A characterization of sets in ℝ2 with DC distance function

Czechoslovak Mathematical Journal - We give a complete characterization of closed sets F ? ?2 whose distance function dF:= dist(·, F) is DC (i.e., is the difference of two convex...     

Enantioselective conjugate addition of aliphatic thiols to divergently activated electron poor alkenes and dienes

Divergently activated double bonds in electron poor 4-oxo-butenoates and (2E,4E)-6-oxo-2,4-dienoates underwent stereoselective and regioselective addition of mercaptans catalyzed by simple Cinchona alkaloids. Application of quinine and quinidine afforded both enantiomers of the 1,4-adducts with respect to the ketone carbonyl group in ees of up to 80%. Single recrystallization of some adducts resulted in further enrichment of up to 99%ee.     

Thermoanalytical and dilatometric studies of the Al2O3–Cu–Mo hybrid composite

Journal of Thermal Analysis and Calorimetry - The present research is focused on the characterization of the composites from Al2O3–Cu–Mo system. The composites were prepared by slip...     

Synthesis and biological activity of new derivatives with the preserved carane system

Abstract

Terpenoid derivatives, which contain a preserved carane system in their structure, exhibit a broad spectrum of biological activities. Among them, we can distinguish insecticides, structures with pharmacological application etc. In the presented paper, the substrate - (–)-cis-caran-trans-4-ol was transformed using the reactions of typical organic synthesis to obtain novel derivatives. Most importantly, bromolactone ((–)-(1R,4R,6S)-2'-(bromomethyl)-4,7,7-trimethylspiro[bicyclo[4.1.0]heptan-3,3'-furan]-5'(4'H)-one) with the preserved carane system was synthesized. This bromolactone was tested for antifeedant activity against the lesser mealworm, Alphitobius diaperinus Panzer, and peach potato aphid (Myzus persicae). In addition, its moderate antibacterial activity was observed against the Bacillus subtilis strain (with Minimal Inhibitory Concentration of 200 µg/mL).     

In a Quest for Selectivity Paired with Activity: A Ruthenium Olefin Metathesis Catalyst Bearing an Unsymmetrical Phenanthrene-Based N-Heterocyclic Carbene

Robust, selective, and stable in the presence of ethylene, ruthenium olefin metathesis pre-catalyst, {[3-benzyl-1-(10-phenyl-9-phenanthryl)]-2-imidazolidinylidene}dichloro(o-isopropoxyphenylmethylene)ruthenium(II), Ru-3 , bearing an unsymetrical N-heterocyclic carbene (uNHC) ligand, has been synthesized. The initiation rate of Ru-3 was examined by ring-closing metathesis and cross-metathesis reactions with a broad spectrum of olefins, showing an unprecendented selectivity. It was also tested in industrially relevant ethenolysis reactions of olefinic substrates from renewable feedstock with very good yields and selectivities.     

Crystal structure and properties ofcatena-poly[manganese(II)-μ-dichloro-μ-L-proline-k 2 o,o′] monohydrate

The crystal structure and some physico-chemical properties of MnCl₂·Pro·H₂O (Pro=L-proline) were studied. This compound is stable up to approximately 313 K. Upon heating the complex loses a molecule of water and is transformed into the oxide in two steps. The IR spectrum was recorded. The compound crystallizes in the orthorhombic space groupP2₁2₁2₁ witha=7.112(2) Å,b=10.196(2) Å,c=13.249(3) Å andZ=4. The manganese atoms in the polymeric chain are bridged by two chlorine atoms and oxygen atoms from the carboxylate group of L-proline. The Mn?Cl bond distances range from 2.535(1) Å to 2.581(1) Å, the Mn?O bond distances range from 2.135(2) Å to 2.153(2) Å and Mn?Mn bond distances are 3.556(1) Å. One molecule of water is hydrogen-bonded with a nitrogen atom of the L-proline ring.