Hydrochloric Acid → 1-Ethyl-6-fluoro-7-hydroxy-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid

HRID 963394Notes

Reaction equation

HRID 963394 reaction equation
[CH2:1]([N:3]1[C:12]2[C:7](=[CH:8][C:9]([F:14])=[C:10](F)[CH:11]=2)[C:6](=[O:15])[C:5]([C:16]([O:18]CC)=[O:17])=[CH:4]1)[CH3:2].Cl.[OH-:22].[Na+]>>[CH2:1]([N:3]1[C:12]2[C:7](=[CH:8][C:9]([F:14])=[C:10]([OH:22])[CH:11]=2)[C:6](=[O:15])[C:5]([C:16]([OH:18])=[O:17])=[CH:4]1)[CH3:2]

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 854165Ethyl 1-ethyl-6,7-difluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate

Product 1

HCID 166386641-Ethyl-6-fluoro-7-hydroxy-1,4-dihydro-4-oxo-quinoline-3-carboxylic acidYield 91%

Procedure

A suspension of 1.2 g of ethyl 1-ethyl-6,7-difluoro-1,4-dihydro-4-oxo-quinoline-3-carboxylate (European Offenlegungsschrift No. 230053, C.A. 108:112498) in 25 ml of 2N aqueous sodium hydroxide solution is heated at reflux for 4 hrs. After cooling to room temperature the reaction mixture is adjusted to pH 3 to 4 with 37% aqueous hydrochloric acid and the precipitate is filtered off under suction, washed with 200 ml of water and 200 ml of diethyl ether and dried. 980 mg (91%) of 1-ethyl-6-fluoro-7-hydroxy-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid are isolated as a colourless solid. M.p.>250°.

Workup

  1. temperatureis heated
  2. temperatureat reflux for 4 hrs
  3. filtrationthe precipitate is filtered off under suction
  4. washwashed with 200 ml of water and 200 ml of diethyl ether
  5. customdried

Sources & evidence

ORD record
ord-ab4a868cead744468bd80a40271c8e45
Source dataset
uspto-grants-1998_06
Patent number
US05763450

Reaction notes

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