Fixation of micelle structure by monomer polymerization: Hydrodynamic properties of polymerized micelles

Polymerized and nonpolymerized micelles of N-acryloyl-11-aminoundecanoic acid and its sodium salt in water and dimethylformamide are studied by viscometry, isothermal diffusion, and dynamic light scattering. It is revealed that the hydrodynamic sizes of polymerized micelles (PMs) obtained via polymerization of the surfactants in aqueous solutions at low concentrations of the latter are significantly larger than those of the starting surfactant micelles. In dimethylformamide, as the surfactant concentration at which the synthesis is carried out is increased, the hydrodynamic size of PMs, which is calculated in terms of the cylindrical particle model, rises from 25 to 220 nm. The formation of additional internal crosslinks reduces the equilibrium rigidity of the PM chains by a factor of 1.5–2.     

Two Distinct Mechanisms of Alkyne Insertion into the Metal–Sulfur Bond: Combined Experimental and Theoretical Study and Application in Catalysis

The present study reports the evidence for the multiple carbon–carbon bond insertion into the metal–heteroatom bond via a five‐coordinate metal complex. Detailed analysis of the model catalytic reaction of the carbon–sulfur (C? S) bond formation unveiled the mechanism of metal‐mediated alkyne insertion: a new pathway of C? S bond formation without preliminary ligand dissociation was revealed based on experimental and theoretical investigations. According to this pathway alkyne insertion into the metal–sulfur bond led to the formation of intermediate metal complex capable of direct C? S reductive elimination. In contrast, an intermediate metal complex formed through alkyne insertion through the traditional pathway involving preliminary ligand dissociation suffered from “improper” geometry configuration, which may block the whole catalytic cycle. A new catalytic system was developed to solve the problem of stereoselective S? S bond addition to internal alkynes and a cost‐efficient Ni‐catalyzed synthetic procedure is reported to furnish formation of target vinyl sulfides with high yields (up to 99 %) and excellent Z/E selectivity (>99:1).     

New biionic transition metal complexes based on the salen ligands: synthesis and application as synthons in the preparation of chiral homo- and heterobimetallic systems

A new approach was used for the development of chiral homo- and heterobimetallic systems resulting in the preparation of four original bimetallic systems, two of which were studied by X-ray diffraction.     

Synthesis of 8,9-(1,3-benzodioxolo-5,6)-5-azatricyclo[8.2.1.0<Superscript>1,5</Superscript>]tridec-11-en-6-one. A convenient route to structural analogs of the alkaloid cephalotaxine

A synthetic route to 8,9-(1,3-benzodioxolo-5,6)-5-azatricyclo[8.2.1.0^1,5]tridec-11-en-6-one structurally isomeric to the pentacyclic cephalotaxine nucleus is suggested. The route is based on the sequence including diallylboration of 2-pyrrolidinone and intramolecular metathesis of the resulting 2,2-diallylpyrrolidine, giving rise to 1-azaspiro[4.4]non-7-ene. This product was N-acylated with 6-bromohomopiperonylic acid chloride and then subjected to intramolecular cyclization according to the Heck reaction. Dedicated to Academicians A. L. Buchachenko and N. S. Zefirov on the occasion of their 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2160–2163, September, 2005.     

Reaction of methyl 2,4-dioxobutanoates with tetracyanoethylene

Reaction of methyl 2,4-dioxobutanoates with tetracyanoethylene yielded methyl 3-acyl-4-cyano-5-(dicyanomethylene)-2-hydroxy-2,5-dihydro-1H-pyrrole-2-carboxylates. X-Ray diffraction data showed that 3-acyl-4-cyano-5-(dicyanomethylene)-2-hydroxy-2,5-dihydro-1H-pyrrole-2-carboxylic acid methyl esters can form supramolecular structures with one-dimensional channels which make possible inclusion of large organic and bioorganic molecules.     

Choline Esterase Inhibitors and Synthetic Oxalic Acid Receptors Based on Calix[4]arene Derivatives

New reversible butyrylcholine esterase inhibitors based on calix[4]arene derivatives were suggested. A series of new distally disubstituted calix[4]arenes were prepared in 60–80% yields. Some of these compounds showed properties of reversible choline esterase effectors, activating it at low concentrations and inhibiting at high concentrations. The macrocycles prepared were tested in extraction of d,l-tartaric, glycolic, d,l-mandelic, d,l-glutamic, malonic, oxalic, and succinic acids and of sodium acetate. Oxalic acid is efficiently transferred through a liquid impregnated membrane under the action of calix[4]arenes with nitrogen-containing substituents.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 305–312.Original Russian Text Copyright © 2005 by Stoikov, Khrustalev, Ibragimova, Stoikova, Evtyugin, Antipin, Konovalov.