Olga G. Ganina

Synthesis and biological evaluation of polymethoxylated 4-heteroarylcoumarins as tubulin assembly inhibitor

A series of syn-restricted polymethoxylated 4-heteroarylcoumarins--the isostuctural analogs of combretastatin A-4--was synthesized by Suzuki-Miyaura cross-coupling reaction and evaluated for antiproliferative activity. The 4-(1-methyl-1H-indol-5-yl)chromen-2-ones exhibit a potent cytotoxicity against HBL100 epithelial cell line with an IC(50) value amounting to 0.098 and 0.078 microM, respectively. The two compounds, having an indolyl moiety, potent inhibit in vitro microtubule assembly with a substoichiometric mode of action. A structure-activity relationship was discussed and the indolyl moiety was proved to be a good surrogate for the 3-hydroxy-4-methoxyphenyl ring of CA-4.

Three-step one-pot organobismuth-mediated synthesis of benzo[b]pyran compounds

Tris[ortho-chloromethylphenyl]bismuth diacetate reacted with phenols and enolisable substrates in the presence of a base to afford good yields of oxaphenanthrene derivatives.

The Direct Non‐Perturbing Leaching Test in the Phosphine‐Free Suzuki–Miyaura Reaction Catalyzed by Palladium Nanoparticles

The aryl halides normally unreactive in the reaction with phenylboronic acid in the presence of a palladium nanoparticle catalyst were shown to become involved, if a more reactive aryl iodide is simultaneously participating in the process. The involvement phenomenon can be interpreted as a direct evidence of the formation of smaller and more reactive palladium nanoparticles through leaching from the initial nanocatalyst. The involvement test was applied both to free unsupported Pd nanoparticles and supported species, thus exhibiting essentially the same character of evolutions of various nanomaterials during the catalytic transformation associated with leaching of reactive species from the initial particles. The system allows for concurrent processing of less reactive aryl bromides and even chlorides together with much more reactive aryl iodides. The interpretation of the observed phenomena and implications for practical realization of nanoparticle catalysts are discussed.

2-(Azidomethyl)phenylboronic acid in the synthesis of isoquinoline derivatives

Abstract2-(Azidomethyl)phenyllead triacetate was obtained by the reaction of 2-(azidomethyl)phenylboronic acid with lead tetraacetate. A strategy for the synthesis of isoquinoline derivatives was proposed that involves a reaction of this organolead reagent with enolizable substrates followed by annelation in the presence of triphenylphosphine. The use of 2-(azidomethyl)phenylboronic acid allowed α-arylation products to be obtained from β-diketones and natural β-oxo lactones in good yields.

Catalytic activity of Pd catalysts on different supports in hydrogenation of 1-phenylethenylphosphonic acid

Activity of palladium catalysts on different crystalline and amorphous supports was studied using hydrogenation of 1-phenylethenylphosphonic acid with molecular hydrogen as an example. Nanoscale Pd0 deposited on the surface of multi-wall carbon nanotubes (MWCNT) supported on microparticles of titanium oxide has proved the highest efficiency. The starting acid was quantitatively reduced for 1 h in the presence of this catalyst, 11 cycles of hydrogenation were carried out without loss of catalytic activity.

Reductive coupling of polyfunctionalized organobismuth and organolead arylating reagents in the synthesis of benzopyran derivatives

Benzopyran derivatives were synthesized in good yields by the reactions of tris[2-(chloromethyl)phenyl]bismuth diacetate and 2-(halomethyl)aryllead triacetates with phenols and naturally occurring 4-hydroxycoumarins in the presence of bases according to a three-step one-pot procedure.