Hydrochloric Acid → 1-Cyclopropyl-6,7-difluoro-5-methyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid

HRID 1279Notes

Reaction equation

HRID 1279 reaction equation
[CH:1]1([N:4]2[C:13]3[C:8](=[C:9]([CH3:16])[C:10]([F:15])=[C:11]([F:14])[CH:12]=3)[C:7](=[O:17])[C:6]([C:18]([O:20]CC)=[O:19])=[CH:5]2)[CH2:3][CH2:2]1.Cl>C(O)(=O)C>[CH:1]1([N:4]2[C:13]3[C:8](=[C:9]([CH3:16])[C:10]([F:15])=[C:11]([F:14])[CH:12]=3)[C:7](=[O:17])[C:6]([C:18]([OH:20])=[O:19])=[CH:5]2)[CH2:2][CH2:3]1

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 14651255Ethyl 1-cyclopropyl-6,7-difluoro-5-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylate

Product 1

HCID 146512541-Cyclopropyl-6,7-difluoro-5-methyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acidYield 92.7%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

To ethyl 1-cyclopropyl-6,7-difluoro-5-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylate (1.9 g) are added 90% acetic acid (20 ml) and conc. hydrochloric acid (5 ml) and the mixture is refluxed for 2 hours. After cooling, the precipitated crystals are isolated, washed with water, ethanol, and diethyl ether in this order to give 1-cyclopropyl-6,7-difluoro-5-methyl-1,4,-dihydro-4-oxoquinoline-3-carboxylic acid (1.6 g), as colorless needles, m.p. 294°-298° C.

Workup

  1. temperaturethe mixture is refluxed for 2 hours
  2. temperatureAfter cooling
  3. customthe precipitated crystals are isolated
  4. washwashed with water, ethanol, and diethyl ether in this order

Sources & evidence

ORD record
ord-b4ccefd875914706b84816f471c88bad
Source dataset
uspto-grants-1998_03
Patent number
US05723648

Reaction notes

Loading…