Wiadomości Chemiczne

Wiadomości Chemiczne, 2002, Vol. 56

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  1. Quantum-chemical methods for selectivity prediction of [2+3] cycloaddition
    Radomir Jasiński, Agnieszka Markowska, Andrzej Barański

  2. Circular dichroism of nucleic acids. Part I. Monomers
    Małgorzata Boczkowska

  3. DeNOx on copper-containing molecular sieves. Part I. Physico-chemical characterisation of catalysts
    Izabela Sobczak i Maria Ziółek

  4. Peptide toxins of cyanobacteria
    Joanna Łukomska, Franciszek Kasprzykowski, Leszek Łankiewicz, Zbigniew Grzonka

  5. Solvatochromism and solvatochromic dyes
    Elwira K. Wróblewska, Jacek A. Soroka, Krystyna B. Soroka

  6. Kasimir Fajans and recent Nobel Prizes in Chemistry
    Józef Hurwic

  7. Notatki chaotyczne XXXVIII. Wokół prawa zachowania masy
    Ignacy Z. Siemion

  8. The fundamental physical constants
    Maciej Suffczyński, Paweł Janiszewski

  9. DeNOx on copper-containing molecular sieves. Part II. Catalytic decomposition of NO
    Izabela Sobczak, Maria Ziółek

  10. Circular dichroism of nucleic acids. Part II. Polymers
    Małgorzata Boczkowska

  11. Ureases: roles, properties and catalysis
    Barbara Krajewska

  12. Chemical synthesis of oligoribonucleotides
    Jan Milecki

  13. Catalysts of carbon dioxide reforming of methane
    Andrzej Lewicki, Tadeusz Paryjczak, Wojciech K. Jóźwiak, Jacek Rynkowski

  14. Characterization of complex equilibria of iminodi(methylenephosphonic) acids with metal(II) ions
    Anna Kamecka, Barbara Kurzak

  15. Methods of L-carnitine determination
    Agata Łącka, Joanna Leszczyńska

  16. Notatki chaotyczne XXXIX. O melatoninie, serotoninie i bufoteninie
    Ignacy Z. Siemion

  17. DeNOx on copper-containing molecular sieves. Part III. Selective catalytic reduction of NO. Effect of O2, H2O and SO2
    Izabela Sobczak i Maria Ziółek

  18. Transient species in multistep NADHŰNAD+ conversion
    Jerzy Gębicki, Andrzej Marcinek, Jan Adamus

  19. Anion recognition
    Kamil Wojciechowski, Zbigniew Brzózka

  20. Enzymatic hydroxylations, their aplications and mechanism of the reaction performed by cytochrome P450 monooxygenases
    Teresa Kołek

  21. Amlodypine, modern calcium antagonist - methods of synthesis
    Halina Hajmowicz, Dominik Jańczewski, Ludwik Synoradzki

  22. Environmental estrogens are not a problem
    Przemysław Mastalerz

  23. Inductively coupled plasma as a source of excitation and ionization for modern analytical techniques
    Elżbieta Skrzydlewska , Maria Balcerzak , Piotr Pasławski

  24. Notatki chaotyczne. XL. Czytając Fausta
    Ignacy Z. Siemion

  25. Syntheses of natural and modified anthracycline antibiotics from a common precursor: 3,4-DI-O-acetyl-L-rhamnal
    G. Grynkiewicz, O. Achmatowicz, I. Fokt, W. Priebe, J. Ramza, B. Szechner, W. Szeja

  26. Synthesis of polyhydroxyindolizidines from a,b-unsaturated d-lactones
    Joanna Rabiczko, Dariusz Socha, Margarita Jurczak, Marek Chmielewski

  27. Chemical structure, antigenic specificity and the role in the pathogenicity of lipopolysaccharide (LPS, endotoxin) on proteus vulgaris bacteria's example
    Antoni Różalski, Agnieszka Torzewska, Beata Bartodziejska, Dorota Babicka, Iwona Kwil, Andrei V. Perepelov, Anna N. Kondakova, Sof'ya N. Senchenkova, Yuriy A. Knirel, Evgeny V. Vinogradov

  28. Derivatives of 1-thiosugars as substrates in glycosylation reactions
    Wiesław Szeja, Joanna Bugla, Aleksandra Niemiec, Gabriela Pastuch, Anna Kasprzycka, Anna Ślusarczyk, Ilona Wandzik, Tadeusz Bieg, Bogdan Przybysz, Jadwiga Bogusiak

  29. Palladium-catalyzed synthesis of glycosides and disaccharides
    Bogusław Kryczka, Stanisław Porwański

  30. Application of sugar allyltins in the synthesis of carbobicyclic derivatives
    Sławomir Jarosz, Stanisław Skóra, Katarzyna Szewczyk

  31. On the N-glycopyranosylammonium salts
    Barbara Dmochowska, Eugenia Skorupowa, Andrzej Wiśniewski

  32. Notatki chaotyczne. XLI. W stronę gastronomii molekularnej
    Ignacy Z. Siemion

  33. Green chemistry: principles, aims , and selected achievements
    Bogdan Burczyk

  34. Chemistry of the noble gases
    Krzysztof Łyczko

  35. A never ending story of vitamin D
    Wojciech Kroszczyński, Bożena Morzycka, Jacek W. Morzycki

  36. Polymeric peroxides - synthesis, properties and applicationscations
    Jan Zawadiak, Mirosław Danch

  37. [2+3] cycloaddition reactions of conjugated nitroalkenes to nitrones
    Andrzej Barański, Radomir Jasiński

  38. Separation and determination of Cr(III) and Cr(VI) in environmental samples
    Jan Kalembkiewicz, Eleonora Sočo

  39. Notatki chaotyczne. XLII. Portret literacki Józefa Jerzego Bogusławskiego
    Ignacy Z. Siemion

  40. Sonoelectrochemistry. The influece of ultrasound on electrode processes and its application in electrochemistry.
    Krzysztof Winkler, Monika Wysocka

  41. Miniaturization in high performance capillary electrophoresis
    Angelika Mrass, Edward Bald

  42. Silylene transition metal complexes
    Hieronim Maciejewski

  43. Betulinic alcohol and its derivatives
    Anna Tomaszkiewicz-Potępa, Magdalena Piękoś

  44. Radon in the environment of groundwaters and upper part of litosphere
    Tadeusz Andrzej Przylibski

  45. Rapid and economical methods of extraction of pesticides in food
    Alfred Błaszczyk, Jan Jasiczak

  46. Teaching of enyironmental protection within a system of on-site and remote te a ching
    Andrzej Burewicz, Hanna Gulińska, Piotr Jagodziński, Małgorzata Miranowicz, Nikodem Miranowicz

  47. Notatki chaotyczne. XLIII. Ciągi wspomnień.
    Ignacy Z. Siemion


QUANTUM-CHEMICAL METHODS FOR SELECTIVITY PREDICTION OF [2+3] CYCLOADDITION

Radomir Jasiński, Agnieszka Markowska, Andrzej Barański

Instytut Chemii i Technologii Organicznej Politechniki Krakowskiej
ul. Warszawska 24, 31-155 Kraków


In general, quantum-chemical methods for prediction of the outcome of cycloaddition reactions can be classified into three groups, depending on the particular reaction steps. The least used first group comprises the reactivity indexes, which are based on the analysis of stationary states of substrates. The second group contains the indirect methods of determination of activation energy, such as PMO, FMO and BL. The third group includes the methods relying on finding and characterization of critical structures on the corresponding potential energy hypersurface.

BL and PMO methods can be applied only for the reactions that obey the principle of non-intercrossing of the energy profiles. These methods are mutually complementary and are used for description of different reaction stages of [2+3] cycloadditions. In the case of a late transition state, the activation energy is controlled primarily by the electronic effects related to formation of new bonds, rather than by the weak donor-acceptor interactions of substrates that are the basis for PMO and FMO methods. Reverse situation occurs when the activation barrier is controlled by an early transition state whose structure resembles substrates. Despite some reported successes, BL method has not become so popular as PMO. This results probably from the narrower scope of potential applications of the former method compared to the later one as well as from the BL method formalism. BL is used for explanation of specific aspects of [2+3] cycloadditions rather than for the reactivity predictions in the literal sense.

Availability of fast computers and advanced quantum-chemical software has caused the [2+3] cycloaddition analysis based on localization and characterization of critical points on the potential energy hypersurface has gained popularity in recent years. Such analysis affords information about reactivity of the reagents, reaction mechanism, and, regio-, stereo- and periselectivity of practically any kind of reactions. By this method, transition state geometry and its physicochemical parameters, such as charge distribution, ionization potential, or dipole moment, can be determined. The transition state dipole moment can be used for prediction of the reaction course in solvents of different polarity. Moreover, there are procedures for direct calculations in the presence of a simulated dielectric medium, such as a solvent.


Wiadomości Chemiczne, 2002, 56, 9.
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CIRCULAR DICHROISM OF NUCLEIC ACIDS. PART I. MONOMERS.

Małgorzata Boczkowska

Centrum Badań Molekularnych i Makromolekularnych PAN, ul. Sienkiewicza 112, 90 - 363 Łódź


The review presents the theoretical basis for the origin of optical activity of nucleic acids. The optical properties of nucleic bases are discussed in terms of theoretical calculations by Hug and Tinoco [10, 11]. Although nucleic bases are themselves optically inactive, the in-plane (p®p*) as well as out-of-plane (n®p*) transition dipoles induced in their rings are responsible for optical activity of nucleosides, nucleotides and polynucleotides. In a case of nucleosides and nucleotides, which are called "monomers", the optical activity originates from the disturbance of the electronic system of a base caused by the presence of a sugar ring. The main factor influencing the character of CD spectra is the torsion angle about the glycosyl bond [14-17]. The experimental spectra of monomers are dominated by in-plane transitions (Rys. 2, 3). In a case of cytidine and guanosine (Rys. 3) the lowering of pH reveals the presence of the out-of-plane transition [14, 24].


Wiadomości Chemiczne, 2002, 56, 39.
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PEPTIDE TOXINS OF CYANOBACTERIA

Joanna Łukomska, Franciszek Kasprzykowski, Leszek Łankiewicz, Zbigniew Grzonka

Katedra Chemii Organicznej, Wydział Chemii Uniwersytetu Gdańskiego, ul. J. Sobieskiego 18, 80-952 Gdańsk


This review presents chemical and biological aspects of secondary metabolites produced by cyanobacteria. The main goal of the work was to present studies related to microcystins and nodularins.

Cyanobacteria (blue-green algae) growing both in freshwater and marine environment release to the medium numerous secondary metabolites. Some of cyanobacteria produce lethal toxins (cytotoxins and biotoxins). Therefore, cyanobacteria can be harmful for mammals, birds and fish, and also cause effects on human health. The secondary metabolites are the mostly derivatives of amino acids (see compounds on Scheme 1) and peptides or depsipeptides (Schemes 2-5). The best described among cyanobacteria toxins are the hepatotoxins: microcystins and nodularins. These toxins cause severe intrahepatic haemorrhage and hypovolaemic shock, and act as tumor promoters. Microcystins and nodularins are potent inhibitors of PP1 and PP2A protein phosphatases.

Microcystins and nodularins, which are cyclic hepta- or penta-peptides, respectively, consists of various uncoded amino acid residues. The most characteristic and unique amino acid residue is Adda [(2S,3S,8S,9S,4E,6E)-3-amino-9-metoxy-2,6,8-trimethyl-10-phenyl-deca-4,6-dienoic acid]. Typical isolation of these toxins is realized by extraction combined with reversed-phase chromatography. Structure-activity relationship studies of microcystins and nodularins have revealed indispensability of Adda moiety, and two carboxyl groups of aspartic and glutamic acids, for the activity towards phosphatases. The total synthesis of both toxins represents quite a big challenge because of the necessity of preparation of Adda, as well as many other uncoded amino acids (D-erythro-b-methyl-aspartic acid, Masp; dehydroalanine, Dha, or dehydrobutyrine, Dhb, and their N-methyl derivatives etc.) prior to a final cyclization. Syntheses of Adda, the compound with four chiral centers and two specific configurations at the double bonds, were carried out mostly by the condensation of the previously obtained C1-C4 and C5-C10 fragments (Schemes 6-8).

Microcystins and nodularins are quite stable compounds in aqueous solution. They can be destroyed and removed by chlorination, or by treatment with ozone (Scheme 9) combined with ultrafiltration. On the other hand, microcystins and nodularins could be modified for example by esterification (Asp and/or Glu residues), transformation of guanidine moiety of arginine, Michael type addition to dehydroamino acids (Dha, Dhb). These modifications provide less toxic compounds, with interesting biological activities.


Wiadomości Chemiczne, 2002, 56, 57.
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DeNOx ON COPPER-CONTAINING MOLECULAR SIEVES. PART I. PHYSICO-CHEMICAL CHARACTERISATION OF CATALYSTS.

Izabela Sobczak, Maria Ziółek

Uniwersytet im. A. Mickiewicza, Wydział Chemii, Grunwaldzka 6, 60-780 Poznań


Since 1986 when Iwamoto and coworkers discovered a very high activity of Cu-ZSM-5 zeolites in NO decomposition a huge number of papers has been devoted to various copper - containing catalysts.

This review paper sums up the results presented in so far published articles concerning physico-chemical properties of micro- and mesoporous molecular sieves modified with copper. Cu-ZSM-5 is the most frequently studied zeolite and Cu-AlMCM-41 belongs to the most frequently studied mesoporous materials. Therefore, in this paper a short characteristic of ZSM-5 and MCM-41 molecular sieves is performed, as well as the precise data from FTIR, ESR and H2-TPR studies applied to the characterisation of Cu-state on the catalyst surface are presented (the Cu-species have been identified on the basis of these data).


Wiadomości Chemiczne, 2002, 56, 83.
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SOLVATOCHROMISM AND SOLVATOCHROMIC DYES

Elwira K. Wróblewska, Jacek A. Soroka, Krystyna B. Soroka

Politechnika Szczecińska, Wydział Technologii i Inżynierii Chemicznej Instytut Chemii i Podstaw Ochrony Środowiska, Zakład Analizy Instrumentalnej, 71-065 Szczecin, Al. Piastów 42


The phenomenon of solvatochromism is presented, taking into account the constitution of solvatochromic dyes [9, 18-25, 35-117], the physical interpretation and mathematical description (models) of solute-solvent interaction.

The discussion covers Onsager's early reactions field model [92, 93] and subseqent qualitative interpretation of the solvent effect on solute dipole moment change by Bayliss and McRea [91]. Subsequently solvatochromic dyes were presented briefly as empirical polarity indicators [9, 18, 49, 101-107, 109, 115-117] with respect to other methods applied to this goal.

Binary solvents mixtures polarity models were critically discussed, taking into account the conceptions of Langhals [118, 120-125], Dawber [126, 134], Bosh and Rosés [135, 141] and Skwierczyński and Connors [139].

After this introduction Soroka's models were presented: the physicochemical V-B-HB model based on solute electronic structural changes in pure solvents [63, 140] and the SA-SAB-SB model of solvatochromism in binary solvent mixtures [127, 128].

Both models describe well the behaviour of many pure solvents, as well as the properties of a number of binary systems series including ones well known from textbooks. These models provide reliable support for advanced investigations and precise interpretation of molecular interactions in liquids.


Wiadomości Chemiczne, 2002, 56, 113.
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Kasimir Fajans and recent Nobel Prizes in Chemistry

Józef Hurwic

Laboratoire de Diélectrochimie, Université de Provence 3, pl. Victor-Hugo, 13331 Marseille CEDEX 03, France


William S. Knowles, Ryoji Noyori and K. Barry Sharples share this year's Nobel Prize in Chemistry for their development of catalytic asymmetric synthesis of great importance for production of new drugs. On this occasion it is interesting to recall the doctoral thesis of Kasimir Fajans at Heidelberg in 1909 on catalytic separation of enantiomers.


Wiadomości Chemiczne, 2002, 56, 151.
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Notatki chaotyczne XXXVIII. WOKÓŁ PRAWA ZACHOWANIA MASY

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2002, 56, 157.
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THE FUNDAMENTAL PHYSICAL CONSTANTS

Maciej Suffczyński, Paweł Janiszewski


The 1998 updated fundamental physical constants are reprinted and described

Translation from:
P. J. Mohr, B. N. Taylor, CODATA recomended values of the fundamentan physical constants: 1998, J. Phys. Chem. Ref. Data, 1999, 28, 1713.


Wiadomości Chemiczne, 2002, appendix, 56.
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DeNOx ON COPPER-CONTAINING MOLECULAR SIEVES.
PART II. CATALYTIC DECOMPOSITION OF NO

Izabela Sobczak, Maria Ziółek

Uniwersytet im. A. Mickiewicza, Wydział Chemii, Grunwaldzka 6, 60-780 Poznań


Part II of the series dealing with DeNOx carried out on dopper-containing molecular sieves is devoted to the various features responsible for the catalytic activity of Cu-molecular sieves in the NO decomposition. The physico-chemical properties of the catalysts were shown in Part I ("Wiadomości Chemiczne" 2002, 56, 1-2, 83), whereas in Part II they are related to the decomposition of NO.

This paper describes the role of the Si/Al and Cu/Al rations, the conditions of the catalysts preparation and activation, the influence of the T-element nature in the framework of molecular sieves as well as co-cations on the yield in the NO decomposition. Moreover, some proposals of the mechanism of this reaction described in the literature are included.


Wiadomości Chemiczne, 2002, 56, 177.
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CIRCULAR DICHROISM OF NUCLEIC ACIDS.
Part II. POLYMERS

Małgorzata Boczkowska

Centrum Badań Molekularnych i Makromolekularnych PAN, ul. Sienkiewicza 112, 90 - 363 Łódź


The review presents the theoretical basis for interpretations of CD spectra of polynucleotides. A simplified version of quantum theory of circular dichroism of a polynucleotide by Tinoco and Johnson [2] is presented in details. It is generally assumed that the optical activity of these polymers is dominated by interactions between dipoles of in-plane transitions occuring at neighbouring bases. The interaction of dipoles coming from different bases strictly depends on geometrical arrangement of bases within the helix. As a result information about geometry of the helix can be inferred from the CD spectra. The circular dichroism caused by the disturbance of the electronic system of a base by the presence of a sugar ring is usually omitted in calculations. Such a theoretical approach allows to understand differences between CD spectra of random DNA and RNA. The distance of a base pair from helix axis appeared to be the main factor responsible for these differences [25]. The approach fails in a case of polymers of non-random sequences, for example containing a repetitive motif of two bases [2, 7, 27]. It is exemplified for the d(CG)n oligomers forming left-handed double helix called Z-DNA, where none of the theoretical calculations is able to predict the inversion of a CD spectrum characteristic for the Z form [7, 35, 36].


Wiadomości Chemiczne, 2002, 56, 203.
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UREASES: ROLES, PROPERTIES AND CATALYSIS

Barbara Krajewska

Uniwersytet Jagielloński, Wydział Chemii, ul. Ingardena 3, 30-060 Kraków. e-mail: krajewsk@chemia.uj.edu.pl


Urea is a ubiquitous compound in nature. It is formed in large amounts as the end product of the catabolism of nitrogen-containing compounds by most of the terrestial animals and also used in agriculture as the most common fertilizer. If it were not for its enzymatic hydrolysis that is 1014 times faster than the nonenzymatic degradation, urea would rapidly accumulate in nature causing serious environmental problems. The hydrolysis of urea is catalyzed by urease (urea amidohydrolase EC 3.5.1.5) [1], an enzyme widely distributed in bacteria, fungi, algae, some invertebrates and higher plants, the first enzyme ever crystallized (1926) [2] and the first one shown to contain nickel in its active site (1975) [3]. The products of the hydrolysis are ammonia and carbamate, the latter spontaneously decomposing to ammonia and carbonic acid in an uncatalyzed reaction. The products generate an increase in pH. Despite extensive research to date the mechanism of urease action has not been fully elucidated [25a, 55a].

The negative effects of both ammonia and the reaction-generated increase in pH brought about by urease activity, have profound medical and agricultural implications [54]. Several ureolytic bacteria have been recognized as pathogenic factors in human/animal infections of urinary and gastrointestinal tracts. In the former they are involved in the urinary stone formation, catheter encrustation and pyelonephritis, and in the latter in chronic active gastritis, peptic ulcers, both caused by Helicobacter pylori, and in hepatic coma. In agriculture urease is essential for converting urea-based fertilizers to utilizable ammonia. Too rapid a hydrolysis, however, results both in plant damage by ammonia toxicity and in the alkalization of soil and finally in the loss of nitrogen by ammonia volatilization, thus creating severe environmental and economic problems. To combat these undesirable ureolytic effects the use of urease inhibitors has been proposed. Final elucidation of the structure of the urease active site and of its catalytic mechanism will substantially facilitate the design of effective urease inhibitors at a molecular level, thus replacing tedious kinetic screening.

This paper summarizes the established knowledge on urease and reviews the recent findings on the enzyme.


Wiadomości Chemiczne, 2002, 56, 223.
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CHEMICAL SYNTHESIS OF OLIGORIBONUCLEOTIDES

Jan Milecki

Uniwersytet im. Adama Mickiewicza, Wydział Chemii, ul. Grunwaldzka 6, 60-780 Poznań


Basic issues and problems of chemical synthesis of oligoribonucleotides are presented. The paper describes three methods for construction of oligonucleotide chains:

(1) a triester method which involves activation of nucleoside phosphodiesters with different azole sulfonates, and currently widely used methods employing PIII synthetic intermediates:

(2) a phosphoramidite method which makes use of activation of nucleoside phosphoramidites by weakly acidic azoles or azole salts,

(3) an H-phosphonate method, which uses nucleoside H-phosphonates activated by acid chlorides, both PIII intermediates are applied mainly in solid-support synthetic methodology.

Problems of choosing appropriate protecting group for the synthesis are discussed. The article presents properties of basic types of protecting groups for lactam, exo-amino (base-labile protection), and hydroxyl groups (acid-labile for 5' protection, acid- or specific reagent-labile for 2' protection). The problem of 2'OH protection is described in detail. In this respect acid-labile groups and alkylsilyl groups are compared and their advantages and disadvantages are discussed. More detailed discussion is devoted to the phenomenon of the silyl group migration during the synthesis of monomeric units for oligonucleotide chain assembly. Basing on the NMR study of the isomerisation reaction it was possible to determine limits of safety of the reaction conditions.


Wiadomości Chemiczne, 2002, 56, 255.
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CATALYSTS OF CARBON DIOXIDE REFORMING OF METHANE

Andrzej Lewicki, Tadeusz Paryjczak, Wojciech K. Jóźwiak, Jacek Rynkowski

Instytut Chemii Ogólnej i Ekologicznej Politechniki Łódzkiej, 90-924 Łódź, ul. Żwirki 36


During the past decade, there has been increasing interest in the catalytic reforming of methane with carbon dioxide. This reaction is considered as more efficient use of natural gas (methane) but also in the context of possible utilization of carbon dioxide. As both CH4 and CO2 are greenhouse gases, this reaction has also important environmental implications.

In this review, an emphasis was put on the recent papers, published in the period 1998-2001, which have not been reported in the comprehensive review of Bradford and Vannice [2]. Some basic thermodynamic and kinetic information about the discussed reaction and CH4 and CO2 activation was recalled. Then different types of catalysts were reported, first of all focused on nickel and platinum group based catalysts. New approaches to the mechanisms of the reaction on catalysts Ni/ZrO2 [28, 29] and Ru/SiO2 and Ru/Al2O3 [42] were shown.

The major difficulty in practical realization of methane reforming with CO2 is thermodynamically favoured coke formation which deactivates the catalysts. The route leading to the improvement of this situation can be an addition of oxygen or water to the feed gas mixture or developing catalysts that minimize the rate of carbon deposition. The modification of the support, an application of bimetallic catalysts or another complex systems seem to be promising. Some of such systems were reported in the review.

Among 112 references cited in this review, 72 were published in the period 1998-2001. Therefore, the authors hope that this contribution presents a useful and reasonable supplement to Bradford and Vannice work [2].


Wiadomości Chemiczne, 2002, 56, 279.
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CHARACTERIZATION OF COMPLEX EQUILIBRIA OF IMINODI(METHYLENEPHOSPHONIC) ACIDS WITH METAL(II) IONS

Anna Kamecka, Barbara Kurzak

Zakład Chemii Bionieorganicznej, Instytut Chemii, Akademia Podlaska, ul. 3 Maja 54, 08-110 Siedlce


The aminopolyphosphonic acids are analogues of aminopolycarboxylic acids in which the carboxyl groups (CO2-) are substituted by the phosphonate moieties (PO32-). 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.

This review discusses coordination preferences of N-substituted iminodi(methylenephosphonic) acids to the divalent metal ions (such as magnesium, calcium, manganese, cobalt, nickel, copper and zinc) in an aqueous solution.

N-substituted derivatives of iminodi(methylenephosphonic) acids exhibit high complexation efficiency towards divalent metal ions. This results from both dinegatively charged phosphonate groups as well as the imino nitrogen present in their structure. A significant preference for an equimolar stoichiometry has been demonstrated in these systems. The only exeption is the N-2-methyltetrahydrofuryliminodi(methylenephosphonic) acid with a tetrahydrofuryl moiety placed in the sterically favoured position that allows its oxygen atom to be an effective metal binding site. Specific interactions between metal ions and furyl oxygen results in higher binding ability of this ligand and a formation of 1:2 species.

The first part of the review deals with the acid-base properties of the considered ligands which are consistent with electronic effect of the substituents attached to the imino nitrogen. The second part of the review describes the binding properties of iminodi(methylenephosphonic) acids in copper(II) complexes. A formation of tridentate bonded species has been demonstrated in these systems. The third part of the review report what is known about magnesium(II), calcium(II) and zinc(II) complexes of the same ligands. While the imino nitrogen is bonded in the predominate complexes in the zinc(II) systems, magnesium(II) and calcium(II) ions prefer a pure phosphonate coordination. Finally, the interactions of manganese(II), cobalt(II) and nickel(II) ions with N-substituted iminodi(methylenephosphonic) acids are described. For these complexes the formation of eight-membered rings is reported.

Coordination properties of iminodi(methylenephosphonic) acids are important factors to understand the role of the ligands and metal ions in biological systems.


Wiadomości Chemiczne, 2002, 56, 315.
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METHODS OF L-CARNITINE DETERMINATION

Agata Łącka, Joanna Leszczyńska

Instytut Podstaw Chemii Żywności, Politechnika Łódzka Ul. Stefanowskiego 4 / 10, 90 - 924 Łódź


L-carnitine (3-hydroxy-4-N-trimethylammonium butyric acid) plays an important role in fats metabolism, acting as an essential carrier of acyl group from cytoplasm into the mitochondria and b-oxidation products from peroxosomes. It is also responsible for detoxication of specific short- and medium-chain fatty acids [1-5]. Although carnitine is not indispensable in food and can be synthesized in the system, its deficiency accompanies many diseases. Deficiency in carnitine is characterised by muscle weakness, cardiomyopathy, deposition of fat in muscles, kidneys, liver as well as metabolic acidosis.

L-carnitine occurs in a free form and esterificated by fatty acids. For diagnostic purposes free and total carnitine are determined after previous ester hydrolysis. Modern methods of carnitine determining are based on reversible reaction of the stoichiometric acetyl-transfer from acetyl-coenzyme A to L-carnitine catalyzed by carnitine acetyltransferase (CAT), and measurement of the content of acetyl-carnitine or free coenzyme A formed [1, 19]. Isomer D-carnitine is inactive in that reaction, nor-carnitine (3-hydroxy-4-dimethylammonium butyric acid) may take part, but this compound does not appear in any biologic materials. Those methods of carnitine determining employ radiometric, spectrophotometric, spectrofluorimetric and enzymatic techniques.

Among the other methods of carnitine determining chromatographic methods are most frequently used, especially HPLC, but also GC chromatography is often used. Using HPLC method, one can determine the carnitine level, either immediately or in the form of 4'-bromophenacyl derivatives [46 - 49]. However, some authors have had difficulties in obtaining these derivatives [29] and sensitivity of determination has been not sufficient for biological samples. Various reagents were used to prepare fluorescent carnitine derivatives in the HPLC chromatography with fluorimetric detection [table 1]. The reactor containing immobilized enzymes was also used [58].

One can also determine carnitine by means of gas chromatography. This method is based on the disintegration of carnitine at temp. 160 ºC in the presence of NaOH and NaBH4 [61, 62]. Under these conditions it is disintegrated into crotonylbetaine, trimethylamine and butyrolacton, which are detected with flame ionization.

Among methods used less frequently mass spectroscopy and capillary electrophoresis are worth mentioning.

Individual O-acyl derivatives content L-carnitine can be determined using the "radio-exchange" method or gas chromatography.


Wiadomości Chemiczne, 2002, 56, 341.
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Notatki chaotyczne XXXIX. O MELATONINIE, SEROTONINIE I BUFOTENINIE

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2002, 56, 361.
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DeNOx ON COPPER-CONTAINING MOLECULAR SIEVES. PART III. SELECTIVE CATALYTIC REDUCTION OF NO. EFFECT OF O2, H2O AND SO2

Izabela Sobczak i Maria Ziółek

Uniwersytet im. A. Mickiewicza, Wydział Chemii, Grunwaldzka 6, 60-780 Poznań


Part I of this series exhibited the physico-chemical properties of Cu-containing molecular sieves, whereas, Part II was devoted to the DeNOx carried out via the decomposition of NO.

Cu-containing molecular sieves are applied not only in the decomposition of NO but also in the selective catalytic reduction of NO with hydrocarbons (HC-SCR). The latter is the subject of this paper. The selective reduction of NO with hydrocarbons is a new alternative for the removal of NO from the exhausts gases. It is addressed, among others, to the reduction of NO in the presence of a large amount of oxygen.

Part III considers also the influence of O2, H2 and SO2 on the activity of Cu-catalysts in both NO reduction with hydrocarbons and NO decomposition.


Wiadomości Chemiczne, 2002, 56, 377.
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TRANSIENT SPECIES IN MULTISTEP NADHŰNAD+ CONVERSION

Jerzy Gębicki, Andrzej Marcinek, Jan Adamus

Instytut Techniki Radiacyjnej, Politechnika Łódzka, 90-924 Łódź, ul. Żeromskiego 116


The conversion of NADH to NAD+ and of the reverse reaction, in the coenzyme as well as in its synthetic analogues, 1,4-dihydropyridines and 9,10-dihydroanthracenes is discussed. Two mechanisms of the NADHŰNAD+ conversion are compared: one-step hydride transfer and stepwise electron-proton-electron transfer.

Direct characterization of transient species in the stepwise process, namely radical cations and radicals, is presented based on the pulse radiolysis and laser flash photolysis studies both in solution and low-temperature matrices. On ionization of NADH and 1,4-dihydropyridines the stability order of the keto and enol tautomers is inversed as compared to their neutral precursors. Both types of radical cations are characterized and their role in the stepwise process is discussed.


Wiadomości Chemiczne, 2002, 56, 397.
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ANION RECOGNITION

Kamil Wojciechowski, Zbigniew Brzózka

Katedra Chemii Analitycznej, Wydział Chemiczny Politechniki Warszawskiej, ul. Noakowskiego 3, 00-664 Warszawa


The article deals with the anion recognition. The aim of this review was to stress that the anion recognition is becoming more and more rapidly expanding field of the ion recognition and modern chemistry in general.

First, the general characteristic of the anions was given, including the size, shape, pH dependence and hydration (see Table 1). These parameters were compared with the respective ones for cations. The importance of the anions for the biological processes was shown on some most representative examples, like inorganic phosphate ions. The biological mechanisms of the "arginine fork" [18], and phosphate/sulfate recognition selectivity were used to show the importance of hydrogen bonding [11-17]. The synthetic cycle of the ATP exemplified the uniqueness of the rotary synthesis based on anion recognition [24]. The discovery of the mechanism of the rotary synthesis was awarded the Nobel Prize in chemistry in 1997. The biological membranes and their role in the ion recognition (binding and transportation) were briefly introduced.

The most spectacular examples of the molecular recognition were compared with the current achievements of supramolecular chemists. Starting from the pioneering work of Park and Simmons [1] to the very recent dendrimeric structures [65, 66], the anion receptors were reviewed. The authors were not trying to introduce any artificial classification of receptors, because in most of the cases at least two types of non-covalent interactions participate in the recognition process. The usefulness of this approach was discussed on the example of polyammonium receptors recognizing the anions by inseparable electrostatic and H-bonding interactions. The following groups of receptors were described: guanidinium, polyamines/polyammonium, metaloorganic (tin, boron, mercury, ferrocenium, cobaltocenium), metal complexes, porphyrines, expanded porphyrines (saphyrines), calix[n]arenes, catenane, cyclodextrine, and gold nanoparticles.


Wiadomości Chemiczne, 2002, 56, 417.
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ENZYMATIC HYDROXYLATIONS, THEIR APLICATIONS AND MECHANISM OF THE REACTION PERFORMED BY CYTOCHROME P450 MONOOXYGENASES

Teresa Kołek

Katedra Chemii, Akademia Rolnicza we Wrocławiu, ul. Norwida 25, 50-375 Wrocław


Enzymatic conversion of a carbon - hydrogen to a carbon - hydroxyl bond is a key part of the biosynthesis and oxidative metabolism in living organisms from bacteria to humans. Biocatalytic hydroxylations are also widely used in organic synthesis, especially to introduce the desired function to the site of the molecule, which is difficult to obtain by chemical methods.

Biocatalytic hydroxylations are most often performed by cytochrome P450 dependent monooxygenases. In a catalytic cycle, one oxygen atom from oxygen molecule is incorporated to water and the other is incorporated into the substrate.

Cytochrome P450 is known to catalyze hydroxylations, epoxidations, N-, S-, and O-oxidations, dealkylation, and dehalogenations.

The mechanism of the hydroxylation reaction has been explored in the context of synthetic applications, selection of the substrate, and enzyme - substrate interaction.

Models involving defined spatial relationships between the mode of substrate-enzyme binding and hydroxylation sites have rationalized the regio- and stereochemistry of hydroxylation.

Many of the steps in sequence of the oxidation reactions are well characterized, but the identity of the final oxidant and the reaction mechanism are still not well understood.

Recent developments in area biohydroxylation have been focused on the use of new biocatalysts and substrates for C-H activation, the use of recombinant strains of yeast and bacteria expressing desired hydroxylase enzymes.


Wiadomości Chemiczne, 2002, 56, 449.
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AMLODYPINE, MODERN CALCIUM ANTAGONIST - METHODS OF SYNTHESIS

Halina Hajmowicz, Dominik Jańczewski, Ludwik Synoradzki

Laboratorium Procesów Technologicznych, Wydział Chemiczny Politechniki Warszawskiej ul. Noakowskiego 3 00-664 Warszawa


The paper is a review of the methods of synthesis of amlodypine (1), 3-ethyl-5-methyl-2-(2-aminoethoxymethyl)-4-(2-chlorophenyl)-1,4-dihydro-6-methyl-pyridino-3,5-dicarboxylate, a modern drug belonging to the calcium antagonists group. The synthesis of amlodypine is a multistep process. A Williamson reaction with the formation of a compound with an ether bond (5) is usually the first step. This reaction is followed by a Hantzsch reaction with the formation of a correspondingly substituted dihydropyridine ring. Two routes of the realization of this step, which limits the overall process yield, are described. Chlorobenzoic aldehyde (8) and 4-(2-RN-ethoxy) ethyl acetylacetate (5) are substrates in both routs. Nitrogen in the dihydropyridine ring originates either from methyl aminocrotonate (7) (route I) or from ammonium acetate (11) (by amination of 5) (route II). Amlodypine (1) is formed in the third step after deprotecting the amine group or introducing the amine group into the molecule. The formation of amlodypine benzenosulfonate (2) can follow or it can be combined with the third step.

There are two valid patents in Poland concerning the preparation of amlodypine benzenosulfonate (2) of Pfizer and of Lek Polska. A patent application of Adamed is under consideration of the Patent Office.


Wiadomości Chemiczne, 2002, 56, 469.
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Environmental estrogens are not a problem

Przemysław Mastalerz

50-525 Wrocław, ul. Gliniana 23/17


In ecological literature the term "environmental estrogens" refers to industrial compounds which contaminate the environment and have estrogen-like biological activity. In a strict sense the term should include also estrogens produced by plants (phytoestrogens) but these are scarcely mentioned by environmentalists who all their attention concentrate on man-made chemicals.

The first observation of hormonal activity of an industrial chemical dates back to 1950 when Burlingtion et al. reported that DDT affects the secondary sex characteristics of male birds [3]. Similar observations multiplied in later years but the observed effects were always weak or very weak and did not attract much interest. The situation changed when environmentalists became aware of the huge propaganda potential of estrogenic activity of pesticides such as DDT and begun using that activity as one of the tools helping their efforts to bring about a ban of man-made pesticidal compounds. In many ecological publications the hormonal activity of industrial compounds was suitably enlarged and horrifying scenarios were developed, some of them predicting even the end of mankind due to cancer and catastrophic reduction of fertility [4-7]. As usual, the mass media are happily helping to ring the alarm bells.

Fortunately there are several reasons to dismiss the environmental estrogens scare. First of all, plants such as rice, wheat, cabbage, potatoes and many other contain substantial amounts of compounds with estrogenic activity but are eaten daily without harm. And there are no scientific grounds to believe that industrial estrogens are more harmful than phytohormones.

Some specific and very recent developments in the field of environmental estrogens include the fertility of males, the alleged synergistic potentiation of weak estrogens and the problem of their cancerogenic activity. The problem of fertility emerged with a publication by Danish scientists [13] who claimed that the sperm counts in otherwise healthy men are very rapidly decreasing. For obvious reasons the problem received much attention and the Danish publication was followed by several papers on sperm counts, e. g. [14, 15]. However, no one was able to confirm the claims of Danish scientists.

The problem of synergism ended with a scandal. The paper claiming a thousandfold increase of estrogenic activity when mixtures are applied instead of single compounds [16] was retracted [21] and one of the authors admitted cheating (Science, 294, 763 (2001))

Finally, the accusation that DDE (one of the metabolites of DDT) is responsible for breast cancer in women [22] was convincingly disproved [23-25]. And so ended the environmental estrogens scare.


Wiadomości Chemiczne, 2002, 56, 483.
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INDUCTIVELY COUPLED PLASMA AS A SOURCE OF EXCITATION AND IONIZATION FOR MODERN ANALYTICAL TECHNIQUES

Elżbieta Skrzydlewska 1, Maria Balcerzak 1, Piotr Pasławski 2

1 Katedra Chemii Analitycznej, Wydział Chemiczny, Politechnika Warszawska ul. Noakowskiego 3, 00-664 Warszawa
2 Centralne Laboratorium Chemiczne, Państwowy Instytut Geologiczny ul. Rakowiecka 4, 00-975 Warszawa


Plasma spectrometric techniques: inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS) are rapidly becoming the most important analytical tools for the determination of trace amounts of elements. High speed, excellent detection limits, wide dynamic range and possibility of accurate multi-element analysis make the techniques particularly suited to the determination of ppb and sub-ppb levels of the analytes in complex matrices. Mass spectrometric methods offer unique capability of rapid isotopic ratios measurements.

Plasma techniques have found wide applications in analysis of geological, environmental and clinical samples. They have proved to be very useful in speciation studies due to extremely low sensitivities offered and the ease of on-line combination with separation techniques, in particular with chromatography.

A brief review of ICP-AES and ICP-MS techniques is presented in the paper. The possibility and limitations of the techniques as analytical tools are discussed. The most important analytical parameters are collected in Table 1. Detailed characteristics of equipment used (Figs 2, 5): sample introduction systems, analyzers (Figs 4a, b and Figs 7-9) and detectors [18, 30, 43] are given. The discussion of experimental parameters, including the choice of analytical wavelengths (ICP-AES) and isotopes (ICP-MS), is presented. The main physical, matrix, chemical and spectral interferences occurring in analysis of real samples are characterized.


Wiadomości Chemiczne, 2002, 56, 495.
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Notatki chaotyczne. XL. CZYTAJĄC FAUSTA

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2002, 56, 523.
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SYNTHESES OF NATURAL AND MODIFIED ANTHRACYCLINE ANTIBIOTICS FROM A COMMON PRECURSOR: 3,4-DI-O-ACETYL-L-RHAMNAL

G. Grynkiewicz1, O. Achmatowicz1, I. Fokt2, W. Priebe2, J. Ramza1, B. Szechner1, W. Szeja3

1Instytut Farmaceutyczny, Warszawa
2M.D. Anderson Cancer Center, Houston, TX, USA
3Wydział Chemiczny Politechniki Śląskiej, Gliwice


While natural anthracycline antibiotics retain their position of clinically important antitumor drugs despite of serious side effects, much effort is directed towards their improvement by rational structural changes.

Most of useful anthracycline antibiotics chemistry is done by dissconnection - modification approach, folloved by de novo glycosidic bond assembly. It is pointed out that 1,2- and 2,3-unasturated pyranosides constitute an important class of intermediates, useful for synthesis of natural and modified antibiotic aminosugars. Glycals derived from 3-amino-2,3,6-trideoxypyranoses and their 1-O-silylated derivatives are useful glycosyl donors for a variety of alcohols. Also anthracycline antibiotics can be obtained from them in simple preparative procedures which are amenable for scale up and technical process development. Moreover, unsaturated pyranoses from 6-deoxy-L- configurational series are useful chiral precursors for anthracycline aglycons synthesis. Remarkably, various synthetic schemes comprising anthracycline antibiotic sugars, aglycons and new synthetic analogues can be traced down to the single common precursor: 3,4-di-O-acetyl-L-rhamnal (24), easily obtained from a commodity chemical (raw material in food industry) L-rhamnose.


Wiadomości Chemiczne, 2002, 56, 535.
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SYNTHESIS OF POLYHYDROXYINDOLIZIDINES FROM a,b-UNSATURATED d-LACTONES

Joanna Rabiczko, Dariusz Socha, Margarita Jurczak, Marek Chmielewski

Instytut Chemii Organicznej Polskiej Akademii Nauk, ul. M. Kasprzaka 44/52, 01-224 Warszawa


The isolation, synthesis and biological properties of polyhydroxylated alkaloids (iminosugars) constitute a well-visible trend in organic chemistry nowadays. Due to their structural resemblance to sugars, iminosugars are recognized by glycosidases, the enzymes that catalyse the hydrolysis of glycosidic bonds in carbohydrates and glycoconjugates. Since glycosidases play a very important role in many biological systems, the iminosugars which inhibit them display interesting biological activities.

Indolizidines represented by castanospermine, swainsonine and lentiginosine are particularly interesting as they exhibit a variety of important biomedical properties.

The present paper is not a survey of the literature, but only deals with syntheses towards lentiginosine, with the aim of illustrating representative approaches in the syntheses of polyhydroxyindolizidines.

The high stereoselectivity of both the conjugate addition of hydrazine and the (1,3)-dipolar cycloaddition of nitrones to the a,b-unsaturated sugar d-lactones, prompted us to use the adducts of both reactions as substrates for the syntheses of polihydroxyindolizidines.

The conjugate addition offers a stereocontrolled entry to derivaties of both D- and L-2-pyrrolidineacetic acids which can be easily transformed into desired indolizidines. As an example, the syntheses of lentiginosine are demonstrated.

The (1,3)-dipolar cycloaddition of Brandi's nitrone to the title lactones proceeded with high stereoselectivity in the case of D- and L-glycero lactones, whereas there was a high kinetic resolution in the case of racemic D,L-glycero lactone. It was shown that adducts can be easily transformed into lentiginosine, 7-hydroxylentiginosine and 7,8-dihydroxylentiginosine.


Wiadomości Chemiczne, 2002, 56, 561.
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CHEMICAL STRUCTURE, ANTIGENIC SPECIFICITY AND THE ROLE IN THE PATHOGENICITY OF LIPOPOLYSACCHARIDE (LPS, ENDOTOXIN) ON PROTEUS VULGARIS BACTERIA'S EXAMPLE

1Antoni Różalski, 1Agnieszka Torzewska, 1Beata Bartodziejska, 1Dorota Babicka, 1Iwona Kwil, 2Andrei V. Perepelov, 2Anna N. Kondakova, 2Sof'ya N. Senchenkova, 2Yuriy A. Knirel, 3Evgeny V. Vinogradov


1Zakład Immunobiologii Bakterii, Instytut Mikrobiologii i Immunologii, Uniwersytet Łódzki, Banacha 12/16, 90-237 Łódź.
2ND. Zelinski Institute of Organic Chemistry, Russian Academy of Siences, Leninsky Prospect 47, Moscow 117913, Russia
3Institute of Biological Sciences, National Research Council, 100 Sussex Drive, Ottawa, Ont. Canada K1A 0R6


Gram-negative bacteria of the genus Proteus from the family Enterobacteriaceae are opportunistic pathogens, which cause mainly wounds and urinary tract infections (UTI), the latter leading to severe complications, such as acute or chronic pyelonephrithis and formation of bladder and kidney stones [6]. Virulence factors and properties of Proteus sp. mediating infectious process are swarming phenomenon, adherence due to the fimbriae or glycocalyx, flagella, invasiveness, urease, amino acids deaminases, proteases, hemolysins, capsular polysaccharide (CPS), and lipopolysaccharide (LPS) [8, 9]. LPS is an integral component of cell wall of bacteria. It also represents the endotoxin which, after being released from bacterial cells, causes a broad spectrum of pathological effects leading in severe cases to the septic shock. Lipopolysaccharide consists of three parts - O- specific chain (O-antigen), core and lipid A; all of them have been studied in Proteus LPS [14-16]. It has been documented that Proteus is an antigenically heterogeneous genus, principally because of structural differences in its O-specific polysaccharide chain of LPS. The serological classification of P. mirabilis and P. vulgaris shares 60 serogroups : 22 described for P. vulgaris, 33 characteristic for P. mirabilis and 5 common for both P. mirabilis and P. vulgaris [11, 20]. Serological classification of Proteus penneri still remains to be completed.

Proteus O-antigens are branched or linear polysaccharides, built up of oligosaccharide repeating units, varying from a trisaccharide to a hexasaccharide. Acidic O-specific polysaccharides represent the majority of Proteus O-antigens; it was found that 80% of Proteus O-antigens were acidic. Uronic acids and amino sugars usually determine the serological specificity of Proteus O-antigens. Amino sugars in Proteus O-antigens are usually N-acetylated. In many O-antigens, sugars constituents carry an O-acetyl groups. Hexuronic acids either have free carboxyl group or are amidated with the a-amino group of amino acids - lysine, serine, alanine or threonine [23]. Chemical and serological studies have been undertaken with the aim to understand on the molecular level the immunospecificity of Proteus LPS and its potential role during infection of bacteria. The O-antigens and O-antisera against Proteus with defined epitope specificity can be used for serodiagnosis and epidemiological studies. It was found that O-specific polysaccharide Proteus bacteria is involved in creation of glycocalyx which allows bacteria to grow in microcolony or in biofilm. Biofilm protects bacteria against action of antimicrobial agents and leukocytes, and it is also a organic gel-like surrounding contributing to stone formation. LPS from the S form of bacteria, containing all three regions also contributes to their resistance against bactericidal action of serum [10, 23]. The present review is mainly focused on the structure, specificity and biological function of Proteus vulgaris LPS.


Wiadomości Chemiczne, 2002, 56, 585.
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DERIVATIVES OF 1-THIOSUGARS AS SUBSTRATES IN GLYCOSYLATION REACTIONS

Wiesław Szeja, Joanna Bugla, Aleksandra Niemiec, Gabriela Pastuch, Anna Kasprzycka, Anna Ślusarczyk, Ilona Wandzik, Tadeusz Bieg, Bogdan Przybysz, Jadwiga Bogusiak1

Wydział Chemiczny, Politechnika Śląska, ul. B. Krzywoustego 8, 44-100 Gliwice
1Wydział Farmacji, Śląska Akademia Medyczna, ul. Jagiellońska 4, 41-200 Sosnowiec


It was found that carbohydrate part of complex glycosides may act as antigens or receptors for proteins, and these findings led to the discovery of the important role of carbohydrates in cell-cell recognition phenomena and cell differentiation.

At the same time the methods of glycosylation underwent rapid development. The present paper gives an overview of development of 1-thiosugar derivatives in oligosaccharide synthesis.

In the first part of this review, recent results of the use of thioglycosides, dithiocarbonates, dithiocarbamates and thiophosphates as glycosyl donors and acceptors are presented. A survey of important methods for the synthesis of thiosugars is presented, followed by discussion of methods converting anomeric substituent into a good leaving group (activation) in nucleophilic substitution reaction. The mechanism and procedures, which provide stereoselective formation of 1,2-cis and 1,2-trans glycoside bond, are discussed. The versatility of 1-thiosugar derivatives in synthetic carbohydrate chemistry is illustrated by selective activation strategies.

The most important synthetic methodologies of the synthesis of oligosaccharides like linear glycosylation strategy in step-by-step and multistep "one-pot" sequence, "armed-disarmed" glycosyl donor, "latent-active" glycosylation, orthogonal strategy are illustrated on several examples.

The last part is devoted to methods for solid support oligosaccharide synthesis.


Wiadomości Chemiczne, 2002, 56, 605.
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PALLADIUM-CATALYZED SYNTHESIS OF GLYCOSIDES AND DISACCHARIDES

Bogusław Kryczka, Stanisław Porwański

Zakład Związków Heteroorganicznych Uniwersytetu Łódzkiego, ul. Narutowicza 68, 90-136 Łódź


Carbohydrates are found in nature in variety of forms, in chemical association with a vast number of compounds, including other sugars, and in materials which perform a range of functions varying from structural to specifically functional in many biochemical ways [1]. The attachment of monosaccharide units to other molecules proceeds usually through the anomeric centre by O-, N-, S- or C-glycosidic bond.

Most synthetically useful glycosylation reaction is nucleophilic displacement at the anomeric centre. It occurs through glycosyl cations, usually from activated leaving groups in suitable glycosyl derivatives, most frequently halides [8] and imidate esters [9].

There are so many variables involved in glycoside and disaccharide synthesis that each target compound requires a particular strategy. That is why so many procedures have been developed to provide the regio- and stereocontrol in the glycosylation step [1]. However, these methodes have been known for many years-and still modified-the selective synthesis of glycosides still determines the main challenge in the chemistry of carbohydrates.

The aim of this paper is to present the role of palladium-catalyzed methodology in glycosylation reactions.

The Heck reaction has been applied first by Daves [24] and Czernecki [25-27] to C-glycosidic synthesis (scheme 1).

Reaction of glycals with various reagents offering nucleophilic carbon centres in the presence palladium-catalyst, affords important means of acces to 2,3-unsaturated C-glycosides (scheme 4) [38-41]. The popularity of this methodology started to flourish when it was found that it was able to control the selectivity by using certain reaction procedures to give fairly predictible results [113].

Allylic carbonates are well-known compounds that undergo a variety of palladium-catalyzed reactions [11, 49]. This methodology [65, 66] has been applied to synthesis of many alkenyl glycosides [77, 78, 80], (schemes 11-13). The reaction proceeds under neutral and very mild conditions and usually gives only one anomer.

The same methodology was extended to the preparation of C-, N-, and S-glycosides as well as unsaturated di- and trisaccharides (Scheme 31), [86, 93]. These products are obtained in good yields by alkylation of ethyl a-O-D2-glycosides, having a leaving group at C-4, with C-, N-, S-nucleophiles, with various carbohydrates or with thiocarbohydrates.

The reaction is regio- and stereoselective for the a-erytro enoside, and only stereoselective for a-threo enoside.


Wiadomości Chemiczne, 2002, 56, 627.
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APPLICATION OF SUGAR ALLYLTINS IN THE SYNTHESIS OF CARBOBICYCLIC DERIVATIVES

Sławomir Jarosz, Stanisław Skóra, Katarzyna Szewczyk

Instytut Chemii Organicznej, PAN, ul. Kasprzaka 44/52, 01-224 Warszawa


Sugar allylic alcohols of the general formula Sug-CH=CH-CH2OH are easily converted into the allyltin derivatives Sug-CH=CH-CH2SnBu3 (7) by conversion into xanthate followed by its thermal rearrangement and subsequent SR2' reaction of resulting thiocarbonate with tri-n-butyltin hydride. Allyltin derivatives 7 undergo a controlled rearrangement with zinc chloride to dienoaldehydes CH2=CH-CH=CH-CH(OR)3CHO with the trans geometry across the internal double bond (3-E). Dienoaldehydes 3-E react with the C2-Wittig-type reagents [phosphoranes: Ph3P=CH-COR or phosphonates: (MeO)2P(O)CH2COR] to afford trienes 18 [CH2=CH-CH=CH-CH(OR)3CH=CH-C(O)-R), which undergo the intramolecular Diels-Alder reaction to give optically pure highly oxygenated bicyclo[4.3.0]indene derivatives 5 with the trans junction between the five and six-membered rings.

Alternatively, the dienoaldehyde 3-E can be converted into - regioisomeric to 18 - triene 24 [CH2=CH-CH=CH-CH(OR)3C(O)-CH=CH-R], cyclization of which furnish optically pure bicyclo[4.4.0]decane derivatives 4 with the cis junction between both six-membered rings. On the other hand, sugar allylic bromides react with with tri-n-butyltin cuprate to afford a mixture of the primary and secondary allyltin derivatives [Sug-CH=CH-CH2SnBu3 (7) and [Sug-CH(SnBu3)-CH=CH2] (15) respectively]. Both isomers 7 and 15 might be converted into the trans dienoaldehyde 3-E by action of ZnCl2. However, thermal behavior of these regioisomers is different. The primary derivative 7 is stable up to at least 170 °C, while the secondary one (15) undergoes elimination of the tributylstannyl moiety already at 140 °C (boiling xylene) to afford dienoaldehyde with the cis-geometry across the internal double bond (3-Z). Such aldehyde was used for the preparation of - isomeric to 5 - derivative of bicyclo[4.3.0]indene with the cis-configuration between both rings (23).

The stereochemistry of all these cyclizations might be rationalized assuming the endo-transition states of the intramolecular Diels-Alder reactions. Mechanism of the rearrangement of sugar allyltin derivatives 7 and 15 to unsaturated aldehydes 3-E and 3-Z is discussed.


Wiadomości Chemiczne, 2002, 56, 661.
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ON THE N-GLYCOPYRANOSYLAMMONIUM SALTS

Barbara Dmochowska, Eugenia Skorupowa, Andrzej Wiśniewski

Wydział Chemii, Uniwersytet Gdański ul. J. Sobieskiego 18, 80-952 Gdańsk


Wiadomości Chemiczne, 2002, 56, 679.
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Notatki chaotyczne. XLI. W STRONĘ GASTRONOMII MOLEKULARNEJ

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2002, 56, 691.
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GREEN CHEMISTRY: PRINCIPLES, AIMS , AND SELECTED ACHIEVEMENTS

Bogdan Burczyk

Instytut Technologii Organicznej i Tworzyw Sztucznych Politechniki Wrocławskiej, Wybrzeże S.Wyspiańskiego 27, 50-370 Wrocław


Green chemistry is the design, development, and implementation of chemical processes or products to reduce or eliminate the use and generation of substances hazardous to human health and the environment [6]. Its aim is to combine technological and economic progress with the safeguarding of the environment, which is one of the challenges of the new millennium [2]. To help to achieve this goal, a set of twelve principles of green chemistry was formulated by Anastas and Warner [7]. These principles apply to a whole chemical process and to its main stages, which are: starting materials (or feedstock), reaction types and reagents, solvents and reaction conditions, and chemical products [7].

This review only covers some of the important efforts and achievements of green chemistry. In Section 3.1 some saccharide- based syntheses are presented. Both simple sugars (glucose, lactose) [17,18,21,24] (Schemata 2,3), and polymeric saccharides [29] (Scheme 4), as well as biomass [36,37] (Schemata 5,6) have been successfully transformed into valuable chemicals. In Section 3.2, new reaction types fulfilling the atom economy principle formulated by Trost [46] are described. The focus is on new oxidation reactions of olefins using clean oxidants: hydrogen peroxide and non-toxic, water-soluble iron catalysts [55,57,60] (Schemata 9-12, Fig.3), and oxygen [70,72,73] (Schemata 14-17). New possibilities of replacing toxic hydrogen cyanide [75,76] and phosgene [77,78,84] with safer reagents (e.g., dimethyl carbonate) were another topic of this Section. Section 3.3 deals with new reaction media. Water emerged as a non-toxic, environmentally benign and cheap solvent for many organic reactions, as it has several advantages: water soluble substrates (e.g., carbohydrates) can be used directly, the aqueous catalyst solution can be recycled easily, and no inert gas atmosphere is needed [94,97-101]. The discovery of water soluble transition metal complexes made it possible to use aqueous/organic biphasic systems which have benefits in catalyst separation and recycling. Such a system has been used, for instance, in the industrial propylene hydroformylation process [120,121,123] (Scheme 29). Many other reactions performed in biphasic systems were reported (Table 2). Water soluble rare earth trifluoromethane sulfonates have been shown to be strong Lewis acids [135,137,138].

Supercritical fluids have been used as new reaction media; they posses a unique combination of gas- and liquid- like properties. Supercritical carbon dioxide (scCO2) and supercritical water (scH2O) were mostly exploited. New polymerization processes in scCO2 were proposed [158,159] (Scheme 32) and new surfactants for scCO2 were discovered [158,159,161-165] (Fig. 4). Promising possibilities of performing oxidation reactions in scH2O were reported, as many organic compounds and oxygen are soluble in scH2O [178,179,183]. Ionic liquids, which are characterized by a lack of measurable vapour pressure, constitute another group of neoteric solvents (Fig. 5). They can serve both as powerful solvents (e.g., in extraction processes) and as reaction media with catalytic properties [185 - 189].

The last Section (3.4) deals with chemical products safe for humans and for the environment. The focus is on polymers, pesticides and surfactants that are produced in a large volume. New “metallocene polyolefins” [196-201] and water soluble, biodegradable polymers [202-204] seem to fulfil this requirement. Selective pesticides, non-toxic to mammals, birds, and beneficial insects have been implemented, among them biopesticides [208-210] (Table 3). Biodegradable “sugar surfactants” [214-217] and chemodegradable, acetal-type surfactants (Figs. 6,7) have been synthesized and some of them are already industrially produced [11,219,222-228].

The review ends with some remarks on the perspectives of green chemistry in the near future (Section 4). In this context, the need for far-reaching educational initiative to promote the scientific principles of green chemistry, which were developed and implemented to the benefit of society, is stressed [2, 243, 244].


Wiadomości Chemiczne, 2002, 56, 709.
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CHEMISTRY OF THE NOBLE GASES

Krzysztof Łyczko

Zakład Radiochemii, Instytut Chemii i Techniki Jądrowej, ul. Dorodna 16, 03-195 Warszawa


This paper summarizes the present state of knowledge of the chemistry of the noble gases. The methods used for preparation fluorides and other halides of the noble gases and their chemical reactivity are presented. The synthesis and properties of compounds containing Xe-O, Kr-O, Rn-O, Xe-N, Kr-N, Xe-C, Xe-Si, Xe-B and Xe-Cl bonds are described. This review paper also reports on exotic molecules HXY (X = Xe or Kr, and Y is a fragment of a molecule with a large electron affinity, i.e. halide or pseudohalide), which have recently been obtained in solid xenon or krypton matrices. Short-living metal carbonyl complexes containing Xe, Kr or Ar atoms and a compound with Au-Xe bonds are described.

Information on the chemistry of elements 112 and 118, thought to be similar to the noble gases, is presented.


Wiadomości Chemiczne, 2002, 56, 771.
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A NEVER ENDING STORY OF VITAMIN D

Wojciech Kroszczyński1, Bożena Morzycka2, Jacek W. Morzycki3

1Instytut Chemii, Akademia Podlaska, ul. 3 Maja 54, 08-110 Siedlce
2Instytut Ochrony Roślin w Poznaniu, Stacja Doświadczalna w Białymstoku,
ul. Chełmońskiego 22, 15-195 Białystok,
3Instytut Chemii, Uniwersytet w Białymstoku, al. Piłsudskiego 11/4, 15-443 Białystok


The existence of vitamin D was discovered as a consequence of human disease. Vitamin D deficiency in childhood produces rickets, which is characterized by inadequate calcification of cartilage and bone. In rickets, the whole bony structure is soft and flexible, so that can hardly support the superposed weight of the body. Rickets was common in the 19th century, when the industrial revolution caused change of an agrarian society to an industrial society. The population in large measure spent much more time inside buildings, which shielded them from ultraviolet light. It was proved that sun light and cod liver oil are equally active in preventing and curing rickets. Further studies led to the discovery of an anti-rachitic vitamin D. A deficiency in vitamin D impairs bone formation in growing animals. The precursor of cholecalciferol (vitamin D3) is 7-dehydrocholesterol (provitamin D3) present in the skin. Irradiation of this compound results in the formation of previtamin D3, which spontaneously isomerizes to vitamin D3 (thermal rearrangement). Vitamin D3 is further converted by enzymatic hydroxylation reactions occurring in the liver and kidneys into an active hormone, which was isolated and identified as 1a,25-dihydroxyvitamin D3. Other biologically active metabolites and analogues of vitamin D were also described. The vitamin D endocrine system was primarily recognized for its critical role in calcium and phosphorus homeostasis. The active form of the vitamin, 1a,25-(OH) 2D3, acts on the intestine, bone, and kidney to increase serum levels of these two elements. Receptors for 1a,25-(OH) 2D3 have also been detected in a wide variety of target tissues and cell types, which are not involved in the calcemic activity. The non-classical actions of 1a,25-(OH) 2D3 have suggested a multitude of potential therapeutic applications of the vitamin D hormone for the treatment of hyperproliferative disorders (e.g. cancer and psoriasis), immune dysfunction and endocrine disorders. A number of new drugs based on the vitamin D analogues has been recently introduced to the pharmaceutical market.

The story of vitamin D is not finished yet.


Wiadomości Chemiczne, 2002, 56, 793.
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POLYMERIC PEROXIDES - SYNTHESIS, PROPERTIES AND APPLICATIONS

Jan Zawadiak, Mirosław Danch

Instytut Chemii i Technologii Organicznej Politechniki Śląskiej w Gliwicach ul. Krzywoustego 4, 44-100 Gliwice


Polymeric peroxides constitute narrow but important class of peroxy compounds. They can be used as free radical source in many radical processes (i.e. polymerisation, oxidation etc) [3-6] as well as selfcombusting fuels [7,19].

To this group belong both poly (alkyl peroxides) [13-43], polyperesters [5,47-50] and poly (acyl peroxides) [6,44-46]. The special kinds of polyperoxides are those having two (or more) peroxy groups of different thermal stability [51-56]. These peroxides are used as precursors for free radical syntheses of block- and graft- copolymers.

Among polyalkyl peroxides vinyl polyperoxides (alternate copolymers of vinyl monomers and oxygen) play a dominant role [32]. However, due to their explosive properties, these peroxides could be hazardous if they form spontaneously [25].

The survey of the preparation methods, and possibility of applications of the above-mentioned polymeric peroxides is presented.


Wiadomości Chemiczne, 2002, 56, 811.
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[2+3] CYCLOADDITION REACTIONS OF CONJUGATED NITROALKENES TO NITRONES

Andrzej Barański, Radomir Jasiński

Wydział Inżynierii i Technologii Chemicznej Politechniki Krakowskiej, ul. Warszawska 24, 31-155 Kraków


The work is an attempt of systematizing of the literature data concerning the regio- and stereoselectivity of [2+3] cycloadditions of conjugated nitroalkenes to nitrones.

In most cases these reactions are regiospecyfic leading to the corresponding 4-nitro-isoxasolidines. In the reactions with trans-b-arylnitroethylenes, trans-configuration of the substituents at C-3 and C-4 positions of the heterocyclic ring is always favored. However, in the case of trans-b-alkylnitroethylenes, usually the 3,4-cis-isomers are formed in majority. If steric effects do not affect significantly the reaction course, the observed regioselectivity can be well explained in the terms of FMO or HSBA theory. The reaction stereoselectivity is hard to predict in advance. It seems that it depends on the equilibrium between the two complementary interactions in the reaction transition state: the attractive secondary overlaps of the reactants pz-orbitals, and the repulsive steric interactions of the reactants substituents. In some cases, the possibility of (Z)-(E) isomerisation of nitrones under reaction conditions has to be taken into account (Scheme 2).

Chemical properties of the cycloadducts resulting from the presence of nitro group in the isoxazolidine ring have also been discussed.


Wiadomości Chemiczne, 2002, 56, 829.
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SEPARATION AND DETERMINATION OF Cr(III) AND Cr(VI) IN ENVIRONMENTAL SAMPLES

Jan Kalembkiewicz, Eleonora Sočo

Katedra Chemii Nieorganicznej i Analitycznej, Wydział Chemiczny, Politechnika Rzeszowska, al. Powstańców Warszawy 6, 35-959 Rzeszów


Learning the biochemical properties of Cr(III) and Cr(VI), especially mutagenic activity of Cr(VI) caused quick development of investigation of Cr speciation in environmental samples. Complex composition of matrix, possible course of the redox reaction of Cr and its low concentration often make difficult application of direct methods of determination of Cr(III) and Cr(VI). The investigation of speciation of Cr by preliminary separation of Cr(III) and Cr(VI) and their preconcentration eliminates a series of analytical problems and creates a possibility of Cr detection with various techniques, also in coupled systems.

The Cr(III) and Cr(VI) in systems HPLC-ICP-AES [7-10], HPLC-ICP-MS [7-9, 11-16], HPLC-AAS [15-18], HPLC-FI-AAS [19-26], HPLC-UV [15, 27-32] were separated, preconcetrated and determined. Independently from HPLC [7-34] also other chromatographic techniques were used [35-38]. Ion-exchange was applied mainly to separation of Cr(III) and Cr(VI) [39-42, 45-48, 51], as well as to separation of Cr(VI) [36,53-57] or Cr(III) [58] from other ions. To separation of Cr(III) and Cr(VI) there were applied: sorption [62-70], biopolymer coating [72] and bioaccumulation [71]. Separation and preconcentration of Cr(III) and Cr(VI) is possible by applying solvent extraction. To extraction of Cr(III) and Cr(VI) and their separation were applied amines [28, 73-76, 98, 108, 110], ammonium salts [77, 104] and non-ammonium salts [83, 84], amine oxides [58, 78-82, 106], carboxylic and hydroxycarboxylic acids [99-101] and other reagents [58, 85-90, 102, 103, 105, 107]. To separation and preconcentration of Cr(III) and Cr(VI) there are proposed ion-exchange membrane [111-115], electrophoresis [36, 116-118], precipitation and co-precipitation [36, 58, 119-123] and other methods of separation [58, 120, 124, 125].

Determination of Cr(III) and Cr(VI) without preliminary separation is possible in environmental samples, in which at the stage of preparing to analysis or during analysis the redox reactions with participation of Cr do not proceed. For direct determination of Cr(VI) spectrophotometric method (UV) is applied with the use of 1,5-diphenylcarbazide [120, 126-150], methylene blue [151], iodonitrotetrazolium chloride [152,153], tetrazolium violet [153], 5-Br-PADAP [154], dibenzyl-dithiocarbamate [155], rhodamine 6G [156, 157], nitrotetrazolium blue [158] and neotetrazolium chloride [159], whereas for determination of Cr(III) there were applied: EDTA [160-162], triphenylmethane reagents [163-168], PAR [169-172] and PAN [173]. For direct determination of Cr(VI) or Cr(III) polarography [174, 175] and others methods [66, 122, 176-180] were applied.


Wiadomości Chemiczne, 2002, 56, 855.
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Notatki chaotyczne. XLII. PORTRET LITERACKI JÓZEFA JERZEGO BOGUSŁAWSKIEGO

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2002, 56, 877.
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SONOELECTROCHEMISTRY. THE INFLUECE OF ULTRASOUND ON ELECTRODE PROCESSES AND ITS APPLICATION IN ELECTROCHEMISTRY.

Krzysztof Winkler, Monika Wysocka

Instytut Chemii, Uniwersytet w Bialymstoku, Pilsudskiego 11/4, 15-443 Bialystok


Sonoelectrochemistry is the field of the research dealing with the influence of power ultrasound on electrochemical processes. The dominant effect of the ultrasound in electrochemical systems is the enhancement of mass transport by macrostreaming due to the propagation of an acoustic wave and microstreaming related to the acoustic cavitation phenomena and microjetts formation on the electrode surface. These effects are responsible for large enhancement of the current and significant modification of voltammograms recorded at stationary electrodes. In the presence of power ultrasounds voltammograms show steady-state sigmoidal shape with an oscillatory behavior. A simple planar diffusion layer model may be employed to analyze the current data.

Ultrasound can also influence physical and chemical properties of electrode surface. Cavitation induced by ultrasound as well as shear forces can cause cleaning of the electrode surface and prevent adsorption and precipitation processes. Sonication can activate the electrode surface, too. High power ultrasound can also change the morphology of the electrode surface.

Ultrasounds are succesfuly applied to a wide range of electrochemical technologies. There are frequently used in electrometalurgy for metal coating, electropolishing, electromachining, and electrochemical etching. The use of ultrasound allow eleiminate highly toxic compounds from the electroplating procedures.

Ultrasound can significantly improve electrochemical synthesis processes. These improvements include enhancment diffusion and trerefore increase of yields and current efficiency, suppresed electrode fouling and alteration of reaction mechanism, and product selectivity control. Polymer films formed at the electrode surface in sonicated solution show better morrphology and mechanic properties.

High rate of mass transfer under sonoelectrochemical conditions allows kinetic study of fast heterogeneous charge transfer processes and chemical steps coupled with rlectron transfer reaction.

The application of ultrasound to analytical procedure can provide numerous benefits of which enhanced mass transport and in situ cleaning of the electrode are the most important. Sonoelectrochemistry analytical methods exhibit high sensitivity and good reproducibility. There are also less time consuming procedures comparison to conventional electroanalytical methods prformed under silent conditions.

Ultrasound allows the formation of emmulsions in heterogeneous systems of immiscible organic and aqueous solvents without stabilizing agents simply by mechanical forces atributed to cavitation processes which arise at the liquid/liquid phase boundaries. Sonoelectrochemical is also used in nanotechnology for formation of nano-size metalic and non-metalic particles. The electrochemical study of electrode reactions of organic reagents in polar water solution can be carried out in these systems. Emulsions stabilized by ultrasound can be also used in quantitative analysis of water insoluble samples.


Wiadomości Chemiczne, 2002, 56, 895.
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MINIATURIZATION IN HIGH PERFORMANCE CAPILLARY ELECTROPHORESIS

Angelika Mrass, Edward Bald

Zakład Chemii Środowiska, Katedra Technologii Chemicznej i Ochrony Środowiska, Uniwersytet Łódzki, ul. Pomorska 163, 90 - 236 Łódź


During the last decade high performance capillary electrophoresis (HPCE) has developed into a powerful analytical method [1-4]. Despite the overwhelming advantages of this technique, it has not yet found widespread use in molecular biology labs in comparison with the slab gel electrophoresis [39]. The main reason for the low acceptance of this method is performing separation in a single capillary which is analogous to using only one lane on a slab gel; despite the high speed of the separation, the overall throughput is still low.

To comply with the current needs for fast and high throughput analysis, especially in the field of DNA sequencing, two approaches have been introduced: a multicapillary scheme called capillary array electrophoresis [6-17,40-59] and a multichannel system etched into the surface of microchips [5,18-38,60-99].

Capillary array electrophoresis (CAE) was first introduced in 1992 [9]. The search for a comprehensive instrument was achieved by several groups seeking an instrument capable of fast, automated, sensitive and most important of all, rugged operation [10-13]. In CAE electrokinetic injection is the most popular method for sample loading [47,48]. However adopting this mode of injection for DNA sequencing requires a thorough sample clean-up [42-45]. To inject unpurified samples a so-called ‘base-stacking’ method has been described [46]. One of the major problem in CAE is detection as it has to meet plenty of demands, among which the most important are: high speed, high sensitivity and high spatial resolution. Numerous approaches have been developed to address these challenges using either scanning [53,54] or imaging technologies [12,13,55-59].

Capillary electrophoresis (CE) on microchips is based upon microfabrication techniques developed in the semiconductor industry [65-69]. The design of microchips for CE has undergone significant development from simple single-channel structures to increasingly complex ones capable of proceeding various analytical steps [70-85]. Sensitive detection schemes are essential in microfabriacted devices in CE due to extremely small size of the detection cell. Laser induced fluorescence (LIF) is so far the most popular for this purpose [86-89]. Other methods successfully coupled to microchips include mass spectrometry [92-95], electrochemical detection [96,97], Raman spectroscopy [98] and holographic refractive index detection [99].


Wiadomości Chemiczne, 2002, 56, 931.
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SILYLENE TRANSITION METAL COMPLEXES

Hieronim Maciejewski

Zakład Chemii Metaloorganicznej, Wydział Chemii, Uniwersytet im. Adama Mickiewicza, 60-780 Poznań


Major advance in organometallic chemistry in the last 15 years has been achieved in the area of silicometallics chemistry, based on silicon to metal multiple bonding and silicon with low coordination numbers. Research in this area has led to a discovery of fundamentally new classes of compounds, such as silylene, silene, silaimine, disilene or silacarbyne complexes. Many of these systems had been unknown prior to their synthesis, even as reactive intermediates.

This paper provides a comprehensive review of the silylene transition metal complexes. The majority of metal - silylene complexes synthesised so far have required donor stabilisation via the addition of a Lewis base. The use of thermally stable bis(amino)silylenes as ligands has led to a synthesis of base-free, stable silylene metal complexes. The chemistry of these compounds is discussed under headings: types of silylene complexes, methods of their synthesis, structure and properties of TM silylene complexes and also their application to catalysis.

Despite the fact that the stable silylene transition metal complexes have been known for less than a decade, the chemistry of these compounds has been comprehensively recognised.


Wiadomości Chemiczne, 2002, 56, 953.
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BETULINIC ALCOHOL AND ITS DERIVATIVES

Anna Tomaszkiewicz-Potępa, Magdalena Piękoś,

Zakład Technologii Organicznej, Wydział Inżynierii i Technologii Chemicznej Politechniki Krakowskiej, ul. Warszawska 24, 31-155 Kraków,


Betulinic alkohol (lup-20(29)-en-3,28-diol) is a naturally occuring triterpene compound forming the principal extractive substance of the birch bark. The content of betulinol in the outer bark varies between 10-30% depending on the growth condition, age, season etc [1-12].

Chemically, betulinol is a pentacyclic triterpene alcohol belonging to a lupane series of compouds. The characteristic feature of the lupane group is the five membered ring E and a-isopropyl group at C-19 [7-18].

Suberin and triterpenoids, the two major component groups in the outer bark of birch, have been investigated by many workers. Analytical procedures, starting with sample extraction and hydrolysis with ethanolic alkali, were developed for routine analysis, which triterpenoids to be identified by the chromatographic and spectroscopic methods. [19-25].

The functional groups in the betulinol molecule comprise primary and secondary hydroxyl groups and a double bond. Typical reactions are given in.Fig.3.

Methods of synthesis and use of the chemical modification of betulinol has been investigated by many workers. The most investigated products from betulinol now are betulinic acid and his derivatives. It was isolated for the first time from many of plants [23-44].

Betulin was convert to betulinic acid using two different synthetic routes. The first approach involved an oxidation of betulin using Jones reagent to betulonic acid and subsequent NaBH4 reduction to betulinic acid. The second approach involved steps utilizing different protecting groups on the alcohol functional groups of betulin and Jones’ oxidation to circumvent the isomerization of the secondary alcohol of betulinic acid [45,46].

Betulinic acid was identified as a highly selective inhibitor of human melanoma. It has recently been reported to possess antitumor activity against cultured human melanoma cells [46]. Betulinic acid has been modified at C-3, C-20 and C-28 positions[20].

A series of w-undecanoic amides of betulinic acid derivatives were synthesized and evaluated for activity in human immunodeficiency virus type 1 (HIV-1) [56].

A novel series of w - aminoalkanoic acid derivatives of betulinic acid were synthesized and evaluated for their activity against human immunodeficiency virus (HIV) [57]. Effect of betulinic acid and radiotherapy on survival was demonstrated by autors [58].


Wiadomości Chemiczne, 2002, 56, 983.
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RADON IN THE ENVIRONMENT OF GROUNDWATERS AND UPPER PART OF LITOSPHERE

Tadeusz Andrzej Przylibski

Zakład Geologii i Wód Mineralnych, Wydział Górniczy, Politechnika Wrocławska, Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław


The article outlines the geochemistry of the only radioactive noble gas, with a special focus on the environments with its highest concentrations - upper lithosphere and groundwaters. The text is based on a review of several hundred works written in the last few decades and on the author’s own research. Special emphasis has been put on the genesis of radon and its migration in these environments, with the dominant role of physical processes, in contrast to almost complete chemical passivity of this element. Another discussed issue is the special significance of the physico-chemical properties of the medium and the centre for radon migration process. What has been also stressed is the significance of the amount and the mode in which radium parent isotopes occur in the environment for the genesis of radon, as well as the importance of half-life, especially that of 222Rn nuclide, for the possibility of its long-distance migration.

The description of radon geochemistry provided a basis for the presentation of the most important and the commonest applications of this element as a natural tracer of processes occurring in the lithosphere, hydrosphere and on the borders of these geospheres. Currently conducted research, aimed at getting more profound knowledge of radon geochemistry, will enable its far better and commoner application as a natural radioactive tracer of many processes occurring in the environment. It will also provide a basis for much more effective radiological protection, related to the most important property of this ubiquitous gas - its radioactivity, as well as enable more effective employment of its medicinal (though still disputed) effect on the human organism.


Wiadomości Chemiczne, 2002, 56, 1003.
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RAPID AND ECONOMICAL METHODS OF EXTRACTION OF PESTICIDES IN FOOD

Alfred Błaszczyk, Jan Jasiczak

Wydział Towaroznawstwa, Akademia Ekonomiczna w Poznaniu, Aleja Niepodległości 10, 60-967 Poznań,
e-mail: fredb@main.amu.edu.pl
jasiczak@po.onet.pl


Food analysis is very important for the evaluation of the nutritional value and quality of fresh and processed products, and for monitoring food additives and other toxic contaminations.

Sample preparation such as extraction, concentration and isolation of analytes, greatly influences the reliable and accurate analysis of food. Currently there are some techniques of sample preparation such as SPE, SPME, MSPD, SFE, which have the following characteristic features:

Solid-phase extraction (SPE) is a rapid and sensitive sample preparation technique, whose use has considerably increased within the last decade. This emerging technology has successfully replaced many tedious conventional methods of isolation and extraction of various chemicals in food (for example pesticide residues, tab. 1). Sample preparation and concentration via SPE can be achieved in a one-step extraction, and the methodology is appropriate for isolating trace amounts of chemical compounds from complex matrices such as food.

Solid-phase microextraction (SPME) is a new sample preparation technique using a fused-silica fibre that is coated on the outside with an appropriate stationary phase [30,31]. This technique has been successfully applied in the analysis of pesticides in food (tab. 2).

Supercritical fluid extraction (SFE) is sample preparation technique, which does not use organic solvents for trapping and for washing out of analytes. SFE usually with carbon dioxide and often with a modifier, is a rapid, selective and convenient method for sample clean-up in environmental analysis. In the past decade, SFE has been applied successfully to the extraction of a variety of organic compounds, e.g. pesticides from herbs [66], food [27] and agricultural samples [1]. Three inter-related factors influence analyte recovery in SFE: solubility in the fluid, diffusion through the matrix and adsorption in the matrix.

Matrix solid-phase dispersion (MSPD), a patented process for the simultaneous disruption and extraction of solid and semi-solid samples, was first reported in 1989 [72]. Since that time, MSPD has found application in numerous fields, but has proved to be particularly applicable for the analysis of drugs, pesticides and other components in food. MSPD enables complete fractionation of the sample matrix components as well as selective elution of a single compound or several classes of compounds from the same sample. The method has been applied to the isolation of pesticides from animal tissues, fruit, vegetables and other matrices (tab. 4).


Wiadomości Chemiczne, 2002, 56, 1035.
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TEACHING OF ENYIRONMENTAL PROTECTION WITHIN A SYSTEM OF ON-SITE AND REMOTE TE A CHING

Andrzej Burewicz, Hanna Gulińska, Piotr Jagodziński, Małgorzata Miranowicz, Nikodem Miranowicz

Wydział Chemii, Uniwersytet im. A. Mickiewiocza, ul. Grunwaldzka 6, 60-780 Poznań


In the course of the "KBN" research project in the Department of Chemistry Didactics at Adam Mickiewicz University in Poznań, the first Polish academic multimedial handbook Teaching of Environmental Protection. This handbook is devoted to full time (on-site) undergraduate and graduate students, but may also be used in a system of remote education of primarily teaching staff. The article describes successfully functioning systems of remote teaching in Poland and abroad and includes a discussion of their effectiveness.

The handbook Teaching of Environmental Protection differs from a conventional handbook in, among others, that each of its pages is not only illustrated by images or diagrams, but films, animations or simulations and includes the fact that all the functions of the learner and/or teacher are registered, which allows presentation, at the appropriate moment, of the appropriate assignment and/or test. The prepared system of hypertextual and hypermedial references simplifies searching out information and its compilation into various conceptual structures. Hence, this is an interactive handbook, with a branching, modular structure with broad potential for an uncomplicated expansion of its content.

The illustration of content prepared for the needs of the handbook are further discussed in the context of a choice of appropriate matters for effective visualization as well as programming tools necessary for this. An important element of this work was the preparation of basic methods of imaging by means of computer tools.

Considering the fundamental role played in chemical education by the experiment, the films included on the pages (windows) of the handbook were assigned to several modules, and then each of them was described with relation to the function that a given group of film sequences can play in the learning-teaching process.

The article presents the first results of the didactic work of teachers employing the modular system of remote teaching, making use of the handbook Teaching of Environmental Protection, and discusses them with relation to results obtained in the Department of Chemistry Didactics, during work with other multimedial products prepared there.


Wiadomości Chemiczne, 2002, 56, 1053.
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Notatki chaotyczne. XLIII. CIĄGI WSPOMNIEŃ.

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2001, 56, 1087.
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