Synthesis and spectral properties of shielded 1,2-disubstituted imidazolines

Shielded 1,2-disubstituted imidazolines were synthesized by condensation of diethylenetriamine with 2-ethylhexanoic acid. UV, IR and¹H and¹³C NMR spectral data were discussed. The effect was studied of branching in an alkyl substituent at the 2 position of the imidazoline ring on the spectral parameters of the synthesized compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 878–882, April, 1991.     

Effect of introducing a cationic system into a thiol‐ene photopolymerizable formulation

Hybrid materials derived from a thiol‐ene and cationic polymerization were obtained from concomitant polymerization. The hybrid materials were cured by both photopolymerization and thermally induced polymerization. The kinetics of the photopolymerization were measured using time resolved‐IR and optical pyrometry. The nucleophilic character of the polysulfide obtained initially in the thiol‐ene polymerization inhibited the development of the cationic photoinitiated polymerization of epoxy monomers. Besides, the epoxide groups underwent a proton catalyzed addition reaction with the thiols to form new sulfides groups in the reaction mixture. It is proposed that the formed sulfides can terminate the growing polyether chains forming dormant species like trialkylsulfonium salts. These salts promote the thermal polymerization of the epoxy monomer in a post treatment, producing hard and transparent materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4829–4843, 2007     

EXAFS study of the local structure and cation distribution in V-Mo-Nb oxide

The local structure and cation distribution in Mo-Nb and V-Mo-Nb oxides with M₅O₁₄ type structures, which are active in the oxidative transformations of ethane, were studied by EXAFS spectroscopy. In the amorphous (or nanocrystalline) state, the oxides have fragments of the M₅O₁₄ structure in the form of stars of pentagonal MO₇ bipyramids connected with MO₆ octahedra along edges and arranged in a disordered matrix of octahedra. Possible crystallographic positions occupied by vanadium cations were revealed.     

Hypoxia‐Activated Prodrugs of PERK Inhibitors

Tumour hypoxia plays an important role in tumour progression and resistance to therapy. Under hypoxia unfolded proteins accumulate in the endoplasmic reticulum (ER) and this stress is relieved through the protein kinase R‐like ER kinase (PERK) signalling arm of the unfolded protein response (UPR). Targeting the UPR through PERK kinase inhibitors provides tumour growth inhibition, but also elicits on‐mechanism normal tissue toxicity. Hypoxia presents a target for tumour‐selective drug delivery using hypoxia‐activated prodrugs. We designed and prepared hypoxia‐activated prodrugs of modified PERK inhibitors using a 2‐nitroimidazole bioreductive trigger. The new inhibitors retained PERK kinase inhibitory activity and the corresponding prodrugs were strongly deactivated. The prodrugs were able to undergo fragmentation following radiolytic reduction, or bioreduction in HCT116 cells, to release their effectors, albeit inefficiently. We examined the effects of the prodrugs on PERK signalling in hypoxic HCT116 cells. This study has identified a 2‐substituted nitroimidazole carbamate prodrug with potential to deliver PERK inhibitors in a hypoxia‐selective manner.     

A Fluoro-Chromogenic Sensor Based on Organic Molecular Framework for Cu<Superscript>2+</Superscript> and F<Superscript>−</Superscript> in Aqueous Soluble DMSO

The 2,2′-dinaphtholazobenzene molecular framework (P) was designed, synthesized and characterized. Its absorption and fluorescence properties revealed that P is a dual sensor for copper ions (Cu²⁺) and fluoride ions (F^?) in DMSO. The colorimetric activities were clearly visible by naked eye upon the addition of the two ions. Fluorescence quenching and enhancement were observed when Cu²⁺ and F^? ions were added respectively. Density Functional Theory (DFT) calculations were carried out to provide an insight into the interaction of guest ions (Cu²⁺ and F^?) with P, and to explain how the molecular orbitals were affected.

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Microdistribution of lead in human teeth using microbeam synchrotron radiation X‐ray fluorescence (μ‐SRXRF)

Lead (Pb) exposure is known to be associated with adverse effects on human health, especially during the prenatal period and early childhood. The Pb content in teeth has been suggested as a useful biomarker for the evaluation of cumulative Pb exposure. This study was designed to employ the microbeam synchrotron radiation X‐ray fluorescence technique to determine the microdistribution of Pb within the tooth to evaluate the reliability of the technique and the effectiveness of tooth Pb as a biomarker of Pb exposure. The results showed that in the incisor sample, Pb primarily deposited in secondary dentine region close to the pulp and secondarily at enamel exterior. In addition, Pb colocalised with Zn, indicating a positive correlation between Pb and Zn. By contrast, in the two molar samples, Pb accumulated principally in the pulp, and secondarily in the enamel. At the same time, Pb in these two molar samples colocalised with Ca instead of Zn as was observed in the incisor sample. Several batches of line scans further confirmed the conclusions. The feasibility of using microbeam synchrotron radiation X‐ray fluorescence to determine the microdistribution of Pb in teeth and of using the tooth Pb, especially in dentine, as a biomarker was discussed. Copyright © 2016 John Wiley & Sons, Ltd.     

Chromatographische Trennung Ton aromatischen Carbonylverbindungen

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