Top Qs
Timeline
Chat
Perspective

Grepafloxacin

Chemical compound From Wikipedia, the free encyclopedia

Grepafloxacin
Remove ads

Grepafloxacin (trade name Raxar, Glaxo Wellcome) was an oral broad-spectrum fluoroquinolone antibacterial agent used to treat bacterial infections. Grepafloxacin was withdrawn worldwide from markets in 1999,[1][2] due to the drug's potential to cause a potentially fatal cardiac arrhythmia.[3]

Quick Facts Clinical data, AHFS/Drugs.com ...
Remove ads

Clinical uses

Grepafloxacin was used for treating exacerbations of chronic bronchitis caused by susceptible bacteria (e.g. Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis),[4][5][6] community-acquired pneumonia (including those, in addition to the above germs, caused by Mycoplasma pneumoniae)[7][8] gonorrhea and non-gonococcal urethritis and cervicitis (for example caused by Chlamydia trachomatis or Ureaplasma urealyticum).[9][10]

Remove ads

Synthesis

Summarize
Perspective

The preparation of quinolones bearing a substituent at position 5 is complicated by the greater electrophilic character of the 8 position. One scheme for resolving the problem consists in blocking access to position 8 by first adding a readily removable group to that center.

Thumb
Grepafloxacin synthesis:[11][12]

The scheme starts with the conversion of the carboxylic acid in (1) to its dimethyloxazoline derivative (3) by reaction with the aminomethyl propanol (2). Lithium diisopropylamide (LDA) then removes a proton from the 8 position; treatment of that anion with trimethylsilyl iodide leads to the silylated intermediate (4). A second round of LDA then generates a carbanion at the only open position; reaction with methyl iodide leads to the corresponding 5 methyl derivative (5). Treatment of that product with cesium fluoride breaks the carbon–silicon bond, removing the silyl group; aqueous acid then hydrolyzes the oxazoline to afford the free acid (6). This last intermediate is then taken on to the quinolone (9) [13] by essentially the same scheme as that used to prepare difloxacin, with the difference that the chain elongation is by means of Grignard reagent of ethyl bromoacetate. Treatment of (9) with 2-methylpiperazine proceeds by reaction at the less hindered of the two amino groups; saponification then affords grepafloxacin (10).

Remove ads

Stereochemistry

Grepafloxacin contains a stereocenter and consists of two enantiomers. This is a racemate, ie a 1: 1 mixture of (R)- and the (S)-forms:

More information Enantiomers of grepafloxacin ...

See also

References

Loading related searches...

Wikiwand - on

Seamless Wikipedia browsing. On steroids.

Remove ads