Bromination of 5-Substituted 3H-Furan-2-ones and 3H-Pyrrol-2-ones

The bromination of 5-alkyl(aryl)-3H-furan-2-ones and 5-alkyl(aryl)-3H-pyrrol-2-ones and also their derivatives takes place at the ethylene bond with the formation of 4-monobromo derivatives. N-Phenyl-3H-pyrrol-2-ones are brominated simultaneously at the ethylene bond of the heterocycle and at the phenyl substituent at the nitrogen atom.     

New scaffolds for combinatorial synthesis. 1. 5-sulfamoylisatins and their reactions with 1,2-diamines

3,3-Dichloro-5-(4-methylpiperidinosulfonyl)-2-indolinone (3) and 5-sulfamoylisatins 4 have been synthesized from 5-chlorosulfonyl-3,3-dichloro-2-indolinone (1). Compounds 4 are promising scaffolds for the solid- and liquid-phase syntheses of new combinatorial libraries of various heterocycles. Thus, the reactions of 4 with 1,2-diamines, such as o-phenylenediamine (5) and aminoguanidine hydrochloride (6), 1,2-diaminoimidazoles (9), and thiosemicarbazide led, respectively, to new heterocycles 7 and 8 and new combinatorial libraries of triazinoindoles 10 and 15. Chemsets 4, 10, and 15 were isolated as crystalline solids that were purified by recrystallization from a suitable solvent and characterized by spectroscopic methods.     

Synthesis and alkylation of indolo[3,2-b]carbazoles

Double Fischer cyclisation was used to prepare indolo[3,2-b]carbazole and its 2,8-di-OMe, OH, Br and F-derivatives. N-monosubstituted derivatives of indolo[3,2-b]carbazole (methyl, hydroxymethyl, dimethylaminoethyl) were obtained starting from 5,11-di-Boc-indolo[3,2-b]carbazole.     

Heterogeneity of glass transition dynamics in polyurethane‐poly(2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer networks

The peculiarities of segmental dynamics over the temperature range of ?140 to 180 °C were studied in polyurethane‐poly(2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer networks (PU‐PHEMA semi‐IPNs) with two‐phase, nanoheterogeneous structure. The networks were synthesized by the sequential method when the PU network was obtained from poly(oxypropylene glycol) (PPG) and adduct of trimethylolpropane (TMP) and toluylene diisocyanate (TDI), and then swollen with 2‐hydroxyethyl methacrylate monomer with its subsequent photopolymerization. PHEMA content in the semi‐IPNs varied from 10 to 57 wt %. Laser‐interferometric creep rate spectroscopy (CRS), supplemented with differential scanning calorimetry (DSC), was used for discrete dynamic analysis of these IPNs. The effects of anomalous, large broadening of the PHEMA glass transition to higher temperatures in comparison with that of neat PHEMA, despite much lower T_g of the PU constituent, and the pronounced heterogeneity of glass transition dynamics were found in these networks. Up to 3 or 4 overlapping creep rate peaks, characterizing different segmental dynamics modes, have been registered within both PU and PHEMA glass transitions in these semi‐IPNs. On the whole, the united semi‐IPN glass transition ranged virtually from ?60 to 160 °C. As proved by IR spectra, some hybridization of the semi‐IPN constituents took place, and therefore the effects observed could be properly interpreted in the framework of the notion of “constrained dynamics.” The peculiar segmental dynamics in the semi‐IPNs studied may help in developing advanced biomedical, damping, and membrane materials based thereon. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 963–975, 2007     

Thermomechanical properties and heat resistance of copolymers of methyl methacrylate with acrylic acid

Copolymers with a mole fraction of acrylate units of 0.20 to 0.69 were prepared by radical copolymerization of methyl methacrylate with acrylic acid. The heat resistance and thermomechanical properties of copolymer films formed from dimethylformamide solution were evaluated, and the possibilities of improving these characteristics were demonstrated.     

Reaction of Triphenylbismuth Bis(arenesulfonates) with Triphenylstibine

Tetraphenylantimony arenesulfonates and diphenylbismuth arenesulfonates were prepared by reaction of triphenylbismuth bis(arenesulfonates) with triphenylstibine in toluene at 25°C. The crystal and molecular structure of diphenylbismuth 2,4-dimethylbenzenesulfonate was studied by single crystal X-ray diffraction. The molecules of the compound in the crystal form chains of Ph₂BiOSO₂C₆H₃Me₂-2,4 fragments linked with oxygen atoms of the sulfo group of the bridging arenesulfonate ligand.     

Supersonic Flow Past a Circular Cylinder with an Isothermal Surface

Supersonic perfect-gas flow past a circular cylinder with an isothermal surface is investigated at the Mach number 5 and Reynolds numbers ranging from 30 to 500,000. It is shown that two branches of the numerical solution of the problem can exist. On the first branch the following flow patterns are successively realized as Re is increased: separationless flow, flow with formation of a local separation zone, and flow with formation of a global separation zone. On the second branch the flow pattern with a local separation zone is observed at all Reynolds numbers; at a certain value of Re this solution jumps to the first branch.     

Reaction of 2-[Aryl(alkyl)amino]malonates with Chloroethynylphosphonates

Russian Journal of General Chemistry - Preparative limitations of the reaction of chloroethynylphosphonates with 2-(alkylamino)malonates have been established. Unlike the reaction of...