Nalidixic acid

IUPAC: 1-ethyl- 7-methyl- 4-oxo- 1,4- dihydro -1 ,8- naphthyridine-3 -carboxylic acid

J01MB02

Antibiotic quinolone

Gyrase inhibitors

Risk

• 2040 mg · kg -1 ( LD50, rat, oral)
• 88.4 mg · kg -1 ( LD50, rat, i.v.)
• 572 mg · kg -1 ( LD50, mouse, oral)
• 101 mg · kg -1 ( LD50, mouse, i.v.)

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Nalidixic acid (trade name: Wintomylon ® ( BR) ) is the first antibiotic in a group of quinolones. The drug inhibits the enzyme gyrase in bacteria. Nalidixic acid in 1962 as primarily effective against Gram -negative bacterial antibiotic with low toxicity discovered (LD50 after oral administration in mice of approximately 3 g · kg -1). From nalidixic acid starting searched for similar but more effective antibiotics. In the following, it was replaced by the much more effective fluoroquinolones. Nalidixic acid is effective against Gram- positive and Gram- negative bacteria. In a low concentration, it is bacteriostatic, i.e. preventing the growth of bacteria while a bactericidal effect at higher concentrations, that is, kills them.

It is used mainly to treat urinary tract infections caused by Escherichia coli, Proteus, Shigella, Enterobacter and Klebsiella.

Production and representation

The four-step synthesis starts with the first step of the reaction of 2- amino-6- methylpyridine with diethyl ethoxymethylenemalonate. The resulting intermediate is then cyclized to 1,8- Naphthyridinstruktur. After saponification of the ethyl ester with aqueous sodium hydroxide solution, the target compound is obtained by N-alkylation using ethyl iodide.