Sulfuric Acid → 7,8-Dimethoxy-2-methyl-3H-pyrimido[4,5-b]quinolin-4-one

HRID 2163594Notes

Reaction equation

HRID 2163594 reaction equation
S(=O)(=O)(O)O.[CH3:6][O:7][C:8]1[CH:9]=[C:10]2[C:15](=[CH:16][C:17]=1[O:18][CH3:19])[N:14]=[C:13]([NH2:20])[C:12]([C:21]([NH2:23])=[O:22])=[CH:11]2.[C:24](OC(=O)C)(=O)[CH3:25].[OH-].[Na+]>O>[CH3:24][C:25]1[NH:23][C:21](=[O:22])[C:12]2[C:13]([N:20]=1)=[N:14][C:15]1[C:10]([CH:11]=2)=[CH:9][C:8]([O:7][CH3:6])=[C:17]([O:18][CH3:19])[CH:16]=1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 7918Acetic Anhydride2×HCID 14798Sodium HydroxideHCID 7815842-Amino-6,7-dimethoxyquinoline-3-carboxamide

Product 1

HCID 1358226487,8-Dimethoxy-2-methyl-3H-pyrimido[4,5-b]quinolin-4-one

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

Concentrated sulfuric acid (1.5 ml.) is added to a slurry of 6,7-dimethoxy-2-aminoquinoline-3-carboxamide (5.0 g., 0.02 mole) and acetic anhydride (40 ml). The slurry dissolves to give a dark orange solution from which a heavy yellow precipitate separates. Acetic anhydride (10 ml.) is added to facilitate stirring and heating continued for an additional 75 minutes. The mixture is cooled, water (50 ml.) added and the resulting solution made alkaline with 5N sodium hydroxide (225 ml.). It is chilled, the precipitate collected by filtration and air-dried. The yellow solid is recrystallized from ethanol. Yield = 2.37 g., M.P. 300° -302° (dec.).

Workup

  1. dissolutionThe slurry dissolves
  2. customto give a dark orange solution from which a heavy yellow precipitate separates
  3. temperatureheating
  4. temperatureThe mixture is cooled
  5. temperatureIt is chilled
  6. filtrationthe precipitate collected by filtration
  7. customair-dried
  8. customThe yellow solid is recrystallized from ethanol

Sources & evidence

ORD record
ord-66f8bddba1f04c9da7bde007054e9096
Source dataset
uspto-grants-1979_01
Patent number
US04134981

Reaction notes

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