Three-component synthesis of 1-substituted 6′,7′-dimethoxy-4′H-spiro[adamantane-2,3′-isoquinolines]

Russian Journal of Organic Chemistry -     

Quantitative analysis of monoclonal antibodies by cation-exchange chromatofocusing

A robust cation-exchange chromatofocusing method was developed for the routine analysis of a recombinant humanized monoclonal IgG antibody. We compare the chromatofocusing method to the conventional cation-exchange chromatography (CEX) employing a salt gradient and show clear advantages of chromatofocusing over CEX. We demonstrate the suitability of the present chromatofocusing method for its intended purpose by testing the validation characteristics. To our knowledge, this is the first chromatofocusing method developed for the routine analysis of monoclonal antibody charge species.     

Formation of gold nanoparticles in the system constituted by chloroauric acid and ED-20 epoxy oligomer

Possibility of obtaining gold nanoparticles in interaction of HAuCl₄·4H₂O with ED-20 epoxy oligomer under heating was examined. Conditions for control over the size of Au nanoparticles in the course of their formation are suggested.     

Structural and Hydrodynamic Characteristics of Dextrans in Liquid-Phase Media

Viscous and volume properties of solutions of dextran with various molecular weights in water and dimethyl sulfoxide were studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 993–996.Original Russian Text Copyright © 2005 by Alekseeva, Rozhkova, Eliseeva, Prusov.     

Separation of mineral salts and nonelectrolytes (ethylene glycol) by dialysis through ion-exchange membranes

A method for the separation of nonelectrolytes (ethylene glycol, for example) and electrolytes using dialysis through ion-exchange membranes was proposed. In addition to its applied importance, this method can be used in analysis for the separation of pure ethylene glycol from low-mineralized solutions followed by the titrimetric determination of its low concentrations. The structure of an aqueous glycol solution in the presence of mineral admixtures was analyzed using computer simulation. It was found that these admixtures affect the structure of the hydration shell of ethylene glycol to increase the rate of its transfer.     

Regioisomerism in the Ritter reaction. 1. Synthesis of 3,3,5,6,7-, 3,3,6,7,8-, 3,3,5,7,8-, and 3,3,5,6,8-pentamethyl-3,4-dihydroisoquinolines from 1,2,3- and 1,2,4-trimethylbenzenes

Reactions of 1,2,3- or 1,2,4-trimethylbenzene with isobutyraldehyde and ethyl cyanoacetate (ECA) or reactions of the corresponding 1-aryl-2-methylpropan-1-ols with ECA afforded isomeric 3,3,5,6,7-, 3,3,6,7,8-, 3,3,5,7,8-, and 3,3,5,6,8-pentamethyl-3,4-dihydroisoquinolines. Isomerization is explained as the ring opening of a spiran intermediate in two possible ways followed by the Jacobsen rearrangement.     

Benzazolin-2-thiones in the michael reaction. 2. Reaction of benzothiazolin- and benzoxazolin-2-thiones with acrylonitrile,acrylamide, and methyl acrylate in the presence of basic catalysts

Depending on the structure of the reagents and the kind of basic catalyst, the addition of benzazolin-2-thiones to an activated double bond takes place at either nitrogen or sulfur. Acrylonitrile, regardless of the catalyst, reacts at the nitrogen atom. In the presence of sodiummethylate, addition to acrylamide takes place only, and to methyl acrylate predominantly at nitrogen. In the presence of triethylamine, a mixture of compounds with a high content of S-derivatives forms.For 1, see [1].Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 688–690, May,Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 688–690, May,     

Quantum chemical calculation of cation interaction with water molecules and ethylene glycol

A computer modeling is carried out for the structure and IR spectra of ethylene glycol-9 water molecules and ethylene glycol-9 water molecules-M⁺ systems, where M⁺ = Na⁺, K⁺. The presence of cations changes the structure of the glycol hydrate shell, which leads to a decrease in the activation energy of glycol self-diffusion in the solution with the addition of salts in comparison with its value in the water-glycol solution.     

The role of tryptophan residues in radiation sensitivity of enzymes as exemplified in horseradish peroxidase

The stability of recombinant wild-type horseradish peroxidase and its tryptophan-less mutant Trp117Phe toward γ-radiation was studied. The absence of tryptophan in the enzyme molecule results in a certain stabilization, which is manifested as the absence of the initial drop in activity and appearance of a lag period for doses of up to 45 Gy. Contrary to the wild-type enzyme, the dose response of the mutant is almost independent of the nature of the substrate used to measure the catalytic activity; this indirectly indicates that Trp117 participates in the oxidation of substrates. Pretreatment of the wild-type recombinant enzyme with hydrogen peroxide destabilizes the enzyme towards irradiation, while the same procedure for the mutant enzyme has virtually no effect on the dose response curve. This suggests the modification of Trp117 in the oxidation of the native enzyme with H₂O₂ in the absence of electron-donor substrates, which is the modification of Trp171 in the recombinant lignin peroxidase. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2355–2358, December, 1999.