Polycyclic aromatic labels such as naphthalene and pyrene were coupled to the C- terminus of N-benzyloxycarbonyl protected -aminobutyric acid (GABA). The photophysical properties of the corresponding fluorescent conjugates were evaluated, as well as their behaviour towards photocleavage by irradiation in MeOH/HEPES buffer solution (80:20), in a photochemical reactor at different wavelengths (254, 300, 350 and 419 nm), followed by HPLC/UV monitoring.

We present here synthesis and properties of new amphiphiles and homoditopical bolaamphiphiles, containing nucleobases. This amphiphilic and bolaamphiphilic compounds were prepared by the addition of the amino group to the isothiocyano group attached to a nucleobase. This compounds are capable of creating several non-covalent interactions, especially the hydrogen bonds resulting in formation of agregates.

Substituted pyrazine derivatives were synthesized and tested against Mycobacterium tuberculosis strain H37Rv. The hydrophobicity of all the pyrazines was determined using the reversed phase high performance liquid chromatography (RP-HPLC) method (isocratic elution with methanol as an organic modifier in the mobile phase, end-capped non-polar C18 stationary RP column). Experimentally derived Log K values (the logarithm of capacity factor K) were that compared with Log P values calculated by commercially available programmes. The synthetic approach, analytical, spectroscopic, lipophilicity and biological data of ten newly synthesized compounds are presented. Structure—activity relationships among the chemical structure, the anti-mycobacterial activity of the evaluated compounds are discussed. 3-(3-Methylphenyl)-aminopyrazine-2,5-dicarboxamide (7) has shown the highest activity against M. tuberculosis H37Rv (63% inhibition).

The aim of this study was to identify new active compounds against Plasmodium falciparum based on our previous research carried out on 3-phenylquinoxaline-2- carbonitrile 1,4-di-N-oxide derivatives. Antimalarial activity was evaluated in vitro against Plasmodium falciparum (3D7 and K1 strains) by the incorporation of [ 3 H]hypoxanthine. Cytotoxicity was tested in KB cells by Alamar Blue assay. Twelve compounds were synthesized and evaluated for antimalarial activity. Eight of them showed a IC 50 < 1 µM against 3D7 strain. Derivative 1 demonstrated high potency (IC 50 = 0.63 µM) and good selectivity (SI=10.35), thereby becoming a new lead-compound.

The pKa values of seleninic acids R-SeO2H were calculated by ab initio (MP2) and DFT (B3LYP) methods using a thermodynamic cycle. None of the method used is capable to provide a reasonable agreement with the experimental values in absolute terms. Trends in pKa values are, however, reasonably well reproduced. The correlation seems to be better described by B3LYP/6-31G(d,p) than MP2/aug-cc-pVDZ as indicated by the correlation coefficient R2.

β-Hydroxy selenides are efficient intermediates for a variety of synthetic transformations. As depicted in Scheme 1 together with classical reactions, such as the reduction to alcohols 1 (path a) or the oxidation to allylic alcohols 1 (path b), simple and convenient conversions into tetrahydrofurans, 2 1,3-oxazolidinones, 3 amino alcohols 3 and β-aryl selenides 4 have been recently reported in the literature. The key step of most of these multi-step procedures consists in the removal of the organoselenium moiety which occurs in radical or ionic conditions and generates substitution (path d) or cyclization products (path c and e). The interesting selenium-assisted substitution of the hydroxyl group by an aromatic compound (path f) or by other carbon nucleophiles 5 has also been recently described. It must be underlined that the products generated from enantiomerically enriched β-hydroxy selenides are obtained without any loss of the enantiomeric purity.

The reaction between diorgano dichalcogenides and o-(trimethylsilyl)phenyl triflate in the presence of CsF at room temperature produced o-bis(organochalcogenide)benzenes in moderate to good yields.

Lewis base adducts with selenenyl halides have been investigated experimentally and theoretically as models for interactions that might be relevant for the activity of Glutathione peroxidase (GPx).[1-3] Recently, we have shown that in donor adducts of selenenium ions with amines or phosphanes the formal donor-acceptor bond is covalent rather than dative.[4] Our findings suggested that in contrast to the description of adducts of the isolobal arsenium ions a description as selenenyl phosphonium and selenenyl ammonium ions appears more appropriate (Scheme 1). We also prepared compounds containing the selenenylphosphonium ion on a synthetic scale and studied their spectroscopic and chemical behaviour.[5] Here we describe ab-initio calculations exploring the reactivity of methyl substituted selenenyl phosphonium ions towards some simple nucleophiles and electrophiles.

The nature of microwave effects during organic syntheses is still a matter of discussion. The present study covers the unknown issue that is an influence of microwave irradiation on reactions, in which one of substrates is able to intramolecular reorientation under microwave conditions. The reactions of triphenylmethanol (i.e., dehydratation and etherification), as an example of compound with active hydroxyl group, were investigated.

Microwave assisted oxidative degradation of starch - estimation of degree of oxidation of the modified biopolymer.Application of microwave irradiation (2.45GHz) to carrying out starch oxidation by hydrogen peroxide – sodium tungstate system was shown. A various methods of carboxyl content determination in the product were compared.