Search results for "Thiophene"
showing 10 items of 284 documents
Synthesis of No-Carrier-Added 4-[18F]Fluorophenol from 4-Benzyloxyphenyl-(2-thienyl)iodonium Bromide
2011
4-[(18)F]Fluorophenol is a versatile synthon for the synthesis of more complex radiopharmaceuticals bearing a 4-[(18)F]fluorophenoxy moiety. In order to prepare 4-[(18)F]fluorophenol in no-carrier-added (n.c.a.) form only a nucleophilic labelling method starting from [(18)F]fluoride is suitable. In this paper a new, two step radiosynthesis starting from 4-benzyloxyphenyl-(2-thienyl)iodonium bromide and [(18)F]fluoride with subsequent deprotection is described, yielding n.c.a. [(18)F]fluorophenol in 34 to 36% radiochemical yield.
Oligothienoacenes versus oligothiophenes: Impact of ring fusion on the optical properties
2010
The impact of backbone rigidity on the optical properties of thiophene-based compounds is studied by analyzing in detail the geometrical, electronic, optical and vibronic features of a family of oligothienoacenes (nnTAs) in comparison to non-fused α-oligothiophenes (nnTs) by means of quantum-chemical calculations. Ring fusion in nnTAs provokes a greater conjugation in the ground state. However, the change in the bond length alternation upon electronic excitation is very similar in both systems, which is also reflected in a similar evolution of the first optical transition energy with increasing oligomer size. Larger transition energies in nnTAsvs.nnTs arise from an electronic effect rather …
Design, synthesis, and biological evaluation of thiophene analogues of chalcones.
2008
Chalcones are characterized by possessing an enone moiety between two aromatic rings. A series of chalcone-like agents, in which the double bond of the enone system is embedded within a thiophene ring, were synthesized and evaluated for antiproliferative activity and inhibition of tubulin assembly and colchicine binding to tubulin. The replacement of the double bond with a thiophene maintains antiproliferative activity and therefore must not significantly alter the relative conformation of the two aryl rings. The synthesized compounds were found to inhibit the growth of several cancer cell lines at nanomolar to low micromolar concentrations. In general, all compounds having significant anti…
5-Substituted-benzylsulfanyl-thiophene-2-sulfonamides with effective carbonic anhydrase inhibitory activity: Solution and crystallographic investigat…
2017
Abstract A series of 5-substituted-benzylsulfanyl-thiophene-2-sulfonamides was prepared by reacting 5-bromo-thiophene-2-sulfonamide with 5-substituted-benzyl mercaptans. The new compounds were investigated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The cytosolic human (h) isoforms hCA I was poorly inhibited by the new sulfonamides (KIs in the range of 683–4250 nM), whereas hCA II, and the transmembrane, tumor associated isoforms hCA IX and XII were effectively inhibited in the subnanomolar–nanomolar range. A high resolution X-ray crystal structure of the adduct of hCA II with one of the new sulfonamides allowed us to rationalize the excellent inhibitory activity of these heterocycli…
Fluorescence Quenching in Hybrid Solar Cells Based on Electrodeposited ZnO
2013
A study about fluorescence phenomena in hybrid donor-acceptor interfaces based on electrodeposited zinc oxide (e-ZnO) having different architectures is performed. In particular ITO/ZnO/P3HT and ITO/ZnO/P3HT:PCBM are investigated and their photoluminescence responses are compared with those of ITO/P3HT and ITO/P3HT:PCBM. As expected, ITO/ZnO/P3HT:PCBM and ITO/P3HT:PCBM present higher exciton quenching than ITO/ZnO/P3HT and ITO/P3HT respectively. Furthermore, the hybrid configuration ITO/ZnO/P3HT:PCBM displays a higher quenching percentage in a wider wavelength range than ITO/P3HT:PCBM, indicating a better photo-induced charge separation in e-ZnO based hybrid devices.
Studies in organic mass spectrometry. Part 20: a hidden ortho effect in the electron ionisation mass spectra of some 2′-alkyl substituted 2-and 3-thi…
1996
The electron-ionisation-induced amide-bond cleavage of some 2′-methyl- and 2′-ethyl-substituted 2- and 3-thiophenecarboxanilides, which yields formally anilylium ions having relative intensities apparently in contrast with the Stevenson‐Audier rule, has been investigated by mass-analysed ion kinetic energy (MIKE) spectrometry and compared to that of the 3 ′- and 4′-isomers. It has been shown that, in the case of the 2 ′-methyl and 2′-ethyl derivatives, the amide-bond cleavage is anchimerically assisted through the hidden migration of a benzyl hydrogen to the nitrogen. Analysis of the MIKE and collision-induced decomposition (CID) MIKE spectra of model compounds indicates that this cryptic o…
Polymer/metal hybrid multilayers modified Schottky devices
2013
Insulating, polymethylmethacrylate (PMMA), and semiconducting, poly(3-hexylthiophene) (P3HT), nanometer thick polymers/Au nanoparticles based hybrid multilayers (HyMLs) were fabricated on p-Si single-crystal substrate. An iterative method, which involves, respectively, spin-coating (PMMA and P3HT deposition) and sputtering (Au nanoparticles deposition) techniques to prepare Au/HyMLs/p-Si Schottky device, was used. The barrier height and the ideality factor of the Au/HyMLs/p-Si Schottky devices were investigated by current-voltage measurements in the thickness range of 1-5 bilayers. It was observed that the barrier height of such hybrid layered systems can be tuned as a function of bilayers …
Haptens, bioconjugates, and antibodies for penthiopyrad immunosensing
2014
4 pages, 1 table, 2 figures.
Palladium-catalyzed domino C-H/N-H functionalization: an efficient approach to nitrogen-bridged heteroacenes.
2015
Palladium-catalyzed domino C-H/N-H functionalization for the synthesis of novel nitrogen-bridged thienoacenes and 10H-benzo[4,5]thieno[3,2-b]indole derivatives from dihaloarene is reported. This domino sequence consists of initial C-H functionalization of the benzo[b]thiophene moiety, followed by Buchwald-Hartwig coupling. This transformation is also useful for the synthesis of highly π-extended compounds.
ChemInform Abstract: Palladium-Catalyzed Domino C-H/N-H Functionalization: An Efficient Approach to Nitrogen-Bridged Heteroacenes.
2015
Palladium-catalyzed domino CH/NH functionalization for the synthesis of novel nitrogen-bridged thienoacenes and 10H-benzo[4,5]thieno[3,2-b]indole derivatives from dihaloarene is reported. This domino sequence consists of initial CH functionalization of the benzo[b]thiophene moiety, followed by Buchwald–Hartwig coupling. This transformation is also useful for the synthesis of highly π-extended compounds.