3.1. Chelation 564 3.2. Acid−Base Character 564 3.3. Photochemistry 565 4. In Vitro Antimicrobial Spectra 566 5. Structure−Activity Relationships 568 5.1. N-1 Ethyl Family 568 5.2. N-1 Cyclopropyl Family 568 5.3. N-1 to C-8 Bridged (Tricyclic) Family 568 5.4. N-1 Aryl Family 569 5.5. Positions C-2, C-3, and C-4 570 5.6. C-4a Substituted Analogues 571 5.7. C-5 Substituents 571 5.8. C-6 Substituents 571 5.9. C-7 Substituents 571 5.9.1. Piperazinyl and Related Moieties 572 5.9.2. Pyrrolidinyl and Related Moieties 572 5.9.3. Cyclobutylaminyl and Related Moieties 572 5.9.4. Bicycloaminyl Moieties 572 5.9.5. Carbon-Linked Substituents 572 5.10. Substituents at C-8 573 5.11. Resume of Structure−Activity Relationships of Quinolones 573

Bacterial topoisomerase inhibitors: quinolone and pyridone antibacterial agents.

https://pubs.rsc.org/en/Content/ArticlePDF/2016/NP/C5NP00096C

Synthetic approaches towards alkaloids bearing α-tertiary amines

4-Quinolone derivatives and their activities against Gram positive pathogens

Publisher Summary Quinolone agents exhibit a bicyclic aromatic core, containing a carbon at the 8th position, yielding a true quinolone, or a nitrogen, and provide a ring system technically termed as naphthyridone. In common usage, both quinolone and naphthyridone structures are encompassed in the class descriptor “quinolone antibacterial agents.” The first generation quinolone compounds generally displayed increased Gram-negative activity over nalidixic acid, but lacked useful activity against Gram-positive cocci, Pseudomonas aeruginosa, and anaerobes. They were, however, generally well absorbed after oral administration and attained high concentrations in the urinary tract, making them useful therapeutically for treatment of urinary tract infections. In the second-generation quinolones, the piperazine ring remains relatively undisturbed, except for alkylation on the distal nitrogen or, less frequently, on the ring carbons. The second-generation compounds are characterized by good to excellent Gram-negative activity, with ciprofloxacin exhibiting the strongest Gram-negative spectrum. The third- and fourth-generation quinolones are characterized by increased structural novelty and complexity, which has resulted in new and useful characteristics. Clinafloxacin, sitafloxacin, and BAY y 3118, all of which bear a chlorine atom at C-8, are among the most potent broad-spectrum agents that have been in the development, and are the only compounds that exhibit Gram-negative activity superior to that of ciprofloxacin. These compounds, with the exception of pazufloxacin, show improved activity against S. pneumoniae compared to ciprofloxacin. The most potent of these agents are gemifloxacin and BAY y 3118, followed by clinafloxacin, sitafloxacin, moxifloxacin, and trovafloxacin.

Chemistry and Mechanism of Action of the Quinolone Antibacterials

https://research.aalto.fi/files/7159697/ms119_Propellanes_TH_2005_8769.pdf

Synthesis of propellane-containing natural products

A series of [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acids and their esters were prepared and evaluated for antibacterial activity. The derivatives with a hydrogen or methyl group at C-1, fluorine at C-6, and piperazinyl or 4-methyl-1-piperazinyl group at C-7 showed superior in vitro antibacterial activity, and the derivatives with 4-methyl-1-piperazinyl group at C-7 had potent in vivo activity. Compound 29a (NM394) showed excellent in vitro antibacterial activity and low toxicity but poor absorption from the gastrointestinal tract. Compound 29ee (NM441), an N-[(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl] derivative of 29a, was found to possess a favorable pharmacokinetic profile and oral activity superior to that of ciprofloxacin in experimental animals.

Studies on pyridonecarboxylic acids. 1. Synthesis and antibacterial evaluation of 7-substituted-6-halo-4-oxo-4H-[1,3]thiazeto[3,2-a]quinoline-3- carboxylic acids.

NM441 is a lipophilic prodrug of a new thiazeto-quinoline carboxylic acid derivative NM394, and when it is administered orally it is readily absorbed and hydrolyzed to its parent compound. After oral administration of NM441 at a dose of 20 mg/kg to dogs, the peak concentration of NM394 in plasma was 2.39 micrograms/ml, whereas it was 0.63 micrograms/ml for NM394 administered alone. The in vivo activity of NM441 was compared with those of ciprofloxacin, ofloxacin, and enoxacin in mouse protection studies. NM441 was as effective as ofloxacin and was twice as effective as ciprofloxacin against systemic infection with Staphylococcus aureus. Against infections with streptococci, NM441 was two to three times as effective as ofloxacin and five times as effective as ciprofloxacin. Against infection with Escherichia coli, NM441 was as effective as ciprofloxacin and ofloxacin, but against infections with Klebsiella pneumoniae, Serratia marcescens, and Pseudomonas aeruginosa, NM441 was two to four times as effective as ciprofloxacin and ofloxacin. NM441 was three to seven times as effective as enoxacin in systemic infections. Against urinary tract infections with E. coli, NM441 reduced the number of bacterial CFU per gram of kidney by 1 to 2 log10 more and, with P. aeruginosa, by 1 to 6 log10 more than did ciprofloxacin and ofloxacin. Against respiratory tract infections with K. pneumoniae, NM441 was as effective as ofloxacin and was twice as effective as ciprofloxacin.

In vivo evaluation of NM441, a new thiazeto-quinoline derivative.

Mass spectrometry of bisbenzylisoquinoline alkaloids.

The synthesis of dl-cepharamine (4) which is a member of hasubanan alkaloids, was accomplished after the model experiments started from 2-tetralone (5) were examined The keto-lactam (30) was synthesized from 7, 8-dimethoxy-2-tetralone (7) via the keto-ester (27) or the keto-nitrile (53) Ketalization of the compound (30), followed by treatment under the Wolff-Kishner reaction condition caused by demethylation of a methoxyl group at C4 to result in the phenolic compound (63) Acetylation of the compound (63), followed by deketalization gave the keto-acetate (65) The diketone (67) was synthesized by bromination of the compound (65) with two equivalents of bromine, followed by heating with anhydrous sodium acetate in acetic acid The target molecule, dl-cepharamine (4), was synthesized from the diketone (67) by successive treatments with BF3·ether-MeOH (monoenolmethylation), LiAlH4 reduction and oxidation with DMSO-phosphoric acid-DCC

Total Synthesis of dl-Cepharamine

Indolecarboxamide derivatives of general formula (I) and a serotonin antagonist mainly comprising the same. The test on the activity of the compounds (I) in the inhibition of Bezold-Jarisch reflex has proved that the activity is 3 to 5 times as potent as those of the conventional drugs and also the duration of action is 5 to 10 times as long as those of the conventional ones. The test on the activity of the same in the inhibition of cisplatin-induced vomiting has also proved that this activity is potent. Since the compounds of the invention have only a low acute toxicity, they are very useful as a serotonin antagonist.

Indole derivatives and medicine

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