Boron tribromide → 1-Ethyl-8-fluoro-6,7-dihydroxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid

HRID 525890Notes

Reaction equation

HRID 525890 reaction equation
[CH2:1]([N:3]1[C:12]2[C:7](=[CH:8][C:9]([O:16]C)=[C:10]([O:14]C)[C:11]=2[F:13])[C:6](=[O:18])[C:5]([C:19]([O:21]CC)=[O:20])=[CH:4]1)[CH3:2].B(Br)(Br)Br>ClCCl.CCO>[CH2:1]([N:3]1[C:12]2[C:7](=[CH:8][C:9]([OH:16])=[C:10]([OH:14])[C:11]=2[F:13])[C:6](=[O:18])[C:5]([C:19]([OH:21])=[O:20])=[CH:4]1)[CH3:2]

Participants

5

Reactant 2

HCID 25134Boron tribromideHCID 86732754Ethyl 1-ethyl-8-fluoro-6,7-dimethoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate

Product 1

HCID 867327551-Ethyl-8-fluoro-6,7-dihydroxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acidYield 91%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 6344DichloromethaneSolvent

Procedure

To a solution of ethyl 1-ethyl-8-fluoro-6,7-dimethoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate (24 g, 74.2 mmol) in Dichloromethane (DCM) (300 mL) was added boron tribromide (35.1 mL, 371 mmol) at −78° C. The mixture was warmed up to rt and stirred at 25° C. overnight. LCMS indicated completion of the reaction. The mixture was diluted with EtOH and concentrated in vacuo. The same procedure was repeated several times to afford 1-ethyl-8-fluoro-6,7-dihydroxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (18 g, 67.4 mmol, 91% yield) as a yellow solid. This product was used in next step reaction without further purification. LCMS (M+H)+: 268.0.

Workup

  1. customcompletion of the reaction
  2. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-8487d4fc80b74223b169b76b06ac439e
Source dataset
uspto-grants-2016_05
Patent number
US09340556B2

Reaction notes

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