- ANTIBIOTIC RESISTANCE BREAKERS
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The invention relates to antibiotic compounds of formula (A1) and pharmaceutically acceptable salts, solvates, tautomers and combinations thereof, wherein X and L are optional linkers and one of RA or R1 comprises Ar1, wherein Ar1 is an antibiotic resistance breaker moiety which comprises an optionally substituted C6-10 aryl, C7-13 aralkyl, C5-10 heteroaryl, C6-13 heteroaralkyl, C5-10 heterocyclyl, C6-13 heterocyclalkyl, C3-10 carbocyclyl, C4-13 carbocyclalkyl, -C(=NR')-NR'R'' or –CH2- CH=CH2 group; wherein after administration of the compound to a bacterial infection this moiety reduces or prevents efflux. The invention also discloses pharmaceutical compositions comprising compounds of formula (A1) and the use of such compounds as medicaments, in particular, to treat bacterial infections, such as drug-resistant bacterial infections.
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- Nano-Fe3 O4@ZrO2-SO3 H as highly efficient recyclable catalyst for the green synthesis of fluoroquinolones
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Nano-Fe3 O4 @ZrO2-SO3 H (n-FZSA), was utilized as a magnetic catalyst for the synthesis of various fluoroquinolone compounds. These compounds were prepared by the direct amination of 7-halo-6-fluoroquinolone-3-carboxylic acids with piperazine derivatives and (4aR,7aR)-octahydro-1H-pyrrolo[3,4-b] pyridine in water. The results showed that n-FZSA exhibited high catalytic activity towards the synthesis of fluoroquinolone derivatives, giving the desired products in high yields. Furthermore, the catalyst was recyclable and could be used at least seven times without any discernible loss in its catalytic activity. Overall, this new catalytic method for the synthesis of fluoroquinolone derivatives provides rapid access to the desired compounds in refluxing water following a simple work-up procedure, and avoids the use of organic solvents.
- Nakhaei, Ahmad,Ramezani, Shirin,Shams-Najafi, Sayyed Jalal,Farsinejad, Sadaf
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p. 739 - 746
(2018/09/26)
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- Conventional and microwave-assisted synthesis of quinolone carboxylic acid derivatives
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Various antibacterial fluoroquinolone compounds are synthesized by the direct amination of 7-halo-6-fluoroquinolone-3-carboxylic acids with a variety of piperazine derivatives and (4aR,7aR)-octahydro-1H-pyrrolo[3,4-b]pyridine using microwave under different reaction conditions. Solvent free high yield microwave synthesis of antibacterial fluoroquinolone compounds is convenient, rapid and environmentally friendly method.
- Mirzaie,Lari,Vahedi,Hakimi
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p. 2865 - 2869
(2017/03/22)
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- Synthesis, characterization, antimicrobial activity of novel n-substituted β-hydroxy amines and βhydroxy ethers contained chiral benzoxazine fluoroquinolones
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Synthesis of novel N-substituted β-hydroxy amines 4(a-j) and β-hydroxyethers 5(a-c) with chiral benzoxazine fluoroquinolones has been described. Benzoxazinefluoroquinolone carboxylic acid 1, on reaction with piperizine in acetonitrile in presence of triethylamine under reflux gives 7- piperazinyl benzoxazine fluoroquinolone 2. The latter is reacted with epichlrohydrine in presence of NaOH in acetone to yield respective N-substituted epoxide 3 with retained chirality, the 3 on treatment with different amines gives respective β-hydroxy amines 4(a-j). On other hand, 3 on treatment with alcohols in presence of NaOH afforded the corresponding β-hydroxy ethers 5(a-c). The structures of the synthesized compounds have been established on the basis of its spectral and analytical data. The antimicrobial activity of newly synthesized compounds ware evaluated against different microorganisms comparing with levofloxacin and found all the compounds exhibited remarkable activity.
- Guruswamy,Arul
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- Crystal structure-based selective targeting of the pyridoxal 5?-phosphate dependent enzyme kynurenine aminotransferase II for cognitive enhancement
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Fluctuations in the brain levels of the neuromodulator kynurenic acid may control cognitive processes and play a causative role in several catastrophic brain diseases. Elimination of the pyridoxal 5?-phosphate dependent enzyme kynurenine aminotransferase II reduces cerebral kynurenic acid synthesis and has procognitive effects. The present description of the crystal structure of human kynurenine aminotransferase II in complex with its potent and specific primary amine-bearing fluoroquinolone inhibitor (S)-(?)-9-(4-aminopiperazin-1-yl)-8- fluoro-3-methyl-6-oxo-2,3-dihydro-6H-1-oxa-3a-azaphenalene-5-carboxylic acid (BFF-122) should facilitate the structure-based development of cognition-enhancing drugs. From a medicinal chemistry perspective our results demonstrate that the issue of inhibitor specificity for highly conserved PLP-dependent enzymes could be successfully addressed.
- Rossi, Franca,Valentina, Casazza,Garavaglia, Silvia,Sathyasaikumar, Korrapati V.,Schwarcz, Robert,Kojima, Shin-Ichi,Okuwaki, Keisuke,Ono, Shin-Ichiro,Kajii, Yasushi,Rizzi, Menico
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supporting information; scheme or table
p. 5684 - 5689
(2010/11/04)
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- Effect of N-1/C-8 ring fusion and C-7 ring structure on fluoroquinolone lethality
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Quinolones rapidly kill bacteria by two mechanisms, one that requires protein synthesis and one that does not. The latter, which is measured as lethal action in the presence of the protein synthesis inhibitor chloramphenicol, is enhanced by N-1 cyclopropyl and C-8 methoxy substituents, as seen with the highly lethal compound PD161144. In some compounds, such as levofloxacin, the N-1 and C-8 substituents are fused. To assess the effect of ring fusion on killing, structural derivatives of levofloxacin and PD161144 differing at C-7 were synthesized and examined with Escherichia coli. A fused-ring derivative of PD161144 exhibited a striking absence of lethal activity in the presence of chloramphenicol. In general, ring fusion had little effect on lethal activity when protein synthesis was allowed, but fusion reduced lethal activity in the absence of protein synthesis to extents that depended on the C-7 ring structure. Additional fused-ring fluoroquinolones, pazufloxacin, marbofloxacin, and rufloxacin, also exhibited reduced activity in the presence of chloramphenicol. Energy minimization modeling revealed that steric interactions of the trans-oriented N-1 cyclopropyl and C-8 methoxy moieties skew the quinolone core, rigidly orient these groups perpendicular to core rings, and restrict the rotational freedom of C-7 rings. These features were not observed with fused-ring derivatives. Remarkably, structural effects on quinolone lethality were not explained by the recently described X-ray crystal structures of fluoroquinolone-topoisomerase IV-DNA complexes, suggesting the existence of an additional drug-binding state. Copyright
- Malik, Muhammad,Marks, Kevin R.,Schwanz, Heidi A.,German, Nadezhda,Drlica, Karl,Kerns, Robert J.
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body text
p. 5214 - 5221
(2011/10/12)
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- KYNURENINE-AMINOTRANSFERASE INHIBITORS
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Compounds of formula (I) : prodrug derivatives and/or pharmaceutically acceptable salt thereof, selectively inhibit the enzyme kynurenine aminotransferase, thereby reducing the synthesis of kynurenic acid. The compounds are used for the treatment of psychiatric and neurological diseases which benefit from an increase in glutamatergic and/or cholinergic neurotransmission, such as schizophrenia, depression, bipolar illness, anxiety and Alzheimer's disease. Furthermore, the compounds of the invention are useful for stimulating attention, memory and other cognitive processes in normal individuals of any age, including children, adolescents and the elderly. Additionally, the compounds of the invention are also useful for treatment of patients suffering from malaria by preventing parasite gametogenesis and fertility based on reduction of xanthurenic acid formation from its bioprecursor 3 -hydroxy kynurenine.
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Page/Page column 13-14
(2009/06/27)
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- Method for the preparation of (-)piperazine benzoxazine derivatives
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There is disclosed a method for the preparation of the antibacterial (-) piperazine benzoxazine derivative having formula I comprising the steps of reacting (+)2-aminomethylene-3-oxo-3-phenylpropionate derivative of formula II with a base in an organic polar solvent, to give a (-) benzoxazine derivative of formula III: and reacting the (-) benzoxazine derivative of formula III with a piperazine derivative of formula IV in an organic polar solvent. STR1
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- Photodegradation products of levofloxacin in aqueous solution
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The photodegradation of levofloxacin (DR-3355, CAS 100986-85-4), the S-(-)-isomer of ofloxacin, was investigated. Levofloxacin in aqueous solution was exposed to near ultraviolet light (peak wavelength 352 nm) for 16 h at room temperature. Nine degradation products (P-2-P-10) were isolated from the reaction mixture by preparative high performance liquid chromatography. The structures of these compounds were deduced from their NMR, MS, UV and IR spectra and optical rotations. The elucidated structures showed that all of these degradation products were analogues altered at the N-methylpiperazine moiety of levofloxacin.
- Yoshida,Sato,Moroi
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p. 601 - 606
(2007/10/02)
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