Synthesis and properties of fluorinated uracils as promising drugs for medicine

Russian Chemical Bulletin - 5-Fluorouracil is a well-known and widely used drug in medical practice for the treatment of cancer. However, there is no analytical review in the literature on the...     

Controlled radical copolymerization of N-vinylpyrrolidone with 1,1,1,3,3,3-hexafluoroisopropyl-α-fluoroacrylate

Narrow disperse copolymers of N-vinylpyrrolidone with 1,1,1,3,3,3-hexafluoroisopropyl-α-fluoroacrylate have been prepared for the first time by reversible addition fragmentation chain transfer pseudo-living radical polymerization in the presence of benzyl dithiobenzoate. The relative activities of the monomers indicating the occurrence of alternating copolymerization have been estimated. The copolymerization of equimolar N-vinylpyrrolidone-1,1,1,3,3,3-hexafluoroisopropyl-α-fluoroacrylate mixtures shows typical features of reversible addition fragmentation chain transfer pseudoliving radical polymerization: deceleration of polymerization compared to the classical radical process, degeneration of the gel effect, successive increase in the number-average molecular mass with conversion, and formation of narrow disperse copolymers.     

Graft and RAFT Reactive Macro Reagents: Bis-[copoly-(divinyl ether-alt-maleic anhydride)]-trithiocarbonate

The alternating cyclocopolymer of maleic anhydride with divinyl ether (MADVE) hydrolyzate, as mimicker of furan related and anionic residues alternation in nucleic acids (NA) backbone, is immune stimulating agonist and competitive antagonist for viral genome NA interventions. The targeted pre-modification of MADVE by antiviral vectors via grafting to the MA anhydride residues before hydrolysis led to more potent and promising antiviral inhibitors. To develop the MADVE capacity for novel modifications we applied the reversible addition – fragmentation chain transfer (RAFT) technique using dibenzyl trithiocarbonate as a RAFT agent. The insertion of trithiocarbonate unit in polymeric chain provided a pseudo living RAFT-polymerization, resulting in: 1) the effective control of polymerization degree (increased with time and conversion), and 2) the narrow dispersive (PDI = 1.1–1.2) products MADVE-S-CS-S-MADVE yield. These products can be used as novel polymeric RAFT-agents for synthesis of new block-copolymers MADVE-(block)-CS₃-(block)-MADVE, for instance with polystyrene blocks. Combined together the RAFT- and graft- reactivity allows both modify the polymer backbone (RAFT-synthesis) and regulate the side groups or branches (grafted to MADVE moieties) with final hydrolysis of unused anhydride units to acidic polyelectrolyte derivatives. This plural reactive capacity of the obtained macro reagents essentially enhances their potential as platform for purposed synthesis of novel (bio-) functional polymeric compounds.     

Driving matrix liquid crystal displays

Liquid crystal displays had a humble beginning with wrist watches in the seventies. Continued research and development in this multi-disciplinary field have resulted in displays with increased size and complexity. After three decades of growth in performance, LCDs now offer a formidable challenge to the cathode ray tubes (CRT). A major contribution to the growth of LCD technology has come from the developments in addressing techniques used for driving matrix LCDs. There are several approaches like passive matrix addressing, active matrix addressing and plasma addressing to drive a matrix display. Passive matrix LCD has a simple construction and uses the intrinsic non-linear characteristic of the LCD for driving. Departure from conventional line by line addressing of a passive matrix has resulted in improved performance of the display. Orthogonal functions have played a crucial role in the development of passive matrix addressing. Simple orthogonal functions that are useful for driving a matrix LCD are introduced. The basics of driving several rows simultaneously (multi-line addressing) are discussed by drawing analogies from multiplexing in communication. The impact of multi-line addressing techniques on the performance of the passive matrix LCDs in comparison with the conventional technique will be discussed.     

Pyrimidines

3-Arylbenzo[f]quinazolines were obtained by reaction in acetic or propionic acid of -naphthylamine, ammonia, and aromatic aldehydes containing an NR₂ or OH group. A mechanism is proposed for the formation of monoarylbenzo[f]quinazolines from the corresponding intermediate 1,3-diaryldihydrobenzo [f] quinazolines by acid cleavage of the C-aryl bond in the 1 position. This mechanism was confirmed experimentally by establishment of the fact of cleavage of 1,3-bis (p-methoxyphenyl)-1,2-dihydrobenzo[f] quinazoline when the acidity of the medium is increased; 3-(p-methoxyphenyl) benzo [f] quinazoline and anisole were obtained in the reaction products. Condensation in the presence of formic acid gave -arylidene-N-formyl--naphthylamines rather than arylbenzo [f] quinazolines.See [1] for communication LXIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1265–1271, September, 1978.     

Effect of chelating agents on the selectivity of a hydrophobic ionic liquid membrane

Selective separation of a model mixture of Cs⁺ and Cu²⁺ ions through a liquid membrane based on a 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide hydrophobic ionic liquid (IL) in the presence of chelating compounds under an electric field gradient has been studied. Modifying the hydrophobic ionic liquid membrane with a crown ether (18-crown-6 (18C6) or dibenzo-18-crown-6 (DB18C6)) provides selective separation of cesium and copper(II) ions.     

Platinum–nickel alloy catalysts for fuel elements

Within the framework of the methods of the electron density functional and the ab initio pseudopotential, the spatial distributions of density of valence electrons and the electron energy spectra were obtained for platinum-based films with supplement atoms of the second metal, action of mechanical stress and oxygen atoms. The most critical factors for increase of the catalyst activity during oxidization of methanol are mechanical stress and dissociated oxygen.     

On the governing equations for the compressing process and its coupling with other processes

As a continuation of a recent linear analysis by Mao et al.(Acta Mech Sin,2010,26:355),in this paper we propose a general theoretical formulation for the compressing process in complex Newtonian fluid flows,which covers gas dynamics,aeroacoustics,nonlinear thermoviscous acoustics,viscous shock layer,etc.,as its special branches.The principle on which our formulation is based is the maximally natural and dynamic Helmholtz decomposition of the Navier-Stokes equation,along with the kinematic Helmholtz decompos...