Diselenides and Selenocyanates as Versatile Precursors for the Synthesis of Pharmaceutically Relevant Compounds.

Organoselenium chemistry has undergone extensive development during the past decades, mostly due to the unique chemical properties of organoselenium compounds that have been widely explored in a number of synthetic transformations, as well as due to the interesting biological properties of these compounds. Diselenides and selenocyanates constitute the promising classes of organoselenium compounds that possess interesting biological effects, and that can be used in the preparation of other selenium compounds. The combination of diselenide and selenocyanate moieties with other biologically relevant molecules (such as heterocycles, steroids, etc.) is a way for the development of compounds with promising pharmaceutical potential. Therefore, the aim of this review is to highlight the recent achievements in the use of diselenides or selenocyanates as precursors for the synthesis of pharmaceutically relevant compounds, preferentially compounds with antitumor and antimicrobial activities.

The influence of cobalt(II) and tin(II) chloride on regioselectivity and kinetics of phenylselenocyclization of 6-methyl-hept-5-en-2-ol.

The reaction of the Δ4-alkenols with PhSeX can follow three possible reaction pathways: two pathways lead to the formation of two regioisomeric cyclic ether products through the process of intramolecular cyclization, while the third represents the addition of the reagent to the double bond of an alkenol. As there are relatively few literature data on the kinetics of these reactions, we have chosen 6-methyl-hept-5-en-2-ol as a substrate of interest in order to obtain valuable results that will enable better understanding of the mechanism of phenylselenoetherification reactions. 6-Methyl-hept-5-en-2-ol is a particularly interesting model-substrate due to its substitution pattern of functional groups involved in the cyclization process. In this research, through synthetic and kinetic studies, we aimed to resolve key questions concerning the influence on kinetics, chemo- and regioselectivity of the reagent's counter ion, steric hindrances in substrate functional groups and the presence of additives.

Synthesis, crystal and solution structures and antimicrobial screening of palladium(II) complexes with 2-(phenylselanylmethyl)oxolane and 2-(phenylselanylmethyl)oxane as ligands.

Two novel Pd(II) complexes with 2-(phenylselanylmethyl)oxolane and 2-(phenylselanylmethyl)oxane as ligands were synthesized. The crystal and molecular structure of the complexes has been determined by single crystal X-ray diffraction. It turned out for both complexes that the two ligands are coordinated to Pd via Se atoms in a trans-fashion and the other two trans-positions are occupied by Cl ions. Detailed 1D- and 2D-NMR analyses revealed the existence of equilibrating trans-diastereomeric species differing in the configuration at four chiral centers (selenium and carbon) in the solution of the complexes. A computational study was also undertaken to assess the relative stabilities of the mentioned stereoisomeric species. The antimicrobial properties of the complexes were investigated against a series of human pathogenic bacterial and fungal strains. The complexes were shown to possess promising broad spectrum moderate antimicrobial activity that is more pronounced against fungal organisms. The noted activity could be completely attributed to the Pd(II) center, whereas the ligands probably mediate the transportation of a Pd(II) species across cell membranes.