Hydrogen Peroxide → 3-Ethoxycarbonyl-7,8-difluoro-1-ethyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

HRID 375253Notes

Reaction equation

HRID 375253 reaction equation
[I-].[K+].[CH2:3]([O:5][C:6]([CH:8]1[CH2:17][N:16]([CH2:18][CH3:19])[C:15]2[N:14]=[C:13]3[CH:20]=[C:21]([F:25])[C:22]([F:24])=[CH:23][C:12]3=[CH:11][C:10]=2[C:9]1=[O:26])=[O:7])[CH3:4].OO.S([O-])([O-])(=O)=S.[Na+].[Na+]>O.C(O)C>[CH2:3]([O:5][C:6]([C:8]1[C:9](=[O:26])[C:10]2[CH:11]=[C:12]3[CH:23]=[C:22]([F:24])[C:21]([F:25])=[CH:20][C:13]3=[N:14][C:15]=2[N:16]([CH2:18][CH3:19])[CH:17]=1)=[O:7])[CH3:4]

Participants

7

Reactant 4

HCID 784Hydrogen PeroxideHCID 4875Potassium IodideHCID 24477Sodium ThiosulfateHCID 189945863-Ethoxycarbonyl-7,8-difluoro-1-ethyl-4-oxo-1,2,3,4-tetrahydrobenzo[b][1,8]naphthyridine

Product 1

HCID 194236943-Ethoxycarbonyl-7,8-difluoro-1-ethyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridineYield 87.5%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent2×

Conditions

Temperature
77 °C

Procedure

A solution of 1.7 g of potassium iodide in 10 cm3 of water is added with stirring at approximately 20° C. to a suspension of 33 g of 3-ethoxycarbonyl-7,8-difluoro-1-ethyl-4-oxo-1,2,3,4-tetrahydrobenzo[b][1,8]naphthyridine in 1,000 cm3 of ethanol. The suspension is heated to 77° C., and 12.7 cm3 of 33% by weight hydrogen peroxide are introduced in the course of 30 minutes at this temperature. The reaction mixture is kept refluxing for a further 30 minutes and is then cooled to approximately 20° C. A solution of 6 g of sodium thiosulphate in 20 cm3 of water is introduced in the course of 5 minutes at this temperature. The precipitate obtained is drained at approximately 20° C. and washed with twice 150 cm3 of water. The wet product obtained is dried under reduced pressure (20 kPa) at approximately 50° C. 28.7 g of 3-ethoxycarbonyl-7,8-difluoro-1-ethyl-4-oxo-1,4-dihydrobenzo[b][1,8]-naphthyridine are isolated in the form of a light yellow solid, melting point 270° C.

Workup

  1. temperatureThe reaction mixture is kept refluxing for a further 30 minutes
  2. temperatureis then cooled to approximately 20° C
  3. customThe precipitate obtained
  4. customis drained at approximately 20° C.
  5. washwashed with twice 150 cm3 of water
  6. customThe wet product obtained
  7. customis dried under reduced pressure (20 kPa) at approximately 50° C

Sources & evidence

ORD record
ord-22d231189b80438e976c1634bf55841f
Source dataset
uspto-grants-1996_01
Patent number
US05484921

Reaction notes

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