Search results for " molecule"
showing 10 items of 1523 documents
Mono-, di- and tri-nuclear Ni(II) complexes of N-, O-donor ligands: structural diversity and reactivity
2002
A series of mono-, di- and tri-nuclear Ni(II) complexes of N, O-donating molecules possessing ---H2C---NH--- and ---HC=N--- moieties have been synthesized and characterized and the structures have been determined by single crystal X-ray diffraction. All these exhibited interesting molecular packing in their crystal lattices. Di-nuclear complexes were found to be cleaved in pyridine to result in mononuclear ones with additional coordinations being provided by pyridine. Di-nuclear complexes were found to form urea adducts as demonstrated based on absorption and vibrational studies.
Effects of two-carbon bridge region methoxylation of benztropine: discovery of novel chiral ligands for the dopamine transporter
2001
6-Methoxylated and 8-oxygenated benztropines were prepared and evaluated for their DAT and SERT activity (binding and uptake inhibition). Methoxylation at the two-carbon bridge of benztropine produced a novel class of potent and selective DAT ligands. An interesting enantioselectivity was also observed for this new class of chiral benztropines. The inactivity of the 8-oxygenated analogues seems to point out that, unlike cocaine and its analogues, interactions of benztropine ligands with DAT may be strongly governed by the nitrogen atom.
Molecular topology applied to the discovery of 1-benzyl-2-(3-fluorophenyl)-4-hydroxy-3-(3-phenylpropanoyl)-2H-pyrrole-5-one as a non-ligand-binding-p…
2014
We report the discovery of 1-benzyl-2-(3- fluorophenyl)-4-hydroxy-3-(3-phenylpropanoyl)-2H-pyrrole- 5-one as a novel non-ligand binding pocket (non-LBP) antagonist of the androgen receptor (AR) through the application of molecular topology techniques. This compound, validated through time-resolved fluorescence resonance energy transfer and fluorescence polarization biological assays, provides the basis for lead optimization and structure−activity relationship analysis of a new series of non-LBP AR antagonists. Induced-fit docking and molecular dynamics studies have been performed to establish a consistent hypothesis for the interaction of the new active molecule on the AR surface. Refereed/…
Synthesis and Dopamine Receptor Selectivity of the Benzyltetrahydroisoquinoline, (R)-(+)-nor-Roefractine
1998
(R)-(+)-nor-Roefractine (1) was synthesized by the Bischler-Napieralski route, using asymmetric reduction of the 1, 2-didehydro precursor imine with sodium (S)-N-CBZ-prolinyloxyborohydride. Compound 1 was able to displace [3H]-raclopride (a D2 dopamine receptor-selective ligand) from its specific binding sites in rat striatum with selectivity vs [3H]-SCH23390 (D1 dopamine receptor-selective ligand).
Six-coordinate CoIII and four-coordinate MII (M = Co, Zn) mixed-valence dimers supported by a deprotonated pyridine amide ligand: magnetism of a CoII…
2009
Using a pyridine amide ligand 4-methyl-2-{N-(2-pyridyl)carbamoyl}pyridine (HL), in its deprotonated form, binuclear mixed-valence homonuclear bimetallic complexes [CoIII,II2(L)3(X)]X·S [X = Cl (1); X = Br, S = CH3OH (2)] and heteronuclear bimetallic complex [CoIIIZnII(L)3(Cl)]Cl·CH3OH·5H2O (3) have been synthesized. Structural analysis revealed that trivalent cobalt is in distorted octahedral and bivalent cobalt/zinc is in distorted tetrahedral environment. Three L(−) ligands provide six-coordination by utilizing three pyridine amide units (pyridine N and amide N donor set) in a facial mode, which in turn places three 4-methylpyridine nitrogens to coordinate to another metal center, which c…
Diastereoselective Intramolecular Additions of Allyl- and Propargylsilanes to Iminium Ions: Synthesis of Cyclic and Bicyclic Quaternary Amino Acids
2010
Chiral imino lactones derived from (R)-phenylglycinol containing an allyl- or propargyltrimethylsilyl group in the side chain readily cyclized in the presence of acidic reagents to afford spirocyclic compounds with high diastereoselectivity. Removal of the chiral auxiliary produced 2-substituted 1-aminocycloalkanecarboxylic acids, whereas further cyclizations by means of metathesis or hydroamination reactions led to bicyclic derivatives of pipecolic acid and proline.
A New Major Triterpene Saponin from the Roots of Cucurbita foetidissima
2000
Foetidissimoside B (1), a novel triterpene saponin, was isolated from the roots of Cucurbita foetidissima. Based on spectroscopic data, especially direct and long-range heteronuclear 2D NMR analysis and on chemical transformations, the structure of 1 was elucidated as 3-O-beta-D-glucuronopyranosyl-echinocystic acid 28-O-beta-D-glucopyranosyl-(1-->3)-beta-D-xylopyranosyl(1-->3)-[beta- D-xylopyranosyl (1-->4)]-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside . Compound 1 did not show any ability to potentiate in vitro cisplatin cytotoxicity in a human colon cancer cell line.
Semisynthesis and cytotoxicity of styryl-lactone derivatives.
1999
The cytotoxicity and the cell-cycle action of altholactone (1), goniofufurone (2), and eight altholactone derivatives (5-12), were determined in vitro on L-1210 cells. Semisyntheses and structure-activity relationships of these compounds are described. The results of this study suggest that the cytotoxicity of altholactone (1), 11-nitro-altholactone (8), and 7-chloro-6,7-dihydroaltholactone (10) is due to the accumulation of the cells in the G2 + M phase of the cell cycle.
Complexes hétéronucléaires Cp2MM′(Cp)(CO)3 (M Nb, Ta; M′ Mo, W) avec groupes carbonyles pontants et semi-pontants: synthèse et comportement dynam…
1991
Abstract Heteronuclear structures Cp 2 MM′(Cp)(CO) 3 (M Nb, Ta; M′ Mo, W) are obtained by heating Cp 2 MH 3 (M Nb, Ta) with Cp 2 M′ 2 (CO) 6 (M′ Mo, W) or starting from Cp 2 M(CO)H and Cp 2 M′ 2 (CO) 4 . These heterobimetallic complexes show three CO coordination modes: terminal, semi-bridging and bridging. The two cyclopentadienyl groups of the Cp 2 M moiety are anisochronous owing to molecular rigidity; rotation barriers around the MM′ bond have been estimated and are greatest with tantalum derivatives.
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…