7-Chloro-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid → Norfloxacin

HRID 729055Notes

Reaction equation

[CH2:1]([N:3]1[C:12]2[C:7](=[CH:8][C:9]([F:14])=[C:10](Cl)[CH:11]=2)[C:6](=[O:15])[C:5]([C:16]([OH:18])=[O:17])=[CH:4]1)[CH3:2].[Si]([N:26]1[CH2:31][CH2:30][NH:29][CH2:28][CH2:27]1)(C(C)(C)C)(C)C.O.O.O.[F-].C([N+](CCCC)(CCCC)CCCC)CCC>N1C=CC=CC=1>[CH2:1]([N:3]1[C:12]2[C:7](=[CH:8][C:9]([F:14])=[C:10]([N:26]3[CH2:31][CH2:30][NH:29][CH2:28][CH2:27]3)[CH:11]=2)[C:6](=[O:15])[C:5]([C:16]([OH:18])=[O:17])=[CH:4]1)[CH3:2]

Participants

Conditions

Temperature: 60 °C

Procedure

0.5 g (1.85 mmol) of 1-ethyl-6-fluoro-7-chloro-4-oxo1,4-dihydro-quinoline-3-carboxylic acid (II, R1 : ethyl; X: chloro) and 1.1 g (5.5 mmol) of 1-(t-butyldimethylsilyl) piperazine (R2 : hydrogen, R3 and R4 : methyl; R5 : t-butyl) are added to 5 ml of pyridine and then heated at 60° C. A solution of 1.73 g (5.5 mmol) of tetrabutylammonium fluoride trihydrate in 5 ml of pyridine is added dropwise to the reaction mixture. After completion of addition, the reaction mixture is heated at 80° C. for 2 hours and then distilled under reduced pressure (10 mmHg, 60° C.). The residue is added with water and then stirred to afford a crystal. After filtering and drying, 0.50 g of a solid product is obtained.

Workup

additionAfter completion of addition
temperaturethe reaction mixture is heated at 80° C. for 2 hours
distillationdistilled under reduced pressure (10 mmHg, 60° C.)
additionThe residue is added with water
customto afford a crystal
filtrationAfter filtering
customdrying

Sources & evidence

ORD record: ord-89447a34551745f9b5e2b2b7bd474a35
Source dataset: uspto-grants-1991_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05051505

Reaction notes

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