- Searching for Novel Inhibitors of the S. aureus NorA Efflux Pump: Synthesis and Biological Evaluation of the 3-Phenyl-1,4-benzothiazine Analogues
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Bacterial resistance to antimicrobial agents has become an increasingly serious health problem in recent years. Among the strategies by which resistance can be achieved, overexpression of efflux pumps such as NorA of Staphylococcus aureus leads to a sub-lethal concentration of the antibacterial agent at the active site that in turn may predispose the organism to the development of high-level target-based resistance. With an aim to improve both the chemical stability and potency of our previously reported 3-phenyl-1,4-benzothiazine NorA inhibitors, we replaced the benzothiazine core with different nuclei. None of the new synthesized compounds showed any appreciable intrinsic antibacterial activity, and, in particular, 2-(3,4-dimethoxyphenyl)quinoline (6 c) was able to decrease, in a concentration-dependent manner, the ciprofloxacin MIC against the norA-overexpressing strains S. aureus SA-K2378 (norA++) and SA-1199B (norA+/A116E GrlA).
- Felicetti, Tommaso,Cannalire, Rolando,Burali, Maria Sole,Massari, Serena,Manfroni, Giuseppe,Barreca, Maria Letizia,Tabarrini, Oriana,Schindler, Bryan D.,Sabatini, Stefano,Kaatz, Glenn W.,Cecchetti, Violetta
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p. 1293 - 1302
(2017/09/01)
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- 7-Oxo-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxamides as Selective CB 2 cannabinoid receptor ligands: Structural investigations around a novel class of full agonists
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Cannabinoid receptor agonists have gained attention as potential therapeutic targets of inflammatory and neuropathic pain. Here, we report the identification and optimization of a series of 7-oxo-[1,4]oxazino[2,3,4-ij] quinoline-6-carboxamide derivatives as a novel chemotype of selective cannabinoid CB2 receptor agonists. Structural modifications led to the identification of several compounds as potent and selective cannabinoid receptor agonists (20, hCB2Ki = 2.5 nM, SI = 166; 21, hCB2Ki = 0.81 nM, SI = 383; 38, hCB2K i = 15.8 nM, SI > 633; 56, hCB2Ki = 8.12 nM, SI > 1231; (R)-58, hCB2Ki = 9.24 nM, SI > 1082). The effect of a chiral center on the biological activity was also investigated, and it was found that the (R)-enantiomers exhibited greater affinity at the CB2 receptor than the (S)-enantiomers. In 3,5-cyclic adenosine monophosphate assays, the novel series behaved as agonists, exhibiting functional activity at the human CB2 receptor.
- Baraldi, Pier Giovanni,Saponaro, Giulia,Moorman, Allan R.,Romagnoli, Romeo,Preti, Delia,Baraldi, Stefania,Ruggiero, Emanuela,Varani, Katia,Targa, Martina,Vincenzi, Fabrizio,Borea, Pier Andrea,Aghazadeh Tabrizi, Mojgan
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experimental part
p. 6608 - 6623
(2012/09/22)
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- AZACYCLIC COMPOUNDS AS INHIBITORS OF SENSORY NEURONE SPECIFIC CHANNELS
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Compounds of the formula (I), and pharmaceutically acceptable salts thereof, are found to be antagonists of SNS sodium channels. They are therefore useful as analgesic and neuroprotective agents wherein: X is -N- or -CH-; n is from 0 to 3.
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- Dihydrobenzoxazines and Tetrahydroquinoxalines by a Tandem Reduction-Reductive Amination Reaction
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A tandem reduction-reductive amination reaction has been applied to the synthesis of 3,4-dihydro-2H-1,4-benzoxazines and 1-acetyl-1,2,3,4-tetrahydroquinoxalines. The nitroketones required for the benzoxazine ring closures were prepared by (A) alkylation of the anion derived from 2-nitrophenol with an allylic halide or (B) nucleophilic aromatic substitution of an allylic alkoxide on 2-fluoro-1-nitrobenzene followed by ozonolysis. Precursors for the quinoxalines were prepared by alkylation of the anion of 2-nitroacetanilide with an allylic halide followed by ozonolysis. Catalytic hydrogenation of the nitroketones using 5% palladium-on-carbon in methanol then gave the target heterocycles by a reduction-reductive amination sequence. The N-methyl derivatives for both ring systems were easily prepared by adding 5-10 equivalents of aqueous formaldehyde prior to the reduction. The dihydrobenzoxazines were isolated in high yield following purification by chromatographic methods; tetrahydroquinoxalines were isolated in a similar manner and possessed differentiated functionality on the two nitrogens.
- Bunce, Richard A.,Herron, Derrick M.,Hale, Lu Y.
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p. 1031 - 1039
(2007/10/03)
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- A simple method for the preparation of aryl phenacyl ether in micellar medium: Part I
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Aryl phenacyl ethers have been prepared by the micellar catalysed reaction of phenacyl bromide with equimolar mixture of phenol(s)- triethylamine in 70% methanol(v/v) 30 °C. The ethers have been characterised on the basis of their IR, 1H and s
- Nallu,Selvakumar, Robinson,Pillay, M. Krishna
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p. 1108 - 1110
(2007/10/03)
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