Sulfuric Acid → Methyl 4-oxo-1,4-dihydrocinnoline-6-carboxylate

HRID 2079990Notes

Reaction equation

HRID 2079990 reaction equation
[CH3:1][O:2][C:3](=[O:14])[C:4]1[CH:9]=[CH:8][C:7]([NH2:10])=[C:6]([C:11](=[O:13])[CH3:12])[CH:5]=1.S(=O)(=O)(O)O.[N:20]([O-])=O.[Na+]>C(O)(=O)C>[CH3:1][O:2][C:3]([C:4]1[CH:5]=[C:6]2[C:7](=[CH:8][CH:9]=1)[NH:10][N:20]=[CH:12][C:11]2=[O:13])=[O:14]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 10856336Methyl 3-acetyl-4-aminobenzoateHCID 23668193Sodium Nitrite

Product 1

HCID 67119550Methyl 4-oxo-1,4-dihydrocinnoline-6-carboxylateYield 16.7%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

To a solution of 3-acetyl-4-amino-benzoic acid methyl ester (2063 mg, 10.68 mmol) in acetic acid (39 mL) was added sulfuric acid (6.5 mL) on an ice bath, then, an aqueous solution (6.5 mL) of sodium nitrite (922 mg, 13.35 mmol) was added thereto, followed by stirring on the ice for 1 hour, and at room temperature for 2 days. The reaction mixture was concentrated until it reached half of the amount, water was added, then an aqueous solution of 2N sodium hydroxide was added on an ice bath to adjust the pH to 5. The insoluble matter was separated by filtration, then, the filtrate was extracted with ethyl acetate, the organic layer was dried over sodium sulfate and then evaporated. Diethyl ether was added to the resulting residue for solidification, the resulting solid was washed with diethyl ether, and 365 mg of the title compound (1.78 mmol, 16.6%) was obtained.

Workup

  1. concentrationThe reaction mixture was concentrated until it
  2. additionwas added
  3. additionan aqueous solution of 2N sodium hydroxide was added on an ice bath
  4. customThe insoluble matter was separated by filtration
  5. extractionthe filtrate was extracted with ethyl acetate
  6. dry with materialthe organic layer was dried over sodium sulfate
  7. customevaporated
  8. additionDiethyl ether was added to the resulting residue for solidification
  9. washthe resulting solid was washed with diethyl ether

Sources & evidence

ORD record
ord-fca7c5b9f724403a88203cf9f5c4ced0
Source dataset
uspto-grants-2011_04
Patent number
US07932272B2

Reaction notes

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