Search results for "DISCOVERY"
showing 10 items of 4119 documents
Synthesis of novel WAY 100635 derivatives containing a norbornene group and radiofluorination of [18F]AH1.MZ as a serotonin 5-HT1Areceptor antagonist…
2009
5-HT1A receptors are involved in a variety of psychiatric disorders and in vivo molecular imaging of the 5-HT1A status represents an important approach to analyze and treat these disorders. We report herein the synthesis of three new fluoroethylated 5-HT1A ligands (AH1.MZ, AH2.MZ and AH3.MZ) as arylpiperazine derivatives containing a norbornene group. AH1.MZ (Ki= 4.2 nM) and AH2.MZ (Ki=30 nM) showed reasonable in vitro affinities to the 5-HT1A receptor, whereas AH3.MZ appeared to be non-affine toward the 5-HT1A receptor. The receptor profile of AH1.MZ and AH2.MZ showed selectivity within the 5-HT system. 18F-labelling via [18F]FETos to [18F]AH1.MZ was carried out in radiochemical yields of …
The first example of natural cyclic carbonate in terpenoids
2006
Abstract The first natural occurring cyclic carbonate terpenoid, the guaianolide hololeucin ( 1 ), was isolated from the aerial part of Centaurea hololeuca . Its structure was elucidated on the basis of extensive proton, 13 C and two-dimensional NMR experiments, as well as by transformation in its diacetyl derivative.
Aerobic epoxidation of olefins catalysed by square-planar cobalt(III) complexes of bis-N,N′-disubstituted oxamides and related ligands
1997
The new square-planar nickel(II) complexes of o-phenylenebis(N′-methyloxamidate) and related ligands catalyse the aerobic epoxidation of olefins with co-oxidation of pivalaldehyde; the modulation of catalytic activity by substituents along this series of metal complexes points out the role of high-valent nicke(IV)-oxo species as the putative intermediate in these oxygen atom transfer reactions.
Pertosylated polyaza[n](9,10)anthracenophanes
1997
Abstract Pertosylated polyaza[n](9,10)antracenophanes have been obtained in high yields by a modification of the Richman-Atkins methodology. Molecular Mechanics calculations as well as the crystal structure of the N,N′,N″,N‴-Tetratosyl-2,6,9,13-tetraaza[14](9,10)anthracenophane 4 derivative reveal the existence of a well defined cavity where both the aromatic moiety and the nitrogen donor atoms converge. Reduced mobility of the aliphatic chain is also observed as well as the presence of some strain at the benzylic positions.
Synthesis and preliminary antibacterial evaluation of Linezolid-like 1,2,4-oxadiazole derivatives
2012
In the present study the synthesis of new Linezolid-like molecules has been achieved by substitution of the oxazolidinone central heterocyclic moiety with a 1,2,4-oxadiazole ring. Two series of 1,2,4-oxadiazoles, bearing different side-chains and containing a varying number of fluorine atoms, were synthesized and preliminarily tested for biological activity against some Gram-positive and Gram-negative bacteria using Linezolid and Ceftriaxone as reference drugs
Terphenyl Derivatives from Allantophomopsis lycopodina.
2016
Three secondary fungal metabolites 1–3 with a benzo[b]naphtho[2,1-d]furan skeleton were isolated from submerged cultures of the ascomycete Allantophomopsis lycopodina. The NMR-based structure elucidation was challenging due to a low H/C ratio of only 0.64 and 0.68, respectively. NMR measurements in two different solvents and the use of NMR experiments such as HSQC-TOCSY and LR-HSQMBC proved to be helpful in this respect. The proposed structures obtained from the comprehensive analysis of the NMR data were verified by comparison of recorded and computed NMR chemical shifts from quantum chemical calculations of several constitutional isomers and were further analyzed with the aid of the DP4 a…
Antiproliferative properties and g-quadruplex-binding of symmetrical naphtho[1,2-b:8,7-b’]dithiophene derivatives
2021
Background: G-quadruplex (G4) forming sequences are recurrent in telomeres and promoter regions of several protooncogenes. In normal cells, the transient arrangements of DNA in G-tetrads may regulate replication, transcription, and translation processes. Tumors are characterized by uncontrolled cell growth and tissue invasiveness and some of them are possibly mediated by gene expression involving G-quadruplexes. The stabilization of G-quadruplex sequences with small molecules is considered a promising strategy in anticancer targeted therapy. Methods: Molecular virtual screening allowed us identifying novel symmetric bifunctionalized naphtho[1,2-b:8,7-b’]dithiophene ligands as interesting ca…
Phytochemical Profile and Apoptotic Activity of Onopordum cynarocephalum.
2012
A phytochemical investigation of acetone and chloroform extracts of the aerial parts of Onopordum cynarocephalum Boiss. et Blanche was carried out. It led to the isolation of two new sesquiterpenes, the elemane aldehyde (2) and the eudesmane (11), together with 15 known compounds: two lignans (1 and 15) and 13 sesquiterpenes (3–10, 12–14, 16, 17). The structures were elucidated by spectroscopic analyses, especially 1D and 2D NMR spectra. The anti-growth effect against three human melanoma cell lines, M14, A375, and A2058, of the different extracts and compounds of O. cynarocephalum was also investigated. Among them, the chloroform extract exhibited the strongest biological activity, while t…
Cytotoxicity and modes of action of four naturally occuring benzophenones: 2,2′,5,6′-Tetrahydroxybenzophenone, guttiferone E, isogarcinol and isoxant…
2012
Abstract Introduction The emergence of drug-resistant cancer cells drastically reduces the efficacy of many antineoplasic agents and, consequently, increases the frequency of therapeutic failure. Benzophenones are known to display many pharmacological properties including cytotoxic activities. The present study was aimed at investigating the cytotoxicity and the modes of action of four naturally occurring benzophenones 2,2′,5,6′-tetrahydroxybenzophenone ( 1 ), isogarcinol ( 2 ), isoxanthochymol ( 3 ) and guttiferone E ( 4 ) on a panel of eleven cancer cell lines including various sensitive and drug-resistant phenotypes. Methods The cytotoxicity of the compounds was determined using a resazu…
Stereoselective Synthesis of (+)-11βH,13-Dihydroestafiatin, (+)-11βH,13-Dihydroludartin, (−)-Compressanolide, and (−)-11βH,13-Dihydromicheliolide fro…
2002
Starting from 2 and 3, obtained from santonin (1), we have synthesized natural guaianolides 4-7. Chemoselective epoxidation of 2 gave (+)-11betaH,13-dihydroestafiatin (4), and epoxidation of 3 followed by regioselective elimination of the hydroxyl group afforded (+)-11betaH,13-dihydroludartin (5). Sharpless' mild regioselective ring-opening of 4 and 5 followed by hydrogenolysis yielded (-)-compressanolide (6) and (-)-11betaH,13-dihydromicheliolide (7), respectively.