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The structures and relative stabilities of 15 S3O2 isomers have been investigated by G3X(MP2), CCSD(T)/aug-cc-pVTZ and MRCI/CASSCF calculations. The global energy minimum is a three-membered sulfur ring with two adjacent sulfoxide groups in a trans conformation, i.e. a vic-disulfoxide of C2 symmetry. The SS bond lengths are 2.136 (2x) and 2.354 angstroms at the CCSD(T)/cc-pVTZ level of theory. There is a strong interaction between the pi* orbitals of the two S=O moieties both in the trans and in the almost degenerate cis conformer. The corresponding chain-like singlet and triplet isomers of connectivity OSSSO lie close in energy (ca. 67 kJ mol(-1)) while five-membered and branched four-membered rings are significantly less stable. The structure of S3O2 is in contrast to that of the isoelectronic analogue S5, which exists as a five-membered twisted heterocycle. 相似文献
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Nagaraju Chirra Varshitha Shanigarapu Naga Pranathi Abburi Ekaterina O. Sinegubova Ravi Kumar Pedapati Yana L. Esaulkova Vladimir V. Zarubaev Srinivas Kantevari 《Journal of heterocyclic chemistry》2024,61(3):496-505
Herein described the synthesis and antiviral evaluation of a novel series of morpholine and thio-morpholine coupled imidazo[2,1-b]thiazoles. The three-step reaction sequence involving the condensation of 1,3-dichloroacetone with thiourea followed by coupling with morpholine and thiomorpholine and finally cyclization with substituted α-bromoacetophenones yielded the desired imidazothiazoles 7(a–l) . Screening of all the new compounds for their in vitro antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1) in MDCK cells, resulted in two potent analogs, 7d (IC50: 1.1 μM, C50: >300 μM, SI = 273) and 7e (IC50: 2.0 μM, C50: >300 μM, SI = 150), with a favorable toxicity profile and are the best anti-influenza hit analogs for further structural optimization. 相似文献
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A method is suggested for the calculation of a reference value and its uncertainty to be used in the frame of an interlaboratory
comparison (ILC). It is assumed that the reference value of the measurand is determined independently from the ILC round.
It is derived from a limited set of measurement results obtained from one or several expert laboratories. The procedure involves
three stages: (1) check of the experimental data and possible corrections; (2) check of the consistency of data, and possibly
increase of the uncertainties in order to attain internal consistency; (3) choice between fully, partially or un-weighted
mean. 相似文献
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Patra A Wijsboom YH Zade SS Li M Sheynin Y Leitus G Bendikov M 《Journal of the American Chemical Society》2008,130(21):6734-6736
The first highly conductive polyselenophene, namely, poly(3,4-ethylenedioxyselenophene) (PEDOS), was synthesized by taking advantage of a novel method for efficiently contracting the selenophene ring. PEDOS shows a relatively low band gap (1.4 eV), very high stability in the oxidized state, and a well-defined spectroelectrochemistry. 相似文献
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Elena V. Suprun Svetlana A. Khmeleva Yana Y. Kiseleva Sergey P. Radko Alexander I. Archakov Victoria V. Shumyantseva 《Electroanalysis》2016,28(9):1977-1983
The tyrosine based electrochemical analysis of synthetic amyloid‐β (Aβ) peptide – an analog of natural peptide implicated in Alzheimer's disease pathogenesis – was applied for a quantitative estimation of peptide aggregation in vitro. The analysis was carried out by square wave voltammetry (SWV) on carbon screen printed electrodes (SPE). The electrooxidation peak current (Ip) for Aβ42 peptide in different aggregation states was directly compared with the size and structure of Aβ42 aggregates occurring in the analyzed sample. Dynamic light scattering (DLS) and thioflavin T (ThT) based fluorescence assay were employed to estimate the size and structure of Aβ42 aggregates. The Ip was found to decrease in a linear fashion when the average diameter of aggregates and the relative ThT fluorescence in Aβ42 solutions exceeded 35 nm and 3, respectively, while being nearly constant below these values. It was suggested that the electrooxidation current is mostly generated by peptide monomers and that a depletion of the monomer pool due to inclusion of Aβ42 molecules in aggregates is responsible for the decrease of electrooxidation current. The direct electrochemistry is emerging as a method complementary to methods based on aggregates’ detection and commonly employed for monitoring Aβ aggregation. The work further enlarges the basis for application of the cost‐effective and rapid electrochemical techniques, such as SWV on carbon SPE, to in vitro studies of Aβ aggregation. 相似文献
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