Cleavage of some annulated tetrahydropyridines under the action of dimethyl acetylene dicarboxylate in protic solvents. New practical route to substituted pyrroles and indoles

Tetrahydropyrrolo[3,2-c]pyridines and tetrahydropyrido[4,3-b]indoles undergo piperidine ring opening under the action of dimethyl acetylene dicarboxylate in alcohols or in aqueous dioxane, providing beta-(alk)oxy-substituted pyrroles (indoles) in moderate to high yields.     

Thermodynamic and functional properties of legumin (11S globulin from Vicia faba) in the presence of small-molecule surfactants: effect of temperature and pH

We report on the effect of a set of water-dispersible small-molecule surfactants (the main and the longest-hydrocarbon components of which are a citric acid ester of monostearate, a sodium salt of stearol-lactoyl lactic acid, and a polyglycerol ester of stearic acid) on molecular, thermodynamic, and functional properties of the major storage protein of broad beans (Vicia faba) legumin in different molecular states (native, heated, and acid-denatured). The interaction between legumin and the surfactants has been characterized by a combination of thermodynamic methods, namely, mixing calorimetry and multiangle laser static and dynamic light scattering. It was found that hydrogen bonds, electrostatic interactions, and hydrophobic contacts provided a basis for the interactions between the surfactants and both the native and the denatured protein in aqueous medium. Intensive association of the protein molecules in a bulk aqueous medium in the presence of the surfactants was revealed by static and dynamic laser light scattering. In consequence of this, both the surface activity and the gel-forming ability of legumin increased markedly, which has been shown by tensiometry, estimation of protein foaming capacity, and steady-state viscometry. A likely molecular mechanism underlying the effects of small-molecule surfactants on legumin structure-forming properties at the interface and in a bulk aqueous medium is discussed.     

Electrochemical Conversions of 2-Methyl-3-nitro-4-phenylquinoline, Its Quinolinium Salts, and Hydrogenated Derivatives

Classical polarography, cyclic voltammetry, and EPR spectroscopy was used to study electrochemical reduction and oxidation of 3-nitro derivatives of 2-methyl-4-phenylquinoline, the corresponding quinolinium perchlorates, and 1,2- and 1,4-dihydroquinolines. The nitro derivatives of quinoline and 1,2-dihydroquinoline are reduced in the first step at the nitro group; the quinolinium cations are reduced at the heterocycle followed by reduction of the nitro group; and in 1,4-dihydroquinolines, the nitro group is not reduced. Electrochemical reduction processes associated with electron transfer in the heterocycle mainly display the same behavior as established for pyridine derivatives. But important differences were observed in electrochemical oxidation: the N-methyl derivative of 1,4-dihydroquinoline is oxidized significantly more easily than the corresponding N-unsubstituted derivative of 1,4-dihydroquinoline (in the 1,4-dihydropyridine series, the difference in pot! enti als is fairly small), and even more easily than the corresponding N-methyl derivative of 1,2-dihydroquinoline.     

Synthesis of biologically active derivatives of 2-aminobenzothiazole

Chemistry of Heterocyclic Compounds - The minireview considers the current trends in the synthesis of some biologically active compounds based on 2-aminobenzothiazole. The presented information...     

Novel regular polyimide‐graft‐(polymethacrylic acid) brushes: Synthesis and possible applications as nanocontainers of cyanoporphyrazine agents for photodynamic therapy

An approach to the synthesis of new regular graft‐copolymers polyimide (PI)‐graft‐polymethacrylic acid is elaborated, including (1) synthesis of multicenter PI macroinitiators, (2) controlled ATRP of tert‐butylmethacrylate on the prepared macroinitiators, and (3) protonolysis of tert‐butyl ester groups of side chains of the resulting PI‐graft‐poly(tert‐butylmethacrylate). Experimental conditions for attaining complete conversions of the first and the third stages of the process are determined by means of ¹H NMR and FTIR‐spectroscopy. Polymer products of the first and the second stages of the process, as well as poly(tert‐butylmethacrylate) side chains cleaved from the PI‐graft‐poly(tert‐butylmethacrylate) copolymers by complete decomposition of the PI backbone under alkaline hydrolysis conditions, are characterized by GPC. The kinetics of poly(tert‐butylmethacrylate) chain growth on a PI macroinitiator under ATRP conditions are studied. The results obtained provide evidence for the controlled character of the ATRP process and the regular structure of the synthesized graft‐copolymers. It is shown that PI‐g‐PMAA PI brushes are significantly more efficient intracellular delivery agents for the potential photosensitizer [tetra(4‐fluorophenyl)tetracyanoporhyrazine free base] than are the commonly used PEG‐micelles. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4267–4281     

Polyamidophosphite Complexes of Metals as Catalysts

Interaction between the equimolecular amounts of glycols (diatomic phenols) and phosphorous acid triamides in diglyme or without solvent gives phosphorus-bearing polyamidophosphites. The structure of these compounds was studied by NMR spectroscopy, and it was shown that a partial disproportionation of amidophosphite fragments into phosphite ones can occur in the course of their synthesis. The chemical properties of the obtained compounds are being studied. First rhodium complexes with polyamidophosphite ligands were obtained. These complexes are shown to be more active hydrogenation catalysts than the corresponding low-molecular complexes. 1