Piperazine → Ethyl norfloxacin

HRID 2418466Notes

Reaction equation

HRID 2418466 reaction equation
[NH:1]1[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.[CH2:7]([O:9][C:10]([C:12]1[C:21](=[O:22])[C:20]2[C:15](=[CH:16][C:17](Cl)=[C:18]([F:23])[CH:19]=2)[N:14]([CH2:25][CH3:26])[CH:13]=1)=[O:11])[CH3:8]>C(N(CC)CC)C>[CH2:7]([O:9][C:10]([C:12]1[C:21](=[O:22])[C:20]2[C:15](=[CH:16][C:17]([N:1]3[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]3)=[C:18]([F:23])[CH:19]=2)[N:14]([CH2:25][CH3:26])[CH:13]=1)=[O:11])[CH3:8]

Participants

4

Reactant 2

HCID 4837PiperazineHCID 12733855Ethyl 7-chloro-1-ethyl-6-fluoro-4-oxo-1,4-dihydro-3-quinolinecarboxylate

Product 1

HCID 12733941Ethyl norfloxacinYield 71.3%

Reagents, catalysts & solvents 1

HCID 8471TriethylamineSolvent

Conditions

Temperature
0 °C

Procedure

A mixture of 18 ml of triethylamine, 10.3 g of anhydrous piperazine, and 8.9 g of 1-ethyl-6-fluoro-7-chloro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid ethyl ester was refluxed with stirring for 20 hrs. The reaction mixture was concentrated under reduced pressure, 30 ml of chloroform was added to the residue, and cooled at 0° C. to give crystals. The crystals were filtered to recover 2 g of 1-ethyl-6-fluoro-7-chloro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid ethyl ester. The above filtrated solution was extracted with diluted hydrochloric acid, the hydrochloric acid layer was neutralized with diluted sodium hydroxide solution, and the neutralized solution was extracted with chloroform. The chloroform layer was washed with water and dried over anhydrous magnesium sulfate, the chloroform was evaporated under reduced pressure. The residue was treated by the same procedure in Example 1 to give 7.4 g (71% yield) of 1-ethyl-6-fluoro-7-(1-piperazinyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid ethyl ester. mp: 178°- 180° C.

Workup

  1. temperaturewas refluxed
  2. concentrationThe reaction mixture was concentrated under reduced pressure, 30 ml of chloroform
  3. additionwas added to the residue
  4. customto give crystals
  5. filtrationThe crystals were filtered
  6. customto recover 2 g of 1-ethyl-6-fluoro-7-chloro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid ethyl ester
  7. filtrationThe above filtrated solution
  8. extractionwas extracted with diluted hydrochloric acid
  9. extractionthe neutralized solution was extracted with chloroform
  10. washThe chloroform layer was washed with water
  11. dry with materialdried over anhydrous magnesium sulfate
  12. customthe chloroform was evaporated under reduced pressure
  13. additionThe residue was treated by the same procedure in Example 1

Sources & evidence

ORD record
ord-a07fd5dd0e774f4ca6f4d97a46647f91
Source dataset
uspto-grants-1984_09
Patent number
US04472579

Reaction notes

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