-].[Na+]>O>[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

Participants

6

Reactant 4

HCID 8117Diethylene GlycolHCID 14798Sodium HydroxideHCID 24654Hydrazine hydrate (1:1)HCID 5951923-Methyl-7,8-dihydroquinolin-5(6H)-one

Product 1

HCID 1200283-Methyl-5,6,7,8-tetrahydroquinolineYield 93.1%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

A mixture of cyclohexane-1,3-dione (11.2 g. 0.1 m), 3-amino-2-methylacrolein (8.5 g. 0.1m) triethylamine (5 ml.) and ammonium acetate (100 mg) were heated with stirring at 120° in an oil bath for 12 hours. The cooled reaction mixture was diluted with ether (50 ml.) and the solution washed with 2N HCl (3 × 15 ml.) The combined washings were adjusted to pH 9.0 with sodium carbonate and extracted with ether (3 × 50 ml.) The combined extracts were dried, evaporated in vacuo and the residual oil distilled at 0.2 mm Hg to give the 3-methyl-7,8-dihydro-5(6H)-quinolone as a colorless crystalline solid b.p. 80° (7.5 g. 48%). A mixture of 3-methyl-7,8-dihydro-5(6H)-quinolone (20 g.), hydrazine hydrate (14 ml), diethylene glycol (150 ml.) and sodium hydroxide (14 g) was heated at reflux with stirring for 1 hour. The condenser was replaced by a Dean and Stark Water Separator and the heating continued for a further 3 hours. The cooled reaction mixture was diluted with water (200 ml.) and extracted with ether (3 × 150 ml.). The combined extracts were dried (MgSO4) and the solvent removed in vacuo and the residual oil distilled at 15 mm Hg to give the title compound as a colourless oil b.p.116° (17 g, 93%) G.L.C. (3% SE30, T=150°) RF =3.5 min.

Workup

  1. temperaturewas heated
  2. temperatureat reflux
  3. waitthe heating continued for a further 3 hours
  4. customThe cooled reaction mixture
  5. extractionextracted with ether (3 × 150 ml.)
  6. dry with materialThe combined extracts were dried (MgSO4)
  7. customthe solvent removed in vacuo
  8. distillationthe residual oil distilled at 15 mm Hg

Sources & evidence

ORD record
ord-fc7c781ca1bc4cc69acbc5caa3a652d3
Source dataset
uspto-grants-1978_05
Patent number
US04092317

Reaction notes

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