Complexes derived from some biologically active ligands

Complexes derived from ampicillin (L1) and amoxicillin (L2) with (Mg(II), Ca(II), Zn(II), Cu(II), Ni(II), Co(II), Ce(III), Nd(III), UO₂(VI), Th(IV)) were prepared and characterized by elemental analysis, electrical conductivity measurements, magnetic susceptibility, IR, UV/Vis, and thermogravimetry. The formed complexes can be formulated as (ML(H₂O)₃(NO₃) _n ) except for Ce(III) which gave (CeL(H₂O)₃(Cl)₂). The ¹H NMR spectra of the Zn(II) complexes are compared to spectra of the ligands. The shift (δ) gave information about the chelating center of the ligands. The ligands and the synthesized complexes, derived from some alkali earth and transition metal ions, were tested as antibacterial reagents. The formed complexes had enhanced activity.     

Discovery of a biologically active thiostrepton fragment

Design, synthesis, and biological evaluation of several domains of the thiopeptide antibiotic thiostrepton led to the discovery of a biologically active fragment. The biological properties of this novel small organic molecule include antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VREF) bacterial strains, as well as cytotoxic action against a number of cancer cell lines.     

An approach for the enantioselective synthesis of biologically active furanones from a Morita-Baylis-Hillman adduct

Herein, we disclose an approach for the asymmetric synthesis of both enantiomers of an anti-inflammatory furanone. The approach is based on the utilization of a Morita-Baylis-Hillman adduct as starting material and has as key step a selective epoxide-opening/benzylic oxidation mediated by Palladium (II). This sequence afforded an advanced intermediate, which was used to accomplish the total synthesis. Experimental evidences allowed us to suggest a mechanistic proposal for the oxidation Palladium(II)-mediated.     

Leaching-out of biologically active elements from enriched granulated phosphogypsum

Leaching-out of biologically active microelements (Mn²⁺, Zn²⁺) from grains of phosphogypsum enriched with macro-and microadditives introduced into its composition before granulation was experimentally studied.     

Synthesis of biologically active pyridazinoquinoxalines

The 2‐(1‐methylhydrazino)quinoxaline 4‐oxides 9a,b were converted into the pyridazino[3,4‐b]‐quinoxalines 10a,b,15a,b,22 and 1,2‐diazepino[3,4‐b]quinoxalines 29a‐c , which were further transformed into the 3‐substituted 1‐methylpyridazino[3,4‐b]quinoxalin‐4(1H)‐ones 5–8 .     

Isolation and sequencing of a new biologically active peptide from human lung carcinoma

A biologically active peptide designated hLCP has been isolated and purified to homogeneity from human lung carcinoma by means of acidic extraction and successive chromatography on Sephadex G-50, Toyopearl HW-40 F and reverse-phase high performance liquid chromatography columns. Analysis showed that peptide consists of thirteen amino acids. Primary structure of hLCP has been deduced by double-coupling Edman degradation combined with enzyme digestion as H-Ser-Pro-Pro-Asp-Gly-Lys-Lys-Glx-Ser-Ala-Asp-Val-Lys-OH. hLCP possessed significant excitatory activity on an electrical stimulation induced contraction. No hLCP could be detected in normal lung tissue. The possibility of using hLCP as a biochemical marker in the clinic for the early detection of lung carcinoma is being investigated.     

Different extraction methods of biologically active components from propolis: a preliminary study

Background  

Propolis is widely used in apitherapy, preparations, and food and beverage additives. Various extraction techniques were applied in the extraction of the biologically active constituents of poplar type propolis in order to compare their efficiency. The methods employed were: traditional maceration extraction, ultrasound extraction (UE), and microwave assisted extraction (MAE).     

Structure of holothurin A a biologically active triterpene-oligoglycoside from the sea cucumber holothuria leucospilota brandt

On the basis of chemical and physicochemical evidence, the structure of holothurin A, a biologically active major obligoglycoside o lanostane-type triterpene holothurigenol ($\text{2}$), has been elucidated to be $\text{8}$.     

Modification of biologically active plant metabolites via the metal complex catalysis reactions as a promising direction in medicinal chemistry

Developed by the authors methods for the functionalization of some plant metabolites or their derivatives, viz., the eudesmane-type methylidenelactones, diterpene and morphinane alkaloids, furanolabdanoids, lupanes triterpenoids, and coumarins, using the metal complex catalysis, are reviewed.     

Mass spectra of dalargin, a biologically active hexapeptide

Electrospray ionization mass spectra (MS and MS² of protonated molecules) of dalargin, hexapeptide used in medicine are presented and all of the fragment ions in MS² are assigned.     

A conformational study of a biologically active conjugated syn-oxime

The conjugated system (E)-tiglaldoxime is the simplest example of a perillartine analog which exhibits sweetness with a taste potency greater than sucrose with almost no bitter aftertaste. In previous studies, the structure of this biologically active compound has been assumed to be planar with the C?C double bond trans to the C?N bond of the oxime moiety. In this article a conformational analysis of this molecule is reported. The results indicate that, although the trans conformer of the planar molecule is indeed the global minimum, other conformers lie within a few kilocalories of this minimum. Hence, other accessible conformations may be available for interaction with the receptor and, therefore, may be biologically active. The structural parameters obtained for this conjugated syn-oxime are nearly identical to those of (E)-acetaldoxime. This fact has implications for the transferability of these parameters to the more complicated perillartine analogs.     

Mechanical composites based on biologically active compounds from larch wood

Mechanical composites were prepared by mechanical chemical processing of a mixture of biologically active preparations of arabinogalactan (AG) and dihydroquercetin (DQ) isolated from larch wood. Their properties were studied using HPLC, ¹³C NMR, and IR spectroscopy. It was found that AG and DQ did not react chemically under the studied conditions. According to x-ray phase and thermal analyses, mechanical processing destroyed the DQ crystalline structure and dispersed it into the AG matrix. The resulting mechanical composites had significantly higher (up to 38 times) solubility in water compared with starting DQ and an unprocessed AG/DQ mixture. It was shown that DQ reduces the extent of destruction of polysaccharide macromolecules during mechanical processing.     

Mass spectrometry of biologically active substances

The mass spectra of 2- and 4-iminobarbituric acid derivatives were studied in relation to the mass spectra of their oxygen analogs. It is shown that the pathways of fragmentation of the investigated compounds depend on the type of substituent attached to the C₅ atom, the position of the imino and oxo groups in the ring, and the specific mass-spectral properties. The fragmentation was studied by means of low-voltage mass spectrometry and deuterium labeling.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 813–817, June, 1978.     

Electrochemical studies of biologically active indolizines

The electrochemical behavior of indolizine ethers, esters, tosylates, sulfonates and other indolizine and azaindolizine derivatives has been investigated by cyclic voltammetry and preparative electrolysis. The cyclic voltammetric data show that the E° values, taken as the midpoints between the anodic and cathodic peak potentials, are sensitive to the identities of the substituents at C-1, C-2 and C-7 positions. The E° values have been correlated with the Hammett substituent parameters. As expected, low E° values are seen for electron donating substituents and higher E° values are seen for electron withdrawing substituents. The cyclic voltammograms of indolizine derivatives with an oxygen atom connected to the C-1 position exhibit a one-electron reversible oxidation and a further, less well-defined, one-electron irreversible oxidation at higher E° values. The cyclic voltammograms of indolizines with hydrogen atom or thienyl substituents connected to the C-1 position exhibit only a one-electron irreversible oxidation. Electrochemical bulk oxidations of indolizines with an oxygen atom at the C-1 position afforded oxoindolizinium salts in decent yields, whereas indolizines with a hydrogen atom at C-1 afforded 1,1′ dimers of indolizines as products in good yields. Bulk oxidation of 1-(α-hydroxybenzyl)-2,3-diphenylindolizine-7-carbonitrile afforded an unexpected ketone product in which the carbonyl group of the indolizine is connected at C-8 instead of at the C-1 position of the starting material. The findings described herein support our hypothesis that certain indolizine derivatives may inhibit lipid peroxidation by an electron transfer mechanism.     

Syntheses of biologically active sialosylglycerol derivatives

New sialosylglycerol derivatives were synthesized and found to inhibit the phospholipase A2 and C activities.