Expeditious synthesis of phenanthridines from benzylamines via dual palladium catalysis

A method for the synthesis of phenanthridines from benzylamines and aryl iodides which uses a dual palladium-catalyzed process is developed. The domino sequence ends via an intramolecular amination and an oxidative dehydrogenation. No protecting group or prefunctionalization of the amine is required, and the process uses dioxygen as the terminal oxidant.     

Membrane Affinity and Antibacterial Properties of Cationic Polyelectrolytes With Different Hydrophobicity

The antibacterial behavior of cationic polyelectrolytes is studied using model membrane experiments and in vitro bacterial investigations. The molecular interaction with lipid films is evaluated by the degree of penetration of the polymers into Langmuir monolayers of neutral or negatively charged lipids. The polymer/lipid interaction results in structural changes of the penetrated lipid layer visualized using AFM. The polymers are found to be effective in inhibiting the proliferation of E. coli, B. subtilis and S. aureus. The influence of the chemical structure on the functional behavior is related to the conformational properties. An optimum structure is identified on the basis of antibacterial and hemolytic tests as well as membrane‐destroying efficacy of the antimicrobial polymers.

     

Time variations of 222Rn concentration and air exchange rates in a Hungarian cave

A long-term radon concentration monitoring was carried out in the Pál-v?lgy cave, Budapest, Hungary, for 1.5 years. Our major goal was to determine the time dependence of the radon concentration in the cave to characterise the air exchange and define the most important environmental parameters that influence the radon concentration inside the cave. The radon concentration in the cave air was measured continuously by an AlphaGuard radon monitor, and meteorological parameters outside the cave were collected simultaneously. The air's radon concentration in the cave varied between 104 and 7776?Bq?m(-3), the annual average value was 1884±85?Bq?m(-3). The summer to winter radon concentration ratio was as high as 21.8. The outside air temperature showed the strongest correlation with the radon concentration in the cave, the correlation coefficient (R) was 0.76.     

Spirobutyrolactone derived from 1-phenyl-3-methyl-2-pyrazolin-5-one

X-ray diffraction and NMR spectral examination have shown that 1-phenyl-3-methyl-2-pyrazolin-5-one reacts with methyl acrylate in methanol to give spiro[(1-phenyl-3-methyl-2-pyrazolin-5-one)-4,5-butyrolactone]. The conformation has been shown to be the same in the crystal and in solution, the pyrazoline ring has been found to be nonplanar, the reasons for the acoplanarity established, stabilizing and destabilizing interactions studied, and the orientation of the phenyl substituent relative to the pyrazolin-5-one ring determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 909–913, July, 1988.     

study of the reverse current range in a knudsen diode with surface ionization under overneutralized conditions in the presence of electron emission from the collector: Part I. Large electrode spacing

The reverse current range of a Knudsen diode with surface ionization is studied under overneutralized conditions in the presence of electron emission from the collector. The difficulty of the problem is associated with the need to consider three particle flows: ions and electrons from the emitter and electrons from the collector. This work consists of two parts. In the first part, the potential distributions and I-V characteristics for plasma regimes, where the potential distribution has a quasi-neutrality portion, are calculated. In the second, the diode with a small electrode spacing, where the near-electrode potential jumps overlap, is investigated. The asymptotic behavior of the current under high negative voltages is examined. Data obtained are compared with the classical Langmuir results for the diode with two opposing electron and ion flows.     

Anchoring transitions of nematic liquid crystals

A crystalline substrate such as mica or gypsum can orient a thin layer of nematic liquid crystal spread on top. By adsorbing one or more other kinds of molecules onto the surface, we have observed transitions in the orientation of the molecules on the surface. These “anchoring transitions” are analyzed via Landau-Ginzburg theory and may be first or second-order. The second-order anchoring transition is the first two-dimensional system where critical fluctuations may be observed optically.     

Synthesis and thermal decomposition of haloalkoxy-sym-triazines

The reaction of 4,6-bis[alkyl(dialkyl)amino]- or (4-alkylamino-6-dialkylamino-sym-triazin-2-yl)trimethylammonium chlorides with ethylene chlorohydrin and the action of phosphorus pentachloride on 2--hydroxyethoxy-sym-triazines give 2--chloroethoxy derivatives of sym-triazine, which on heating are converted to imidazo[1,2-a]-sym-triazine derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 262–265, February, 1977.