Synthesis and Spatial Structure of the Derivatives of 2,5-Dioxo-3,3-Bis(Trifluoromethyl)-6,7-Benzo-1,4,2-and 2,5-Dioxo-4,4-Bis(Trifluoromethyl)-6,7-Benzo-1,3,2-Oxazaphosphepines

Abstract

Hexafluoroacetone imine easily interacts with compounds (I, R = OMe, OCH₂CF₂CHF₂, NEt₂, Ph) in two directions unlike hexafluoroacttone and gives 1,4,2-oxazaphosphepines (II) (pathway I) or 1,3,2-oxszaphosphepines (III) (pathway 2). The compound (II) (R = NEt₂) lightly hydrolyzes to yield the salt (IV). The structure of heterocycles II-IV) has been confirmed by X-ray analysis (see fig. I, II, R = OMe; fig. 2, IV). The detail structural peculiarities of the compounds am discussed.     

Novel bicyclic derivatives of 1,3-selenazine

Bicyclic isoselenoureas (1-selena-3-azaspiro[5.5]undec-2-en-2-ylamines and 3-selena-1-azabicyclo[3.3.1]non-2-ylideneamines) were obtained by intramolecular cyclization of selenoureas leading to 1,3-selenazine ring formation and tested for antioxidant activity.     

Modification of gamma-carbolines with N-substituted propionamides as a new approach to mitoprotective agents

An approach to the modification of biologically active gamma-carbolines with the N-substituted propionamide fragments by the reaction of N-substituted acrylamides with gamma-carbolines catalyzed by cesium fluoride has been suggested. The compounds synthesized were studied for the influence on the functional characteristics of brain mitochondria, in particular, on the membrane potential, calcium-induced “swelling” and calcium capasity of the rat brain mitochondria.     

Influence of some lime-containing additives on the thermal behavior of urea

Urea is one of the main nitrogen fertilizers used in agriculture. But being well soluble in water, hardly 50% of its nitrogen is assimilated by plants. One possibility to eliminate this disadvantage is to use coating agents for modification of urea to obtain a controlled-realized fertilizer. The aim of this research was to study the influence of different lime-containing additives on the thermal behavior and decomposition kinetics of urea in oxidizing atmosphere. Commercial fertilizer-grade urea (46.4% N) and analytical-grade CaO, MgO, CaCO₃, MgCO₃ were used in the experiments. In addition, one Estonian limestone and one dolomite sample were used as additive or coating material. The experiments with a Setaram Setsys 1750 thermoanalyzer coupled to a Nicolet 380 FTIR Spectrometer by a heated transfer line were carried out under non-isothermal conditions up to 900 °C at the heating rate of 5 °C min^?1 and to calculate kinetic parameters, additionally, at 1, 2, and 10 °C min^?1 in the atmosphere containing 80% of Ar and 20% of O₂. The differential isoconversional method of Friedman was used to calculate the kinetic parameters. The results obtained indicate that thermooxidative decomposition of urea as well as the blends of urea with lime-containing materials and urea prills coated with limestone or dolomite powder follows a complex reaction mechanism.     

A Comparative Study of Biocathodes Based on Multiwall Carbon Nanotube Buckypapers Modified with Three Different Multicopper Oxidases

14 Single‐ and multi‐walled carbon nanotubes from different sources were characterized in detail, and the characteristics obtained were carefully analyzed. The carbon material with the highest capacitance, and also other superior properties (“Taunit‐M” from “NanoTechCenter”, Russia), was chosen for further modification and fabrication of buckypaper based electrodes. These electrodes were biomodified with plant and fungal laccases, as well as fungal bilirubin oxidase. The designed biocathodes were investigated in simple buffers and also in a complex physiological fluid (human serum). Biocathodes based on immobilized fungal laccase were bioelectrocatalytically inactive in chloride containing media at neutral pH. In spite of the quite high current densities realized using biodevices based on plant laccase and fungal bilirubin oxidase, the limited thermal stability of the enzymes renders the biocathodes inadequate for practical applications in implanted situations.     

Novel trialkylsilyl(germyl)-substituted thienyl- and furylbenzimidazoles and their N-substituted derivatives – synthesis,structure and cytotoxic activity

The reaction of 1,2-phenylenediamine with a variety of silicon- or germanium-containing 2-furaldehydes or 2-thienylcarbaldehydes in DMFA gave the corresponding benzimidazole derivatives in moderate yields (36–49%) in the presence of sodium hydrogen sulfite. As a result, a new series of silyl, germyl substituted hetarylbenzimidazoles were synthesized and their in vitro cytotoxicity was studied. The quaternisation of N-substituted benzimidazoles by heating with various alkyl, allyl and propargyl chlorides and bromides leads to the formation of benzimidazolinium salts. Potential cytotoxic activity of synthesized new benzimidazoles and benzimidazolinium salts was tested in vitro on two monolayer tumour cell lines: MG-22A (mouse hepatoma), HT-1080 (human fibrosarcoma) and normal mouse fibroblasts (NIH 3T3) and compared with corresponding benzimidazoles.     

The Use of tert-Butyl Vinyl Ether in Stepwise Electrophilic Addition Reactions

tert-Butyl vinyl ether (1) reacts with p-TolSCl to give 2-tert-butoxy-2-chloroethyl p-tolyl sulfide (2). In the presence of SnCl₄, 2 reacts with silyl enol ethers, allyltrimethylsilane, and vinyl ethers to form a C-C bond. In the case of vinyl ethers, the reaction proceeds through the formation of the 5-membered sulfonium salt intermediate which in turn can react with H₂O, TMSCN, allyltrimethylsilane, and Grignard reagents.     

Synthesis of 5-Hydroxymethyl-8-methyl-3-(3-aryl-[1,2,4]oxadiazol-5-yl)-2H-pyrano[2,3-c]pyridin-2-ones and Their Esters

New 5-hydroxymethyl-8-methyl-3-(3-aryl-[1,2,4]oxadiazol-5-yl)-2H-pyrano-[2,3-c]pyridin-2-ones and their esters were synthesized. The structure of obtained compounds was determined through a complete ¹H NMR analysis.     

Synthesis of New Azocompounds and Fused Pyrazolo[5,1‐c][1,2,4]triazines Using Heterocyclic Components

Diazotization of 3‐methyl‐4‐phenyl‐1H‐pyrazol‐5‐amine 1 in hydrochloric acid has been reported to afford the corresponding diazonium salt 2 . The latter underwent azocoupling with a variety of active methylene compounds (barbituric 3a and thiobarbituric 3b acid, 2‐hetarylpyrimidine‐4,6‐dione 6a , 6b , 4‐hydroxy‐6‐methylpyridin‐2(1H)‐one 10a , 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one 10b , 4‐hydroxy‐1‐p‐tolyl‐1H‐pyrazole‐3‐carboxylic acid ethyl ester 14 , 1,3‐thiazolidine‐2,4‐dione 16a , 2‐thioxo‐1,3‐thiazolidin‐4‐one 16b ) to yield new pyrazolylazo derivatives. Fused pyrazolo[5,1‐c][1,2,4]triazines 5 , 9a , 9b , 12 , 13 were obtained by heterocyclization reactions. Copyright © 2013 HeteroCorporation     

Solvent‐Free Iodination of Arenes using Iodine–Silver Nitrate Combination

A simple and environmentally safe general method of iodination of aromatic substrates under sovent‐free conditions using the I₂/AgNO₃ combination in a solid state is reported. Both activated and deactivated aromatic compounds afford the respective aryl iodides in generally high yields (80–90%).