Isolation and identification of anthraquinones of Caloplaca cerina and Cassia tora

Five hydroxyanthraquinone derivatives physcion, emodin, fallacinal, teloschistin, and 1,3-dimethoxy-8-hydroxy-6-methyl-9,10-anthraquinone were isolated from the lichen Caloplaca cerina growing in Serbia. Three anthraquinone derivatives, namely physcion, emodin, and rhein were isolated and identified from the Thai medicinal plant Cassia tora. Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May 2006.     

Column high-performance liquid chromatographic determination of norfloxacin and its main impurities in pharmaceuticals

A gradient reversed-phase column high-performance liquid chromatographic method was developed for the detection and quantification of norfloxacin and its major impurities in norfloxacin-containing pharmaceuticals. Chromatographic separations were performed under the following experimental conditions: column, Zorbax SB RP-18 (5 microm, 250 x 4.6 mm); injection volume, 20 microL; mobile phase, 0.05 M NaH2PO4 (pH 2.5)-acetonitrile (87 + 13) for 16 min and (58 + 42) for 9 min (stepwise gradient); and flow rate, 1.3 mL/min. All analyses were performed at 25 degrees C, and the eluate was monitored at 275 nm using a diode array detector. Linearity (correlation coefficient = 0.999), recovery (99.3-101.8%), relative standard deviation (0.2-0.7%), and quantitation limit (0.12-0.47 microg/mL) were evaluated and found to be satisfactory. The method is simple, rapid, and convenient for purity control of norfloxacin in both raw materials and dosage forms.     

Sorbent-excluding sample preparation method for GC–MS pesticide analysis in apple peel

Apple peel is frequently exposed to pesticides, especially in the last stages of the pesticide treatment practice. For a certain period, peel retains most of the applied pesticides, which precisely indicates the presence of pesticide residues. This study was conducted to establish and evaluate the method for the residue analysis of pyrimethanil, cyprodinil, trifloxystrobin, bifenthrin and boscalid by GC–MS in peel of Granny Smith, Golden Delicious and Idared varieties. The method consisted of few steps, without the routine usage of sorbents, and resulted in efficient removal of waxes, targeted as main interferences in GC–MS analysis. The matrix effect, boscalid selectivity issue, trend of lower trueness for bifenthrin in all matrices and for all analytes in Granny Smith matrix were in some way associated with the waxes. Finally, the method was applied to the analysis of three varieties of apple orchard samples, after 9 and 5 months of treatment with commercial formulations that contain pyrimethanil, cyprodinil and boscalid as active ingredients. Since the developed method consisted of few steps and used nontoxic and economic reagents, it could be implemented as a fast, economic and reliable screening method.     

Transition metal complexes with thiosemicarbazide-based ligands. Part LVI: Nickel(II) complex with 1,3-diphenylpyrazole-4-carboxaldehyde thiosemicarbazone and unusually deformed coordination geometry

Synthesis of a new nickel(II) complex, [Ni(Ph₂PzTSC-H)₂] with 1,3-diphenylpyrazole-4-carboxaldehyde thiosemicarbazone (Ph₂PzTSC), is described. The compounds have been characterized by elemental and thermal analysis, molar conductivity and spectral (UV–Vis, IR, ¹H NMR, and ¹³C NMR) measurements. In the case of complex the magnetic measurement has been also performed. Crystal and molecular structures of both the free ligand and the complex have been determined by single crystal X-ray analysis. It was found that the ligand coordinates in a bidentate NS fashion, in its deprotonated thioenolato form. The cis-square-planar geometry of the complex is significantly distorted tetrahedrally. The Cambridge Structural Database (CSD) study has been performed to obtain geometrical and structural informations on similar nickel(II) complexes in order to compare structural data.     

Semilattices of Nil-extensions of Simple Regular Semigroups

Semigroups decomposable into a semilattice of Archimedean semigroups, having certain additional properties such as the intra-, left, right and complete -regularity, have been investigated in many papers. In the present paper, we study the -regular ones. Among other things, we characterize them as semilattices of nil-extensions of simple regular semigroups. The obtained results generalize some results given by Munn, Putcha, Shevrin, Bogdanovi, iri, and others.2000 Mathematics Subject Classification: 20M10, 20M17     

Structure and properties of a series of 2-cinnamoyl-1,3-indandiones and their metal complexes

A series of seven 2-cinnamoyl-1,3-indandiones and their metal(II) complexes were synthesized and characterized by means of spectroscopic (IR, NMR, electron absorption and emission spectroscopy) and/or single-crystal X-ray diffraction methods. The optical spectra of the organic compounds show very strong absorption in the visible region and weak fluorescence with moderate to strong Stokes shift. The effect of concentration, water addition and metal ion complexation on the optical properties was also studied. In search of potential practical application, the complexation of 2-cinnamoyl-1,3-indandiones with metal(II) ions was investigated. A series of non-charged complexes with Cu(II), Cd(II), Zn(II), Co(II) and Ni(II) was isolated and analyzed by elemental analyses and IR. Most of the complexes show presence of water molecules, most probably coordinated to the metal ion, thus forming octahedral geometry. For the paramagnetic Cu(II) complexes a distorted, flattened tetrahedral structure is proposed, basing on the EPR data. The optical properties of the metal complexes, however, do not differ appreciably from those of the free ligands.     

Stereospecific ligands and their complexes. IV: Synthesis,characterization and cytotoxicity of novel platinum(IV) complexes with ethylenediamine-N,N′-di-S,S-2-propanoate and halogenido ligands: Crystal structure of s-cis-[Pt(S,S-eddp)Cl2]·4H2O and uns-cis-[Pt(S,S-eddp)Br2]

The syntheses of two novel platinum(IV) complexes of formula [PtX₂(S,S-eddp)]·nH₂O (S,S-eddp = ethylenediamine-N,N′-di-S,S-2-propanoate ion, X = chlorido (1) or bromido (2), n = 4, 0) are reported. The complexes have been obtained by direct reaction of corresponding potassium hexahalogenidoplatinate(IV) with neutralized ethylenediamine-N,N′-di-S,S-2-propanoic acid (H₂-S,S-eddp). The complexes were characterized by elemental analysis, infrared, ¹H and ¹³C NMR spectroscopy. The spectroscopically predicted geometrical configurations of the obtained complexes were confirmed by X-ray analyses of the crystal structures of the s-cis-[Pt(S,S-eddp)Cl₂]·4H₂O and uns-cis-[Pt(S,S-eddp)Br₂]. These complexes displayed significantly lower in vitro cytotoxicity in comparison to cisplatin.