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An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

No abstract is provided for this article.

No abstract is provided for this article.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Phenolic organochalcogen chain-breaking antioxidants, i.e. 6-bromo-8 (hexadecyltellanyl)-3,3-dimethyl-1,5-dihydro-[1,3]dioxepino[5,6-c]pyridin-9-ol and 2-methyl-2,3-dihydrobenzo[b]selenophene-5-ol, have been investigated in a two-phase (chlorobenzene/water) lipid peroxidation model system as potent inhibitors of lipid peroxyl radicals with various co-antioxidants at various pH values. The pH has a significant effect on the chain-breaking antioxidant activities of phenolic organochalcogens. The key chain-breaking mechanism profile was attributed to the first oxygen atom transfer from the lipid peroxyl radicals to the Se/Te atom, followed by hydrogen atom transfer in a solvent cage from the nearby phenolic group to the resulting alkoxyl radical. Finally, regeneration of organochalcogen antioxidants could take place in the presence of aqueous-soluble co-antioxidants. Also, in the presence of aqueous soluble N-acetylcysteine at pH 1-7, both antioxidants behaved as very good inhibitors of lipid peroxyl radicals. The role of aqueous soluble mild co-antioxidants in the regeneration studies of organochalcogen antioxidants has been investigated in a two-phase lipid peroxidation model system. The importance of the phase transfer catalyst has been explored in the inhibition studies of selenium containing antioxidants using an Fe(II) source. The overall pH-dependent antioxidant activities of organochalcogens depend on their hydrogen atom transfer ability, relative stability, and distribution in the aqueous/lipid phase.

The warming climate-induced intensification of hydrological cycle is amplifying extreme precipitation and increasing flood risk at regional and global scales. The evaluation of flood risk, which depends on assessment indicators, weights, as well as data quality, is the first step toward mitigation flood disasters. In this study, we accepted ten risk assessment indicators concerning hazard of disaster-causing factors, sensitivity of hazard-forming environments, and vulnerability of disaster-bearing bodies. We used a combined weighting method based on the analytic hierarchy process and entropy weight (AHP-EW) technique to evaluate rainstorm-induced flood risks across the Yellow River Basin (YRB) from 2000 to 2018. We observed flood hazards are intensifying across the YRB. Specifically, areas with medium flood hazards expanded from the lower to the middle and upper YRB. The sensitivity to floods exhibited a spatial pattern of increasing from southeast to northwest (lower to upper YRB). The increase in vegetation coverage in the middle and upper reaches of the YRB reduces the sensitivity to flood disasters. Flood vulnerability shows an increasing trend, with higher vulnerability mainly observed in the middle and lower YRB. The overall flood risk in the YRB shows an increasing trend, with a 9-fold increase in flood risk from 2000 to 2018. Medium to high flood risk and vulnerability can mainly be identified in the middle and lower YRB, where population and gross domestic product are concentrated. The intensifying rainstorm-induced flood risks over urban areas in these regions should arouse public concern.

The aromatic nucleophilic substitution (S N Ar) reactions of N ‐(2‐bromo‐3‐nitrobenzyl)aniline ( 18 ), N ‐(2‐bromo‐3‐nitrobenzyl)‐4‐methylaniline ( 19 ) and N ‐(2‐bromo‐3‐nitrobenzyl)‐4‐nitroaniline ( 20 ) with [ n BuSeNa] afford N ‐[2‐(butylselanyl)‐3‐nitrobenzyl]aniline ( 21 ), N ‐[2‐(butylselanyl)‐3‐nitrobenzyl]‐4‐methylaniline ( 22 ) and N ‐[2‐(butylselanyl)‐3‐nitrobenzyl]‐4‐nitroaniline ( 23 ), respectively. The bromination of 21 results in the formation of cyclic isoselenazolines 7‐nitro‐2‐phenyl‐2,3‐dihydrobenzisoselenazole ( 27 ) and 2‐(4‐bromophenyl)‐7‐nitro‐2,3‐dihydrobenzisoselenazole ( 28 ). The bromination of 22 affords isoselenazolines 2‐(4‐methylphenyl)‐7‐nitro‐2,3‐dihydrobenzisoselenazole ( 29 ) and 2‐(2‐bromo‐4‐methylphenyl)‐7‐nitro‐2,3‐dihydrobenzisoselenazole ( 30 ) along with some other products. The bromination of 23 under identical conditions gave 2‐(2‐bromo‐4‐nitrophenyl)‐7‐nitro‐2,3‐dihydrobenzisoselenazole ( 31 ). The oxidation reaction of 21 – 22 with H 2 O 2 yielded isoselenazoline Se ‐oxides 7‐nitro‐2‐phenyl‐2,3‐dihydrobenzisoselenazole 1‐oxide ( 33 ) and 2‐(4‐methylphenyl)‐7‐nitro‐2‐phenyl‐2,3‐dihydrobenzisoselenazole 1‐oxide ( 34 ), respectively. The new isoselenazolines and isoselenazoline Se ‐oxides, stabilized by intramolecular secondary Se ··· O interactions, have been structurally characterized by single‐crystal X‐ray diffraction studies and investigated by computational studies. In addition to the synthesis and characterization, the glutathione peroxidase (GPx)‐like activities of isoselenazolines and isoselenazoline Se ‐oxides have been evaluated by coupled reductase assays.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Drug combinations have the potential advantage of greater analgesia over monotherapy. The present study was aimed to assess any possible interaction (additive or potentiation) in the antinociceptive effects of etoricoxib; a novel cyclooxygenase-2 inhibitor, and tramadol; a typical opioid agonist when administered in combination against mechanical hyperalgesia induced by spinal cord injury in rats. The nature of interaction was analyzed using surface of synergistic interaction (SSI) analysis and an isobolographic analysis. Etoricoxib or tramadol when administered alone to rats, exhibited different antihyperalgesic potencies (ED50 etoricoxib: 0.58±0.19 mg/kg, po; ED50 tramadol: 9.85±0.57 mg/kg, po). However, both the drugs were found to be long acting against this model of hyperalgesia. Further, etoricoxib and tramadol were co-administered in fixed ratios of ED50 fractions. One combination (0.29/4.79 mg/kg, po: etoricoxib/tramadol) exhibited additivity and other three combinations (0.15/2.39, 0.08/1.19, and 0.04/0.59 mg/kg, po: etoricoxib/tramadol) resulted in potentiation when analyzed by SSI. The SSI was calculated from the total antihyperalgesic effect produced by the combination after the subtraction of the antihyperalgesic effect produced by each of the individual drug. In the isobolographic analysis, the experimental ED50 was found to be far below the line of additivity also indicating a significant (P <0.05) synergistic antihyperalgesic effect when etoricoxib and tramadol was co-administered to rats. The synergistic antihyperalgesic effect of etoricoxib and tramadol combination suggests that these combinations may have clinical utility in mechanical hyperalgesia associated with spinal injury.

Singlet fission is a process by which two molecular triplet excitons are generated subsequent to the absorption of one photon. Molecules that enable singlet fission have triplet state energy at least half of the bright singlet state energy. This stringent energy criteria have challenged chemists to device new molecular and supramolecular design principles to modulate the singlet-triplet energy gap and build singlet fission systems from a wide range of organic chromophores. Herein, we report for the first time intramolecular singlet fission in the seminal naphthalenediimide (NDI) scaffold constrained in a push-pull cyclophane architecture, while individually the NDI chromophore does not satisfy the energy criterion. The challenging synthesis of this highly contorted push-pull cyclophane is possible from the preorganized pincer-like precursor. The special architecture establishes the shortest co-facial NDI⋯NDI contacts (3.084 Å) realized to date. Using broadband femtosecond transient absorption, we find that the correlated T-T pair forms rapidly within 380 fs of photoexcitation. Electronic structure calculations at the level of state-averaged CASSCF (ne,mo)/XMCQDPT2 support the existence of the multi-excitonic T-T pair state, thereby confirming the first example of singlet exciton fission in a NDI scaffold.

No abstract is provided for this article.

Licofelone, a competitive inhibitor of cyclooxygenases 1 and 2 and 5-lipoxygenase enzyme, is under clinical evaluation for its effectiveness in the treatme

Among the various organoselenium heterocycles, a new class of benzoselenazoles has attracted a great attention of scientists. The ever-growing interest for five-membered benzoselenazole heterocycles amongst the chemists has made commendable...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The syntheses of the three selenenium cations 17 – 19 derived from N ‐[ n ‐butyl‐(3‐nitrobenzylimino)]phenyl selenide ( 14 ) are described. Precursor 14 was synthesized by treating N ‐(2‐bromo‐3‐nitrobenzylimino)benzene ( 12 ) with in situ generated n BuSeNa. The selenenium cation 17 with chloride as counteranion was isolated when 14 was treated with sulfuryl chloride (SO 2 Cl 2 ) in the presence of triethylamine (Et 3 N). The selenenium cations with bromide ( 18 ) and tribromide ( 19 ) as counteranions, were synthesized by treating 14 with Br 2 in the presence of Et 3 N. Reaction of 19 with thiophenol afforded two unexpected products: the cyclic diselenide 20 and the bicyclic selenide 21 . Oxidation of 18 with hydrogen peroxide afforded the ebselen derivative, 2‐(4‐bromophenyl)‐7‐nitro‐1,2‐benzisoselenazol(2 H )‐3‐one Se ‐oxide ( 22 ). The presence of nonbonding Se ··· O/Se–N intramolecular interactions in 18 and 19 have been confirmed by single‐crystal X‐ray studies. Glutathione peroxidase‐like antioxidant activities of 17 – 19 and related compounds have been determined by the coupled reductase assay. It is proved that the high GPx‐like activities of cations involve the formation of corresponding intermediate selenoxide in the catalytic cycle. The isolated selenoxide 22 shows the highest GPx‐like activity among the series of compounds. The compounds have been further investigated by density functional theory calculations at the B3LYP level of theory using the 6‐31+G(d) basis set to identify nonbonding Se ··· O/N interactions. The second perturbation energy was obtained through natural bond orbital (NBO) analysis and NBO charges were calculated to ascertain the positive charge at the selenium atom. Nucleus‐independent chemical shifts (NICS) calculations have also been carried out.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.