Search results for "thiophene"
showing 10 items of 284 documents
Synthesis and biological evaluation of 2-(3 ',4 ',5 '-trimethoxybenzoyl)-3-amino 5-aryl thiophenes as a new class of tubulin inhibitors
2006
2-(3',4',5'-Trimethoxybenzoyl)-3-amino-5-aryl/heteroaryl thiophene derivatives were synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization, and cell cycle effects. SARs were elucidated with various substitutions on the aryl moiety 5-position of the thienyl ring. Substituents at the para-position of the 5-phenyl group showed antiproliferative activity in the order of F=CH(3) > OCH(3)=Br=NO(2) > CF(3)=I > OEt. Several of these compounds led to arrest of HL-60 cells in the G2/M phase of the cell cycle and induction of apoptosis.
A Theoretical Study on the Low-Lying Excited States of 2,2′:5′,2′′-Terthiophene and 2,2′:5′,2′′:5′′,2′′′-Quaterthiophene
2005
The nature and properties of the low-lying singlet and triplet valence excited states of 2,2':5',2-terthiophene (terthiophene) and 2,2':5',2:5,2'-quictterthiophene (tetrdthiophene) are discussed on the basis of high-level ab initio. computations. The spectrascopic features determined experimentally for short α-oligothiophenes are rationalised on theoretical grounds. Special attention is devoted to the nonradiative decay process through intersystem crossing (ISC) from the singlet to the triplet manifold, which is known to be relatively less efficient in tetrathiophene. Along the geometry relaxation of the S 1 state of terthiophene, the S' 1 and T 2 states become degenerate, which leads. to a…
A theoretical study of the electronic spectrum of bithiophene
1995
The electronic spectrum of bithiophene in the energy range up to 6.0 eV has been studied using multiconfigurational second order perturbation theory (CASPT2) and a basis set of ANO type, with split valence quality and including polarization functions on all heavy atoms. Calculations were performed at a planar (trans) and twisted geometry. The calculated ordering of the excited singlet states is 1Bu, 1Bu, 1Ag, 1Ag, and 1Bu with 0–0 transition energies: 3.88, 4.15, 4.40, 4.71, and 5.53 eV, respectively. The first Rydberg transition (3s) has been found at 5.27 eV. The results have been used in aiding the interpretation of the experimental spectra, and in cases where a direct comparison is poss…
Identification and optimization of small molecule antagonists of vasoactive intestinal peptide receptor-1 (VIPR1).
2012
Identification, synthesis and structure-activity relationship of small-molecule VIPR1 antagonists encompassing two chemical series are described.
NLO properties of polythiophenes galvanostatically electrodeposited on ITO glasses
2008
International audience; A study of nonlinear optical properties of ClO4-doped polythiophenes, galvanostatically electrodeposited on ITO glasses, was carried out using second and third harmonic generation measurements. The effect of the oxidation state of the polymeric films was studied by comparing the nonlinear optical response of oxidised and reduced polythiophenes. Reduced polymeric films show higher values of the second and third order susceptibilities and a lower absorbance in respect to the oxidised ones. The morphology of the polythiophene films was studied by scanning electron and atomic force microscopes.
Sesquiterpene lactones and acetylenes from Artemisia reptans
1994
Abstract The aerial parts of Artemisia reptans yielded a new thiophene acetylene, four new guaianolides, a new acyclic sesquiterpene related to davanone and several known compounds.
Exploiting the Chiral Ligands of Bis(imidazolinyl)- and Bis(oxazolinyl)thiophenes : Synthesis and Application in Cu-Catalyzed Friedel–Crafts Asymmetr…
2021
Five new C2-symmetric chiral ligands of 2,5-bis(imidazolinyl)thiophene (L1–L3) and 2,5-bis(oxazolinyl)thiophene (L4 and L5) were synthesized from thiophene-2,5-dicarboxylic acid (1) with enantiopure amino alcohols (4a–c) in excellent optical purity and chemical yield. The utility of these new chiral ligands for Friedel–Crafts asymmetric alkylation was explored. Subsequently, the optimized tridentate ligand L5 and Cu(OTf)2 catalyst (15 mol%) in toluene for 48 h promoted Friedel–Crafts asymmetric alkylation in moderate to good yields (up to 76%) and with good enantioselectivity (up to 81% ee). The bis(oxazolinyl)thiophene ligands were more potent than bis(imidazolinyl)thiophene analogues for …
ChemInform Abstract: Oxidative (Cross-)Coupling Reactions Mediated by C-H Activation of Thiophene Derivatives by Using Molybdenum(V) Reagents.
2015
The use of MoCl5 renders possible the preparation of various synthetically important polycyclic thienoacenes.
Donor-Acceptor Polythiophene Copolymers with Tunable Acceptor content for Photoelectric Conversion Devices
2004
The synthesis and characterization of a new series of substituted polythiophenes containing an electron acceptor anthraquinone moiety in the side chain are reported. The acceptor molar content was varied by the co-polymerization of both alkylthiophene and thiophene bearing anthraquinone monomers in different ratios. NMR analysis shows a good correlation between the monomer feed composition at the beginning of the polymerization and the actual unit composition of the backbone. The conjugation length and the chemical composition of the copolymers as a function of the molecular weight have been studied by size exclusion chromatography. Small angle X-ray scattering and UV-Vis absorption spectra…
New acetylenes fromChrysanthemum coronarium L.
1990
The investigation of the aerial parts of Chrysanthemum coronarium yielded, in addition to several known compounds, two new acetylenic sulfoxides 9 and 10, and a new thiophene spiroacetal enol ether 11. Their structures were deduced by spectroscopic and chemical methods.