Differential capacity curves at adsorption of organic ions: Model approach I

Theoretical analysis of the double-layer model has been carried out in the presence of the specific adsorption of organic cations accompanied by considerable increase of the inner-layer dimensions. The formulae for calculation of the differential capacity curves of an electrode have been derived. A flat minimum at high negative charges, caused by the diffuse structure of the double layer, has been predicted on the capacity curves. The presence of such minima has been verified experimentally on the mercury and bismuth electrodes. By computer calculation it has been shown that, although. relatively good agreement of the theoretically calculated capacity curves with the experimental curves could he obtained, a physically unrealistic interaction parameter of the specifically adsorbed ions had to be used. As demonstrated, this result is a result of the double-layer model assuming linear dependence of the inner-layer integral capacity of the surface coverage and its independence from the electrode charge.     

A New Preparation of 1,3,3‐Trimethylbicyclo[2.2.2]octan‐2,6‐dione,a Never Isolated Intermediate in a Total Synthesis of (+)‐Norpatchoulenol. Formal Total Synthesis of (±)‐Iso‐Norpatchoulenol

A new preparation and the isolation and spectroscopic characterization of 1,3,3‐trimethylbicyclo[2.2.2]octan‐2,6‐dione ( 3 ), a so far elusive key intermediate in the Liu–Ralitsch total synthesis of (+)‐norpatchoulenol ((+)‐ 1a ), is described. The preparation of 3 constitutes also a formal total synthesis of (±)‐iso‐norpatchoulenol ((±)‐ 1b ), since 3 is correlated to an intermediate in the Monti and co‐workers synthesis of (±)‐ 1b .     

Synthesis of 8-arylated catechin and epicatechin derivatives via Suzuki cross-coupling

8-Arylated catechin and epicatechin derivatives have been prepared in good to excellent yields via Suzuki cross-coupling in the presence of Pd₂(dba)₃ as the Pd(0) source and Sphos as the phosphine ligand.     

Analysis on distribution coefficients of Strontium and Cesium for safety assessment studies

The distribution coefficients of strontium and cesium in an Italian nuclear site were studied. Distribution coefficient is a fundamental parameter in safety assessment studies on radionuclide migration into the environment. A sensitivity analysis to identify the main influencing factors on the variation of distribution coefficient in subsoil was carried out. Cation exchange capacity was identified as the main influencing parameter, thus a correlation between cation exchange capacity and distribution coefficient was estimated. In this way, the determination of cation exchange capacity, that is less consuming, makes it possible to easily obtain a preliminary, but reliable distribution coefficient on extensive sites.     

Ultrasound assisted,synthesis of N-(7-(R)-2-oxa-8-azabicyclo[4.2.0]octan-8-yl)isonicotinamide derivatives and their biological evaluation

In this study, new series of azetidine derivatives were synthesized ( 4a-n ) from isoniazide ( 1 ), Aromatic aldehydes ( 2a-n ), dihydropyran ( 3 ) using SnCl₂ catalyst, via one pot multicomponent reaction/cycloaddition reaction. The synthesized azetidine derivatives were characterized by IR, ¹H NMR and ¹³C NMR and have been screened for antimicrobial, antituberculosis and anti-inflammatory activities. In relation to Staphylococcus aureus (ATCC 25923) promising antibacterial activity was shown, compounds 4e and 4k , followed by compounds 4h , 4n , 4f , 4g and 4l . The synthesized azetidine derivatives, 4a , 4e , 4j and 4m (with zone 12 mm) displayed antituberculosis activity. But its lower potential than, the standard streptomycin (with zone 18 mm). Further 4d compound alone displayed similar activity.     

Synthesis of novel thiazol-5-ylpyrimidine derivatives and their antimicrobial evaluation

Novel thiazol-5-ylpyrimidine derivatives were designed and synthesized. The chemical structures of all new synthesized compounds were assigned by studying their elemental analyses and spectral data (FT-IR, ¹HNMR, ¹³C NMR, and MS). The target compounds, 8 and 9a-9d were evaluated for their antimicrobial activity in vitro against gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus, gram-negative bacteria, Salmonella abony and Escherichia coli and fungi, Aspergillus flavus and Fusarium oxysporum. In particular, compounds 9a-9c exhibited moderate to good activity against gram-positive bacteria, S. aureus, gram-negative bacteria, S. abony and fungus, Fusarium oxysporum in comparison with reference drugs.     

Inhibition of histamine mediated responses by Mirabilis jalapa: confirming traditional claims made about antiallergic and antiasthmatic activity

The roots of Mirabilis jalapa are used traditionally in allergic skin disorders and asthma. The effect of an ethanol:acetone (1:1) extract of the roots of M. jalapa was studied for antihistaminic activity using a guinea pig tracheal chain preparation and clonidine-induced mast cell granulation in mice. Its antiallergic activity was evaluated using milk-induced eosinophilia and albumin-induced paw oedema in mice. The extract (0.5 mL of 100 mg mL(-1)) inhibited histamine-induced guinea pig tracheal chain contractions non-competitively. The extract (100 or 200 mg kg(-1) i.p.) inhibited milk-induced eosinophilia, albumin-induced paw oedema and protected mast cells against clonidine-induced granulation. The study justified the folkloric use of M. jalapa in the treatment of allergic diseases and asthma.     

Magnesium ferrichromate nanoparticles: an efficient and recyclable catalyst in the synthesis of pyrano[2,3-c]pyrazole derivatives

Research on Chemical Intermediates - Magnetically separable magnesium ferrichromate nanoparticles (MgFeCrO4 NPs) were synthesized by aqueous combustion synthesis (ACS) using glycine as the fuel....