Substituted alpha-(phenylhydrazono)phenylacetonitrile derivatives have been discovered which constitute a series of potent uncouplers of oxidative phosphorylation. Systematic variation of substituents on both benzene rings has clearly demonstrated the importance of steric congestion around the ionisation site and delocalisation of negative charge in the anionic form. Replacement of the cyano group by other electron-withdrawing groups leads to a dramatic decrease in uncoupling activity. The sub-nanomolar levels of uncoupling activity found in certain members indicate that these compounds are the most potent uncouplers yet reported.
Abstractα-Methyl-γ-butyrolactone (III) has been prepared directly from γ-butyrolactone (I) in 89 % yield by selective monomethylation conditions: K2CO3/DMC/210°C/7 h. The reaction mechanism was elucidated and described. An intermediate and two byproducts: methyl tetrahydro-3-methyl-2-oxofuran-3-carboxylate (II), 3-(methoxycarbonyl)propyl methyl carbonate (IV) and 3-(methoxycarbonyl)butyl methyl carbonate (V) were identified. The high temperature disproportionation of K2CO3 in the presence of dimethyl carbonate to MeOK was observed. The new selective synthesis of 2-methyl-1-tetralone (VI) from α-methyl-γ-butyrolactone (III) by Friedel-Crafts conditions was performed in 79 % yield.
The emission properties of three 4-azafluorenone and five new α-carboline fluorophores in both solution and thin solid films were investigated. Fluorescence of the azafluorenone is clearly enhanced in thin solid films due to the presence of phenyl/biphenyl rotors, and these derivatives can be classified as green Aggregation-Induced Emission luminogens (AIEgens) with a non-emissive heteroaromatic core structure. Compared to azafluorenones, emission of α-carbolines is hypsochromically shifted to the blue region of the electromagnetic spectrum, and most of these derivatives exhibit strong violet-blue fluorescence in both solution and thin solid film layers. Further, the effective mobility and electroluminescence of new α-carbolines were investigated in prepared organic field-effect transistors and organic light-emitting diodes, respectively.
Tourism is currently an integral part of the benefits to national economies. It becomes an eye-catching sector and helps a large group of other industries to prosperity and profitability. Stated contribution deals with linking tourism and air transport, which is now continually gaining in volume. Increasing volumes of air transport is a signal of increased movements of tourists, whether under national or international lines. The article is focused on tourism in Slovakia and on its influence on Slovak airports.
STABILIZATION OF POLYPROPYLENE BY ESTERS OF 2,2,6,6 -TETRAMETHYL 4 -PIPER ID I NOL E ai4arta Povaiancov5, aPeter Danko, aMilan Karva5, bMarta Klimov6, 'Pavol ZauEik, 'Jtilius Our:tlisThe eifcct of the sabstituznts R and X in esters of 2,2,6,5-tetra-methy<.-! -piperidinole of t i i s general formula 1 (311 tha,r stabilizing efficien-y in polypropylene was investigated. As the subslituents R , the aliphatic alkyls CH3(CH2),, were used, whc?re 11=0-15, X=H. !3y thc derivative where R is an alkyl with 1 3 t~ 17 carbon aioms the sffect of the substituent X was also investigated where X is ti, O', OH, OR.' Both the thermooxidation and photooxidation stability of PP uers found to be increased with the insrcasing chain length R. The effect of the substituents X is various. Both ;NO' and ZN-Oii stabilizers have high efficiency during the processing of PP. At the long-term thermooxidation stress, the IN-OR,' 74-0' and -N -O H derivatives are more efficient than,;N-H compounds which are the most efficient against the effect of the ultraviolet radiation and photooxidation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.