Water → 1-Cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid

HRID 1357329Notes

Reaction equation

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

Participants

Conditions

Temperature: 80 °C

Procedure

1500 g of ethyl 1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate, 128.4 g of water, and 4500 g of acetic acid were introduced and 53 g of sulfuric acid were added. The mixture was heated at reflux for 4 hours. 2020 ml of distillate were then distilled off until a bottom temperature of 109° C. was reached. The suspension was then cooled to 80° C. and 2204 g of 4% strength by weight sodium acetate solution were added dropwise. The pH was then in the range 3 to 4. The mixture was then cooled to 20° C. and the solid was filtered off with suction. The solid was washed with 2000 ml of water and dried in vacuo at 50° C. 1329 g of 1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid were isolated, which corresponds to a yield of 98%.

Workup

temperatureThe mixture was heated
temperatureat reflux for 4 hours
distillation2020 ml of distillate were then distilled off until a bottom temperature of 109° C.
addition2204 g of 4% strength by weight sodium acetate solution were added dropwise
temperatureThe mixture was then cooled to 20° C.
filtrationthe solid was filtered off with suction
washThe solid was washed with 2000 ml of water
customdried in vacuo at 50° C

Sources & evidence

ORD record: ord-4df1b9ff63154bbab22e31d0e2f228b7
Source dataset: uspto-grants-2003_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06590101B2

Reaction notes

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