Sulfuric Acid → Ethyl 1-cyclopropyl-7-(4-ethoxycarbonyl-1-piperazinyl)-6-fluoro-8-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylate

HRID 2351905Notes

Reaction equation

HRID 2351905 reaction equation
[CH:1]1([N:4]([CH:27]=[C:28]([C:34](OCC)=[O:35])[C:29]([O:31][CH2:32][CH3:33])=[O:30])[C:5]2[C:10]([N+]([O-])=O)=[CH:9][C:8]([F:14])=[C:7]([N:15]3[CH2:20][CH2:19][N:18]([C:21]([O:23][CH2:24][CH3:25])=[O:22])[CH2:17][CH2:16]3)[C:6]=2[CH3:26])[CH2:3][CH2:2]1.S(=O)(=O)(O)O.C(=O)([O-])[O-].[K+].[K+]>C(OC(=O)C)(=O)C>[CH:1]1([N:4]2[C:5]3[C:10](=[CH:9][C:8]([F:14])=[C:7]([N:15]4[CH2:16][CH2:17][N:18]([C:21]([O:23][CH2:24][CH3:25])=[O:22])[CH2:19][CH2:20]4)[C:6]=3[CH3:26])[C:34](=[O:35])[C:28]([C:29]([O:31][CH2:32][CH3:33])=[O:30])=[CH:27]2)[CH2:2][CH2:3]1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 11430Potassium CarbonateHCID 15631832diethyl [N-cyclopropyl-N-[3-(4-ethoxycarbonyl-1-piperazinyl)-2-methyl-4-fluoro-6-nitrophenyl]aminomethylene]malonate

Product 1

HCID 15631833Ethyl 1-cyclopropyl-7-(4-ethoxycarbonyl-1-piperazinyl)-6-fluoro-8-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylateYield 22.9%

Reagents, catalysts & solvents 1

HCID 7918Acetic AnhydrideSolvent

Procedure

To a solution of diethyl [N-cyclopropyl-N-[3-(4-ethoxycarbonyl-1-piperazinyl)-2-methyl-4-fluoro-6-nitrophenyl]aminomethylene]malonate (1.0 g) in acetic anhydride (5 ml) is added conc. sulfuric acid (2 ml) with keeping at 50°-70° C. After stirring for 30 minutes, the reaction mixture is poured into ice water, and neutralized with potassium carbonate. The mixture is extracted with ethyl acetate, and the solvent is distilled off, and the resulting residue is purified by silica gel column chromatography (solvent, dichloromethane:methanol=10:1) and then recrystallized from ethyl acetate to give ethyl 1-cyclopropyl-7-(4-ethoxycarbonyl-1-piperazinyl)-6-fluoro-8-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylate (0.19 g), as colorless prisms, m.p. 200°-202° C.

Workup

  1. customwith keeping at 50°-70° C
  2. extractionThe mixture is extracted with ethyl acetate
  3. distillationthe solvent is distilled off
  4. customthe resulting residue is purified by silica gel column chromatography (solvent, dichloromethane:methanol=10:1)
  5. customrecrystallized from ethyl acetate

Sources & evidence

ORD record
ord-89489a0fbf9740ec871949a8920b8215
Source dataset
uspto-grants-1989_10
Patent number
US04874764

Reaction notes

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