Wiadomości Chemiczne, 2009, Vol.63
Uniwersytet Wrocławski, Wydział Chemii, ul. F. Joliot-Curie 14, 50-383 Wrocław
The important role of palladium nanoparticles has been recently demonstrated in many catalytic systems designed for C-C bond forming reactions [1-4]. There are examples of catalytic systems described earlier as homogeneous in which Pd(0) nanoparticles were now identified. In the article three different palladium catalytic systems are discussed. In the first one, Pd(0) nanoparticles, obtained by chemical reduction of PdCl2 and stabilized by polyvinylpyrrolidone, were used for Heck coupling in [Bu4N]Br medium. Decrease of nanoparticles size in reaction conditions was explained as a result of dissolution of Pd(0) colloid and simultaneous formation of catalytically active monomolecular anionic palladium complexes . The second example presents application of Pd(II) and Pd(0) supported on alumina-based oxides in Suzuki-Miyaura reaction . Reduction of Pd(II) to Pd(0) nanoparticles under reaction conditions was confirmed. In contrast to the first described case, in Suzuki-Miyaura reaction the size of Pd(0) nanoparticles was the same before and after the catalytic cycle. The catalytic activity of both palladium forms was quite high, however Pd(0) formed in situ was slightly more efficient as catalyst. In the third part of the article studies of palladium reduction in anionic complexes of [IL]2[PdX4] type are shown, where IL = imidazolium cation . These complexes catalyzed well Suzuki-Miyaura cross-coupling, but they were not stable under reaction conditions and decomposed to Pd(0) nanoparticles and Pd black. Using ESI-MS method it was possible to identify polynuclear (Pd3, Pd5) intermediate forms, stabilized with imidazolium cations or N-heterocyclic carbenes. In all systems discussed in the article co-existence of Pd(0) nanoparticles and monomolecular complexes was observed. That is important for understanding of the nature of catalytically active forms in C-C bond forming reactions.
Keywords: C-C bond forming reactions, Heck reaction, Suzuki-Miyaura reaction, Pd(0) nanoparticles, palladium colloid, N-heterocyclic carbene
Uniwersytet Humanistyczno-Przyrodniczy Jana Kochanowskiego, Instytut Chemii,
ul. Świętokrzyska 15, 25-408 Kielce, * firstname.lastname@example.org
In the last decades, free radicals have been discussed to play a key role in the pathology of several diseases, such as cancer, artheriosclerosis or inflammatory diseases [1, 2]. Numerous dietary antioxidants, e.g. vitamin C, phenolic and polyphenolic compounds as well as carotenoides are considered as effective agents in prevention of these diseases . The chemical diversity of antioxidants occurring in food makes it difficult to separate individual antioxidant compounds from the animal or vegetable matrix and quantify them. Antioxidant activity is widely used as a parameter to characterize the redox status of different biological or dietary samples. Many analytical methods for determining of total antioxidant activity (TAA) have been proposed in the literature of the last decade.
The present review deals with the methods involving electron-transfer reactions with chromogen compounds: the trolox equivalent antioxidant capacity (TEAC) [6-29], the DPPH assay [31-41], the ferric reducing antioxidant power (FRAP) assay [42-48], the cupric reducing antioxidant capacity (CUPRAC) assay [49-55], and the Folin-Ciocalteu (FC) method . These assays enable to measure the activity of an antioxidant through the reduction of an oxidizing agent, which changes colour during the redox reaction. The degree of colour change corresponds to the concentration of antioxidant in the sample. The main purpose of this review is to describe and discuss the chemical fundamentals of these methods. The applications of voltammetry and other electroanalytical methods were also demonstrated [58-71]. In addition, properties and the use of reference compounds in the antioxidant activity assessment was considered [72-85].
The summary contains conclusions on the scope of application, the most important advantages and shortcomings of the methods described [50, 86-88].
Keywords: antioxidants; free radicals; total antioxidant capacity
Katedra Chemii Analitycznej i Ekologicznej, Wydział Chemii, Uniwersytet Opolski,
ul. Oleska 48, 45-052 Opole
Allelopathy has been defined by the International Allelopathy Society as "any process involving secondary metabolites produced by plants, microorganisms, viruses and fungi that influence the growth and development of agricultural and biological systems, including positive and negative effects ". Allelochemicals can be released into the environment and despite what effect they evoke towards living organisms this kind of specific chemical interactions is known as "allelopathy".
Allelopathic phenomena have been observed and studied from ancient times. Theophrastus from Eresos, a disciple of Aristotle, reported an inhibitory effect of pigweed Polygonum spp. on alfalfa in ca. 350 B.C., whereas Pliny described the harmful effects of several plants on cropland in ca. 1 A.D. [2-5]. Although chemical interactions between plants have been known for thousands years, the term allelopathy was used for the first time in 1937 . It derives from Latin words allelon ("of each other") and pathos ("to suffer") and refers to the chemical interactions among species. In recent years there has been an increasing interest towards the perspective of exploiting allelopathy and allelochemicals as an alternative strategy for controlling weeds in particular, but also for controlling insects and plant diseases.
Plants produce a wide variety of secondary metabolites that play important roles in ecological interactions. This is one, probably the most pronounced, of a variety of ways in which certain plants can protect themselves against competition, infection or feeding in their natural habitats. Some of secondary metabolites may also play an important role in chemical mediation of growth and development of plant communities. These substances are called "allelochemicals" and are relea-sed into the environment in order to interfere with the growth of competing plants or act as chemical defence against pathogens and animals. Therefore such compounds might be considered as constituents of plant defence system and could be treated as a kind of chemical weapons. Originally, compounds like allelochemicals were thought to occur exclusively in higher plants. Ongoing research, however, has revealed them also to be synthesized by bacteria, lower plants and fungi.
Allelochemicals may furnish an entirely new generation of naturally produced weed-controlling compounds, replacing synthetic herbicides and other pesticides with non-acumulatting easy-degradable substances.
Keywords: allelopathy, allelochemicals, terpenes, phenolic compounds, natural pesticides
1 Zakład Biologii Strukturalnej, Katedra Endokrynologii Ogólnej,
Uniwersytet Medyczny w Łodzi,
ul. Żeligowskiego 7/9, 90-752 Łódź
2 Self-Assembling Systems, Delft University of Technology (Delft, Holandia)
Studies on properties and function of nucleic acids constitute the most fascinating cognitive area in biology, chemistry and medicine. Dynamic development of the required techniques, primarily Nuclear Magnetic Resonance (NMR) , or crystallization techniques, allowed to obtain a detailed information about structural diversity of complicated biological compounds, for example peptides and nucleic acids.
The replacement of one of the nonbonding oxygens of internucleotide bond by sulfur, selenium, methyl or other functionalized alkyl groups creates a stereogenic centre at the modified phosphorus atom . This arises a question about availability of stereoregular, P-defined analogues of DNA and RNA.
Short synthetic oligonucleotides are indispensable tools in biomolecular and structural studies [5, 6]. They also have potential as therapeutics [13, 14] for manipulation of genes expression in a sequence specific manner.
The block synthesis assuming incorporation of P-chiral, diastereomerically pure dimeric building blocks is attractive, reliable and patent for automated approach to the synthesis of "chimeric oligonucleotides", both in solution and on solid support .
The attention of researches turned toward chimeric constructs of 16 containing, in successive internucleotide positions, phosphates and methanephosphonates.
Reynolds et al.  found that for therapeutic applications, only chimeric oligonucleotides 16 with incorporated RP-dinucleoside methanephosphonates had acceptable binding affinity towards complementary template of DNA and RNA. Isosequential chimeric oligomers, constructed either from diastereomeric mixtures of dinucleoside methanephosphonates, or from those with SP-configuration, form less stable duplexes with the same complementary RNA templates. The preparation of the aforementioned chimeras utilized a "dimeric building blocks" approach . The corresponding dinucleoside (3',5')-methanephosphonates 17 were separated into diastereomers by chromatographic methods. After removal of the 3'-O-protecting group, the required RP-isomers were activated at the 3'-O-position, and used as such for condensation via the phosphoramidite method . Attempts towards their P-epimerization and recycling have failed. Such situation was notwithstanding the requirement of a cost-effective synthesis of new potential therapeutics. Therefore, Stec
et al. [36-38], and efforts were undertaken in the design of a cost-effective synthesis of RP-dinucleoside (3',5')-methanephosphonates 17.
Keywords: block synthesis, chimeric oligonucleotides, phosphoramidite approach, H-phosphonate approach, phosphotriester approach
1 Katedra i Zakład Chemii Nieorganicznej i Analitycznej,
Wydział Farmaceutyczny Collegium Medicum w Bydgoszczy,
UMK w Toruniu ul. Skłodowskiej Curie 9, 85-094 Bydgoszcz
2 Zakład Biochemii Środowiska, Wydział Hodowli i Biologii Zwierząt, Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy,
ul. Mazowiecka 28, 85-084 Bydgoszcz,
3 Zakład Chemii Surowców Kosmetycznych, Wydział Farmaceutyczny Uniwersytetu Medycznego w Łodzi, ul. Muszyńskiego 1, 90-151 Łódź
Vanadium is a trace element, which may be beneficial for human and developed as clinically useful metallopharmaceutical. Over the last 20 years a wide range of medicinal aspects of various compounds of vanadium have been investigated and documented [10-21]. Vanadium displays relevant biological actions such as insulin-mimicking or spermicidal [5-7] as well as it shows antitumor activity [3, 4]. This review has focused on vanadium inorganic compounds and organic complexes which have insulin-mimetic and anti-diabetic properties. Vanadium-based therapeutic agents belong to the class of compounds in which active is the metal ion and the ligand plays only an ancillary role - delivers active metal to target tissues what may have important implications for the bioavailability and pharmacokinetic properties of vanadium.
Vanadium salts such as oxovanadium(IV) sulphate (vanadyl sulphate) VOSO4 or sodium orthovanadate(V) NaVO3 and some vanadium organic complexes are potent insulin-mimetic compounds for treating both type I and type II in animal model, cell culture systems and human diabetes. Many studies have demonstrated that the oral administration of vanadium compounds normalizes blood glucose levels, stimulates glucose intake into cells and causes inhibition of glikoneogenesis and lypolysis. Vanadyl sulphate and other simple salts are effective but unfortunately have poor uptake through gastrointestinal system and have some toxic effects. Complexation with organic ligands may improve vanadium efficacy and decrease toxic side effects. Since 1990 several vanadium compounds (vanadyl, vanadate and peroxovanadate) with organic ligands have been proposed for this purpose. This review describes vanadyl complexes with ligand such as maltol and its derivatives, picolinate ion, flavonoids, sulphur containing compounds and hypoglycemic drugs (metformine and thiazolidenodiones). In recent years some VO(IV) complexes with maltol - bis(maltolato)oxovanadium (BMOV) and ethylmaltol (BEOV) have been proposed for clinical use in humans. BEOV has in 2000 completed I-st phase of human clinical trials. To asses the insulinomimetic and anti-diabetic activities of vanadium(IV) complexes several in vitro- and in vivo systems have been performed. Hypoglycemic and glucose normalizing activity were investigated in vivo in both type I and II diabetic animal (mice and rats) models. In vitro insulinomimetic activity was examined in isolated rat adipocytes.
Alternatively for improving bioavailability and anti-diabetic efficacy of vanadium several novel drug delivery systems such as chitosan-hydrogel or enteric-coated capluses containing vanadium [55, 56, 60] compounds have been tested.
Keywords: vanadium compounds, diabetes
Katedra Chemii Organicznej, Wydział Chemiczny, Politechnika Gdańska,
ul. G. Narutowicza 11/12, 80-952 Gdańsk
Nowadays the battle with tumor diseases and bacterial infections is an important test for the scientists. Therefore a lot of attention is focused on obtaining novel, more effective, selectively acting and less toxic drugs. Because of that reason, compounds with wide range of action like acridines/acridones are of great interest for scientists. This study contains synthesis and biological activity of acridine/acridone derivatives which are used in medicine as an antitumor agents and those which are at clinical trials. Among the synthetic methods there are modifications of Ullmann synthesis [2, 3, 9]. Lately Belmont et al. [11, 12] described a new methodology for the synthesis of 1,3,7-trisubstituted acridines, 1-amino-acridine and tetrahydro-cyclopenta[c]acridine-2,5-diones (Scheme 5). The starting materials are commercially available quinolines. Among acridine/acridone group there are compounds with diffe-rent molecular targets, e.g. topoisomerase inhibitors [1, 19-33], telomerase inhibitors [1, 34], protein-kinases inhibitors [36-40], P-glycoproteine inhibitors [56, 57, 76], conjugates with metals  and hypoxia-selective derivatives [2, 41-55]. This paper also describes compounds useful in Alzheimer disease [5, 16], antibacterial [2, 5], antiparasites [4, 5] and antiviral infections [5, 13, 14].
Keywords: acridine/acridone derivatives, biological activity, synthesis, clinical application
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław
Wydział Chemii, Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław
Witnessed within the last decades rapid development of the chemistry of Group 4 metals can be ascribed to the interesting structural properties of such complexes, as well as to wide range of their industrial applications. Species of titanium and zirconium bonded to aryloxo ligands are very good fodder for asymmetric organic syntheses, are very often used as base compounds for material engineering and catalysts or initiators for different kind of polymerization processes, and also for production of biodegradable materials. A carefully chosen ligand plays a crucial role in construction of potential candidates for these applications.
Aryloxides form a big family of mono-, bis- and poliaryloxo ligands. They are very versatile since their structure and electronic properties are easily modified by changing of ring substitution patterns [10, 11], introducing of O, S, NR, Se, Te heterogroups  between aromatic rings [12-14], changing their numbers [15, 16] or even linking them by carbon chains [17, 18]. All those modifications can influence the structure and catalytic activity of formed complexes.
Apart from aryloxides, also amino- and iminoaryloxides form the second group of ligands successfully utilized in chemistry of Group 4 metals. Chemical properties of these ligands can be easily modified through changing aromatic rings by using substituents influencing electronic properties and steric demands. For example, nitrogen atom changed by introduction of a group containing additional centre of coordination results in obtaining tridendate ligand . Mannich condensation is the main synthetic method for obtaining these compounds . Usage of primary, secondary or tertiary amine, as well as a change in reaction stechiometry or even a condition can lead to amine-aryloxide, amine-bisaryloxide or benzoxazine.
Syntheses of transition metal compounds with aryloxide or amine/iminearyloxide species are generated by direct ligand reaction with a metal precursors MRn, M(OR)n, M(NR2)n, MCln (R = alkyl).
Monodendate aryloxo ligands have a tendency to form μ-bridges between metal centres, which result in formation of oligomeric compound [M(OAr)n]m. Reactions of bisaryloxo ligands H2(LEtBu,Me) (E = -, CH2, C2H4) with chosen titanium and zirconium precursors produce heteroleptic, monomeric and tetrahedral complexes [12, 19, 20]. Change of a bridging group between phenyl rings to C2H4 increases the size of chelating ring in formed complexes [MX2(LC2H4tBu,Me)] [20, 35, 36] and at the same time decreases the inversion barrier which is the reason for relatively easy conformation changes in solutions.
Imine-aryloxide complexes of Group 4 metals have been known since 1960 , but mainly in last decade we can witness the rapid development of this group. Here, one of the most interesting species are complexes with tetradendate amino-bisaryloxo ligands. These compound can adapt a different symmetry which depends on a ligand structure, with additional electron pair donor D .
First literature reports on the use of titanium complexes in polymerization of cyclic esters are from 1958 . Mono-, and bisaryloxide complexes were reported to act as initiators for that reaction but the highest activity was obtained when heteroleptic titanium compounds supported by tridendate ligand (H2LN-R'tBu)  were used.
Catalytic activity in lactide polymerization on titanium and zirconium complexes strongly depends on metal and aromatic rings substituents .
Transition metal complexes of Group 4 metals stabilized by aryloxo and imine/aminearyloxo ligands play a very important role among relatively new non-metalocene catalysts for olefin polymerization. Monoaryloxide complexes are not effective in that process , titanium and zirconium species with bisaryloxo ligands, in which aromatic rings are linked by CH2 are less effective in ethene [68, 69] polymerization when compared to cyclopentadienyls .
Zirconium and hafnium amine-bisaryloxides are highly effective in 1-hexene polymerization and structure of a ligand plays here a key role . Additional donor of electron density is also an important factor influencing molecular mass and polymer tacticity. Imine-aryloxide species with bulky groups in ortho- or NO2, OMe in para- positions are highly effective in polyethylene production.
In asymmetric syntheses titanium and zirconium species are used for different processes, for example enantioselective oxidation, reduction, nucleophilic addition, cycloaddition and many others [81-84].
Keywords: titanium, zirconium, aryloxide complexes, catalysts/initiators, lactide polymerization, enantioselective sythesis
Uniwersytet Łódzki, Wydział Chemii, Zakład Chemii Węglowodanów, ul. Narutowicza 68, 90-136 Łódź
Heterocyclic compounds focus an attention for many reasons. Many of them are biologically active compounds, natural products, drugs, synthetic materials and practically useful chemicals [1-5]. Therefore, organic chemists have been making extensive efforts to produce these heterocyclic compounds by developing new and efficient synthetic transformations.
Among a variety of new synthetic transformations, transition-metal-catalyzed reactions are very attractive methodologies for synthesis of heterocyclic compounds, since they permit to construct complicated molecules directly from readily accessible starting materials under mild conditions. For this purpose palladium is one of the most widely used transition metals mainly due to the mild reaction conditions used, high yields, a tolerance of a large variety of functional groups, and high regio-, stereo- and enantioselectivity observed .
Pd0-catalyzed allylic alkylations and PdII-catalyzed oxidative cyclization of hydroksy(amino)alkene(alkyne)nucleophiles in the intermolecular mode have been particularly notable in this area due to their ability to elicit control in the aforementioned areas, often under very mild conditions.
Pd0-catalyzed intra- or intermolecular heteroannulation through allylic alkylation, the so-called Tsuji-Trost reaction, generally employs allylic acetates [9-14], carbonates [15-29] or vinyl epoxides [30-34] bearing a hydroxy or an amino group as the substrates. Allylsilanes have also been used as precursors of the η3-allyl intermediates, starting from PdCl2 and CuCl2, affording the corresponding THF and THP derivatives in quite good yields [38-40].
The PdII-catalyzed cyclization of alkenyl alcohols has led to cyclic enols by β-hydride elimination, or to oxygen heterocycles bearing a vinyl group through a β-hydroxy elimination, if the alkenol possesses an allyl alcohol moiety. Using this methodology a large variety of oxygen- or nitrogen-containing heterocycles have been obtained even in an asymmetric fashion [51-95].
Keywords: palladium catalysis, cyclization, heterocycles
Uniwersytet im. A. Mickiewicza, Wydział Chemii,
ul. Grunwaldzka 6, 60-780 Poznań
The development of a one-stage procedure for hydrocarbons oxidation to produce oxygen bearing products is still a challenging task for chemical technology. In the presented paper, the recent achievements in heterogeneous oxidation of benzene to phenol and propene to propylene oxide, as well as an oxidative functionalization of light paraffins have been demonstrated. The successful use of molecular sieves modified with transition metal cations as catalysts for oxidation reactions, performed in the presence of nitrous oxide as an oxidant has been shown.
One-stage benzene to phenol hydroxylation was developed and commercialised on the base of iron modified high silica zeolites as catalysts and N2O as an oxidant. However, structure of the active iron complex and mechanism of the oxidation reaction are still under debate. The most important ideas are presented in the paper.
Panov and co-workers [5, 10, 29] underline the role of binuclear iron complex accommodated on ion-exchangeable centres in zeolite channels which easily undergo autoreducion at high temperature and subsequent reoxidation as a result of contact with N2O. Ryder and Bell [35, 36] indicate (FeO2)+ complex as responsible for benzene hydroxylation, while Hensen and co-workers [37, 38] claim, that not only iron but also aluminium cation is involved in active centre leading to formation of Fe-O-Al complex.
Oxidation of light paraffins over N2O/Fe-ZSM-5 system results in oxydehydrogenation of alkanes and formation of olefins [68, 72, 80]. The possible mechanisms of N2O decomposition in the presence of alkanes and ODH products, developed in the literature [58, 80-82], are presented.
Propylene epoxidation, performed over transition metal cations (iron, vanadium and mixed system) modified molecular sieves, is also presented. Mainly all-silica mesoporous molecular sieves [91, 93, 94] and amorphous silica [7, 95, 96] characterised with very low acidity, show suitable properties as matrices for accomodation of transition metal cations.
Keywords: benzene hydroxylation, light paraffins oxydehydrogenation, propene epoxidation, nitrous oxide, molecular sieves, transition metal cations
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie,
Wydział Technologii i Inżynierii Chemicznej,
ul. Pułaskiego 10, 70-322 Szczecin
Pressure-sensitive adhesives (PSA) are organic materials based on self-adhesive polymers with adhesion and cohesion properties and used to bond surfaces . Three properties which are useful in characterizing the nature of PSA are tack (initial adhesion), peel adhesion (adhesion) and shear strength (cohesion). Scientific interest in UV-curable system developed in the 1940s, when the first patent was granted for unsaturated polyester styrene inks that polymerize readily under UV exposure . Ultraviolet (UV) cross-linking technology is well established in the market and allows the manufacturing of a wide range of various photoreactive UV-cross-linkable pressure-sensitive adhesives (PSA). Industrial applications of UV cross-linkable acrylic PSA have grown tremendously over the last 10 years. The balance between adhesive and cohesive strengths within the cross-linked layers is very important for the performance of UV-cross-linkable PSA. Dual cross-linking (UV and thermal) enables manufacturing of acrylic PSA layers with different adhesion-cohesion properties and offers opportunities to develop novel products in form of self-adhesive tapes with innovative features. UV radiation is used to induce cross-linking of the photoreactive acrylic PSA formulations containing suitable prepolymers, oligomers, unsaturated multifunctional monomers and conventional or unsaturated photoinitiators. Discussed herein is a new generation of photoreactive acrylic PSA that uses this dual (UV and thermal) cross-linking system. These dual cross-linkable acrylic PSA containing incorporated photoreactivity and thermal reactive cross--linking agents are characterized by excellent adhesive and cohesive performance and can be used for production of a wide range of self-adhesive materials.
Keywords: dual cross-linking (UV and thermal), acrylic, pressure-sensitive adhesives (PSA)
a Katedra i Zakład Chemii Nieorganicznej i Analitycznej,
Wydział Farmaceutyczny Collegium Medicum w Bydgoszczy,
UMK w Toruniu ul. M. Skłodowskiej-Curie 9, 85-094 Bydgoszcz
b Zakład Chemii Surowców Kosmetycznych, Katedra Kosmetologii, Wydział Farmaceutyczny Uniwersytetu Medycznego w Łodzi
ul. Muszyńskiego 1, 90-151 Łódź
Metal-based therapeutics have played an important role in modifying the pharmacological properties of known/new drugs [2, 60]. Both cobalt(II) and cobalt(III) complexes have been investigated for their antiviral, antifungal, antibacterial and antitumor properties [13-24]. Cobalt(III) compounds have been explored for their biological activity since 50' of XX century and they are still being examined especially for their anticancer properties. Oncological diseases are still actual and very important problem. The new mechanism of drug action has been researched. Development of tumor-selective cytotoxic agents, which would strongly injure tumor cells but affect as little as possible the normal tissues and organs having no side effect on a patient's organism, plays a key role . The search for selective anticancer drugs (tumor-activated prodrugs; TAP) led to compounds that can exploit the characteristic, unique microenvironment of tumor cells, such as selective enzyme expression, low extracellular pH and hypoxia. Tumor hypoxia provides a basis for the selective targeting of solid tumor . This property has been explored for reduction by endogenous enzymes or radiation for quinones, N-oxides and nitroaromatics. Complexes of nitrogen-based ligands with many transition metals such as cobalt have been investigated as potential hypoxia activated prodrugs. Such complexes are very stable in the low-spin Co(III) oxidation state. They have reduction potentials in the appropriate range to undergo reduction by cellular reductases, but this is inhibited in oxygenated cells, apparently by competition for cellular reductants between the Co(III) complex and oxygen .
Cobalt(III) plays "passive" role in the complexes, but it chaperones and delivers cytotoxic ligand, which is deactivated when coordinated to the metal centre. In hypoxic regions of reduction to cobalt(II), the anticancer agent would be released from less stable Co(II) complex and thereby activated in their sites of action. Many studies have described developments and prospect for cobalt(III) - based pharmaceuticals for their red-ox properties as promising antitumor agents - hypoxia activated prodrugs . Structure, enhanced reactivity with potential biological targets upon reduction, correlations between electrochemical parameters and anticancer activity in hypoxic tumor cells have been presented for cobalt complexes of nitrogen mustards or Schiff bases. Moreover Co(III) complexes of azahydroxy-CBI toxins show selective toxicity following irradiation under hypoxic but not aerobic conditions as potential hypoxia-selective cytotoxins.
Keywords: cobalt(III) complexes, antitumor effect, hypoxia drug activation
1 Katedra Chemii Organicznej, Wydział Chemiczny, Politechnika Gdańska,
ul. G. Narutowicza 11/12, 80-952 Gdańsk
1 Zakład Immunologii Klinicznej i Transplantologii, Akademia Medyczna w Gdańsku, ul. Dębinki 1, 80-210 Gdańsk
Mycophenolic acid (MPA) 1 (Fig. 1) is one of the most substituted phtalides. Its chemical structure incorporates a highly functionalized, hexasubstituted benzene ring [3, 4]. This compound is one of the oldest known antibiotics [1, 2]. MPA is the most potent uncompetitive inhibitor of inosine 5'-monophosphate dehydrogenase (IMPDH). This enzyme catalyzes a rate - limiting step in the de novo biosynthesis of purine nucleotides . Mycophenolic acid as an IMPDH inhibitor functions as antifungal, antiviral, antibacterial and immunosupressive agent [5-11]. Its derivatives: mycophenolate mofetil (MMF; CellCept(r), Roche AG) and mycophenolate sodium (MPS; Myfortic(r), Novartis Pharma AG) are used in combination with corticosteroids and calcineurin inhibitors (cyclospo-rine A or tacrolimus) for the treatment and prophylaxis of organ rejection in solid organ transplants. The metabolic lability of mycophenolic acid and severe side effects in clinical treatment are the main reasons for the development of new synthetic pathways of its derivatives .
This paper reviews the most important approaches in mycophenolic acid synthesis and its derivatives and displays structure-reactivity relationships of these compounds. Synthesis of mycophenolic acid as one of the highest substituted phtalide is described [23-35]. The most common synthetic approach in preparation of highly substituted benzenes is by using benzene ring constructions with five or six required substituents [28-30]. First of these methods  is based on construction of the pentasubstituted resorcinol derivative via thermal addition of the alkynyl ether to the cyclobutenone (Scheme 3). The synthetic strategy of the second method [28, 30] is depicted in Scheme 4 and the key step of this approach involves reaction between 16 and 17. Alternative approach to total mycophenolic acid synthesis is preparation of its intermediates . Mycophenolic acid derivatives were divided into five groups, according to their chemical structure. For each of them synthetic pathway was shown and structure-biological activity relationships were described . It has been found that replacement of the mycophenolic acid lactone ring with other cyclic groups resulted in loss of potency. A phenolic hydroxyl group and the aromatic methyl substituent were found to be essential for high activity. Replacement of the methoxy group with ethyl, vinyl or methyl resulted in compounds with higher activity than mycophenolic acid itself . It has also been discovered that substitution with small alkyl groups in the ? position to the carboxylic group results in enhanced potency . Furthermore monocyclic and indol derivatives were obtained and the carboxyamide derivative was selected for screening against prostate cancer . Also new monocyclic analogues were obtained but they did not show any anticancer activity . There have been synthesized several analogues of mycophenolic adenine dinucleotide [50-52] or mycophenolic adenine methylene-bis(sulfonamide)s  which showed inhibitory activity against IMPDH. Recently, a series of novel IMPDH inhibitors based on a methoxy-(5-oxazolyl)-phenyl (MOP) moiety have been designed .
Keywords: mycophenolic acid, MPA, synthesis, MPA analogues, biological activity
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław
Wydział Nauk o Żywności, Uniwersytet Przyrodniczy,
ul. Norwida 25, 50-375 Wrocław
Compounds with lactone moiety exhibit many biological acitivities (for example antimicrobial, antifeedant, cytostatic). One of the most attractive methods to obtain optically active lactones are regio- and stereoselective biotransformations. These together with mild reaction conditions are the main advantages of the processes compared to chemical synthesis of lactones. In this review examples of such biotransformations are presented.
The lactones may be obtained via direct biotransformation of substrate or in chemoenzymatic synthesis. In the second case the enzymatic step is the key one, leading to optically pure or enriched intermediate which is further transformed into desired, optically active product.
As the products of direct biotransformation, lactones can be formed from fatty acids like ricinoleic or vernolic acid [1, 2], aromatic compounds (benzoic acid, mandelic acid, catechol)  as well as in the result of lactonization of epoxyesters by enzymatic systems of fungi or plants. In the last case the biocalysts is the apple pulp or Jerusalem artichoke pulp [4-6]. Hydrolysis of amides and nitriles is also applied to the synthesis of lactones. Especially useful in this regard are microorganisms, which exhibit both enzymatic activities [7-9]. Microbial reduction of carbonyl group in ketoesters or ketoacids is also very useful method. The reduction may occur in γ or δ position, leading to γ- or ε-hydroxyacids which cyclize to the corresponding lactones [10-13]. Reduction of carbonyl group in β-position is the first step of a synthesis of lactones with 7- or 8-membered rings [14-16].
The application of hydrolysis or transesterification processes catalyzed by hydrolytic enzymes, mainly lipases from Pseudomonas sp., also leads to enzymatically enriched lactones. The substrates may be γ-ketoesters, γ-hydroxyamides, meso-diols or meso-diesters [10, 17-19]. Among the oxidation reaction the most known is Baeyer-Villiger reaction in which cyclic ketones are directly oxidized to the lactones by enzymes called Baeyer-Villiger monooxygenases (BVMO) . The reaction is highly regioselective and can be applied to the production of unsaturated lactones . In this area of research genetically modified strains of Escherichia coli are applied [21, 24], although the wild strains are also used, for example to the production of ε-caprolactone from cyclohexanone .
Another reaction catalyzed by oxidoreductases is the oxidation of hydroxyl group to carbonyl or carboxyl one [25-27]. In this first case horse liver alcohol dehydrogenase (HLADH) found application in the oxidation of meso-diols to lactones. The ability of different fungal strains to the regioselective hydroxylation of unactivated carbon atom found an application to the synthesis of lactones with eudesmane and germacrane systems [28-30].
Resolution of racemates is an alternative strategy used to the synthesis of lactones in optically pure forms. This aim can be achieved by enzymatic cleavage of lactone ring catalyzed by lactonases. These enzymes of microbial origin belong to esterases and are often induced during the growth of microorganisms on cyclic ketones as the carbon sources [31, 32, 34]. Enzymatic resolution of pantolactone by lactonase from Fusarium oxysporum is an example of industrial biotransformation . Lipases can also be applied to the enantioselective hydrolysis of lactone ring [35-37].
The other functional groups present in the molecule can also be converted during the resolution of racemic lactones [39-44]. The examples are hydrolysis of acetoxylactones or esterification of hydroxylactones.
Keywords: lactones, biotransformations, lipases, lactonases, lactonization, hydrolysis, transesterification, reduction, oxidation
Instytut Chemii Organicznej, Wydział Chemiczny, Politechnika Łódzka,
ul. Żeromskiego 116, 90-924 Łódź
In marked contrast to enantioselective Michael reactions promoted by chiral Lewis acids, organocatalytic Michael reactions have not been used as standard transformation in organic chemistry until quite recently. During the past few years chiral organocatalysts have emerged as a broadly applicable class of catalysts for enantioselective Michael reaction. This review summarizes these advances emphasizing the structural and mechanistic features that contribute to high enantioselectivity in organocatalytic Michael reactions.
The first part of this review deals with the development of covalent catalysis in organocatalytic asymmetric Michael reactions. To date, several chiral secondary amines have been employed to promote formation of electron-rich enamines from enolizable aldehydes and ketones, which then react with various α,β-unsaturated electrophiles to afford products [7-24]. In contrast, chiral imidazolidinones and diarylprolinol ethers are most often used to activate α,β-unsaturated carbonyl compounds by forming electron-deficient iminium ions, which render the β-carbon more electrophilic then their carbonyl precursors for nucleophilic attack [2a, 7, 25-34].
The second part of this review documents the development of non-covalent catalysis [35-64]. In this regard, chiral Bronstedt bases [35-39], chiral phase-transfer catalysts [40-49] and chiral hydrogen-bond donors [50-64] have emerged in the past few years as readily accessible organocatalysts of asymmetric Michael reaction. The most efficient catalysts such as cinchona alkaloids and their derivatives, quaternary ammonium salts obtained from cinchona alkaloids and chiral thiourea derivatives, respectively are revived and the modes of actions are discussed.
Furthermore, the major developments of organocatalytic asymmetric Michael reactions are also reviewed.
Keywords: organocatalysis, Michael reaction, asymmetric synthesis
1 University of Colorado at Boulder, Department of Chemistry and Biochemistry, 215 UCB, Colorado 80309-0215, USA
2 Politechnika Łódzka, Wydział Biotechnologii i Nauk o Żywności, Instytut Biochemii Technicznej, ul. Stefanowskiego 4/10, 90-924 Łódź
Cyclic, 5-membered derivatives of three- and tetracoordinated phosphorus constitute an important group of organophosphorus compounds in light of their increased reactivity towards nucleophilic reagents. This surprising reactivity is caused by steric strain present in 5-membered heterocyclic ring, which is then released on formation of reaction intermediates possessing pentacovalent phosphorus atom. This problem was thoroughly analyzed by Westheimer in his classical paper . The title cyclic compounds found an application in the chemical synthesis of biophosphates such as phospholipid derivatives [15-17, 19-21] or nucleoside phosphates [14, 18], however, in spite of numerous efforts (especially by the groups of Ugi and Ramirez) their applicability to efficient formation of internucleotide linkage was rather limited [22-26]. Further development of this matter was achieved by Stec and coworkers , who in 1991 applied appropriately protected P-chiral nucleoside-
-3'-O-(2-thiono-1,3,2-oksathiaphospholane)s for the synthesis of stereoregular oligo(nucleoside phosphorothioate)s. In fact, the oxathiaphospholane method was for many years a unique successful approach to stereocontrolled synthesis of phosphorothioate analogs of oligonucleotides. The method was later modified and applied for preparation of other phosphorothioate analogs of nucleotides [29-36], including compounds not containing sulphur [37-39]. Further modification led to so called dithiaphospholane approach, allowing an efficient synthesis of oligo(nucleoside phosphorodithioate)s  and other phosphorodithioate analogs of nucleotides [41-44]. An alternative approach to the synthesis of stereoregular oligo(nucleoside phosphorothioate)s, involving an application of P-chiral nucleoside oxazaphospholidine derivatives had at first a limited success (Agrawal et al. [45-47], Beaucage et al. ), however, recent achievements of Wada et al.  made compounds of this series efficient precursors for stereocontrolled synthesis of phosphorothioate analogs of oligonucleotides.
Keywords: biophosphates, chemical synthesis, phosphorylation, phosphitilation, cyclic organophosphorus reagents, oxathiaphospholanes, dithiaphospholanes, oxazaphospholidines
Uniwersytet im. Adama Mickiewicza w Poznaniu, Wydział Chemii,
Zakład Chemii i Technologii Węgla, ul. Grunwaldzka 6, 60-780 Poznań
Electrochemical capacitors (also known as supercapacitors, ultracapacitors or electric double-layer capacitors) have been extensively investigated at a number of research centres in the world. The main reason of this interest is the possibility of their use as an alternative or complement to other electric energy storage or generation devices, e.g. batteries or fuel cells as well as their potential applications in many fields including surge-power delivery devices for electric vehicles, backup-power storage for calculators, starting power for fuel cells, etc. .
Research concerning electrochemical capacitors is presently divided into two main areas: (a) the redox supercapacitors (also called pseudocapacitors) and (b) the electrochemical double layer capacitors (EDLC) .
Development of electrochemical capacitors is connected with a search of optimal electrode materials able to a high, efficient accumulating of electrical energy, high dynamic of charge exchange with a simultaneous long durability .
The most widely used materials for electrochemical capacitors are active carbons. This is due to their unique physico-chemical properties such as: high electrical and thermal conductivity, low density, high corrosion resistance, well developed surface area, controlled porosity as well as availability and relatively low cost [2, 4].
This paper presents the review of literature on the influence of the physico-chemical properties of active carbons on their capacitance parameters. Much attention has been paid to the redox supercapacitors.
Keywords: active carbons, chemical treatment, surface functional groups, electrochemical capacitor, pseudocapacitance
Katedra Chemii i Technologii Nieorganicznej
Politechnika Śląska, Gliwice, ul. B. Krzywoustego 6, 44-100 Gliwice
Project-analytical framings in Clean Coal Technology (CCT, in polish CTW) are studied in Poland in more and more detailed manner.
These studies indicate at the some kind of hierarchy of necessities, which is adapted to our technological, financial and investment potentiality. The principal aim is an energetic development of the country. In that situation chemical production is shifted at the margin of necessities. It is represented by the products mentioned in the title of this work i.e. hydrogen, methanol and liquid fuels according to Fischer-Tropsch technology.
As a starting point there were assumed: access to efficient resources of bituminous and brown coals (Fig. 5), obligate relations: raw material - desirable final products in adequate scale and necessity of increase of diesel fuel production about 2 Mt/year .
According to this in Poland there was found the first documented concept of the new investments in hydrogen and methanol production and IGCC . Hence, it is necessary to extend resources basis by brown coal.
Also necessity of CO2 emission reduction by implementation of zero-emission technologies was pointed out. Hence, CO2 sequestration is a new technological challenge. But for accepted plans of CCT development the new concepts of technological solutions appear based on CO2, mainly by methanol production.
Keywords: Clean Coal Technology, energy, bituminous/brown coal, hydrogen, methanol synthesis, Fischer-Tropsch synthesis, diesel fuel, sequestration/chemism of CO2
1 Katedra Chemii Analitycznej, Wydział Chemiczny, Politechnika Gdańska,
ul. Narutowicza 11/12, 80-233 Gdańsk,
2 Akademia Medyczna w Gdańsku, Międzywydziałowy Instytut Medycyny Morskiej i Tropikalnej, Zakład Toksykologii Środowiska,
ul. Powstania Styczniowego 9b, 81-519 Gdynia
An intensive development of new technologies, proceeding urbanization and consumption way of human life lead to adverse and often irreversible changes in the environment. Wide spectrum of pollutants reaches particular environmental compartments. Pollutants present in abiotic part of the environment undergo numerous processes of transport and physicochemical changes which lead to appearance of new compounds. From abiotic environmental compartment chemicals reach plants, animals and - finally - human beings. It should be remembered that toxic substances present in the environment can lead to permanent damage not only in the case of particular species but also of entire ecosystems. For this reason, it is important to undertake proper actions in monitoring of emission and reduction of emission of pollutants to particular environmental compartments, as well as assessment of threats resulting from already introduced toxins.
Presently realized chemical monitoring enables conducting identification and quantitative determination of chemicals of possible toxic action only in narrow range. Furthermore, serious limitation of this system of quality assessment of particular environmental elements are present due to complex interactions that occur between pollutants and their varying bioavailability.
Bioanalytical methods appear as a solution for abovementioned problem, where proper living organisms are used as indicators of burden degree of given environmental compartment by different kinds of xenobiotics. Toxicity tests, in other words bioassays, can constitute source of information on summary burden of samples tested by differentiated in kind and amount mixture of pollutants (also with taking into account mutual interactions between them) [1-5].
Landfills pose very specific manifestation of anthropopression, where application of ecotoxicological tests can greatly contribute to more effective protection of surface and underground water resources. Due to fact that in Poland until 1970 there no obligations to monitor content of wastes gathered in communal landfills, very often also dangerous wastes were directed there; mostly in form of batteries, fluorescent lamps, lacquer wastes, overdue pharmaceuticals and plants protection chemicals, postproduction wastes as well as used oils and lubricates. There is a great probability of negative impact of landfills on the quality of underground waters (it concerns mainly those landfills where no sealing is present).
Keywords: landfills, underground water, pollution, chemical analytics, biotests
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław
Ochrona Środowiska, Collegium Polonicum Uniwersytetu im. Adama Mickiewicza w Słubicach
ul. Kościuszki 1, 69-100 Słubice
Mercury is a global pollutant and is identified as a highly toxic element because of its accumulative and persistent character in the environment and living organisms. Therefore, routine monitoring and control of mercury are becoming increasingly important in natural environment. Several analytical techniques have been developed for the determination of mercury and cold vapor atomic absorption spectroscopy (CV-AAS) is the most widely used one. However, CV-AAS is not straightforwardly applicable to some environmental, clinical, or biological samples in view of low analyte content and matrix of the sample. Atomic fluorescence spectrometry (AFS) detection, especially coupled with the cold vapor (CV) technique, is becoming popular and replacing atomic absorption spectroscopy for mercury analysis due to its simple instrumentation, relatively low cost of operation, high sensitivity and selectivity and ultra low detection limits, which can be evidenced by its approval by the US Environmental Protection Agency for the analysis of mercury in uncontaminated water.
Speciation analysis brings important information on the real toxicity and migration pathways of mercury. The need for this kind of information has stimulated development of analytical solutions allowing separation of mercury species such as sequential extraction procedures and hyphenated techniques. The paper presents perspectives of development and application of determinations of total mercury and mercury species in environmental samples by the atomic fluorescence spectroscopy method based on cold vapor generation (CV-AFS). The different sequential extraction procedures in estimation of mercury mobility and bioavailability were also critically reviewed. Ranges of published detection limits achievable for mercury species determination by using different hyphenated techniques are also given. High pressure liquid chromatography coupled to AFS has become a very important tool in determination of mercury species in environmental samples in last years.
The paper presents the possibilities of current analytical methods available with use this technique.
Keywords: mercury, speciation, fractionation, atomic fluorescence spectrometry, hyphenated techniques, environmental samples
a Zakład Ochrony Środowiska i Higieny Transportu,
Gdański Uniwersytet Medyczny
ul. Powstania Styczniowego 9B, 81-519 Gdynia
b Katedra i Zakład Chemii Analitycznej, Gdański Uniwersytet Medyczny
Al. Gen. J. Hallera 107, 80-416 Gdańsk
The paper presents overview of literature pointing up usefulness of two chemometric methods of data exploration: cluster analysis (CA) and principal component analysis (PCA) for interpretation of multidimensional data obtained during surface water monitoring programme. The exceptional importance of fresh water quality rests on the fact that it determines condition and development of all human beings as well as animals and plants.
In sections 1 and 3 a concise description of the two methods of pattern recognition was presented. CA provides visual presentation of clustering mode of samples or variables in the form of tree-like scheme called dendrogram [3, 9]. Samples which exhibit considerable similarity fall into one cluster and at the same time they differ to the greatest extent from samples belonging to other clusters [1, 70-74]. PCA enables significant reduction of data matrix dimension without an excessive loss of information [5, 6, 82]. In addition, PCA provides intelligible graphic visualization of the data structure by scattering samples, described by many variables, on plane formed by the following principal components .
In CA methods of calculation the distance between different clusters or objects in a hierarchical dendrogram were also mentioned . They define whether two clusters or objects are sufficiently similar to be joined together into one cluster. It was also denoted that among most commonly applied methods Ward's clustering method turns out to be the best and most effective for surface water monitoring results as it gives the largest number of correctly classified observations.
The sections 2 and 4 present several examples of the two multidimensional chemometric techniques application in assessment of surface water quality. It was perceived that CA and PCA allow classification of sampling stations in relation to chemical composition of water and therefore permit to pinpoint areas with similar water quality [5, 82]. CA and PCA also help to indicate areas with distinctive chemical composition of water [6, 73, 90, 105]. They also help to identify factors which determine water quality at different regions [4, 5, 88, 113]. When applied for the results acquired from one watercourse at different sites CA and PCA enable to examine changes of water quality downstream [73, 80, 114]. The two chemometric methods are also useful tools for determination if season of sampling or specific weather conditions can influence variation of physicochemical parameters of water [90, 95, 103]. Other chemometric methods applied for monitoring results evaluation are mentioned in section 5 [74, 75, 116].
Keywords: cluster analysis (CA), principal component analysis (PCA), chemometrics, surface water, assessment of river water quality
Katedra Chemii Fizycznej, Wydział Chemiczny, Politechnika Rzeszowska
Al. Powstańców Warszawy 6, 35-959 Rzeszów
* Grace Sp. z o.o., ul. Rubież 46, 61-612 Poznań
Limonene (Fig. 1) is one of the most abundant and readily available terpenes [5-7, 9-15]. It constitutes approximately 90% of orange and grapefruit peel oil  and hence it is potentially available in large amounts as a by-product of the citrus industry . In contrast to relatively inexpensive limonene, products of its oxidation, such as: ?-terpineol, carveol, carvone, perillyl alcohol, menthol and limonene oxide (Fig. 5), are compounds of a very high market value  and they are widely used (apart from the epoxide) in the flavor and fragrance industry . Limonene oxide can be applied as a building block in the synthesis of drugs [18, 19] and biodegradable polymers .
Since an industrial method of limonene conversion into its ketone - carvone (used as a mint flavor for foods and oral hygiene products ) - involves several stages and the use of environmentally hazardous chemicals (Fig. 6) , it does not remain in accordance with 'green chemistry'. The latter problem concerns also the methods of limonene oxidation based on chromium(VI) compounds [25-28]. Hence a lot of attention is paid to limonene oxidation using environmentally benign oxidants, namely dioxygen and hydrogen peroxide.
Literature studies revealed that a variety of approaches to limonene oxidation by oxygen and hydrogen peroxide had been published so far. The oxidation of limonene using dioxygen can be performed catalytically and photochemically [80-86]. Generally, a complex mixture of limonene oxidated derivatives (Fig. 8) is obtained using Wacker-like systems [44-51] as well as all sorts of cobalt catalysts [52-56]. Transition metal complexes can also activate dioxygen for the oxidation of limonene giving a mixture of products [78, 79]. Limonene epoxides are usually produced by Mukaiyama systems, where peracid is in-situ generated from oxygen, aldehyde and transition metal complex [59-77].
The oxidation of limonene by hydrogen peroxide usually leads to its epoxidation [90-98, 100, 101]; however, sometimes other limonene derivatives are formed [99, 134-136]. Limonene oxidation using hydrogen peroxide proceeds in the presence of catalysts which are transition metal complexes [90-105], heteropolyanions [109-120], aluminum oxide [121-125] as well as titanium-containing catalysts [126-131]. Furthermore, hydrogen peroxide reacts with nitriles forming peroxycarboximidic acid which can epoxidize limonene in Payne reaction [132, 133].
Keywords: limonene, oxidation, dioxygen, hydrogen peroxide
Instytut Chemii Organicznej, Wydział Chemiczny, Politechnika Łódzka,
ul. Żeromskiego 116, 90-924, Łódź
Through the years, α,β-diamino ac6ds and their derivatives have attracted a great deal of attention among organic chemists because of their biological significance [1, 2] (Fig. 1-3). This review deals with the synthetic approaches of α,β-diamino acids and their derivatives (e.g., esters, amides) using asymmetric synthesis methods described in the literature up to the end of 2008. Aziridines and 3-amino-β-lactams are beyond the scope of this review and will be only considered as intermediates in the synthesis of acyclic derivatives.
The methods found in the literature can be classified essentially in two main categories: methods that require a new carbon-carbon single bond construction (Fig. 4) and method based on the functional groups transformation reactions within the carboxylic acids skeleton (Fig. 5).
A great number of C-C forming methods are the addition reactions of glycine derivatives or nitro compounds to imines (Mannich-type reactions). The asymmetric induction requires chiral substrate usage (e.g., chiral sulfinimines, chiral glycinates) [30-37, 61-67] (Scheme 1-6, 22-24) or results from the application of chiral catalysts (e.g., chiral Lewis acids, chiral PTC catalysts and other organocatalysts) [39-48, 50-60] (Scheme 7-21). Strecker's reaction using chiral imines or related compounds is also often used [69-77] (Scheme 25-27).
Methods begining from the existing carbon skeleton and based on the modification of the functional groups are as follows: catalytic asymmetric diamination and aminohydroxylation of α,β-unsaturated carboxylic esters (Scheme 31-36)
[92-100, 107-109]. Subsequent transformation of the hydroxy group into the amine group in the hydroxyamino acids derivatives is then necessary [100-109]. The direct introduction of the amino moiety into the β-amino esters via electrofilic amination is also described (Scheme 41-43) [120-131]. The title compounds can also be obtained by catalytic enantioselective reduction of dehydrodiamino acids derivatives (Scheme 40) [117-119].
Keywords: α-amino acids, β-amino acids, α,β-diamino acids, diamines, asymmetric synthesis, stereoselective synthesis
Zakład Radiochemii i Chemii Koloidów,
Wydział Chemii Uniwersytetu Marii Curie Skłodowskiej
Pl. M.C. Skłodowskiej 2, 20 031 Lublin
Contamination of environment with substances originated from industrial and military activity, including radioisotopes belongs to dangerous occurrences accompanying our life. Most anthropogenic radionuclides come from above ground nuclear weapon tests and as radioactive fallout were deposed in surface layer of soil. This way soil became source of their distribution . Physicochemical properties of soil changes mostly in first genetic layers that is characteristic for specific soil type [2-4]. Translocation of radionuclides and mostly their vertical migration give information not only of contamination of studied area but also their transfer to plants [6-19]. Word literature has been dealing with migration of radionuclides for years [20-24]. The main factors influencing migration of radionuclides comprises their sorption on particles of soil, transportation with water, dispersion that is responsible for distribution in porous environment, precipitation and co-precipitation, half life time of the radionuclide. Moreover very important are: properties of the soil (type, soil organic matter contents, pH), genetic level, type of soil colloids, ionic composition of underground water, chemical form of radionuclide (free ion, compound) origin of contamination (nuclear power plant, nuclear explosion). Studies on migration of radionuclides mostly aim on describing the influence of selected factors on this process [30-42].
Separate place is devoted to studies on presence of radioisotopes in successive layers (vertical intersection) [6, 12-19, 25-29] and calculation on these data, among others, vertical migration rate. Special attention should be paid to elaboration of some theoretical models of vertical migration of anthropogenic radiouclides in depth of the Earth [16, 49-54]. Migrating in soil 90Sr belongs to radionuclides of average velocity, its mean migration rate down in soil is usually lower than 1cm/y [6, 51-54].
Keywords: radionuclides, strontium, soil, migration, sorption
Wydział Chemii, Uniwersytet Wrocławski,
ul. F .Joliot-Curie 14, 50-383 Wrocław
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław
Wydział Chemiczny Politechniki Wrocławskiej,
Wybrzeże S. Wyspiańskiego 27, 50-370 Wrocław
A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, and chemicals from biomass. The biorefinery concept is analogous to today's petroleum refineries, which produce multiple fuels and products from petroleum . Three biorefinery systems are distinguished in research and development [11, 13]: the "whole-crop biorefinery", the "lignocellulosic biorefinery" and the "green biorefinery". Moreover, a concept of "two platform biorefinery" emerged , which includes the sugar platform as a basis for (bio)chemical conversion of biomass and the syngas (thermochemical) platform which convert biomass into synthesis gas.
This review focuses on the recent developments of basic biorefinery technologies. The whole-crop biorefinery (Figure 1) produces chemicals from sugars by biochemical (Scheme 1) and chemical (Schemes 2-11) transformations, of which twelve compounds, selected by US National Renewable Energy Laboratory (NREL)  are classified as "block (or platform) chemicals" with the potential to be transformed into new families ("trees") of valuable substances. These compounds are: 1,4-diacids (succinic, fumaric, malic), 2,5-furandicarboxylic acid, 3-hydroxypropionic acid, aspartic acid , glutamic acid, glucaric acid, itaconic acid, levulinic acid, 3-hydroxybutyrolactone, glycerol, sorbitol, and xylitol/arabinitol. The lignocellulosic biorefinery (Figure 2) uses biomass consisting of cellulose, hemicelluloses and lignin - an abundant and cheap feedstock. Among the potential products of the "sugar platform" are: cellulosic ethanol and hydrogen obtained by biochemical routs, and furfural, 5-hydroxymethylfurfural, the platform chemicals, (Schemes 3-11), obtained by chemical synthesis. The "syngas platform" covers three basic processes: aqueous - phase reforming of sugar polyols [109-111, 113-115] and glycerol [116-118], fast pyrolysis of biomass [121-128] and gasification of biomass [121-125]. Aqueous - phase reforming of glucose and sorbitol produces hydrogen, whereas integrated with catalytic cascade processes allows to produce liquid biofuels, i.e., branched hydrocarbons and aromatic compounds used in gasoline or longer chain linear hydrocarbons in diesel and jet fuels. Fast pyrolysis produces bio-oil that can be upgraded to transportation fuels. Synthesis gas is produced in gasification processes and may be converted into methanol or liquid hydrocarbons (so-called synthetic "Biomass-To-Liquid", BTL-fuel) [131-133]. Finally, green biorefinery (Figure 3) uses green (wet) biomass rich in juice and oil to obtain food and non food goods, and from the latter a huge number of chemicals "produced" by Nature, i.e., by the vast diversity of plant.
Keywords: biorefineries, biomass conversion, biochemical processes, chemical transformations, biomass gasification
Uniwersytet Opolski, Wydział Chemii, Katedra Technologii Chemicznej
i Chemii Polimerów,
ul. Oleska 48, 45-052 Opole
In the last decade ionic liquids have focused a considerable interest in many aspects of chemistry. The unique properties that can easily be tailored influence their attractiveness. Presently, the ionic liquids are used as solvents for numerous organic, inorganic, and organometallic compounds, including catalysts and cocatalysts of various reaction types [1-4]. Having polar, but weakly coordinating character, the ionic liquids were found to be a good medium for the olefin oligomerisation and polymerisation reactions carried out with the use of transition metal compounds [7, 10].
The ionic liquid enabled to perform the olefin oligomerisation (ethylene, propylene, butene) in the biphasic mode. Such system ensures high activity and selectivity of a catalyst, mild reaction conditions, and an easy separation of the products from the reaction mixture, what results in re-use of the catalyst in the multi-steps reaction cycles. Therefore, application of the ionic liquids overhelm the problems of the standard homogeneous oligomerisation processes [5, 6, 12-14].
Similarly, the ionic liquids can be applied in the olefin polymerisation with the use of organometallic catalysts. The most often used ionic liquids are those having imidazolium cation and chloroaluminate anion [10, 13-15]. They constitute not only a medium, but also they are a specific support of the catalyst precursor. Furthermore, they can participate in the catalytic process. It was found that even small modification of the ionic liquid cation can have considerable influence on the performance of the polymerisation reaction and the properties of the obtained product .
In the presented paper the actual trends concerning the oligomerisation and polymerisation reactions carried out in the ionic liquid medium are presented.
Keywords: ionic liquids, olefins, oligomerisation, polymerisation
Akademia Medyczna im. Piastów Śląskich we Wrocławiu, Katedra Chemii Analitycznej, ul. Szewska 38, 54-206 Wrocław
The aim of this work was to present regularities in the phase equilibria in the Tl2Te-MxTey systems, where M stands for metals belonging to periods IV-VI and groups 11-15 of Periodical Table. Additionally, the Tl2Te-As2Te3, Tl2Se-Bi2Se3 and Tl2Te-Tl2Se systems were considered. The phase diagrams are presented in a simple form in Fig. 1 for the following systems: Tl2Te-Cu2Te , Tl2Te-ZnTe , Tl2Te-CdTe , Tl2Te-HgTe [4-6], Tl2Te-In2Te3 [7, 8], Tl2Te-PbTe , Tl2Se-Tl2Te , Tl2Se-Bi2Se3 , Tl2Te-Ga2Te3 , Tl2Te-Ag2Te , Tl2Te-SnTe , Tl2Te-Sb2Te3 , Tl2Te-Bi2Te3 , Tl2Te-GeTe  and Tl2Te-As2Te3 .
The state of phase equilibria illustrated by the phase diagram depends on the tendency to chemical compounds formation by the components of a system. This tendency can be observed in the number of compounds formed, their melting points and the type of melting process (congruent or noncongruent).
The tendency to compounds formation or at least the melting points of the compounds formed increases with increase of the atomic number of the metal within a group of systems containing as the second component tellurides of metals from a given group in the Periodic Table.
There is no correlation between type of phase diagram and metal position in a given period. Thus, increasing the number of outer shell electrons for consecutive elements M of the same group does not affect the tendency to the chemical compounds formation.
Regardless of the compounds number - terminal solid solutions have been observed only in some telluride systems. The data in Table 1 show that solid solutions are formed when the value of relative difference between thallium and metal M radii is smaller than 10%.
All salt systems arranged in decreasing order of their ionic potentials ratios μTl+/μM+ are presented in Table 2. While this ratio decreases the tendency to congruent compounds formation increases abruptly from 1 to 2 at the value of a ratio equal to 0.21, exactly as in the case of typical salts .
The influence of molecular stability coefficients on the number of compounds existing in the system (Table 3) has been discussed. The greater difference is between the values of molecular stability coefficients the more compounds are formed.
The impact of a common anion change on the shape of phase diagrams for the systems Tl2Te-Bi2Te3  and Tl2Se-Bi2Se3  as well as the regularities in the chalcogenide systems with a common cation has been described.
All compounds being components of the systems presented in this work are listed in Table 4.
Keywords: tellurides, selenides of metals, phase diagram, ternary compounds
Katedra Chemii, Uniwersytet Przyrodniczy we Wrocławiu, ul. Norwida 25, 50-375 Wrocław
Baeyer-Villiger (BV) reaction is oxidation of ketones, leading to cleavage of one of the C-CO-C bonds with simultaneous insertion of an oxygen atom into the cleaved bond. Resulting products obtained from cyclic ketones are lactones, while esters are obtained from acyclic ketones. Numerous strains of microorganisms produce enzymes catalyzing BV oxidation. These enzymes participate in the processes of degradation of natural and synthetic ketones, which can be used by the microorganisms as carbon source (Scheme 3 and 4). The enzymes are monooxygenases (Baeyer-Villigerases, BVMOs), usually containing flavinoadenine nucleotide and cooperating with NAD(P)H reductases.
Research on the role of BV oxidation in degradation processes has evolved into intensive studies on the mechanism of this reaction and its use in synthesis, especially after isolation (in 1976) of cyclohexane monooxygenase from Acinetobacter sp. NCIB9871(CHMOAcineto 1) . Subsequently, further strains were identified which produced BVMOs catalyzing oxidation of ketones of diverse structures. In addition to the best-characterized cyclohexane monooxygenase, there are: cyclopentanone, phenylacetone, cyclododecanone, aliphatic ketone and 2-oxo-3-en-4,5,5-trimethyl-cyclopentenylacetic acid monooxygenases. The adjective characterizing a given BVMO is derived from the ketone constituting carbon source, or from the ketone which is oxidized with the highest yield. In addition to these ketones, the enzymes accept their various structural analogues, therefore it is possible to select a biocatalyst which carries out oxidation of a given substrate. Among BVMOs, particularly selective are the enzymes carrying out BV oxidation of steroidal ketones: these enzymes operate only on steroid substrates, mostly containing 3-oxo--4-en moiety, but also they exhibit regioselectivity as well - the oxidation of ketones takes place only at C-17. During the regioselective enzymatic oxidation, "atypical" lactones [2, 4], which are not produced in chemical BV oxidation processes, are sometimes formed. Products of stereoselective enzymatic reactions are optically pure lactones and esters, which are starting points for further asymmetric synthesis of biologically active compounds, including medicines.
The application of genetic engineering allows obtaining recombinant microbial strains, which are non-pathogenic and produce larger amounts of the enzyme than the wild-type strains. The recombinants are also able to produce mutated BVMOs exhibiting higher selectivity and/or lifetime, as well as activity towards different spectrum of substrates than the parent enzymes . However, reaction yields of transformations carried out by the recombinants are still not significantly better than the results obtained with the wild-type strains. The recombinants usually require an expensive reagent, isopropyl-β --D-tiogalactopyranoside (ITPG), to induce their BVMOs .
Enzymatic BV oxidation, due to the selectivity of the enzymatic action, is competitive to the chemical oxidation. The enzyme selectivity allows for using pure products, including enantiopure compounds, with high yield. The process is environmentally friendly, because the oxidizer in the enzymatic BV reaction is molecular oxygen, and the amount of byproducts is limited.
Synthetic application of BVMOs is limited by three principal factors: isolation of the enzyme in amounts suitable for large-scale applications, decrease in the enzymatic activity in the presence of the substrate and/or the product, and the isolation of the product. Separation of the unreacted enantiomer of the substrate in the process of kinetic separation of the racemic mixture, or separation of regioisomeric lactones are costly and time-consuming operations. Another possible problem is the fact that some strains producing useful BVMOs are pathogenic. Therefore, multidirectional research efforts are devoted to overcome the aforementioned barriers with the goal of establishing economically viable methods of biotransformations .
Keywords: Baeyer-Villiger biooxidation, cyklohexanone monooxygenase, regioselectivity, enantioselectivity
Zakład Farmacji Szpitalnej Wydziału Farmaceutycznego
Uniwersytetu Medycznego w Łodzi, ul. Muszyńskiego 1, 91-151 Łódź
Intercalators constitute a group of compounds which interact reversibly with DNA double helix. The insertion of planar, polycyclic aromatic systems between adjacent base pairs leads to topological changes in the double helix (lengthening, unwinding) and disrupts replication, transcription and repair processes [1-4]. Some of the monointercalators e.g. doxorubicin are valuable drugs, but their clinical effectiveness is limited by their undesirable side effects, and development of multidrug resistance . In order to overcome these limitations bisintercalators have been designed. Dimerization of monointercalating compounds was supposed to enhance their anticancer activity and minimize side effects [1, 7].
Many research groups have been interested in designing various groups of bisintercalating agents of diverse chemical structure and biological properties, such as echinomycin antibiotics [5, 7-10], 7H-pyridocarbazole derivatives [19-21], bisanthracyclines [7, 12, 16], bisnaphthalimides [7, 22-37], bisacridines [38-48] and bisimidazoacridones [50-52].
There have been a number of modifications undertaken on polyaromatic rings, and linker chains in an attempt to improve the compounds' activity.
The structure-activity relationships have been suggested. It has been discovered that introduction of small lipophilic substituents or additional heterocycles into ring systems may lead to significant changes in binding affinity and cytotoxic activity of the compounds.
It was discovered that many tumor types contained elevated polyamine levels and an active polyamine transporter for importing exogenous polyamines. Designing bisintercalators with aminoalkyl chains similar to polyamines has given a chance to improve selectivity in drug delivery to rapidly proliferating cells by utilizing the polyamine transporter. More extensive SAR studies revealed significant influence of length and rigidity of a linker binding two intercalating moieties on binding affinity and antiproliferative activity of bisintercalators.
Intercalation and topoisomerases inhibition are not the only possible modes of action of the compounds. Some of them exert cytotoxic effect through induction of apoptosis e. g. bisnaphthalimidopropylspermidine (BNIPSpd, (29) Fig. 9) or disrupting repair process of DNA double helix (WMC-26, (55) Fig. 18).
In this work we presented enormous chemical diversity of bisintercalators and depicted multiplicity of structural modification of dimeric molecules which may lead to enhanced cytotoxic activity becoming valuable anticancer drugs.
Keywords: antineoplastics, intercalators, bisintercalation, echinomycin antibiotics, anthracycline antibiotics, bisnaphthalimides, bisacridines, bisimidazoacridones
1 Instytut Niskich Temperatur i Badań Strukturalnych, Polska Akademia Nauk, ul. Okólna 2, 50-422 Wrocław
2 Department of Chemistry, SLU, Box 7015, SE-75007, Uppsala, Sweden
3 Wydział Elektroniki Mikrosystemów i Fotoniki, Politechnika Wrocławska, ul. Janiszewskiego 11/17, 50-372 Wrocław
The main goals of the presented paper were focused on synthesis of nanocrystalline BaTiO3 materials doped with chosen rare earth ions (Eu3+ and Yb3+) utilizing sol-gel technique. Structure, morphology, optical and electrical properties were characterized. Size effects and their influence on the mentioned physicochemical properties were discussed. Strong effect of the dopant concentration on the structure of BaTiO3 was found. In case of the Eu3+ ions doping results in stabilization of tetragonal phase of BaTiO3 whereas addition of the Yb3+ ions favors formation of the cubic structure. Besides that all introduced ions could be considered as inhibitors for the grain growth process. Moreover resulted powders showed co-existence of the tetragonal (ferroelectric) and cubic (paraelectric) phases. The amount of the tetragonal phase depends on the heat treatment temperature and concentration of the incorporated rare earth ions.
The structural changes of a matrix were studied using the Eu3+ and Yb3+ ions as optical probes. Their luminescence properties were dependent on the sintering temperature. In case of the Eu3+ ions we have found that the intensities of 5D0→7F2 transitions increased with the increasing temperature. It means higher Eu3+ ions symmetry associates with higher temperature [1-4]. On the other hand in nano-crystals doped with Yb3+ ions a higher intensity of SHG (second harmonic generation) was observed in the tetragonal phase, whereas the isotropic cubic phase was detected by the absence of a SHG signal. Cooperative emission, indicating the presence of Yb3+ ion pairs, was easily detected in the cubic phase and not seen in the ferroelectric tetragonal structure .
BaTiO3 nanoceramics were fabricated from the nanopowders using LTHP (low-temperature high pressure) sintering process [6, 7]. The impedance spectra indicated the complex nature of the effects appearing in the analyzed BaTiO3 nanoceramics. Four types of physical mechanisms contributing to the overall conductivity were found, namely hopping, diffusion, two relaxation mechanisms and the dc conduction. The studied samples show a ferroelectric-paralelectric phase transition observed for the higher frequency regions.
Keywords: nanomaterials, barium titanate, sol-gel technique, doping, optical and electric properties
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław
Transition metal nanoparticles (also called metal colloids or nanoclusters) are ordered multi-atom sets characterized by a very small size, generally less than 20 nm. They are intermediate species between single atoms and crystals of macroscopic dimensions [1-8]. Nanoparticles have been synthesized by a variety of methods. The most common synthetic procedures involve chemical reduction of transition metal salts or complexes. By the choice of reduction conditions (kind of the reducing agent, type of the stabilizing agent and the elementary reaction parameters like temperature and concentration) it is possible to obtain colloids showing different particle sizes and morphologies. These two factors play a decisive role from the point of view of catalytic activity of nanoclusters.
Palladium nanoparticles have been obtained by chemical reduction of PdCl2 aqueous solution using pyrogallol, hydrazine or chromium(II) acetate as the reducing agent. All these systems have demonstrated a very high catalytic activity in important carbon-carbon bond forming reactions (methoxycarbonylation, Heck and Suzuki processes) carried out under mild conditions [48, 49]. Some of the C-C coupling reactions have also been successfully catalyzed by nickel nanoparticles, however they require more harsh conditions [65, 66].
Cobalt and iron nanoparticles present magnetic properties attractive for application of these materials as removable electronic media of high capacity, as well as biosensors or magnetic probes for biological imaging and therapeutic use [9, 18]. The extreme reactivity of nanoparticles, specifically towards oxygen and water, complicates their synthesis, however it is also beneficial in catalytic applications
[16, 17]. Conversion of CO/H2 mixture to hydrocarbons, known as Fischer-Tropsch synthesis, representing one of the most important routes to fuels production, is catalyzed very effectively by iron and cobalt nanoparticles. Monometallic and bimetallic cobalt nanoparticles are excellent catalysts of Pauson-Khand type couplings leading to cyclopentanones .
Keywords: metal nanoparticles, metal colloids, catalysis, C-C bond forming reactions, Fischer-Tropsch process
Zakład Ziem Rzadkich, Wydział Chemii, Uniwersytet im. A. Mickiewicza, ul. Grunwaldzka 6, 60-780 Poznań
The aim of this review is to evaluate the use of chemiluminescence (CL) as the method for determination of a wide group of organic and inorganic compounds. Chemiluminescence can be defined as the light emission resulting from the transition of an electronically excited state produced in a reaction [1, 2]. CL, in spite of complicated processes occurring in reaction systems, has been used since many years in chemical analysis [13, 22, 30]. Although many chemiluminescence reagents investigated, only a limited number, such as luminol, tris(2,2-bipyridyl)ruthenium(III), potassium permanganate and the Fenton reaction, generating chemical sources of reactive oxygen and nitrogen species, were successfully used for analytical applications. The Fenton system Fe(II)/(III)-H2O2 is the source reactive oxygen species and hydrogen radicals [52, 53]. Analytical techniques based on CL have been used in, e.g.: pharmacological studies, clinical and environmental diagnostics [14-17, 22-30, 39-47, 62-65]. Ultra-weak intensity of generated emission (1-104 hν · s-1 · cm-2) requires very sensitive detectors and special apparatus, as our detection system for CL measurements based on single photon counting .
Studies of CL systems characterised by low intensity of the CL emission require the use of sensitizers. Due to their specific luminescence properties, the lanthanide ions, mainly europium(III) and terbium(III) and their complexes, can be successfully used as chemiluminescence fluorophores [11, 57, 71, 75, 76]. Examples of chemiluminescent methods used for determination of organic molecules (aminoacids, antibiotics, chemotherapeutics), based on the lanthanide(III) ions emission, as a result of the energy transfer process from the excited products of the organic molecule oxidation to the Ln(III), are presented [77, 78].
Keywords: chemiluminescence, lanthanide ions, analytical application
Wydział Chemiczny, Politechnika Rzeszowska, ul. W. Pola, 35-959 Rzeszów
One of the major drawbacks of solution phase organic synthesis is laborious processes of purification and isolation of individual products. Problems intensify in the case of preparation of compound libraries for pharmaceutical and agrochemical research. Application of oligomeric or polymeric specific reagents in purification processes can simplify significantly the isolation of organic products. Techniques of purification with reactive polymers have been worked out in the mid-1990s independently by groups of Kaldor, Flynn and Hodge as solid phase scavenging, complementary molecular reactivity and molecular recognition (CMR/R) or polymer-supported quench (PSQ), respectively [55-58]. They are based on differences in the reactivity of impurities in comparison to desired products with reference to functional groups of polymers. The methodologies have been intensively developed for the last decade as an effective alternative to time-consuming and somehow difficult classical methods of purification such as extraction in water-organic solvent systems, chromatography, crystallization or distillation [23, 25]. As a result of that, many new scavenging resins were synthesized and commercialized [51-54]. Their application seems to be particularly useful for purification of products from combinatorial synthesis. The synthesis of libraries of amides, carbamides, sulfoamides or amines can be taken as examples. The methods are also useful in many cases when classical methods of purification do not give desired effects. Removing of metal ions impurities from pharmaceutical products can be a good example . The effectiveness of purification by reactive polymers was proven both in the case of single reactions and multi-step transformations.
In this review the basic principles of using functionalized polymers in purification of organic reaction products were described. The division of scavenging resins depending on the chemical nature of functional group immobilized on polymers and their applications was performed. Methods of synthesis of different types of oligomeric and polymeric scavengers and their morphology were discussed. Numerous examples of practical applications of scavenging resins in modern organic synthesis were presented.
Keywords: functionalized polymers, polymer-supported reagents, scavenging resins
Zakład Chemii Środowiska, Wydział Chemii, Uniwersytet Łódzki,
ul. Pomorska 163, 90-236 Łódź
Thiols are chemically and biochemically very active components of the sulfur cycle of the natural environment. Low molecular-mass thiols, such as homocysteine, cysteine, cysteinylglycine and glutathione are critical cellular components that play numerous roles in metabolism and homeostasis, and are important in a variety of physiological and pathological processes [1, 2]. Plasma thiols are being investigated as potential indicators of health status and disease risk [3-8].
Because of high affinity to oxidation low-molecular-mass thiols exist in biological samples mostly as symmetrical, unsymmetrical and protein-bound disulfides. Thus, determination of total thiol content must comprise disulfide bond disruption step. A reducing agent is necessary both for the reduction of the sulfide bonds and to keep the thiol in a reduced form until start of derivatization.
Most of thiols lack the structural properties necessary for the production of signals compatible with common HPLC detectors, such as UV absorbance and fluorescence. Therefore, an analyst must resort to derivatization for signal enhancement and labile sulfhydryl group blocking if fluorescence or UV-Vis detection methods are employed. Ultraviolet detection is less specific and less sensitive than fluorescence one, nevertheless, its sensitivity is sufficient for detection and quantitation of endogenous and exogenous thiols in biological samples in physiological and pathological conditions. Moreover, equipment for HPLC-UV analysis is often a part of an existing, standard instrumentation in hospital laboratories and staff is usually well experienced in its use. All methods, except those based on electrochemical and tandem-mass spectrometry detection, depend on pre- or post-column derivatization of thiols. Useful reagents must form thiol derivatives with sufficient absorption and/or fluorescent yield to measure thiols at trace concentrations. Furthermore, the ideal reagent should show no absorption and should react rapidly and specifically with thiols to form stable products. Numerous reagents are available for the thiol derivatization. A majority of the reagents can be classified by type of the reactive moiety into three categories: activated halogen compounds, disulfides, and compounds possessing maleimide moiety, and are reviewed with some experimental details in excellent works [36-41].
Keywords: high performance liquid chromatography, derivatization, thiols, UV-Vis detection
1 Politechnika Rzeszowska, Wydział Chemiczny,
al. Powstańców Warszawy 6, 35-959 Rzeszów
2 Instytut Chemii i Techniki Jądrowej, ul. Dorodna 16, 03-195 Warszawa,
3 Department of Chemistry and Biochemistry, University of Detroit Mercy, 4001 W. McNichols Road, Detroit, MI 48221-3038, USA
Molecular sieves are porous, crystalline materials usually synthetic or natural zeolites, that contain well-defined pores of precise and uniform size. The term zeolite originally described a group of natural crystalline aluminosilicates, however nowadays the term covers many different materials such as aluminophosphates or gallium-silicalites. During the last few decades microporous and mesoporous materials have been considered for medical use due to biological properties and stability in biological environment [1-4]. Zeolites have been investigated as drug carriers, dietetic supplements, antimicrobial agents or as adjuvants in anticancer therapy [3-9].
Unique 'magnetic' zeolite was obtained by Shan et al. Zeolite nanocrystals were in situ combined with superparamagnetic magnetite (Fe3O4) nanoparticles in the hydrothermal synthesis procedure. An high amount of enzymes adsorption and a good biocatalytic performance is shown by those newly formed magnetite/zeolite composite nanoparticles .
Zeolite of the CuX type has been used as a support for a antitumoral drug-cyclophosphamide. The in vivo tests show that the intensity of the antitumoral effects of the CuX zeolite- cyclophosphamide system is similar in comparison to the one achieved by cyclophosphamide alone . Ion-exchanged zeolites have also been used as a novel approach to storage and delivery of nitric oxide (NO) . Zeolite surface coatings offer antimicrobial protection through the controlled release of antimicrobial agent and can be applied to different types of surfaces or incorporated in many types of polymers [17, 18]. Rivera group prove that both zeolitic materials and drugs could be simultaneously administrated to a patient without any loss of an individual pharmaceutical effect of each product . Zeolite matrix has been also used to stabilize erythromycin solutions. An existing commercial product based on diisopropylsebacate/ethanol solution of 4% erythromycin and zinc acetate (Zineryt(r), Yamanouchi Pharma) has been compared to analogical system where active compounds are loaded into porous material .
Natural clinoptilolite is the main and active component of the antidiarrheal drug acting as adsorbent of bile acids, Aflatoxine B and Glucose . Recent studies show that this material can also be utilized as an adjuvant in anticancer therapy [10-13, 46-47]. The new antacid drug Neutacid(r) is based on the neutralizing capacity of the purified natural zeolite - clinoptilolite from the Tasajera deposit (Cuba) for therapy of patients suffering from hyperacidity produced by gastric dyspepsia and gastric-duodenal ulcer . Mesoporous material MCM-41, due to the pore size tunability and functionalization possibilities, can especially encapsulate a variety of different drug molecules and release them in controlled ways [27, 28, 30-36]. Zeolites containing silver ions are used as antimicrobial agents [53-57]. Zeolites are the main ingredient of commercially available anti-bleed agents .
Keywords: microporous materials, mesoporous materials, zeolite, drug delivery systems, drug carriers
1 Katedra Chemii Organicznej, Wydział Chemiczny, Politechnika Gdańska,
ul. G. Narutowicza 11/12, 80-233 Gdańsk
2 Zaklad Immunologii Klinicznej i Transplantologii, Gdański Uniwersytet Medyczny, ul. Dębinki 1, 80-210 Gdańsk
Bacterial cell wall peptidoglycan (PGN) is a potent immunostimulator and immune adjuvant. Numerous studies reported on immunoactivities of bacterial PGN, most of which have been reproduced by a chemically synthesized low-molecular PGN fragment, muramyldipeptide (MDP) 1 (Fig. 1) [2, 4, 5, 7, 8, 10, 13]. Another type of PGN fragment, desmuramylpeptides (DMPs), has also been chemically synthesized to mimic PGN containing meso-DAP, and the DMPs exerted similar bioactivities to MDP. In 1984  reported that γ-D-Glu-meso-DAP was the minimum structural unit capable of eliciting bioactivities induced by DMPs. Recently demonstrated that intracellular protein carrying a nucleotide-binding oligomerization domain (NOD), NOD2 an intracellular receptor for MDP and DMPs containing DAP was recognized by another NOD protein, NOD1 [8, 33]. Replacement of the N-acetylmuramyl moiety with various acyl groups thus represents an important approach to the design and synthesis of new immunologically active MDP analogues - desmuramylpeptides, e.g. FK-156 9, pimelautide 11 (Fig. 2), 7-(oxoacyl)-L-alanyl-D-isoglutamines, carbocyclic MDP analogues (Fig. 13) [3, 13] in which a more lipophilic cyclohexane ring is present instead of the polyhydroxy pyranose ring of D-glucosamine, and the adamantyl-substituted MDP analogue LK-415 (Fig. 8) . The FK-156 isolated from Streptomyces olivaceogriseus [21, 22] and its synthetic analogue of FK-565 10 (Fig. 2) have been reported to be a potent stimulant of antibody production and free of pyrogenicity. These compounds with close structural resemblance to bacterial cell wall peptidoglycan peptides, exhibit very interesting biological activities. Both FK-156 10 and FK-565 11 (Fig. 3) enhance host defense ability against microbial infections, exhibit strong antiviral activity and remarkable antitumor potency [2, 13, 14, 18].
Also other acyl-DMPs were obtained and their activity described (Table 1). The most promising DMPs analogues were series of phthalimido-DMPs 46-53 (Fig. 7). In these compounds N-acetylmuramic acid residue was replaced by various N-phthaloylated amino acids [42-49] or phthalimido substituted aminoethoxyacetic acid to give immunologically active acyclic MDP analogues like LK-423 46 (LK-413 47, LK-511 48, LK-512 49, LK-508 50) (Fig. 7) [42, 47-49]. LK-423 has been selected for further studies to develop an anti-inflammatory pharmaceutical agent. In 2001 Gobec et al.  reported the synthesis of new adamantyl-DMPs LK-415 55 and LK-517 56 (Fig. 8) with 1-adamantyl-carboxamido moiety replacing N-acetylglucosamine fragment in MDP. Their efficiency in modulating the production of cytokines IL-12, TNFα, IFNγ, IL-4, and IL-10 was measured in vitro in ionomycin and PMA activated cultures of PBMC, co-incubated with the analogues tested. The results were compared with the activity of MDP. All substances were strong regulators of IL-12 synthesis and IFNγ synthesis as well. Introduction of diethyl phosphonate moiety into LK-517 was of great importance for augmented T-cell cytokine production. Dzierzbicka et al.  described synthesis of three analogues of DMPs 57a,b, 58 modified with an amino-acridine/acridone residue. The screening data indicate that the analogues 57a,b and 58 (Fig. 9) exhibit low cytotoxic activity. Uehara et al.  reported MDP and DAP-containing desmuramylpeptides in combination with chemically synthesized Toll-like receptor agonists (Fig. 10) synergistically induced production of IL-8 in a NOD2- and NOD1-dependent manner, respectively, in human monocytic cells in culture. In 2008 Kawasaki et al.  designed synthesis of DAP containing PGN fragments and tracheal cytotoxin (TCT) (Fig. 5) and investigated their biological activity. Recently, N-acetylglucosamine-1,6-anhydro-N-acetylmuramylpentapeptide (Fig. 12) and evaluation of its turnover by AmpD from Escherichia coli has been reported . The synergism of MDP and DMPs with other chemotherapeutics is also promising in the therapy of many infectious and anticancer diseases.
This paper reviews the most important approaches to desmuramylpeptides (DMPs), their derivatives and displays structure-reactivity relationships of these compounds.
Keywords: desmuramylpeptides, DMPs, FK-156, FK-565, DAP, structure, biological activity
Zakład Chemii Analitycznej i Analizy Instrumentalnej, Wydział Chemii UMCS, Plac Marii Curie Skłodowskiej 3, 20-031 Lublin
From the chemical and electrochemical points of view aminophenol isomers are a group of compounds which can exhibit the properties typical of both the amines and/or phenols [1-5]. The position of the amine group and hydroxyl group in the aromatic ring is decisive to determine different properties of particular isomers. As concerns the chemical properties, including the ability to form electroactive films, out of the ortho, meta [6, 7] and para [6, 8, 9] isomers of aminophenol the o-aminophenol (oAP) seems to be the most important. The paper presents the process of chemical [12-16] and electrochemical [20-32] oxidation of oAP based on literature data. The products of chemical oxidation are: 2-aminophenoxasin-3-one of quinone diimine and quinones. As a result of the process of electrochemical oxidation of oAP many products were obtained, depending on conditions in which the process was carried out. For the oAP polymer were proposed: the ladder network structure of closed type, the structure with partially open ring, or simultaneous co-existence of both these structures.
The preparation of polymer film from poly(o-aminophenol) (PoAP) as well as its structure and properties were also described. The preparation of PoAP film of determined structure depends largely on conditions in which the electropolymerization process is performed and also on the purity of oAP used as initial substrate [62, 63]. The electrochromic properties of the film depend on the potential applied in the course of electrode process, pH, and the kind of electrolyte anions [27, 58]. The potential range of electrical conductivity was also discussed, as well as transport across modified PoAP electrodes [71-74] and electrodeposition of metals on modified PoAP electrodes [75-77].
The paper presents some applications of oAP and PoAP, such as the modification of Amberlite XAD-2 resin , production of actinomycin D [52-57], or possibilities of their application in electrodes [80-86] and as anti-corrosion coating .
oAP is an important organic compound also in view of its impact on a living organism. Therefore some biochemical properties of oAP such as the metabolism of oAP in human erythrocytes [36-40] or the damage of DNA due to oAP [41-45] could not be omitted.
Keywords: o-aminophenol, poly(o-aminophenol), electroactive polimer film
Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław
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