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Abstract Star-like water-soluble macromolecules with fullerene as the branching site were synthesized by the reaction of fullerene C60 with polyvinylpyrrolidone whose molecules contain one terminal primary amino group. The initial and C60-containing polymers were studied by UV spectroscopy, thin-layer chromatography, centrifugal sedimentation, translation diffusion, and viscometry in aqueous buffer solutions. Diffusion-sedimentation and sedimentation two-detector analyses of the initial and fullerene-containing samples were performed. The molecular weights of the polymers were estimated by the Svedberg equation. The proportion of the fullerene-containing segment in the samples synthesized was determined, and the number of the branches in the fullerene-containing macromolecules was estimated.

The methods of flow birefringence, low shear viscometry, and circular dichroism were used to investigate the DNA conformation in solution during the interaction with coordination compounds [Co(NH3)6]Cl3 and [Co(NO2)6]Na3. It has been shown that the compound [Co(NO2)6]Na3, which dissociates in an aqueous solution to produce a negative complex ion [Co(NO2)6]^3-, binds to a DNA molecule, causing considerable changes in its parameters. For the binding to occur, the complex ion must undergo a transition to its aqueous form. Even a low cobalt content is shown to produce DNA shrinkage. It is attended by an increased DNA optical anisotropy. This effect was observed for both compounds used. The comparison of these data with earlier results on DNA−Fe³⁺ interaction has revealed some features common to the DNA binding to trivalent metal ions. We have suggested that the mutual orientation of DNA statistical segments is changed because of the formation of intramolecular linkages between trivalent ions and remote DNA chain segments.

The addition of amines to 5,5-dimethyl-2,4-hexanedione goes preferentially at the acetyl group as the less sterically hindered.

Conclusions 1.The1H and13C NMR spectra of the chelate enol forms of RCOCH2COCH3 dicarbonyl compounds with R=OC2H5, C2H5, CH3, CH(CH3)2, C6H5 and C(CH)3=CH2 have been analyzed.2.Determination has been made of the relative contents of two possible chelate enol forms of the diketone tautomers, these forms differing in the position of the enol proton. In running through the above R listing, there is an increase in the fraction of the tautomer in which the enol proton is located near the RCO group oxygen.

Conclusions 1.Carbon-chain polymers with ß-diketone and ß-keto ester functional groups in the side chains have been synthesized.2.The tautomeric equilibrium of the polymeric ß-dicarbonyl compounds polymethacryloylacetone and poly(vinyl acetoacetate) and low-molecular models of these polymers has been studied. The effect of the macromolecular nature of the polymeric ß-diketones on the tautomeric equilibrium is expressed as a significant difference between their thermodynamic equilibrium parameters and those of the low-molecular analog.

1.It was shown that trypsin forms complexes with vinylpyrrolidone-vinylamine copolymers, polyvinylimidazole, and poly(2-methyl-5-vinylpyridine) at a pH below its isoelectric point. The role of electrostatic interaction in the complexing process was ascertained.2.The bonding with polybases of variable structure does not lower the trypsin activity and does not involve its native structure. A stabilization of trypsin under the conditions of the autocatalytic process, and also during heat and acid-base denaturation, is observed here.3.The stabilizing capacity of the polymers is substantially higher than that of the corresponding monomeric bases (imidazole and N-ethylimidazole).4.A method was proposed for approximately estimating the complexing constants in the investigated systems. The effect of the pH of the medium on the bonding constant of trypsin with poly(N-vinylimidazole) was studied.

The fractions of poly(methacrylamido D-glucose) with molecular weights 7< M·10-4< 550 have been studied in water by the methods of molecular hydrodynamics. Kuhn-Mark-Houwink equations were obtained. The hydrodynamic invariant and the sedimentation parameter were also calculated. The equilibrium rigidity and the hydrodynamic diameter of molecules modeling macromolecules in solution were evaluated on the basis of the theory of the wormlike necklace model with the effects of excluded volume taken into account at different values of the excluded-volume parameter. The effect of fraction polydispersity on the quantitative values of exponents in the equations of the Kuhn-Mark-Houwink type and the Kuhn segment length is discussed.

In order to obtain multicomponent polymer systems exhibiting biological activity microcrystalline cellulose was used as a matrix for biologically active compounds, such as dimethylbenzylalkylammonium chloride, poly‐N‐vinylpyrrolidone, copolymer of N‐vinylpyrrolidone and crotonic acid, and complex of dimethylbenzylalkylammonium chloride with copolymer of N‐vinylpyrrolidone and crotonic acid. Adsorption interaction of microcrystalline cellulose with these was studied under various conditions. Adsorption isotherms of compounds of polymer nature are of similar character and are described by the Freundlich equation. The isotherms of dimethylbenzylalkylammonium chloride are described by the Langmuir equation. Characteristics of the resulting compounds were obtained using XPS and IR Fourier spectroscopy, WAXS, and SEM. Chemical interaction between microcrystalline cellulose and dimethylbenzylalkylammonium chloride takes place. This interaction leads to a new labile morphological cellulose structure accessible to penetration, which is confirmed at a morphological level by SEM.

Some unsaturated acylaminophenoxymethylpenicillins and their methyl esters were synthesized and characterized. The antimicrobial properties of these compounds and their sensitivity toward penicillinase depend on the position of the unsaturated acylamino group in the benzene ring.

The previously unknown monomers, the p-nitrophenyl esters of the p-crotonoyl- and the p-, m-, and o-acryloyl(methacryloyl)aminophenoxyacetic acids, were synthesized and characterized. The obtained compounds are capable of copolymerization with N-(2-hydroxypropyl)methacrylamide.

In an effort to determine the factors affecting penicillin stability in acid media, benzylpenicillin anilides were synthesized and subsequently hydrolyzed at 30° in a mixture of dimethylformamide and glycocoll buffer at a pH of 2.0. The log of the penicillin anilideß-lactam ring amide bond hydrolysis velocity constant was found to vary linearly with the amine pK. The hydrolysis reaction was found to follow Hammet's equation. The value of the constant? (-0.12) indicates insensitivity of the reaction to structural changes in the anilide molecule.

To examine the stability of penicillin and its derivatives in an alkaline medium the hydrolysis of substituted anilides of benzylpenicillin was studied at pH 9.1 and temperatures of 25, 30, and 40°. The velocity constants of the reaction and the activation energy of the process were calculated; hydrolysis of the amide bond of theß-lactam ring of anilides of benzylpenicillin under these conditions was shown to be a pseudomonomolecular reaction. A satisfactory correlation was found between the logarithms of the velocity constants of the reaction and the pK of the amine. Hammett's equation is applicable to this process. The low absolute values of?=0.33 indicate that the reaction is only slightly sensitive to structural changes in the anilide molecule.

A series of alkylated statistical copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride containing C6H13 - C12H25 side aliphatic group in the chain were studied by the methods of molecular hydrodynamics (velocity sedimentation, translational diffusion and viscous flow) in 0.1M NaCl and salt free water solutions, and by flow birefringence. The competition between electrostatic and hydrophilic/hydrophobic interactions manifests differently depending on the ionic strength and the length of the side chains. It was found that the radical length noticeably affects the characteristics of copolymer macromolecules. The hydrodynamic volume decreases and the shear stress optical coefficient increases considerably for the samples with C12H25 side chain groups. This is explained by drastic increase in the hydrophobic interactions which dominate over the electrostatic interactions.