M. N. Gorbunova

New biocide guanidine-containing nanocomposites

New water-soluble nanocomposites based on Ag and copolymers of 2,2-diallyl-1,1,3,3-tetraethylguanidiniumchloride with N-vinylpyrrolidone [poly(AGC-VP)] and vinylacetate [poly(AGC-VA)] have been developed. The average silver particle size ranged from 52 to 62xa0nm for poly(AGC-VA) and from 28 to 30xa0nm for poly(AGC-VP), with the corresponding UV–vis absorption peak position at 405–410xa0nm. The using of copolymers resulted in improvement in bactericide properties of composites. Following these results, the newly developed nanocomposite scaffold may be considered for new water-soluble medicines and biocides.

Synthesis of Vinyl-Containing Lupane- and a-Secolupane-Type Triterpene Esters

Vinyl-containing lupane- and oleanane-type C-3 and C-28 esters were synthesized from betulin and A-secotriterpene alcohols. The reaction of 2,3-secolupane alcohol 5 with vinylacetic acid produced ester 8 and a recyclization product, methyl 2β,3β-dihydroxylup-20(29)-en-28-oate (13), which was formed quantitatively in the reaction of 5 with maleic acid.

New water-soluble silver nanocomposites

New water-soluble nanocomposites consisting of silver nanoparticles and N-vinylpyrrolidone-N,N-diallyl-N′-acetylhydrazine copolymer, exhibiting cytotoxic activity toward MS melanoma cells, were prepared.

Polysulfones of new structural types as perspective antioxidant agents.

A series of polysulfones of new structural types on the basis of azanorbornenes, 2,2-diallyl-1,1,3,3-tetraethylguanidiniumchloride and tris(diethylamino)diallylaminophosphonium salts were obtained by free radical polymerization reaction. Their antioxidant properties in lipid peroxidation induced by iron/ascorbate and in erythrocyte hemolysis by H2O2 were evaluated. The polysulfone of 2,2-diallyl-1,1,3,3-tetraethylguanidinium chloride showed protection of erythrocytes against hydrogen peroxide and thermal shock, protected epithelial cells against UV irradiation, was not toxic for erythrocytes, epithelial cells SPEV and 3T3 fibroblasts. The polysulfone of N-benzyl-2-azanorbornene-5 inhibited lipid peroxidation in liver homogenate, did not exhibit cytotoxicity in SPEV and 3T3 cells, protected these against UV irradiation. Both compounds had low bioavailability and may be recommended for further investigations as excipients to be externally applied.

New Polymeric Derivatives of Betulin

Betulin monomaleate was synthesized by reaction of betulin with maleic acid in the presence of dicyclohexylcarbodiimide, and its copolymers were prepared.

Copolymers of betulin esters and silver nanocomposites based on them

New biologically active silver nanocomposites based on the copolymer of lup-20(29)-ene-3,28-diol 28-O-vinylbenzoate with N-vinylpyrrolidone were prepared by the borohydride method. The formation of spherical nanoparticles with a mean diameter of 67 nm was confirmed by scanning electron microscopy. The synthesized copolymers and silver nanocomposites exhibit cytotoxic activity and show promise for the development of new materials for medical purposes.

Synthesis of lupane and a-secolupane allylamides

Lupane C-28 monoallylamides with α-ketoxime and α-hydroxyoxime groups in ring A were prepared from betulonic acid. Formation of A-secolupane C-3(28) mono- and diallylamides was used as an example to demonstrate that a one-step synthesis of 2,3-secotriterpene amides was possible by fragmentation of betulin and betulonic acid α-oximes by oxalylchloride or thionylchloride with subsequent amidation of the 2,3-secotriterpenoic acids formed in situ by allylamine. The proposed method enabled the yield of 2,3-secolupane C-3,C-28 diamides to be increased by five times compared with the previously described five-step method for preparing A-secotriterpene amides from betulonic acid.

Synthesis by radical polymerization and structure of drag reducing terpolymers based on acrylamide, acrylonitrile, and 2-acrylamido-2-methylpropanesulfonic acid

Terpolymers of acrylamide, acrylonitrile, and sodium 2-acrylamido-2-methylpropanesulfonate were prepared by radical copolymerization in aqueous solution. The terpolymers obtained are enriched in acrylamide units and depleted of acrylonitrile units relative to the initial monomer ratio. The acrylamide–acrylonitrile–sodium 2-acrylamido-2-methylpropanesulfonic acid terpolymers show high performance as drag reduction agents. Under the conditions of thermal, salt, and acid aggressions, the terpolymer containing 71.6 mol % acrylamide, 10.5 mol % acrylonitrile, and 17.9 mol % sodium 2-acrylamido-2-methylpropanesulfonate ensures drag reduction no less than 70%.

Novel olygomeric C-3 esters of betulin derivatives

ABSTRACT Novel copolymers of C-3 esters of betulin derivatives (3-hydroxy-1-cyano-2,3-seco-2-nor-19β,28-epoxyoleane 3-O-vinylbenzoate (I), 3-hydroxy-1-cyano-2,3-seco-2-nor-19β,28-epoxyoleane 3-O-vinylacetate (II), methyl 3-hydroxy-1-cyano-2,3-seco-2-norlup-20(29)-en-28-oate 3-O-vinylbenzoate (III)) with N-vinylpyrrolidone and acrylonitrile have been prepared by free radical copolymerization. Kinetic regularities of the process were investigated. New water-soluble silver nanocomposites based on (III) copolymer with N-vinylpyrrolidone [poly((III)-VP)] have been developed. The average silver particle size ranged from 40 to 52u2009nm, with the corresponding UV–vis absorption peak position at 400u2009nm. The nanocomposite obtained has a significant cytotoxic activity toward melanoma cell line and may be considered for the development of new materials for medical applications. GRAPHICAL ABSTRACT

Synthesis and potential applications of silver-porous aluminium oxide nanocomposites as prospective antiseptics and bactericides

Alumina micro-spheres with mesoporous structure called porous aluminium oxide (POA) were prepared through a hydrothermal method using Al2(SO4)3·18H2O followed by a thermal decomposition process. Silver nanocomposites of POA (Ag/POAs) with high biochemical activity were synthesized by sorption of silver nanoparticles in the matrix of POA. Synthesis of Ag/POAs using photochemical reduction enables the producing silver nanoparticles preventing their aggregation. Ag/POAs demonstrated a stronger bactericidal activity than POA. The colony-forming ability of Escherichia coli was completely lost in 1 day on Ag/POAs at silver nanoparticles concentration of 0.241u2009ppm. Staphylococcus epidermidis displayed higher tolerance to Ag/POAs at all silver nanoparticles concentrations, the growth of Staphylococcus epidermidis was stopped at concentration of 0.374u2009ppm. The bactericidal activity of Ag/POAs against bacteria in drinking water was found to be highly effective, the growth of bacteria was completely lost in 1 day at silver nanoparticles concentration of 0.108u2009ppm.Graphical Abstract