Ethyl 5-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate → 4-Hydroxy-5-methoxyquinoline-3-carboxylic acid

HRID 423719Notes

Reaction equation

HRID 423719 reaction equation
C([O:3][C:4]([C:6]1[C:15](=[O:16])[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][C:13]=2[O:17][CH3:18])[NH:8][CH:7]=1)=[O:5])C>[OH-].[Na+]>[CH3:18][O:17][C:13]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:14]=1[C:15](=[O:16])[C:6]([C:4]([OH:5])=[O:3])=[CH:7][NH:8]2

Participants

3

Reactant 1

HCID 9992162Ethyl 5-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate

Product 1

HCID 457897434-Hydroxy-5-methoxyquinoline-3-carboxylic acidYield 52%

Reagents, catalysts & solvents 1

HCID 14798Sodium HydroxideSolvent

Procedure

A mixture of 5-methoxy-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid ethyl ester (1 g, 7.1 mmol) in 10% NaOH solution (50 mL) was heated to reflux overnight and then cooled to room temperature. The mixture was extracted with ether. The aqueous phase was separated and acidified with conc. HCl solution to pH 1-2. The resulting precipitate was collected by filtration to give 5-methoxy-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid (A-4) (530 mg, 52%). 1H NMR (DMSO) δ: 15.9 (s, 1 H), 13.2 (br, 1 H), 8.71 (s, 1 H), 7.71 (t,J=8.1 Hz, 1 H), 7.18 (d,J=8.4 Hz, 1 H), 6.82 (d,J=8.4 Hz, 1 H), 3.86 (s, 3 H); ESI-MS 219.9 m/z (MH+).

Workup

  1. temperaturewas heated
  2. temperatureto reflux overnight
  3. extractionThe mixture was extracted with ether
  4. customThe aqueous phase was separated
  5. filtrationThe resulting precipitate was collected by filtration

Sources & evidence

ORD record
ord-ccc8018cf6dd4e49acf8982b88cda33c
Source dataset
uspto-grants-2012_01
Patent number
US08101767B2

Reaction notes

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