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The thermodynamics of the binding of a series of structurally related Ru(II) antitumor complexes to DNA purine bases is analyzed by using the density functional theory method. The structural and thermodynamical characteristics have helped in obtaining the possible structure-activity relationship and describing the distinct difference in cytotoxicities of the series of structurally related antitumor complexes.

A new anion sensor [Ru[(bpy).sub.2]([H.sub.2]biim)][(P[F.sub.2]).sub.2] (bpy = 2,2'-bipyridine and [H.sub.2]biim = 2,2'-biimidazole) is prepared and characterized. The results have shown that the compound is an eligible sensor for various anions as it donates protons for hydrogen bonding to different anions and further actualizes monoproton transfer to the O[Ac.sup.-] anion, changing color from yellow to orange brown.

Density functional theory (DFT) calculations are carried out on the electronic structures and trend in DNA-binding affinities of a series of Ru(II) complexes [[Ru[(bpy).sub.2](p-R-pip)].sup.2+] (R = -OH, -C[H.sub.3], -H, -N[O.sub.2], (bpy = 2,2-bipyridine, pip = 2-phenylimidazo[4,5-f] [1,10]-phenanthroline). The results have shown that the substituents on the intercalative ligands have important effects on the electronic structures, trend in the DNA-binding affinities and spectral properties of the complexes.

The thermodynamics of the binding of a series of structurally related Ru(II) antitumor complexes, that is, α-[Ru(azpy) 2Cl 2] 1, β-[Ru(azpy) 2Cl 2] 2, α-[Ru(azpy)(bpy)Cl 2] 3, and cis-[Ru(bpy) 2Cl 2] 4to DNA purine bases (gunine, adenine at N7 site) has been studied by using the DFT method. The binding of imine form of 9-methyladenine (9-MeAde) to the Ru(II) moiety in a didentate fashion via its N6 and N7 atoms was also considered. The geometrical structures of the DNA model base adducts were obtained at the B3LYP/(LanL2DZ + 6−31G(d)) level in vacuo. The following exact single-point energy calculations were performed at the B3LYP/(LanL2DZ(f)+6−311+G(2d, 2p)) level both in vacuo and in aqueous solution using the COSMO model. The bond dissociation enthalpies and free energies, reaction enthalpies and free energies both in the gas phase and in aqueous solution for all considered Ru(II)-DNA model base adducts were obtained from the computations. The calculated bond dissociation enthalpies and free energies allow us to build a binding affinity order for the considered Ru(II)-DNA model base adducts. The theoretical results show that the guanine N7 is a preferred site for this series of complexes and support such an experimental fact that α-[Ru(azpy)(bpy)(9-EtGua)H 2O] 2+( 3-(9-EtGua)) is isomerized to α′-[Ru(azpy)(bpy)(9-EtGua)H 2O] 2+( 3′-(9-EtGua)). On the basis of structural and thermodynamical characteristics, the possible structure−activity relationship was obtained, and the distinct difference in cytotoxicities of this series of structurally related antitumor complexes was explained theoretically. [ABSTRACT FROM AUTHOR]

A visible-light-driven desaturative β-alkoxyoxalyation of N-aryl cyclic amines with difluoromethyl bromides and H 2 O has been reported. This tandem reaction is triggered by homolysis of the C-Br bond to produce the difuoroalkyl radical, which undergoes the subsequent defluorinated β-alkoxyoxalylation cascades to afford a wide range of β-ketoester/ketoamides substituted enamines. The prominent feature of this reaction contains photocatalyst-free, transition-metal free, and mild conditions. The 18 O labeling experiment disclosed that H 2 O is the oxygen source of the carbonyl unit.

The fruit of Fructus Mori is food and medicine, which has been demonstrated to have a significant neuroprotective effect. However, the effective constituent remains unknown. We speculate that the glycopeptide in the extract of the fruit has similar activity. To address this hypothesis, we isolated a novel pectin-like glycopeptide (FMP-6-S4) with a molecular weight of 11.23 kDa from the fruit. It contains about 20% of peptide comprising 17 amino acids and 80% glycan consisting of L-rhamnose (L-Rha), D-galactose (D-Gal), D-galacturonic acid (D-GalA), L-arabinose (L-Ara) and d-glucose (D-Glc) in molar ratios of 7.25:4.62:77.66:5.62:4.85. The backbone of the glycan part consisted of 1,4-linked α-D-Gal p A and 1, 2-linked α-L-Rha p , while the branches were composed of hexenuronic acid (HexA) substituted at the C-3 position of partial galacturonic acid, and traces of galactose, glucose, and arabinose were substituted at the C-4 position of rhamnose. The in vitro experiments revealed that FMP-6-S4 might inhibit Aβ 42 (β-amyloid peptides 42) aggregation and decrease Aβ 42 production by modulating APP (amyloid precursor protein) processing.

A green, sustainable, and straightforward method for the synthesis of unsymmetrical oxalamides via photoinduced C-N/C═O bond formation of bromodifluoroacetamide, amine, and H 2 O through a triple-cleavage process has been developed. In addition, this approach also provides access to the known bioactive compounds, and a feasible reaction mechanism is proposed. Moreover, the advantages of this transformation, including mild reaction conditions, a broad substrate scope, and operational simplicity, make this protocol attractive for further applications.

A visible-light-induced radical tandem cyclization/arylation between 2-amino-1, 4-naphthoquinone and N -allyl-2-bromo-2,2-difluoroacetamides has been developed without an external photocatalyst. The transformation could be carried out at room temperature and gave a variety of C-3-functionalized 2-amino-1,4-naphthoquinone derivatives in moderate to excellent yields. Moreover, mechanistic studies revealed that the reaction is driven by the formation of an electron donor-acceptor (EDA) complex.

Fenclorim is a commercial herbicide safener with fungicidal activity used for chloroacetanilide herbicides, which might be suitable as a lead compound for screening novel fungicides. However, little has been reported so far on the structure-activity relationship of fungicidal activities of fenclorim or its analogues. Here, a series of 4-chloro-6-substituted phenoxy-2-phenylpyrimidine derivatives was synthesized by a substructure splicing route using fenclorim as a lead compound. The structures of synthesized derivatives were characterized by 1 H NMR, 13 C NMR, and HRMS. Their fungicidal and herbicide safening activities were then evaluated. The results revealed that compound 11 had the best fungicidal activity against Sclerotinia sclerotiorum and Thanatephorus cucumeris , which was better than that of the control pyrimethanil. Moreover, compounds 3 , 5 , and 25 exhibited excellent safening activities against fresh weight, plant height, and root length, respectively. Such activities were significantly improved when compared to fenclorim. In summary, these findings look promising for the preparation of new fungicides and herbicide safeners based on the structure of fenclorim., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

In this study, a permanganate/redox mediator system for enhanced transformation of a series of emerging contaminants was evaluated. The presence of various redox mediators (i.e., 1-hydroxybenzotriazole, N -hydroxyphthalimide, violuric acid, syringaldehyde, vanillin, 4-hydroxycoumarin, and p -coumaric acid) accelerated the degradation of bisphenol A (BPA) by Mn(VII). Since 1-hydroxybenzotriazole (HBT) exhibited the highest reactive ability, it was selected to further investigate the reaction mechanisms and quantify the effects of important reaction parameters on Mn(VII)/redox-mediator reactions with BPA and bisphenol AF (BPAF). Interestingly, not only HBT accelerated the degradation of BPA, but also BPA enhanced the decay of HBT. Evidence for the in situ formation of HBT · radicals as the active oxidant responsible for accelerated BPA and BPAF degradation was obtained by radical scavenging experiments and 31 P NMR spin trapping techniques. The routes for HBT · radical formation involving Mn(VII) and the electron-transfer pathway from BPA/BPAF to HBT · radicals demonstrate that the Mn(VII)/HBT system was driven by the electron-transfer mechanism. Compared to Mn(VII) alone, the presence of HBT totally inhibited self-coupling of BPA and BPAF and promoted β-scission, hydroxylation, ring opening, and decarboxylation reactions. Moreover, Mn(VII)/HBT is also effective in real waters with the order of river water > wastewater treatment plant (WWTP) effluent > deionized water.

An efficient photocatalytic decarboxylative 3-position alkylation of coumarins by using alkyl N-hydroxyphthalimide esters as alkylation reagents has been developed. A variety of NHP esters derived from aliphatic carboxylic acids (primary, secondary, and tertiary) has been proved to be tolerated for this decarboxylation process, affording a broad scope of 3-alkylated coumarin derivatives in moderate to excellent yields. This protocol was highlighted by its mild conditions, readily available starting materials, operational simplicity, and wide functional group tolerance.

The aim of this work is to develop a biobased functional reactive diluent for thermosetting epoxy resins suitable for high-performance applications. An advanced organosilicon-grafted cardanol novolac epoxy resin (SCNER) was synthesized from cardanol novolac epoxy resin and heptamethyltrisiloxane. After the chemical structure of SCNER was identified by Fourier transform infrared, 1 H NMR, and 13 C NMR, it was used to modify the diglycidyl ether of the bisphenol A (DGEBA)/methylhexahydrophthalic anhydride system. The SCNER showed unique advantages, reducing the viscosity of DGEBA and improving the properties of the cured resin. With 10 wt % SCNER, the cured resin exhibited a higher tensile strength (78.84 MPa) and impact strength (32.36 kJ·m -2 ). The single glass transition temperature ( T g ) step proved the homogeneous phase structure of the cured resin. Inevitably, the T g of the cured resin decreased for the addition of SCNER. The dynamic mechanical analysis results indicated that the storage modulus of the cured resin decreased with the increasing content of SCNER. The morphology showing the ductile fracture of the cured resin was testified by scanning electron microscopy. The dilution and toughening properties of SCNER paves the way to a wide range of possible "eco-friendly" applications, especially in the fields of coatings, paintings, and adhesives., Competing Interests: The authors declare no competing financial interest.

High-throughput screening (HTS) assays capable of profiling thousands of environmentally relevant chemicals for in vitro biological activity provide useful information on the potential for disrupting endocrine pathways. Disruption of the estrogen signaling pathway has been implicated in a variety of adverse health effects including impaired development, reproduction, and carcinogenesis. The estrogen-responsive human mammary ductal carcinoma cell line T-47D was exposed to 1815 ToxCast chemicals comprising pesticides, industrial chemicals, pharmaceuticals, personal care products, cosmetics, food ingredients, and other chemicals with known or suspected human exposure potential. Cell growth kinetics were evaluated using real-time cell electronic sensing. T-47D cells were exposed to eight concentrations (0.006-100 μM), and measurements of cellular impedance were repeatedly recorded for 105 h. Chemical effects were evaluated based on potency (concentration at which response occurs) and efficacy (extent of response). A linear growth response was observed in response to prototypical estrogen receptor agonists (17β-estradiol, genistein, bisphenol A, nonylphenol, and 4-tert-octylphenol). Several compounds, including bisphenol A and genistein, induced cell growth comparable in efficacy to that of 17β-estradiol, but with decreased potency. Progestins, androgens, and corticosteroids invoked a biphasic growth response indicative of changes in cell number or cell morphology. Results from this cell growth assay were compared with results from additional estrogen receptor (ER) binding and transactivation assays. Chemicals detected as active in both the cell growth and ER receptor binding assays demonstrated potencies highly correlated with two ER transactivation assays (r = 0.72; r = 0.70). While ER binding assays detected chemicals that were highly potent or efficacious in the T-47D cell growth and transactivation assays, the binding assays lacked sensitivity in detecting weakly active compounds. In conclusion, this cell-based assay rapidly detects chemical effects on T-47D growth and shows potential, in combination with other HTS assays, to detect environmentally relevant chemicals with potential estrogenic activity.

An effective, regioselective C-2 arylation of imidazo[2,1-b]thiazoles catalyzed by Cu(I) has been developed. This arylation proceeded smoothly without promotion of the ligands, and various functional (22 samples) groups were well tolerated. Preliminary mechanistic studies of this arylation are also reported., (© 2011 American Chemical Society)

Gallium(III) triflate-catalyzed ring opening of epoxides affords beta-hydroxy sulfides with high regioselectivity and chemoselectivity in high yields (84-97%) under solvent-free conditions. Additionally, a simple, efficient, and environmentally benign one-pot procedure for the synthesis of beta-hydroxy sulfoxides in sole water has been developed for the first time. The process, promoted by a H2O2-Ga(OTf)3 system, affords beta-hydroxy sulfoxides in high yields (81-94%) and high chemoselectivity without any detectable overoxidation to beta-hydroxy sulfones. The catalyst could be recovered easily after the reactions and reused without evident loss of activity.

Via a catalytic cycle in the presence of scandium triflate (2 mol %)/DMF (1 mol %)/benzoyl chloride (5 mol %), aromatic ketones were treated with bis(trichloromethyl) carbonate (BTC) to afford aryl-(Z)-vinyl chlorides. All metal triflates tested in the reaction showed highly catalytic activity. A plausible addition-elimination mechanism was proposed. The present work describes the first catalytic and green route to the synthesis of aryl-(Z)-vinyl chlorides. [reaction: see text]

Studies on the electronic structures and trend in DNA-binding affinities of a series of Ru(II) complexes [Ru(bpy)2(p-R-pip)]2+ (bpy = 2,2-bipyridine; pip = 2-phenylimidazo[4,5-f] [1,10]-phenanthroline; R = -OH, -CH3, -H, -NO2) 1-4 have been carried out, using the density functional theory (DFT) at the B3LYP/LanL2DZ level. The electronic absorption spectra of these complexes were also investigated using time-dependent DFT (TDDFT) at the B3LYP//LanL2DZ/6-31G level. The computational results show that the substituents on the parent ligand (pip) have a significant effect on the electronic structures of the complexes, in particular, on the energies of the lowest unoccupied molecular orbital (LUMO) and near some unoccupied molecular orbitals (LUMO+x, x = 1-4). With the increase in electron-withdrawing ability of the substituent in this series, the LUMO+x (x = 0-4) energies of the complexes are substantially reduced in order, for example, epsilon(LUMO)(1) approximately epsilon(LUMO)(2) > epsilon(LUMO)(3) > epsilon(LUMO)(4), whereas the pi-component populations of the LUMO+x (x = 0-4) are not substantially different. Combining the consideration of the bigger steric hindrance of complex 2, the trend in DNA-binding affinities (K(b)) of the complexes, that is, K(b)(2) < K(b)(1) < K(b)(3) < K(b)(4) can be reasonably explained. In addition, the experimental singlet metal-to-ligand charge transfer ((1)MLCT) spectra of these complexes can be well simulated and discussed by the TDDFT calculations.