Pyridine → ethyl 6,7-dimethoxy-2-methyl-4-oxo-3,4-dihydro-1(2H)-quinolinecarboxylate

HRID 597201Notes

Reaction equation

HRID 597201 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][C:12]=1[O:13][CH3:14])[NH:9][CH:8]([CH3:15])[CH2:7][C:6]2=[O:16].C(Cl)Cl.N1C=CC=CC=1.Cl[C:27]([O:29][CH2:30][CH3:31])=[O:28]>O>[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][C:12]=1[O:13][CH3:14])[N:9]([C:27]([O:29][CH2:30][CH3:31])=[O:28])[CH:8]([CH3:15])[CH2:7][C:6]2=[O:16]

Participants

6

Reactant 4

HCID 1049PyridineHCID 6344Dichloromethane2×HCID 10928Ethyl chloroformateHCID 214397206,7-Dimethoxy-2-methyl-2,3-dihydroquinolin-4(1H)-one

Product 1

HCID 15480676ethyl 6,7-dimethoxy-2-methyl-4-oxo-3,4-dihydro-1(2H)-quinolinecarboxylate

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A mixture of 570 mg. of l-ethyl 6,7-dimethoxy-3-aminomethylene-2-methyl-4-oxo-1,2,3,4-tetrahydroquinoline-1-carboxylate, 1.78 ml. of 1N sodium hydroxide and 3 ml. of ethanol was heated under reflux for 24 hours and then stored at 25° C. for 3 days. The solvent was removed by evaporation in vacuo, and the residue was dissolved in ethyl acetate. The ethyl acetate solution was washed with water and then it was concentrated to give 540 mg. of an oil. The oil was chromatographed using 30 g. of silica gel, and using 6:4 benzene-ethyl acetate as solvent, giving 6 fractions. Fractions 1 and 2 were combined and recrystallized from ethyl acetate-hexane to give 49 mg. of the title product, m.p. 92°-93° C. Fractions 3-6 were combined to give 152 mg. of 6,7-dimethoxy-2-methyl-4-oxo-1,2,3,4-tetrahydroquinoline. This latter material was dissolved in 3 ml. of methylene chloride, and 3 ml. of pyridine followed by 0.5 ml. of ethyl chloroformate was added. After 20 minutes, the reaction mixture was diluted with an excess of methylene chloride and water. The organic phase was separated and washed successively with dilute hydrochloric acid, saturated sodium bicarbonate and brine. The methylene chloride solution was then dried, and evaporated in vacuo to give an oil. The oil was recrystallized from ethyl acetate-hexane to give 95 mg. of the title compound, m.p. 92°-93° C.

Workup

  1. customto give 152 mg
  2. dissolutionThis latter material was dissolved in 3 ml
  3. customThe organic phase was separated
  4. washwashed successively with dilute hydrochloric acid, saturated sodium bicarbonate and brine
  5. dry with materialThe methylene chloride solution was then dried
  6. customevaporated in vacuo
  7. customto give an oil
  8. customThe oil was recrystallized from ethyl acetate-hexane
  9. customto give 95 mg

Sources & evidence

ORD record
ord-4f5daf94f4a44a4a930db13db63b4d23
Source dataset
uspto-grants-1977_03
Patent number
US04013662

Reaction notes

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