Hydrochloric Acid → 1,4-Dihydro-2-(methylthio)-4-oxo-3-quinolinecarboxylic acid

HRID 2189512Notes

Reaction equation

HRID 2189512 reaction equation
C([O:3][C:4]([C:6]1[C:7]([S:17][CH3:18])=[N:8][C:9]2[C:14]([C:15]=1[OH:16])=[CH:13][CH:12]=[CH:11][CH:10]=2)=[O:5])C.Cl>[OH-].[Na+]>[CH3:18][S:17][C:7]1[NH:8][C:9]2[C:14]([C:15](=[O:16])[C:6]=1[C:4]([OH:5])=[O:3])=[CH:13][CH:12]=[CH:11][CH:10]=2

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 1784701074-Hydroxy-2-methylsulfanyl-quinoline-3-carboxylic acid ethyl ester

Product 1

HCID 465076311,4-Dihydro-2-(methylthio)-4-oxo-3-quinolinecarboxylic acidYield 85%

Reagents, catalysts & solvents 1

HCID 14798Sodium HydroxideSolvent

Procedure

4-Hydroxy-2-methylsulfanyl-quinoline-3-carboxylic acid ethyl ester (8 g, 30 mmol) was heated under reflux in NaOH solution (10%, 100 mL) for 1.5 h. After cooling, the mixture was acidified with concentrated HCl to pH 4. The resulting solid was collected via filtration, washed with water (100 mL) and MeOH (100 mL) to give 2-methylsulfanyl-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid (A-16) as a white solid (6 g, 85%). 1H NMR (CDCl3) δ 16.4 (br s, 1H), 11.1 (br s, 1H), 8.19 (d, J=8 Hz, 1H), 8.05 (d, J=8 Hz, 1H), 7.84 (t, J=8, 8 Hz, 1H), 7.52 (t, J=8 Hz, 1H), 2.74 (s, 3H); ESI-MS 235.9 m/z (MH+).

Workup

  1. temperatureAfter cooling
  2. filtrationThe resulting solid was collected via filtration
  3. washwashed with water (100 mL) and MeOH (100 mL)

Sources & evidence

ORD record
ord-c82e494cc614468abaac56314d9cb452
Source dataset
uspto-grants-2012_12
Patent number
US08324242B2

Reaction notes

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