Search results for "Pyrazole"
showing 10 items of 315 documents
Synthesis and anti-staphylococcal activity of new 4-diazopyrazole derivatives.
2012
Abstract Several new 4-diazopyrazole derivatives 6a – g and 9a – c were obtained by the reaction of 1-(R-substituted-phenyl)-3-(1,3-dimethyl-1 H -pyrazol-5-yl)ureas 5a – g and N -(1,3-dimethyl-1 H -pyrazol-5-yl)-2-(R-substituted-phenyl)acetamides 8a – c respectively with a sevenfold excess of nitrous acid in acetic acid solution. The compounds were assayed for their activity against the Staphylococcus aureus reference strains ATCC 25923, ATCC 29213 and ATCC 6538, as well as six veterinary strains. The best anti-staphylococcal profile was showed by [(R-substituted-phenyl)acetyl](4-diazonio-1,3-dimethyl-1 H -pyrazol-5-yl)azanides 9a , c . Compound 9c was also able at 3.1 μg mL −1 to inhibit o…
Recent advanced in bioactive systems containing pyrazole fused with a five membered heterocycle
2015
In this review we report the recent advances in bioactive system containing pyrazole fused with a five membered heterocycle, covering the time span of the last decade. All of them are represented around the common structure of the pyrazole ring fused with another five membered heterocycle containing the nitrogen, sulfur and oxygen atoms in all their possible combinations. The classification we have used is based in terms of the therapeutic area providing, when possible, some general conclusions on the targets and mechanisms of action as well as the structure-activity relationships of the molecules.
Pyrazole amino acids: hydrogen bonding directed conformations of 3-amino-1H-pyrazole-5-carboxylic acid residue
2017
A series of model compounds containing 3-amino-1H-pyrazole-5-carboxylic acid residue with N-terminal amide/urethane and C-terminal amide/hydrazide/ester groups were investigated by using NMR, Fourier transform infrared, and single-crystal X-ray diffraction methods, additionally supported by theoretical calculations. The studies demonstrate that the most preferred is the extended conformation with torsion angles ϕ and ψ close to ±180°. The studied 1H-pyrazole with N-terminal amide/urethane and C-terminal amide/hydrazide groups solely adopts this energetically favored conformation confirming rigidity of that structural motif. However, when the C-terminal ester group is present, the second con…
The Reactivity of 4’-Substituted Spiro[Isoindole-1,3’-pyrazoles] Derivatives: Substitution/Elimination Reactions and Access to Biaryl Derivatives
2017
This paper describes aspects of the chemistry of 4’-substituted spiro [indole-1,3’-pyrazoles]. These compounds underwent substitution and/or elimination reactions to afford some new spiro- as well as biaryl derivatives of potential pharmaceutical relevance. Mechanistic considerations are discussed as well.
Efficient Green Light-Emitting Electrochemical Cells Based on Ionic Iridium Complexes with Sulfone-Containing Cyclometalating Ligands
2013
A new approach to obtain green-emitting iridiumA complexes is described. The synthetic approach consists of introducing a methylsulfone electron-withdrawing substituent into a 4-phenylpyrazole cyclometalating ligand in order to stabilize the highest- occupied molecular orbital (HOMO). Six new complexes have been synthe- sized incorporating the conjugate base of 1-(4-(methylsulfonyl)phenyl)-1 H- pyrazole as the cyclometalating ligand. The complexes show green emission and very high photoluminescence quantum yields in both diluted and concentrated films. When used as the main active component in light-emit- ting electrochemical cells (LECs), green electroluminance is observed. High efficienci…
Photoassisted Mineralization of Aromatic and Aliphatic N Heterocycles in Aqueous Titanium Dioxide Suspensions and the Fate of the Nitrogen Heteroatoms
2008
Abstract The photoassisted degradation of aromatic heterocycles (pyrrole, imidazole, pyrazole, isoxazole, oxazole and thiazole) and N-containing alicycles (aliphatic heterocycles: pyrrolidine, 4-butanelactam and 5-pentanelactam) was examined in liquid–solid dispersions. Complete mineralization (TOC) of the aromatic heterocycles was attained within ca. 1 h of UV irradiation of the TiO 2 /heterocycle system in acidic (pH 3), near-neutral (pH 6.0–7.6) and alkaline (pH 11) media. Mineralization kinetics were, in general, not appreciably influenced by the presence of acid but tended to be somewhat slower in alkaline media. N-alicycles were photomineralized more slowly than were the aromatics. Th…
COX-2-dependent and COX-2-independent mode of action of celecoxib in human liver cancer cells.
2011
Celecoxib (Celebrex((R)), Pfizer) is a selective cyclooxygenase-2 (COX-2) inhibitor with chemopreventive and antitumor effects. However, it is now well known that celecoxib has several COX-2-independent activities. To better understand COX-2-independent molecular mechanisms underlying the antitumor activity of celecoxib, we investigated the expression profile of the celecoxib-treated COX-2-positive (Huh7) and COX-2-negative (HepG2) liver cancer cell lines, using microarray analysis. Celecoxib treatment resulted in significantly altered expression levels of 240 and 403 transcripts in Huh7 and HepG2 cells, respectively. Confirmation of the microarray results was performed for selected genes b…
Pyrazolo[3,4-h]quinolines promising photosensitizing agents in the treatment of cancer.
2015
A new series of pyrazolo[3,4-h]quinolines, heteroanalogues of angelicin was conveniently prepared with a broad substitution pattern. A large number of derivatives was obtained and the cellular photocytotoxicity was evaluated in vitro against 5 different human tumor cell lines with GI50 values reaching the nanomolar level (14.52e0.04 mM). Selected compounds were able to photoinduce a massive cell death with the involvement of mitochondria. Their photodamage cellular targets were proteins and lipids and they did not cause any kind of DNA photodamage. This latter event is of considerable importance in the modulation of long term side effects, generally associated with the use of classical furo…
Unexpected synthesis by a non-classical Pschorr reaction of 3,5-dimethyl-1-phenyl-1,5-dihydro-4H-pyrazolo[4,3-c]quinolin-4-one, with binding affinity…
2014
The reaction of the diazonium salt 12 derived from N-(2-aminophenyl)-N,3-dimethyl-1-phenyl-1H-pyrazole-5-carboxamide with copper sulfate and sodium chloride in the presence of ascorbic acid afforded the unexpected products 3,5-dimethyl-1-phenyl-1,5-dihydro-4H-pyrazolo[4,3-c]¬quinolin-4-one (17) and N-methyl-2-(3-methyl-1-phenyl-1H-pyrazol-5-yl)aniline (19), accompanied by N-(2-chlorophenyl)-N,3-dimethyl-1-phenyl-1H-pyrazole-5-carboxamide (18). Products 17 and 19 are formed via a non-classical Pschorr reaction. The formation of 17 represents an alternative to the literature synthesis of this biologically active compound. The molecular structure of 18 was confirmed by single-crystal X-ray ana…
Central side-effects of therapies based on CB1 cannabinoid receptor agonists and antagonists: focus on anxiety and depression
2009
Both agonists (e.g. Delta(9)-tetrahydrocannabinol, nabilone) and antagonists (e.g. rimonabant, taranabant) of the cannabinoid type-1 (CB(1)) receptor have been explored as therapeutic agents in diverse fields of medicine such as pain management and obesity with associated metabolic dysregulation, respectively. CB(1) receptors are widely distributed in the central nervous system and are involved in the modulation of emotion, stress and habituation responses, behaviours that are thought to be dysregulated in human psychiatric disorders. Accordingly, CB(1) receptor activation may, in some cases, precipitate episodes of psychosis and panic, while its inhibition may lead to behaviours reminiscen…