Fluorescence from 3,5-diphenyl-8-CF3-BODIPYs with amino substituents on the phenyl rings: Quenching by aromatic molecules.

The photoluminescence from n-hexane solutions of the dyes obtained by the introduction of amino groups into the meta position of the phenyl rings of 3,5-diphenyl-8-CF3-BODIPY was found to be strongly quenched by some aromatic molecules (benzene and toluene). On the contrary, the introduction of an amino group into the para position does not lead to significant quenching. The quenching of photoluminescence from the meta derivatives obeys the mixed static + dynamic mechanism. Temperature-dependent time-resolved fluorescence measurements were performed to determine the Stern-Volmer constants of the static and dynamic components of quenching. It follows from these data that the binding energy between luminophore and toluene molecules is about 5.0 kcal/mol in the ground state and larger than 3.4 kcal/mol in the excited state. Complexation with toluene facilitates the intramolecular charge transfer in the BODIPY derivatives with the meta position of the amino groups, resulting in photoluminescence quenching.

Growth-Stimulating Activity of Natural Polymer-Based Nanocomposites of Selenium during the Germination of Cultivated Plant Seeds.

The growth-stimulating activity of three selenium nanocomposites (NCs) in various matrices based on arabinogalactan (NC Se/AG, 6.4% Se), starch (NC Se/St, 2% Se), and carrageenan (NC Se/Car, 12% Se) with respect to plants of radish, soybean, and potato was investigated. It was shown that the treatment of plant seeds with NCs stimulated root growth during germination. It was found that the studied NCs affected both the level of lipid peroxidation and the activity of the antioxidant enzyme glutathione peroxidase (GPX). The treatment of radish seeds with NCs stimulated root growth during their germination and reduced the content of diene conjugates (DC) in root tissues. It was shown that soaking seeds in NC Se/AG solution increased the GPX activity in the tissues of the radish root by 40%. Stimulation of soybean root growth under the influence of NC Se/Car may also be associated with the activation of GPX. Furthermore, in potato plants, this NC led to the stimulation of germination; however, this was probably due to the activation of other antioxidant enzymes. The results obtained allow us to consider Se NCs as potential plant growth stimulants.

Selenium Nanocomposites Having Polysaccharid Matrices Stimulate Growth of Potato Plants in Vitro Infected with Ring Rot Pathogen.

The influence of nanocomposites (NC) of selenium in matrices of arabinogalactan (Se/AG) and starch (Se/St) on in vitro vegetation of potato plants, peroxidase activity, and reactive oxygen species has been thoroughly studied. It has been shown that these nanocomposites of selenium have antimicrobial effect to the phytopathogenic bacterium Clavibacter michiganensis ssp. sepedonicus (Cms). In the present investigation, it has been shown that Se/AG NC (6.4% of Se) and Se/St NC (12.0% of Se) have no negative impact on the potato plants healthy and Cms infected, while stimulating their growth, number of leaves and weight of the vegetative part. Se/AG NC has shown a positive effect on potato plants by increasing its immune status by increasing the ROS content and increasing the peroxidase activity. With the use of the element analysis technique, it has been shown that scrutinized nanocomposites are not accumulated in potato plants after the bactericidal processing with the nanocomposites. Se/AG NC and Se/St NC as potential agents used for treatment of potato plants against pathogenic bacteria.

Catalyst-free 1 : 2 annulation of quinolines with trifluoroacetylacetylenes: an access to functionalized oxazinoquinolines.

Metal- and solvent-free reaction of quinolines with two molecules of aryltrifluoroacetylacetylenes afforded 3-arylethynyl-3-trifluoromethyl-1,3-oxazinoquinolines in up to 92% yields. The formation of a zwitterionic intermediate in the first step triggered a multistep domino reaction. This one-pot synthesis opens an easy access to novel quinoline derivatives bearing trifluoromethyl, acetylene and ketone functions, thus providing a powerful tool for drug design.

Transition metal-free one-pot double C-H functionalization of quinolines with disubstituted electron-deficient acetylenes.

Transition metal-free one-pot reaction of quinolines with acylarylacetylenes and water proceeds in the presence of KOH (55-60 °C, MeCN, 48 h) to afford 2-aryl-3-acylquinolines in up to 66% yield. Here, a formal replacement of the acetylene moiety by the aryl and acyl substituents in the quinoline scaffold takes place. In fact, it has been proved experimentally that the reaction involves the ring cleavage, accompanied by the rearrangement and insertion of the electron-deficient acetylene moiety to form a dihydroquinoline intermediate with an aldehyde functional group in position 4. This intermediate gives the corresponding doubly functionalized quinolines.

Metal-free stereoselective annulation of quinolines with trifluoroacetylacetylenes and water: an access to fluorinated oxazinoquinolines.

Metal-free reaction between quinolines, aryltrifluoroacetylacetylenes and water at -18 °C-rt in MeCN resulted in stereoselective assembly of trifluoromethylated oxazinoquinolines with up to 99% yield that was essentially in contrast to a similar reaction with pyridines. The annulation proceeded via the 1,3-dipolar adducts of quinolines with trifluoroacetylacetylenes followed by intramolecular cyclization involving the trifluoroacetyl group and a molecule of water.

Silver-Containing Humic Substance-Based Nanocomposites-Agents for Healing of Potatoes from the Ring Rot.

The influence of silver-containing humic substance (HS)-based nanocomposites (NCs) obtained from mud, shale, and coals of three kinds of deposits in Mongolia on the viability and ability to biofilm formation of a phytopathogenic gram-positive bacterium Clavibacter michiganensis subsp. sepedonicus (Cms), as well as peroxidase activity and potato plant growth in vitro, has been investigated. The maximum reduction of the viability of bacterial cells was found in the case of incubation with HS-mu/Ag NC and HS-coal/Ag NC. It was found that HSs, including HS-mu and HS-sl, and NCs synthesized on the base of these HSs, HS-mud/Ag NC and HS-sl/Ag NC reduce more than twofold the activity of peroxidase in potato tissues. It was also found that HS-co and HS-coal/Ag NC stimulate the potato peroxidase activity, as well as biofilm formation of Cms bacterium. No negative effect of the studied NCs on the growth of potato has been revealed. Moreover, NC HS-mud/Ag based on mud had a stimulating effect on leaf formation in plants.

2-(1-Hydroxypropyn-2-yl)-1-vinylpyrroles: the first successful Favorsky ethynylation of pyrrolecarbaldehydes.

1-Vinylpyrrole-2-carbaldehydes react with acetylene at atmospheric pressure in a NaOH/EtOH/DMSO system at 7-10 °C to afford 2-(1-hydroxypropyn-2-yl)-1-vinylpyrroles in 53-94% yield. Thus, the first base-mediated direct ethynylation of pyrrolecarbaldehydes with free acetylene under modified conditions of the Favorsky reaction has been implemented to pave an expedient route to important biomolecules containing a pyrrole ring.

New Cretaceous marsupial from Mongolia and the early radiation of Metatheria.

A marsupial mammal from Mongolia representing a previously unreported group, Asiadelphia, offers unequivocal evidence that metatherians were represented on the continent of Asia during the Late Cretaceous (Campanian), even in the northern arid interior. Asiatherium is known by skull, left and right mandibles, and most of its postcranial skeleton. Comparisons of the dentition, ear region, and aspects of the postcranium not only allow its diagnosis as an Asian group of metatherians but also permit a diagnosis of the Metatheria based on the unequivocally apomorphous condition of the dental formula and probable replacement pattern of the protometatherian, in contrast to the more primitive therian dental formula, represented by the few known Aegialodontidae and the first dental eutherians. It appears an inescapable conclusion that the first metatherians had a more derived dental formula (and probably replacement pattern) than the earliest dental eutherians, regardless of what specific derivation from a therian ancestry is contemplated. Such a diagnosis also supports the metatherian status of other Cretaceous Asian and American taxa such as the Deltatheroida and Kokopellia. The hypothesis that Metatheria originated in North America is largely dependent on the preponderance of Cretaceous forms from North America and negative evidence from Asia (i.e., on the lack of lower latitude Early Cretaceous tropical faunas). Conversely, the relative Cretaceous paucity of placentals from North America and their greater abundance in Asia suggests the earliest flowering of the Eutheria in an unspecified region of the Old World. The concept of a holophyletic Theria (= Tribosphenida) employed here, based on the biologically significant apomorphy of the molar form-function of the first therian, entails only the tribosphenic mammals (infraclasses Tribotheria, Metatheria, and Eutheria) but not the sundry quasi-triangular-toothed mammals and their derivatives in the Mesozoic (Eupantotheria, Peramura, Monotremata, etc.). It is suggested that the Asiadelphia and Deltatheroida, the protospecies of both, with the apomorphic therian dental formula, are ancient lineages of Metatheria independent from their North American relatives probably since the early part of the Late Cretaceous.