Wiadomości Chemiczne, 2003, Vol. 57
Polska Akademia Nauk, Centrum Chemii Polimerów ul. M. Curie-Skłodowskiej 34, 41-819 Zabrze
The use of enzymatic catalysis, in an organic medium, for synthesis of polysaccharides, polyesters, polyaromatics and polypeptides has experienced important developments over past few years. The review deals with recent advances in synthesis of biodegradable polymers, and aliphatic polyesters in particular, via in vitro enzymatic catalysis. Recently, biodegradable aliphatic polyesters have attracted great interest in medicine as well as environmentally acceptable materials for packaging industry and agriculture. The enzyme-catalysed condensation reactions, ring-opening polymerisation, and corresponding transesterification of macromolecular substrates, as tools for their preparation, are discussed. Enzymes in polymer synthesis offer several advantages as substrate selectivity, enantio-, regio- and chemoselectivity. They enable, under mild reaction conditions and in the presence of or without organic solvents (in bulk), creation of useful polymeric materials with elimination of the potentially toxic catalysts. Some of functional polymers, difficult to obtain by conventional methodologies, may be synthesised using enzymes as catalysts. Although enzymatic procedures sometimes are not suitable for a large-scale preparation they can be successfully applied for new synthetic strategies for modelled polymers with desired topology and structure, including structure of the polymer end groups.
Instytut Technologii Organicznej i Tworzyw Sztucznych, Politechnika Wrocławska, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław; e-mail: firstname.lastname@example.org email@example.com
The survey applies to oxidation reaction of substituent phenols in the presence of catalysts. The transition metal complexes with various types of attached to polymer support ligands were used as these catalysts. Especially, we have paid attention to the hydroquinone oxidation to p-benzoquinone using hydrogen peroxide and atmospheric oxygen in the presence of Cu(II) complexes with ligands containing nitrogen (for example: pirydyl, aminoamidyl or guanidyl groups). Oxidation reactions of substituent phenols proceeds in accordance with Michealis-Menten kinetic in all of described systems. It can preclude neither an influence of support kind applied to the catalyst preparation nor an influence of ligand kind chelating metal ions on oxidation kinetic. The comparison of the oxidation kinetic in several systems showed the domination of polymer-metal complexes over the native metal ions and also over the catalysts being the metal complexes with the low molecular compounds (containing the same ligands as these, which were attached to polymer support).
Wydział Chemiczny, Politechnika Warszawska, ul. Noakowskiego 3, 00-664 Warszawa
The condensation reaction of p-tert-butylphenol with formaldehyde leads in one step, with relatively high yield, to macrocyclic phenol-formaldehyde tetramer - calixarene. This calixarene easily undergoes modification in the reaction with various substrates and a macrocyclic product functionalized at both 'narrow' and 'wide' rims can be prepared. According to this way, various calixarene derivatives exhibiting properties of selective complexation of various species can be obtained. The majority of applications of calixarenes and their derivatives are focused on selective complexation of cations and anions.
The review demonstrates the possibility of syntheses of calixarenes with chromoionophoric properties. Usually, urea groups are used as anion binding receptors and chromogenic groups are introduced into the calixarene structure in close proximity to the ion-binding site.
Methods of synthesis of chromoionophoric calixarenes able to complex selected anions were elaborated. In these calixarenes urea groups were connected to the calixarene ring in the reaction of an amine derivative with chromophoric isocyanate or active urethane. Several derivatives with naphthylurea and other chromophoric groups were prepared. The chemical structures of chromoionophoric calixarenes were confirmed by elemental analysis, as well as IR and proton NMR spectroscopies. It was found that calixarene ionophore with chromogenic urea groups show changes in the 1H NMR and phosphorescence spectra in the presence of nitrate, dihydrophosphate and hydrophosphate anions.
Chromogenic ditopic calixarene containing ester groups at the narrow and naphthylurea groups at the wide rim of calixarene was also described. The complexation of sodium ions by ester groups and dihydrophosphate anions by urea groups was confirmed via changes in the NMR spectra.
The method of obtaining and preliminary properties of the calixarene macromonomer, which possesses the ability of selective dihydrophosphate anions complexation, are also presented. The complexing properties of the macromonomer were very similar to that of the symmetric calixarene with four naphthyl urea groups at the wide rim. The resulting calixarene macromonomer containing chromophoric receptor groups (urea) and polymerizable group (allyl) is going to be covalently bonded with the polymer matrix by copolymerization with acrylic comonomers.
Katedra Chemii, Wydział Technologii Drewna,
Akademia Rolnicza im. A. Cieszkowskiego,
ul. Wojska Polskiego 75, 60-625 Poznań
Poly (phenylene sulfides) are oligomeric materials with excellent plastic performance of commercial interest. They form durable insulating coatings and are cementing agents. The products of medium molecular weight, containing oligomers up to octamers, are formed by the reaction of sulfur or sodium sulfide with para-substituted chlorobenzenes [2, 29]. The reaction is not a simple stepwise polycondensation. HS( formed in a one-electron transfer process initiates the chain formation and the reaction goes with reactive intermediate radicals and radical cations. This reaction can be called the reactive intermediate polycondensation. The reaction temperature must be higher than 150o C to cleave the disulfide linkage homolytically allowing surviving the chain forming carriers.
In this paper I report the reaction of chloronitrobenzene derivatives with sodium sulfide and disulfide in polar solvents. The reaction carried out in this solvent gives the highest reaction rate and leads to products with relatively high molecular weight. An activation of N-methyl-2-pyrrolidone molecule to a radical form by a transfer of electron from HS- (scheme 3) . In the reaction of 1-chloro-4-nitrobenzene with sodium sulphide or disulphide in N-methyl-2-pyrrolidone at high temperatures oligomeric products were obtained . The mechanism of the reactive intermediates polycondensation reaction are described. The reaction of 1-chloro-4-nitrobenzene with sodium sulphide and disulphide in N-methyl-2-pyrrolidone proceeds as follows: the first stage is the substitution of sulphur for chlorine. In the second stage there is a progressive reduction of nitro groups in agreement with the date of S.
Instytut Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej, ul. Gdańska 7/9, 50-344 Wrocław
Hydrocarbon oils and petroleum derived fluids are commonly used in technology. However, in many applications the requirements of the tasks exceed the performance capabilities of classical fluids and the synthesis of new products to meet the extraordinary demands is necessary. Chemically and physiologically inert siloxanes, thermally stable poly(a-olefins) PAO and esters showing excellent resistance to nuclear radiation are some examples of synthetic oil. The fluids of ester structure, which are similar to natural triglicerydes, are very important class of synthetic oils. Ester oils possess superior physicochemical and performance properties as well as are non-toxic and easy biodegradable in comparison to many traditional derived fluids . This paper is focused on specific application areas for which ester fluids are either currently used or being seriously considered for use. A special attention is given to ester oil synthesis including the methods based on indirect esterification, transesterification and enzymatic catalysis [11,12,49]. It is emphasised excellent thermo-oxidative properties of neopentyl alcohol esters . Dicarboxylic acids esters, which are commonly used as synthetic fluids together with the compounds of oligomer, character are also discussed . A new class of ester oils such as dialkyl carbonates and their synthesis using dimethyl carbonate as starting material are included . Further sections of the paper are focused on phosphate esters and oils produced from native triglicerydes [76,95]. The effect of fatty acids structure on the properties of obtained products is reported. The methods of chemical modification of fatty acids structure such as selective hydrogenation, oligomerisation, alkylation, methatesis and acylooxylation are discussed. The last part of the paper deals with hydrolytic decomposition of esters in which steric hindrance and resonance effect play an important role .
Zakład Chemii Bioorganicznej, Centrum Badań Molekularnych i Makromolekularnych PAN ul. Sienkiewicza 112, 90-363 Łódź
Immobilized metal affinity chromatography (IMAC) is a widely used technique for separation of proteins with natural surface-exposed histidine residues and recombinant proteins with polyhistidine fusion tags in particular [1-7]. IMAC is a type of an affinity chromatography which gives an opportunity to separate proteins based on the binding of proteins to transition metals. This occurs via the electron-donating side chain of residues such as histidine and cysteine, which substitute water molecules coordinated to the metal.
Due to the fact that metal affinity is sensitive to the exposure and spatial arrangement of histidine residues, IMAC can probe structural changes expressed on protein surfaces as a result of partial digestion, unfolding, or association with other molecules . Overall, IMAC is a quick method which limits the number of procedures in the process of puryfing proteins thereby reducing the cost of their isolation. This paper describes influence of the type and the number of electro-donor surface groups, the type of metal immobilized with the stationary phase and pH of the mobile phase on the selectivity of an affinity separation.
Instytut - Centrum Medycyny Doświadczalnej i Klinicznej PAN, ul. Pawińskiego 5, 02-106 Warszawa, e-mail: firstname.lastname@example.org
Ion exclusion chromatography (IEC) is applied mostly to separate ionic compounds from the non-ionic ones. Wheaton and Bauman were first to describe this technique in 1953 . At present about 10% of all ion chromatographic determinations are performed using IEC and this is approximately the number of determinations using the more common technique of ion pair (ion interaction) chromatography [2-6]. In the recent years the number of IEC determinations displays a strong tendency to increase.
The characteristic feature of IEC technique is the electric charge sign of dissociated ion-exchange resin functional groups that is the same as the electric charge sign of the analyzed ionic compound. It follows that samples of negatively charged ions e.g. dissociated acidic compounds are separated on cation exchange resins with anionic functional groups. Usually these are sulphonic acid groups. Similarly, samples containing positively charged species (bases) are separated on the anion exchange resin containing cationic functional groups. Usually these are tetraalkylammonium groups [2, 6]. In a sense these rules are in contrast to those of ion exchange chromatography, where anions are separated on anion exchange resins and cations are separated on cation exchange resins. However, the same columns can be used in both techniques. For the specific requirements of ion exclusion chromatography large ion exchange capacity is preferential [2, 9]. Along with these, to increase the capacity the column dimensions and the functional group concentration in the support are maximized. The usual supports are based on the macro-porous styrene and divinylbenzene copolymer.
IEC finds application in the separation of a wide range of small, neutral or partially ionized molecules. In IEC the strong as well as weak electrolytes are eluted unseparated, the first at the beginning and the latter at the end of the elution. The retention volumes of the remaining electrolytes were found to be proportional to their dissociation constant values. The dead and inner volumes of the chromatographic column can be determined from the observed dependence of retention volumes onto dissociation constant values. The retention mechanism is described by the analytical equations and on the results obtained from the computer simulation of the column performance (using global thermodynamic and chromatographic equations or the Craig method). The mixed retention mechanism involving hydrophobic adsorption, p-electron interactions and screening effect is observed for weak electrolytes and aromatic compounds [8, 13, 14]. Aromatic compounds are retained almost solely involving interaction of the solute with the unfunctionalized regions of the stationary phase.
The purpose of this paper is to survey the field. The retention mechanism of analyzed compounds in ion-exclusion chromatography has been described. The influence of some physicochemical parameters describing the sample, the chromatographic column and the mobile phase on the retention is discussed. Finally, practical applications are briefly presented.
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław
Zakład Zjawisk Międzyfazowych, Wydział Chemii, Uniwersytet Marii Curie-Skłodowskiej, Pl. Marii Curie-Skłodowskiej 3,, 20-031 Lublin
This paper reviews the most important problems of interparticle interactions, which determine effectiveness of many technologies (such as: painting, printing, xerographing) and physical phenomenon (for example: flocculation, aggregation, agglomeration, coagulation and wetting).
This paper presents an evolution of theoretical models of adhesion phenomena. Hertz at the end of XIX century investigated creation of the contact between two particles. He based his conclusion on mechanical side of phenomena only. This observation gave beginning for Griffith's testing, which elaborated theory of brittle fracture (1920). In this theory he coupled surface energy g and elasticity.
At the thirties Bradley and Derjaguin presented independently adhesion induced deformation. Bradley based his investigation on expotential relationship interaction between two molecules. Derjaguin interpreted these phenomena with the aid of geometrical and thermodynamical analysis.
The fifties there was a great development of trybology and fracture mechanics. Irwin introduced new technical term of strain energy G released when the crack area varied by dS. After that Krupp generalized Derjaguin model and added influence of plastic deformation.
At the early seventies two theories were created. First theory created by Johnson, Kendall and Roberts (called JKR), and second one by Derjaguin, Muller, Toporow (called DMT theory). These two models were and still are base to interpreting interparticle interactions.
The next model is Dugdale model developed for crack tip plasticity and is quite simple: the stresses in the cohesive zone are constant and equal to the yield stress of the testing material.
In 1983 Muller assuming a Hertzian profile, compared his earlier thermodynamic method, in which the force of attraction decreases from 2pWA to pWA, for more correct value by summing up the interactions in the Hertzian fixed gap.
In this publication range of application each of these theories are introduced.
1 Zakład Hydrotechniki Morskiej, Instytut Morski, ul. Długi Targ 41/42, 80-830 Gdańsk,
tel.: (048 058) 552- 00- 93
2 Katedra Chemii Analitycznej, Wydział Chemiczny, Politechnika Gdańska, ul. Narutowicza 11/12 , 80-952 Gdańsk, Faks: (048 058) 347-26-94 tel.: (048 058)347-21-10, e-mail: Chemanal@.pg.gda.pl.
This work presents different analytical techniques of isolation, preconcentration and determination of organic compounds in water samples.
One of unique analytical techniques which do not require any sample preparation before its injection into a chromatographic column is Direct Aqueous Injection (DAI). A classical DAI based procedure, described by K.Grob, for determination of halogenoorganic compounds in water using GC with electron capture detection (GC-ECD) is presented. Advantages and limitations of the technique are discussed. New areas of DAI application are suggested including analytical tasks (determination of organic substances in different aqueous samples) for which solvent and gas extraction techniques are not effective.
The techniques of isolation and preconcentration are used in many cases of determination of organic compounds in environmental samples.
The review is aimed at description of applicability of Liquid-Liquid Extraction, Membrane Extraction, Gas Extraction and Solid Phase Extraction to determine organic compounds of different chemical nature in water samples. The characteristics of techniques are discussed with respect to: detection limits, time and labor required, possibility of automation, analysis cost and possibility of elimination of solvents, which can be a source of environmental pollution. The studies on the techniques modification to extend their application ranges are discussed, too.
Katedra Farmakognozji Wydziału Farmaceutycznego CM UJ, ul. Medyczna 9, 30-688 Kraków
Triterpenes are the group of natural compounds widespread in the plant kingdom . They exhibit a range of biological activities. One of the most explored structures alike is betulin. This is a lupane type triterpene which is the main constituent of the extract of the white birch bark . Betulin moiety is composed of four six- and one five membered rings with one isopropenyl and two hydroxyl groups (1) .
Betulin and its derivatives show: antitumor [3-8], antiviral (HIV-1) [9, 10], antiinflammatory [12-13] and antiprotosoal  properties. The most promising, however, is antitumor activity. Betulinic acid - a product of the selective oxidation of betulin displays proapoptotic activity against several highly resistant tumor cells in vitro and in vivo [3-8]. Apoptosis i.e. cell-suicide is induced only in "mutant" cells and not in normal ones. EC50 (effective concentration causing death of 50% of the ill cells) of betulinic acid and its derivatives lie in the pM range [3, 4, 6, 7].
Isolation, biogenesis and preparation of several modified betulin derivatives are reviewed in this article. Among the described reactions are: several routes of selective oxidation of betulin [3, 18, 23, 28-35, 38-48], dehydration [9, 35, 48-52], isomerisation [23, 38, 41-46], dehydrogenation [46-48], hydrogenation [53-55], glycosidation [59-61], esterification [28, 41, 42, 56, 57], preparation of amides (with the use of aminoacides) [5, 59] and synthesis of aminoderivatives [29, 58]. Some of these reactions give unexpected products [33, 43, 44].
The biological potency of these compounds may be due to their steroid-like structures (all-trans conformation and some more similarities). The exact mechanisms of the activities, however, remain unknown [3-8].
The ease of obtaining highly pure betulin and the potent biological activity of its derivatives can be the reason for singling out the compound as a lead, model triterpene for further chemical and biological investigations.
Politechnika Krakowska, Instytut Chemii i Technologii Organicznej ul. Warszawska 24 31-155 Kraków tel. (12) 628 27 22, fax: (12) 628 20 37, e-mail: email@example.com
This review attempts to briefly summarise the recent developments in the synthesis and application of 1,8-naphthyridine derivatives as biological active compounds. A large number of these compounds still evolves interest of chemists and pharmacologists. From among of one thousand papers, which appeared within the last fifteen years, most described applications of 1,8-naphthyridine derivatives as biologicaly active compounds.
Nalidixic acid (1) was the first 1,8-naphthyridine derivative approved as the drug with antibacterial activity. There are many routes to the synthesis of nalidixic acid. The main routes are presented in the Schemes 1, 4, and 6. This compound was the first from the quinolone's family applied as the chemotherapeutic drug. Modification of the structure of nalidixic acid brought the discovery of a new group of most potent antibacterial compounds called fluoroquinolones. Enoxacine (16), esafloxacine (21), tosulfoxacine (22), trovafloxacine (23) and alatrofloxacine (24) are the examples of 1,8-naphthyridine derivatives belonging to that group. General reaction scheme of synthesis of 16 and 21 is similar to synthesis of nalidixic acid (Scheme 7), while synthesis of the compounds 22, 23, and 24 presented in Scheme 8 is quite different. Moreover, many other 1,8-naphthyridine derivatives 31-40 have been intensively studied as antibacterial agents in vitro, but none of them has been applied as a drug.
A number of 2- and 7-substituted 1,8-naphthyridines 41 showed some antimalarial activity in vivo , while the compounds of general structure 42 were found inactive .
2(4)-Piperazinyl-1,8-naphthyridines (45) have been pharmacologically investigated for their antyhipertensive activity [33(35]. 1,8-Naphthyridines 46, bearing a phenyl group in position 2, were found to be selective antagonists for the A1 adenosine receptor subtype .
A series of 1,8-naphthyridines 47-49 exhibited appreciable diuretic and antikaliuretic activity in rats [37(39].
In search for potential anticancer compounds study such as SAR (structure activity relationship) and QSAR (quantity structure activity relationship) have been used. As the result of the research the structure of the compounds 50 has established as the most potent inhibitor of tubulin polymerization. The nitrobenzo-1,8-naphthyridines (52) constitute a group of potential interest for the design of new cytotoxins .
Moreover, 1,8-naphthyridine derivatives have been found to be active as inhibitors of platelet aggregation agents 53-54 [42,43]; antiviral 56-57 [45,46] and antialergic agents 62 [50,51]. These derivatives possess bronchodilating 64 [52,53], antiflammatory and sedative properties 67 [54-57].
Katedra Chemii Farmaceutycznej Collegium Medicum Uniwersytetu Jagiellońskiego, 30-688 Kraków, ul. Medyczna 9, e-mail: firstname.lastname@example.org
a1-Adrenergic receptors (a1-AR) are members of the superfamily of G protein coupled receptors that transduce signals across the cell membrane. a1-ARs are comprised of multiple subtypes that have been identified by both pharmacological and binding studies . To date, they are classified into a1A, a1B, and a1D and the corresponding cloned counterparts termed a1a , a1b , and a1d-AR, respectively. These subtypes have different tissue distributions with the ?1A receptors predominating in lower urinary tract tissue, whereas this receptor subtype is less prevalent in the vasculature [2 - 4]. In recent years, the search for new selective a1-AR antagonists has intensified, due to their importance in the treatment of hypertension and of benign prostatic hyperplasia (BPH) [5 - 7]. Tamsulosin, the first a1A-AR "selective" antagonists for the treatment of BPH, was approved in 1997 [9, 12]. A number of a1A subtype selective antagonists representing different structural classes of compounds were disclosed recently. These include: quinazolines [8 - 13], phenylalkylamines [9, 12, 14], piperidines [9, 15 - 23], arylpiperazines [24 - 36] and related compounds [37, 38]. A review on the development of a1 selective antagonists are presented.
Zakład Chemii Organicznej, Instytut Chemii, Uniwersytet Śląski, ul. Szkolna 9, 40-006 Katowice
AZT was a first anti-HIV drug found during screening performed by National Institute of Health (Bethesda, USA) . Anti-HIV drugs or potential drugs grouped according to the molecular target or compound class can be found in the NIH database at [http://www.niaid.nih.gov/daids/dtpdb/intro.htm] [2-13]. HIV integrase is one of the potential targets of anti-HIV drugs. Integrase is an enzyme that catalyzes the insertion of retrotranscribed viral DNA into the cellular host genome. Its structure is known  but until now there is no certified drug targeted at this enzyme. In the 90' several integrase inhibitors were described [18-28]. The investigations of these compounds allowed finding new active compounds, e.g., styrylchinolines that was described in recent years [29-32, 39]. In particular, the current publication discusses structure-activity relationships (SAR) for these compounds (Figure 1). It appeared that the SAR data from ex-vivo experiments  can be both visualized and interpreted by the use of the Kohonen maps of the electrostatic potetntial of the molecular surface [34-38] as shown in Figure 2. Finally, the results of the Merck investigations on HIV-1 integrase inhibitors have been briefly discussed (Figure 3) [38, 39].
Zakład Materiałów Wybuchowych Wojskowa Akademia Techniczna, ul. Kaliskiego 2, 00-908 Warszawa
In the present work a survey of literature data concerning shock wave synthesis of dense modifications of carbon and boron nitride is presented. Transformations of graphite and graphitic boron nitride under shock loading are characterised. Various types of explosive set-ups used for shock loading of samples containing carbon materials and graphitic boron nitride are presented. In conclusion some characteristics of the products of shock wave synthesis are described.
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław
Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk,
Ul. Sienkiewicza 112 90-363 Łódź. e-mail: email@example.com
Carbohydrates play very important role in biological systems. Both carbohydrates and their derivatives are involved in many biological processes, such as cell-cell recognition, cell growth and energy transfer. In spite of very high importance in living processes, carbohydrates remain one of the less exploited class of biologically active molecules.
There is a lot of different methods which can be used in carbohydrates analysis . The Nuclear Magnetic Resonance (NMR) spectroscopy is one of the most attractive, important and powerful tool for analyzing the conformation and molecular architecture of carbohydrate molecules. This method serves the possibility of solving the majority of problems in this area, without any different methods – particularly in the liquid phase. The biggest advantage of NMR spectroscopy is that it is a nondestructive method. Both one- and two-dimensional NMR methods have provided valuable information about small and large molecules, ranging from the anomeric configuration of a monosaccharide to the sequence of monosaccharide residues in a bigger oligo- or polysaccharide compounds. After first years of applications mainly in primary carbohydrate structures, NMR spectroscopy has recently reached a level of sophistication, which allows both the structural and conformational analysis of carbohydrates in solution. This article reviews the applications and possibilities of current NMR techniques to the structural and conformational characterization of carbohydrate and its derivatives. Both 1D and 2D (COSY, HSQC, HSQC-TOCSY, HMBC) NMR spectra of the GOTCAB saponin 1 are presented as examples of utilization of NMR in the structure elucidation of the carbohydrate derivatives.
Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk,
ul. Sienkiewicza 112 , 90–363 Łódź
Over the past decade there has been a surge of interest in enantioselective synthesis which has led to find convenient metods of measuring enantiomeric purity or enantiomeric excess of many compounds. The enantiomeric excess can be determined by the following principal methods: (a) chiroptical, (b) chromatography (GS, HPLC, TLC ), (c) isotopic dilution, (d) kinetics, (e) electrophoresis, (f) calorimetry, (g) nuclear magnetic resonance.
In this paper there are presented studies, which were performed in aim to determine of ee by NMR in liquid and solid state.
Determination of enantiomeric purity using NMR in liquid requires the intervention of a chiral auxiliary to convert an enantiomeric mixture into a mixture of diastereomers. Three types of chiral auxiliary are widely used. Chiral derivatising agents (CDAs) form diastereomers while chiral solvating agents (CSAs) and chiral lanthanide shift reagents (CLSRs) form diastereomeric complexes in situ with the substrate enantiomers.
In recent years Solid–State NMR (SS NMR) has emerged as a powerful tool for the analysis of solids. In particular the ODESSA (One Dimensional Exchange Spectroscopy by Sideband Alternation) technique permit to recognize differences between enantiomers and racemates as well to assess the enantiomeric excess.
Instytut Chemii Organicznej Polskiej Akademii Nauk,
ul. M. Kasprzaka 44/52, 01-224 warszawa
Synthesis of oxacephalotin and oxacephamandol which are more active then natural, containing sulfur congeners, and isolation of clavulanic acid, a patent inhibitor of (3-lactamase enzymes, directed attention of academic and industrial laboratories to the synthesis of oxygen analogs of penicillins and cephalosporins.
The present review directs attention to the stereocontrol of a desired configuration in the formation of the bridgehead carbon atom. Five possible methods leading to basic skeletons of the title compounds are discussed (Scheme 1). Three of them involve nucleophilic substitution at C-4 of the azetidin-2-ones performed as inter or intramolccular process, and two of them involve cycloaddition reactions between ketenes and iminoethers, or between vinyl ethers and isocyanates. Owing to the general application stereospecificity, and high asymmetric induction, the last method seems to be most advantageous. The weak point of the nucleophilic substitution methodology is that a nuclcophilc enters 3-substituted azetidin-2-one ring preferentially anti to the existing substituent or if there is no substitutent at C-3, stereoselectivity in generation of a new stereogcnic center at C-4 is low. All methods arc illustrated by examples taken from the literature.
Wydział Chemii Uniwersytetu Jagiellońskiego, ul. Ingardena 3, 30-060 Kraków
The hetero-Diels-Alder (HDA) methodology employing a,b-unsaturated thiocarbonyl compounds represents a straightforward and efficient approach to sulfur-containing six-membered heterocycles. This review presents applications of a,b-unsaturated thiocarbonyl compounds in heterodiene reactions and covers the literature published in the last two decades.
The a,b-unsaturated thiocarbonyl compounds, formally present 1-tia-1,3-butadiene system and include the following groups of compounds: thiochalcones, enaminothiones, a,b-unsaturated thioamides and compounds containing thiocarbonyl groups conjugated with carbon-carbon double bonds of carbo- and heteroaromatic rings. In general, reactions of 1-tia-1,3-butadiene systems with dienophiles belong to cycloadditions with normal electron demand, although there are some examples of cycloadditions with inverse electron demand.
The first chapter concerns the cycloadditions of thiochalcones. Most of them are synthesized from chalcones in reactions with Lawesson reagent. Thiochalcones are unstable, at room temperature they are in equilibrium with two dimeric forms: thiopyran and 3,4-dihydro-1,2-dithiin. Both compounds are formed by heterodiene cycloaddition of two molecules of thiochalcone. At higher temperatures the dimers undergo decomposition to thiochalcones. Thiochalcones generated in situ by heating the dimers were successfully used in cycloadditions to acryloamide, styrene and enol ethers well as in an asymmetric hetero Diels-Alder (AHDA) reactions with (-) dimenthyl fumarate and in the reactions catalyzed by ytterbium triflate.
The next chapter deals with the reactions of enaminothiones. These compounds reacted smoothly with dienophiles containing electron withdrawing groups yielding cycloadducts in high yields. Some cycloadducts easily eliminated amine furnishing stable 2H-thiopyran derivatives. Reactions of enaminothiones with substituted b-nitrostyrenes proceeded in region- and stereoselective manner. In contrast to enaminothiones, a,b-unsaturated thioanilides were found to be less reactive in hetero-Diels-Alder reactions. Two molecules of thiocinnamamide underwent cycloaddition in acetyl chloride yielding N-acylated derivative of 3,4-dihydro-2H-thiopyran. N-acylated a,b-unsaturated thioanilides was successfully used in heterodiene reactions with N-phenylmaleimide, cyclopentene and enol ether. A recent applications of N-acylated a,b-unsaturated thioanilides deal with intramolecular hetero-Diels-Alder reactions leading to tricyclic thiopyran derivatives.
The compounds containing thiocarbonyl group conjugated with carbon-carbon double bond of furan or thiophene skeleton undergo cycloaddition with maleic anhydride, cyclopentene and norbornene yielding fused 2H-thiopyran derivatives in good yield. Some of the cycloadducts are unstable and spontaneously rearrange to aromatized compounds. An application of some organometallic reagents e.g. (Me2Al)2S in thionation of aromatic ketones extended their use to synthesis of various thiopyrans via hetero-Diels-Alder reactions.
1Instytut Chemii i Techniki Jądrowej, ul. Dorodna 16, 03-195 Warszawa,
2Instytut Chemii i Ochrony Środowiska, Wyższa Szkoła Pedagogiczna, ul. Armii Krajowej 13/15, 42-200 Częstochowa, e-mail: firstname.lastname@example.org
This short review gives an overview over the oxidation mechanism of methionine (Met) relevant for processes which may lead to the oxidation of amyloid b-peptide (bAP) involved in the pathogenesis of the Alzheimer disease. The bAP-structure dependent CuII-catalyzed oxidation of C-terminal Met35 seems to be the key to the known propensities of this peptide to form reactive oxygen species and free radicals.
Wydział Chemii Uniwersytetu Gdańskiego, ul. J. Sobieskiego 18, 80-952 Gdańsk
Uronic acid are widely encountered in many important biopolymers of plant and animal origin in the form of glycosiduronic acids. Because degradation takes place during the hydrolises of the polymers only chemical synthesis can afford the great variety of pure oligosaccharides, needed to explore the structure-activity relationship or to mimic the biological properties of these domains. Due to a low reactivity of uronic acids towards glycosidation an alternative methods of synthesis of oligosaccharides containig uronic acid units are used.
The selective oxidation of carbohydrates derivatives has been intensively studied in the last decades and continues to be an area of timely interest. This holds especially for the conversion to uronic acid. Some common oxidation method for sugar hydroxymethyl group are collected in this brief review.
Perhaps the most common transition metal in oxidation reagents is chromium. Chromic acid (Jones oxidation) is already so common that the classic version does not deserve any further comments. The development of milder version of the Jones oxidation began with the introduction of the Collins oxidation protocol. It has gained very wide use because of its simplicity (CrO3 is added into a dichloromethane solution of pyridine, and then the alcohol to be oxidized is added). Pyridinium chlorochromate (PCC) is a useful oxidant for the conversion of alcohols to carbonyls. The reagent is slightly acidic in character and the yields are usually better than with Collins oxidation. The use of aprotic solvents led to the development of pyridinium dichromate (PDC) as a neutral counterpart to the Collins oxidation. The advantages of this reagent include that only a small excess is needed (large excess of reagents makes large scale work difficult). Some examples of use of chromic oxidants in sugar chemistry are described in this paper.
In the oxidation of very sensitive molecules, the use of dimethyl sulfoxide together with a suitable electrophilic compound has proven to be very profitable. A synthetically important and often used method is the Swern oxidation, where DMSO is activated with oxalyl chloride. The reaction is performed at low temperature in dichloromethane solution. The low temperature is essential, since at higher temperature the DMSO-(COCl)2 complex decompose explosively. In order to tie up the HCl formed during the reaction and to liberate the alcohol complex, one commonly uses triethylamine as the base. The additional carbonyl group formed in the oxidation of sugar derivatives is particularly useful functionality in sugar synthesis. It can function as an electrophilic site or it can be induced to behave as a nucleophile. Its subsequent over-oxidation with NaClO2 leads to uronic acid. These aspects of use of Swern oxidation are described.
Recently catalytic methods using stable organic nitroxyl radicals like 2,2,6,6,-tetramethyl(piperidin-1-yloxyl) [TEMPO] as mediator have been developed. Reaction with TEMPO and its derivatives are of industrial interest. Substituted nitroxyl radicals are prepared in large amounts in high yield starting from the inexpensive basic chemicals. Additionally the mediator TEMPO can be easily recovered in quantitative yield after the oxidation of saccharides.
2Katedra Chemii Organicznej, Wydział Technologii Chemicznej Słowackiego Uniwersytetu Technicznego, Radlinskeho 9, 81237 Bratysława, Słowacja
2Instytut Chemii Organicznej, Biochemii i Biotechnologii, Politechnika Wrocławska, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław
Sweet tasting food-stuffs have been always, in all probability, an integral part of human diet. This problem concentrate scientific interest of dietetics but also chemists and biologists. In the article actual knowledge on the natural and synthetic non-saccharide sweeteners is reviewed. The sweeteners presented here are divided, depending of their origins, on the compounds isolated from natural sources and compounds synthesized from simple organic precursors.
One of the most important groups of naturally devided sweeteners are peptides [6,7,11,15]. Some of them, particularly thaumatins find practical application as additives to a tooth-paste, food, drinks and drugs [5-7] The majority of intensely sweet naturally occurring compounds belong to the family of terpenoids comprise monoterpenoids [1,19,20], sesquiterpenoids  as well as di- and triterpenoids [20,23-25,29,30]. Their most prominent representatives such as perillartine, stevioside and glycyrrhizin are presented more detaily. Other groups of sweet tasting naturally occurring substances, mentioned in this paper are steroidal saponins [39,41], dihydroisocumarins [43,44], flavanoids and related compounds [47-49,51-53] and less common species such as haematoxylin [56,57], telosmosides  and monatin [59,60].
The second part of the article is devoted to synthetic sweeteners [1-3]. The well known representatives such as saccharin , cyclamates , Acesulfame-K , aspartame [1,2], alitame [71,72], neotame [73,74] and sucralose [65,75] are presented more detaily and methods of their synthesis are briefly reported.
Organoleptic properties of the most compounds are characterized and related to the molecular structure of sweetener is discussed. New trends and perspectives of application non-saccharide sweeteners are formulated.
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław
Centrum Badań Molekularnych i Makromolekularnych PAN
ul. Sienkiewicza 112, 90-363 Łódź, e-mail email@example.com
RNA interference (RNAi) is a natural biological mechanism for sequence-specific posttranscriptional gene silencing triggered by double-stranded RNA (dsRNA) homologous to a silenced gene. RNAi is found in a wide range of eukaryotes including human cells. The natural function of RNAi appears to be protection of a genome against invasion by mobile genetic elements such as transposons and viruses which produce aberrant RNA or dsRNA in a host cell. Specific mRNA degradation prevents transposon and virus replication. The majority of studies on the molecular mechanism underlying RNAi activity has been conducted in vivo using Drosophila melanogaster and Caenorhabditis elegans or in selected mammalian cell cultures. It has been demonstrated that long dsRNA is cleaved to 21–23 nucleotide long fragments by RNase III-like nuclease Dicer. These short interfering RNAs (siRNAs) are essential sequence–specific mediators of RNAi. They are bound by RNAi specific enzymes of nuclease complex RISC that targets mRNA for degradation. In this complex siRNA recognises, binds and cleaves the target mRNA. Cleavage occurs in the middle of the mRNA region recognized by the siRNA. The second model, which has been proposed for RNAi to explain the mechanism by which siRNA direct target mRNA destruction, requires RNA-dependent RNA polymerase (RdRP) to convert the target mRNA into dsRNA. RdRP is hypothesized to use antisense strand of siRNA as a primer in mRNA templated synthesis of complementary chain RNA. The resulting dsRNA is proposed to be cleaved then by Dicer for generation of secondary siRNA.
Short interfering RNAs can be synthesized chemicaly or by in vitro transcription with T7 RNA polymerase, or expressed from siRNA coding vectors in the cells. These 21-nt siRNA duplexes cause efficent inhibition of exogenous and endogenous genes expression in a sequence-specific manner. Detailed analysis of potential modifications, that can be introduced into siRNA strands shows, that chemical modifications of sense strand are tolerated without loss of RNAi activity. However, some modification of antisense strand of siRNA (especially in the middle of the chain as well as modification of the 5’end) completely abolish RNAi. These results indicate that two strands of siRNA have different function in RNAi. RNAi approach can be broadly used for analysis of gene functions, and, what is even more important, this phenomenon can be used for searching new agents for therapeutic applications.
Uniwersytet w Białymstoku, Instytut Chemii, Al. Piłsudskiego 11/4, 15-443 Białystok
Progress in combinatorial chemistry is largely determined by development of specific synthetic organic chemistry tools such as solid supports, linkers, polymer supported reactions and methods of analysis, screening and deconvolution of combinatorial libraries. This review article presents basic terms related to polymer supported synthesis, enumerates major advantages of supported reactions, and gives a comprehensive, up to date, overview of support matrices used for immobilization of small and large molecules. The review covers the literature up to September 2002. The supports reviewed include (i) polymeric gels (Merrifield gel, TentaGel, ArgoGelTM, JandaJelTM, PEGA, PEG-PS, PEG-POP, SPOCC, PS-TTEGDA, CLEAR, DendroGel, Pepsyn, and Sucholeiki paramagnetic gel), (ii) soluble polymers (LPS, PEG, ROMP-polymer, PAMAM-dendrymer, Boltron), (iii) macroporous supports (CPG, Pepsyn K, PolyHIPE, ArgoPoreTM) and other developments including SMART reactors, MicroTubeTM, membranes, pins, and cellulose. For most of the supports reviewed basic characteristics such as swelling in different solvents, solvent usability, typical loading, typical anchoring groups, preparation, and recent applications are given or cited. The reviewed literature suggests that the supports most often used for synthesis of small molecules and peptides are based on gel matrices. The variety of available supports, many of which were introduced in the last years, shows that this area of synthetic methodology may grow dynamically in the future.
Wydział Inżynierii Procesowej, Materiałowej i Fizyki Stosowanej,
Al. Armii Krajowej 19, 42-200 Częstochowa
2Politechnika Wrocławska, Instytut Chemii Nieorganicznej i Metalurgii Pierwiastków Rzadkich, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław
3Wyższa Szkoła Oficerska Wojsk Lądowych, ul. Czajkowskiego 100, 54-150 Wrocław
This paper is a review of hydrometallurgical processes of removal and separation of zinc(II) and cadmium(II) ions from chloride, sulphate and other medium aqueous solutions. The following physicochemical methods were described: solvent extraction, transport across liquid membranes (bulk liquid membranes, emulsion liquid membranes, supported liquid membranes and polymer liquid membranes [1,2]), and foam separation (ion flotation, precipitate flotation, and adsorbing colloid flotation [3,4]). In solvent extraction and transport through liquid membranes, the derivatives of phosphoroorganic compounds and amines, as well as nonionic crown ethers were used as extractants and ion carriers. As collectors for foam separation the regular surfactants as well as ionizable lariat ethers were applied. It was found, that the main factor influencing the separation selectivity of zinc(II)/cadmium(II) was the diameter of cavity in the crown ether of applied macrocycles. In all physicochemical processes the removal and separation selectivity of Zn(II) and Cd(II) are influenced by the physical properties of an aqueous phase, i.e. pH, ionic strength, as well as metal ions concentration.
Department of Chemistry of Natural Compounds, Institute of Chemical Technology, Prague, Czech Republic
The potential of sucrose as a raw material from renewable resources is discussed in the term of its degradation to compounds with a lesser number of carbon atoms, the modification on all hydroxyl groups, the development of macromolecules, partial transformation of sucrose, and the enzymatic oligosaccharide synthesis.
0-525 Wrocław, ul. Gliniana 23/17
Since the discovery of its marvellous insecticidal properties by Paul Mueller in 1939, DDT continues to stir human minds and to inspire countless scientists to study DDT effects on living creatures, from bacteria and insects to humans. There is probably no other chemical compounds which was studied as extensively and thoroughly as DDT and which provoked so many discussions and contradictory opinions. DDT was prized as the most useful compound which saved millions from unnecessary death due to malaria but was also condemned as a deadly poison threatening the life on Earth. It is important to know where is the truth.
This article was inspired by the fact that the voices of condemnation prevail in popular and scientific literature and, in the consequence, most people believe that DDT is harmful and its banning was prudent. However, the truth is quite different but it is deeply buried and difficult to find in the multitude of publications dealing with the biological properties of DDT. The problem is more difficult because of the fact that the oldest and most fundamental papers on biological activity of DDT are now forgotten and are never quoted in recent literature. My purpose is to remedy that situation by giving an unbiased picture of the good and bad sides of DDT such as emerges from a thorough search of the literature.
In this article I provide evidence that the ban of DDT was a very serious mistake and that DDT continues to serve the mankind in its fight against malaria, in disregard of all bans and condemnations. Nobody seems to remember now that after the ban in 1970s the temporary retreat from using DDT against mosquitoes killed several hundred million people which unnecessarily died of malaria. It appears that DDT ban stands out as the biggest homicidal act in all history of mankind. Responsibility is of course with politicians who voted for the ban and the scientists who advised them to do so.
There are still other reasons why it was necessary to write this article. My purpose is not to vindicate DDT but to expose the multitude of false opinions about that insecticide. Thus, it is not true that DDT is cancerogenic in humans or that its hormonal properties threaten our survival, as prophesized by authors of some recent books. It is also not true that DDT was ever a serious hazard for fish and wildlife. DDT never threatened hawks and eagles or pelicans and the countless papers which say otherwise are simply wrong.
I provide plenty of published evidence in support of my efforts to rectify mistakes and deliberate lies which are so common in the literature on biological efffects of DDT. Unfortunately my litereature search revealed that in several cases the public was deliberately misled by scientists, who helped with their publications to spread false opinions about DDT. This provokes severe doubts concerning the integrity of ecologically minded scientists.
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław
Zakład Chemii Bionieorganicznej, Instytut Chemii,Akademia Podlaska, ul. 3 Maja 54, 08-110 Siedlce
Aminopolyphosphonic acids and their derivatives have received considerable attention because of their interesting biological activity and a wide range of uses for industrial, chemical, agricultural and pharmacological purposes.
The area of metal phosphonate chemistry has developed significantly in the last three decade. The coordination chemistry of this group of ligands is rich due to their versatility in adopting monodentate, bridging and chelating modes of coordination. Phosphonates and aminophosphonates are potent chelating agents for variety metal ions including the alkaline earth ions, the divalent ions as well as the trivalent ions.
In this article we are summarizing and discussing the acid-base properties and the metal ion-coordinating properties of compounds involving one, two or more phosphonic groups. This work is aimed at being brief indicating the main achievements in researches over coordination preferences of this group of ligands.
The present considerations are restricted to complexes in solution, involving the alkaline earth ions and the divalent ions of the second half of the 3d series as well as Zn2+ and Cd2+.
The acid-base properties of the considered ligands depend on many factors such as the number of phosphonic groups in one molecule, the presence of other functional groups (e.g. COOH, NH3+, OH), the distance between functional groups and electronic effects of the substituents.
These ligands contain a range of potential donor atoms. As a result, various bonding modes for a given chelating ligand are involved, and are reviewed with reference to ligand structure and the resulting coordination complexes. It is shown that depending on the pH and the nature of the metal ion in solution these ligands can bind to a metal ion via oxygen(s) (mostly with alkaline earth ions), and in a N,O bonding mode (usually with d metals).
Coordination properties of phosphonic and aminophosphonic acids are important factors to understand the role of the ligands and metal ions in biological systems.
Międzynarodowe Laboratorium Silnych Pól Magnetycznych i Niskich Temperatur, ul. Gajowicka 95, 53-421 Wrocław
In a family of sulfide and selenide compounds are known composite crystals with incommensurate layered crystal structure and with a general formula (MX)1+n(TX2)m where M = Pb, Sn, Sb, Bi and rare earth metals (Ln), T = Ti, V, Cr, Nb and Ta, and X = S and Se which in the English scientific literature are called „misfits". The crystal structure of misfits consist of two types of slabs with strong intra-slab bonding and a weaker interaction between them. One type of slabs (TX2) is a three-atom-thick sandwich of a transition metal T layer between layers of chalcogenide atoms X, the second one (MX) consists of a two-atom-thick double layer of atoms each with the same number of M and X atoms. The paper presents a description of part of the whole class of misfits compounds, the rare earth misfits (LnX)1+n (TX2)m. Some physical properties of them, mainly the electrical and magnetic properties, originate from the first or the second types of slabs and may be changed independently.
The Introduction gives a short history of discovery of the misfits compounds and their location in the family of composite crystals. Then details of the crystal structure of lantanide misfits have been presented, types of slabs and their geometric forms, preffered crystal structures and the direction of incommensurability. Two next parts present the way of determination of their chemical formula and methods of their synthesis.
The described physical properties concern the electrical resistivity, superconductivity, magnetism, and some spectral properties. On this basis possible band structures are presented. Particular attention is devoted to the similarities and differences of the physical properties between parent compounds LnX, TX2 and the misfits (LnX)1+n (TX2)m. Finally, some perspective studies of the rare earth misfits are considered.
1 Instytut Ochrony Roślin w Poznaniu, Stacja Doświadczalna w Białymstoku, ul. Chełmońskiego 22, 15-195 Białystok
2 Instytut Chemii, Uniwersytet w Białymstoku, al. J. Piłsudskiego 11/4, 15-443 Białystok
The agrochemical industry is continuously searching for new active compounds to combat pests. The main aim of this research is to develop new substances with lower application rates, increased selectivity and decreased undesired ecological impact. Most synthetic agrochemicals with chiral structure are marketed as racemates even though the desired biological activity may be derived from only one enantiopure isomer. However, some newly introduced compounds are marketed as the most biologically active stereoisomers. When agrochemicals have chiral structures, efforts should be made to define the mode of action, toxicity, and metabolic pathway of each enantiopure isomer. If there are large differences in the biological activities of individual stereoisomers, it is desirable to use only the most active one. In this review article some stereochemical aspects of several groups of important agrochemicals including aryloxypropanoate herbicides (Fig. 1), acylanilides (Fig. 2), triazine herbicides, ureas and cyanoacrylates (Fig. 3), triazole fungicides (Fig. 4), morpholine derivatives (Fig. 5), organochlorine insecticides (Fig. 6), pyrethroid insecticides (Fig. 7 and 8), pheromones and antifeedants (Fig. 9), and organophosphorus compounds (Fig. 10), will be discussed.
Politechnika Krakowska, Instytut Chemii i Technologii Organicznej ul. Warszawska 24 31-155 Kraków,
tel. (12) 628 27 22, fax: (12) 628 20 37, e-mail: firstname.lastname@example.org
At the present time tuberculosis is completely treatable. However, it[MS1] is still a major cause of morbidity and mortality among the poorest people. Tuberculosis is the main source of death from among infectious diseases worldwide. In turn, infectious diseases remain the leading cause of death in the world today, greater than cardiovascular disease or cancer. According to the data provided by World Health Organization (WHO), one-third of the world's population is infected with Mycobacterium tuberculosis. In contrary to general expectation, the incidence of mycobacterial disease has significantly increased since 1990 worldwide. This problem has been aggravated by the human immunodeficiency virus (HIV) pandemia and the recent increase in incidences of microbial resistance to antibiotics. Another problem is the lack of the viable research program to develop the new range of the antituberculosis drugs. Since the mid 90’s no new drugs have been introduced, with the exception of a few minor modifications of existing formulas.
This review presents history and current summary of the developments in the application and synthesis of tuberculostatic chemotherapeutics. One of the first type of drugs used were salts of heavy metals, which were discontinued quickly due to the high degree of their toxicity. However pirazinamide(2), introduced in 1936 is still being used today. Modern antituberculosis therapies started in 1944 with the Waksman’s discovery of the streptomycin (12). From among modern drugs the most popular are: PAS (15), INH (18), and EMB (34). Schemes 7, 8 and 14, 15 show the methods of synthesis of these compounds. Similarly, schemes 9?11 show the same for the cycloserine (22) antibiotic, and figures 2, 3 and 4 present the structures of the kanamycin 33 cyclic polipeptide 38 and ansamycin 39 antibiotics. Furthermore, detailed description of the methods of synthesis of fluorochinolones 44, 45 and 46 (introduced in 80’s) can be found in schemes 19, 20 and 22. In this article there is also information about the direction of the new research trends taking place in the field of the new antituberculosis agents.
1Katedra Chemii Analitycznej, Wydział Chemiczny, Politechnika Warszawska, ul. Noakowskiego 3, 00-664 Warszawa
2Centralny Ośrodek Badawczo-Rozwojowy Opakowań, ul Konstancińska 11, 02-942 Warszawa
This paper presents a powerful analytical technique which uses an inductively coupled plasma (ICP) ionization source and mass spectrometric (MS) detector with a time of flight (TOF) analyzer. The technique has been introduced in 1993 and has attracted rapidly the attention of researchers in the field of atomic spectroscopy as a method that offers substantial improvement of figures of merit of widely used ICP-MS technique with quadrupole filters [42-46].
A mass spectrum in ICP-TOFMS technique is generated for a packet of ions simultaneously extracted from a continuous ion beam generated in plasma and accelerated to the same kinetic energy (Ek = 0.5 mv2) (Fig. 3). Setting the ions to the same kinetic energy results in different velocities acquired by the ions of different masses. The separation of the ions of different m/z is accomplished due to different times of their passing a fixed path (field-free region) in the instrument (Fig. 6 and 8). Extremely low time difference (nanosecond regime) between adjacent masses reflects in quasi-simultaneous detection of all isotopes reaching the detector.
The technique offers extremely high speed: spectral frequency 20-30 kHz (i.e. 20000-30000 mass spectra can be accumulated per second), an ability to obtain full elemental analysis for a packet of ions extracted from a continuous ion beam and a significantly better, as compared with quadrupole ICP-MS, precision of the measurements [53, 56, 57, 79].
Analytical performance and applicability of the technique in multi-clemental analysis of various materials have been extensively examined since 1998 when the ICP-TOFMS spectrometers have been commercially available (from LECO, USA („LECO Renaissance") and GBC, Australia („Optimass 8000")). The technique has turned to be particularly suited for detection of fast transient signals generated, e.g. by laser ablation [59-63], chromatographic systems [64-71], capillary clectrophoresis [69, 72] and FIA [73-77].
The basic principles, analytical capabilities of the ICP-TOFMS technique and characteristics of the instruments used are discussed in this paper. Analytical applications of the technique are presented.
Wydział Chemii Uniwersytetu Marii Curie-Skłodowskiej, Pl. M. Curie-Skłodowskiej 3, 20-031 Lublin
Membrane electrodes sensitive to various drugs have found many applications in pharmaceutical analysis. The sensors offer the advantages of simple design, construction and manipulation, reasonable selectivity, fast response time. With previous preconcentration of the sample, the detection limits of potentiometric techniques using membrane sensors, may equal or surpass those of some expensive and sophisticated techniques such as spectrophotometry, gas-liquid chromatography, high-performance chromatography.
In this review the ion-selective electrodes for drugs, containing ion-pair complexes and comprising a plasticized poly(vinyl) chloride membrane are described. The material used in this review was obtained from the major analytical, electroanalytical and pharmaceutical journals. The article is intended to whose who deal with ion-selective electrodes in organic and pharmaceutical analysis.
1Instytut Chemii Nieorganicznej I Metalurgii Pierwiastków Rzadkich,
Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, email@example.com
2Instytut Inżynierii Chemicznej i Urządzeń Cieplnych, Politechnika Wrocławska
Ul. Norwida 4/6, 50-373 Wrocław, Monikaq@iic.pwr.wroc.pl
The term ‘pervaporation’ was firstly used by Kober in 1917 to name phenomena observed during laboratory experiment . He noted, “In the course of some experiments on dialyzation, my assistant, Mr. C.W. Eberlein, called my attention to the fact that a liquid in a collodion bag, which was suspended in the air, evaporated, although the bag was tightly closed. At first we were inclined to ascribe it to evaporation through a small aperture at the top of the bag, but further experiments and especially the speed of evaporation soon forced us to the conclusion that the aqueous vapour is given off through the membrane, as though the water were suspended as a solid without any membrane present. This phenomenon we have named pervaporation.”
Usually, we think about membrane like about strainer, which holds bigger participle, and passes the smaller one. But in pervaporation process, we use smooth, non-porous membranes without “holes”. The clue of pervaporation phenomena is that this technique is based on a solution-diffusion mechanism combined with a phase change from liquid phase on feed membrane side to gas phase on permeate membrane side. Therefore it can be used to solve separation problems encountered with traditional, equilibrium-based, separation techniques. The driving force in pervaporation is a difference in chemical potential between feed and permeate side. The separation is achieved by different mass transfer rates of the components through the membrane. Generally, the mass transfer of the permeants in pervaporation process can be distinguished by the three different steps [2, 3, 4, 5]:
1. selective absorption on membrane surface at the feed side,
2. selective diffusion through the membrane (in some cases this effect is con-nected with molecular solvatation of the permeants in membrane volume),
3. desorption into the vapour permeate on the permeate side.
Nowadays, among the various membrane processes, pervaporation is considered as one of the most promising processes for many industrial applications from dehydration of alcohols to recover organic compounds from wastewater . Other applications of the pervaporation technology such as separation of organics mixtures and breaking azeotropes have also made progress.
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław
Zakład Chemii Farmaceutycznej i Analizy Leków, Katedra Chemii Farmaceutycznej i Biochemii, Uniwersytet Medyczny, ul. Muszyńskiego 1, 90-151 Łódź
Nitric oxide (NO) is a gas substance which plays the role of a carrier of signals in human organism. Molecules of the gas are produced by a single cell and transmitted via cellular membranes into another cell where they regulate its function. This is an entirely new mechanism of signal transmission in biological systems.
Recently, it has been demonstrated that the production of nitric oxide from L-arginine is a common biochemical pathway controlling the activity of guanyl cyclase. Isomorphic forms of nitric oxide synthase play a role in the regulation of blood vessels tone, blood flow, activity of platelets, gastrointestinal tract motor activity and reactivity of the respiratory tract. Nitric oxide produced by inducible form of synthase plays a significant role in immunological response and pathophysiological changes present in inflammatory reactions and shock. Nitric oxide is also produced in neurones of the central and peripheral nervous system.
Currently drugs which could activate of inhibit biochemical reactions concerning the release of nitric oxide are being investigated. With these drugs, the role of the system arginine?nitric oxide in physiological and pathological conditions could be explained. We are looking for donors of nitric oxide in various classes of chemical compounds. The research concentrates mainly on the following: O-nitro- and O-nitroso- compounds, S-nitro- and S-nitrosocompounds and N-nitro- and N-nitrosocompounds, C-nitro- and C-nitrosocompounds, oximes, heterocyclic NO donor compounds, nitroxyl (HNO/NO-) generating compounds, hydroxylamine, N-hydroxyguanidines, inorganic NO donors and transition metal nitrosyls.
The tested groups of compounds affect the production of exogenous nitrous oxide or stimulate its endogenous production to various degrees. In the course of conducted studies new applications for well-known drugs appear, and numerous new compounds await registration. One may expect many novel therapeutic options based on nitric oxide.
This study has been based on Methods in nitric oxide research  and current bibliography. In this part of study we present NO donors form the groups: O-nitro- and O-nitrosocompounds, S-nitro- and S-nitrosocompounds and N-nitro- and N-nitrosocompounds.
Instytut Chemii, Uniwersytet w Białymstoku Al. Piłsudskiego 11/4, 15-443 Białystok
Linkers constitute fundamental tools of polymer supported synthesis and combinatorial chemistry. Synthesis of any compound on solid support requires an efficient method for binding substrate molecules to solid phase and methods for cleavage of product molecules from the support after completion of the synthetic sequence. This review article presents role of linkers in solid-phase synthesis, analogy between linkers and protecting groups, and properties of linkers that need to be considered when planning synthesis of a particular compound on solid support. Basic concepts of linker methodology are presented and illustrated with selected examples. In addition the role of the linker as protection or activation of functional group of the substrate and an element controlling regio- or chemoselectivity is mentioned. The selected, representative examples of classical and recently elaborated linkers are classified according to the condition of cleavage. These include acid sensitive, base or nucleophile sensitive, photolabile, safety catch linkers, traceless linkers and cyclative cleavage linkers.
Instytut Chemii, Uniwersytet w Białymstoku, Al. J. Piłsudskiego 11/4, 15-443 Białystok
One of the most important fields in modern synthetic chemistry is the preparation of molecules which can recognize and bind others and then catalyze transformations of the bound molecules i.e. „artificial enzymes”, and the construction of systems which can reproduce themselves or otherwise store and process information at the molecular level [5 ? 8]. The above mentioned properties of these novel synthetic structures will result not only from the presence therein of the various required elements, but also from their relative arrangements in space and the three-dimensional shape of the overall assembly. In other words, spatially separated elements combine to achieve an overall effect in these structures. Hence, there will be a requirement for molecules with well-defined geometries in which conformational freedom is kept under close control. This criterion can be met by designs based on rigid frameworks. The steroid nucleus is one of the largest rigid units which is readily available. There are many steroidal compounds which might be chosen as starting materials for more elaborate frameworks. However, bile acids are the most valuable group of these compounds due to their chemically different hydroxyl groups, enantiomeric purity, unique amphiphilicity, availability and low cost.
Bile acids are natural polyhydroxylated steroidal acids existing in bile as sodium salts of N-acyl derivatives of glycine and taurine. They are synthesized from cholesterol and can solubilize hydrophobic substances by the formation of micellar aggregates and thus help in the digestion of fat lipids.
In this review applications of bile acids as building blocks in the synthesis of macrocyclic and also open-chained supramolecular hosts are presented.
Politechnika Krakowska, Instytut Chemii i Technologii Organicznej ul. Warszawska 24 31-155 Kraków tel. (12) 628 27 22, fax: (12) 628 20 37, e-mail: firstname.lastname@example.org
This review shows examples of application of Et3N in oxidations, eliminations, substitutions, and addition reactions.
Triethylamine (Et3N) appears to be most popular organic amine base in organic synthetic chemistry. The popularity comes from its low price along with easiness of removal by distillation. However, Et3N is a very dangerous fire hazard when exposed to the heat, flame, or oxidizers. Their salts with inorganic acids are somewhat insoluble in most organic solvents of low polarity and for that reason may by removed from the reaction media by simple filtration.
Examples of application of Et3N in oxidation reactions are shown in ozonolysis of cycloalkene 1-8 [3-5] (figs 1-4-5), and figs 1-6-8 show oxidation of 1-14, 1-16, and 1-18 alcohols, employing activated DMSO [6-12]. Various oxidation processes of hydrazones with iodide in the presence of Et3N are presented in fig. 1-9 . Elimination reactions, concerned mainly with dehydrohalogenations, are described in examples of halogen derivatives of lactone 2-1 , ketone 2-3 [18,19], sulfone 2-6 , and acids 2-9 and 2-11 [21,22] (figs 2-1-5). Dehalogenation of 2-13 , 2-17 [26-28], and 2-22 [31-37] acid chlorides are presented in figs 2-6-8, while formation of nitrile oxides in figs 2-11-13 [38-42]. Competitive dehydrobromination and dehydrochlorination reaction occurs in the presence of Et3N in 1,1,1-trichloro-3-bromo-3-fenylopropane (2-35) is described in fig. 2-15 . Mechanizm and examples of transformation of chlorosulfonyl chlorides are presented in figs 2-17-20 [47-51], and dimerization of aldiminium salts  in fig. 2-25 as well. Applications of Et3N in carbon-carbon bond formation in an intramolecular Heck reaction are shown in fig. 3-1 [70-74]. Example of use of Et3N in enolboronation of carbonyl compounds is described in fig. 3-2 [75-78], and additionally, in synthesis of silyl enol ethers can be found in figs 3-3-6 [89-104]. Application of Et3N as the base in neutralizing the acids liberated in preparing diazo ketones and mixed anhydrides are indicated in fig. 3-7 [105-107] and fig. 3-8 [108-117] respectively, while in protecting of hydroxy group in figs 3-9-11 [118-126]. Use of Et3N as the effective catalyst in cyjanoethylation reaction of active methyl group in acetylacetone (4-2)  and alkylpyridine methiodides 4-4-5, 4-8-9  are shown in figs 4-1-3, and in isomerization reaction of pyrazolines 4-14  and cycloaddition of indane-1,3-dione (4-16)  in figs.4-5?6.
Zakład Analizy Wody i Gruntów, Wydział Chemii, Uniwersytet im. Adama Mickiewicza ul. Drzymały 24, 60-613 Poznań, e-mail: email@example.com
The paper presents perspectives of development and application of determinations of arsenic, antimony and selenium by the methods based on hydride generation [1,2, 4-17]. This technique employed in spectrometric methods: absorption atomic spectrometry (AAS), atomic fluorescence (AFS), microwave (MIP) or inductively excited plasma (ICP) with emission or mass detection has become a very important tool in determination of environmental samples [3, 18]. The paper presents the possibilities of current analytical methods available with the use of this technique. First of all the detection limit can be decreased by in-situ preconcentration of volatile hydrides on the cell walls [19-36]. The possibility of speciation determinations based on the differences in the kinetics of hydride generation by different species present in the sample is discussed . Speciation analysis brings important information on the real toxicity of migration pathways of the element studied [37-78]. The need for this kind of information has stimulated development of new analytical solutions allowing separation of species in the chromatographic system or capillary electrophoresis, with selective spectrometric methods ICPMS, AAS or AFS in combination with hydride generation used for detection [79-115]. The progress in the hydride generation technique is closely related with recent attempts at direct analyses of solid samples [120-123], without the need to convert them into liquids, which facilitates the analytical process and permits simultaneous or almost simultaneous determination of many elements [124-126].
Wydział Chemii, Zakład Chemii Analitycznej, Uniwersytet im. Adama Mickiewicza, ul. Grunwaldzka 6, 60–780 Poznań
The paper presents a review of spectrophotometric methods for determination of nitrates (III), (V) and nitric oxides [1–48] with particular emphasis on the possibilities of the Griess–Ilosvay method. The original method [50, 51] developed for determination of nitrates (III) and based on derivatisation of these compounds to nitrogen dyes has undergone many modifications over the decades. The aim of the modifications was to enhance the method’s sensitivity, decrease the level of determination, simplify the procedure and its adjustment to achieve the most effective determination also in the presence of a complex matrix [52–67]. The increasing demands of analytical chemistry and the need to determine trace or ultratrace amounts of nitrates have prompted further improvement of the Griess–Ilosvay method by combining it with methods of analyte enrichment such as liquid–liquid–extraction [68–80] and liquid–solid extraction [81–94]. The recent need for routine determinations in the monitoring of the natural environment has led to the development of the fast flow–through – injection methods [95–127], making the analytical process more effective and convenient to use. One of the most recent achievements in analytical chemistry of nitrates (III) and (V) has been the development of optical sensors (optrodes) [128–132]. They are used in modified versions of the Griess–Ilosvay method and permit a direct and relatively easy determination of the contents of nitrates preserving a high sensitivity of the method. The paper gives a comparative review of the modifications of the Griess–Ilosvay method from the earliest to the most recent
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław
T. Cukierda, last changes: