Ethanol → 3-Ethoxy-7,8-difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

HRID 1756795Notes

Reaction equation

HRID 1756795 reaction equation
C(OC([CH:6]1[CH2:15][N:14]([CH3:16])[C:13]2[N:12]=[C:11]3[CH:17]=[C:18]([F:22])[C:19]([F:21])=[CH:20][C:10]3=[CH:9][C:8]=2[C:7]1=[O:23])=O)C.OO.S([O-])([O-])(=O)=S.[Na+].[Na+].[CH2:33]([OH:35])[CH3:34]>O.[I-].[K+]>[CH2:33]([O:35][C:6]1[C:7](=[O:23])[C:8]2[CH:9]=[C:10]3[CH:20]=[C:19]([F:21])[C:18]([F:22])=[CH:17][C:11]3=[N:12][C:13]=2[N:14]([CH3:16])[CH:15]=1)[CH3:34]

Participants

7

Reactant 4

HCID 702EthanolHCID 784Hydrogen PeroxideHCID 24477Sodium ThiosulfateHCID 98835423-Ethoxycarbonyl-7,8-difluoro-1-methyl-4-oxo-1,2,3,4-tetrahydrobenzo[b][1,8]naphthyridine

Product 1

HCID 189946053-Ethoxy-7,8-difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Reagents, catalysts & solvents 2

HCID 4875Potassium IodideCatalystHCID 962WaterSolvent2×

Conditions

Temperature
77 °C

Procedure

A solution of 3.78 g of potassium iodide in 20 cm3 of water is added with stirring at approximately 20° C. to a suspension of 71 g of 3-ethoxycarbonyl-7,8-difluoro-1-methyl-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 30 cm3 of 33% by weight hydrogen peroxide is added in the course of 60 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 11.4 g of sodium thiosulphate in 50 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 300 cm3 of water. The wet product obtained is dried under reduced pressure (20 kPa) at approximately 60° C. 73 g of 3-ethoxy-7,8-difluoro-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine are isolated in the form of a white solid, melting point above 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 300 cm3 of water
  6. customThe wet product obtained
  7. customis dried under reduced pressure (20 kPa) at approximately 60° C

Sources & evidence

ORD record
ord-af16c9eeee664f30a421e7bba968ca1b
Source dataset
uspto-grants-1995_08
Patent number
US05442070

Reaction notes

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