Modification of PP fibres with alkaline copolyamides

Copolyamides with 5.9‐19.7 wt.% of nylon salt ADETA (adipic acid + diethylenetriamine) and 94.1‐80.3 wt.% of ϵ‐caprolactam were synthesized and their properties were estimated. Blended polypropylene/copolyamides fibres containing 5‐15 wt.% of copolyamides were prepared and their properties were evaluated. The electrical properties, hydrophilicity and especially dyeability of modified PP fibres are positively influenced by a higher amount of the copolyamide in the PP and also by a higher amount of the nylon salt ADETA in the copolyamide.     

Enantioselective multicomponent synthesis of fused 6-5 bicyclic 2-butenolides by a cascade heterobicyclisation process

The successive coupling of an alkoxy(aryl/heteroaryl)carbene complex of chromium with either a ketone or an imide lithium enolate and then a 3-substituted (H, TMS, PhCH(2), PhCH(2)CH(2), Me) propargylic organomagnesium reagent has afforded novel hydroxy-substituted bicyclic [4.3.0]-γ-alkylidene-2-butenolides with three modular points that has allowed the efficient introduction of molecular complexity, including a homopropargylic alcohol core. The selective formation of these five- or six-component heterobicyclisation products is the result of the regioselective integration of the Grignard reagent as a propargyl fragment followed by a cascade CO/alkyne/CO insertion, ketene trapping and elimination sequence. By using lithium enolates of chiral N-acetyl-2-oxazolidinones and the corresponding propargylic organocerium reagents, both enantiomers of these bicyclic heterocycles were efficiently prepared with very high enantiomeric purity. Architecturally, these fused bicyclic butenolides are characterised by a highly unsaturated and oxygenated core and they exhibit strong blue fluorescence in solution.     

Lactide Polymerisation with Air‐Stable and Highly Active Zinc Complexes with Guanidine–Pyridine Hybrid Ligands

New class of air‐stable catalysts for lactide polymerisation: Guanidine–pyridine hybrid ligands (picture, left) were used to prepare a series of zinc complexes (e.g., depicted cation [ZnL₂(CF₃SO₃)]⁺, where L is the quinoline‐containing ligand with R¹=R²=R³=R⁴=Me), in which the ligand binds through two different N‐donor atoms. The zinc complexes show high activity in ring‐opening polymerisation of d,l ‐lactide (right), giving polylactide with molecular masses up to 176 000 g mol^?1 and in high yield.

     

Die Bestimmung von Adrenalin allein und in Mischungen

Ohne Zusammenfassung     

Structure elucidation,DNA binding,DFT, molecular docking and cytotoxic activity studies on novel single crystal (E)-1-(2-fluorobenzylidene)thiosemicarbazide

Compound 3 {(E)-1-(2-fluorobenzylidene)thiosemicarbazide} – a new Schiff base of thiosemicarbazide has been synthesized, characterized and reported for crystal structure. Planer side chain in the crystal structure was observed co-planer with aromatic ring plane and molecules were connected into centrosymmetric dimmers via intermolecular hydrogen bonding. DFT geometry optimization and the relevant quantum parameters indicated unstable and reactive nature of compound 3. Experimental and theoretical findings for DNA binding by UV–visible, cyclic voltammetry and molecular docking studies showed consistency in kinetic (K_b) and thermodynamic (ΔG) parameters and that compound 3 significantly interacted with DNA via intercalation. Viscometric analysis further comprehended intercalation as possible binding mode of the compound with DNA and non-denaturing of DNA in the presence of 10% aqueous DMSO. Docked parameters further assured the drug like characteristics of the investigated compound as fit in Lipinski’s criteria. Dose dependant cytotoxic activity of compound 3 against human Huh-7 cell line indicated its anti-cancer potential at 100?µg/ml concentration.     

Chiral auxiliary based approach toward the synthesis of C-glycosylated amino acids

[reaction in text] In a chiral auxiliary based method C-glycosylated amino acids can be obtained by a 1,3-dipolar cycloaddition of a chiral glycine equivalent and C-1 allyl- or vinyl-derived carbohydrate building blocks as the key step. The products are formed regio- and diastereoselectively. Reductive cleavage of the N-O bond of the isoxazolidine and of the chiral auxiliary leads to C-glycosylated amino acids. The use of (-)-menthone to (+)-menthone as the auxiliary leads to the corresponding diastereomers.     

New Factorial Designs to Evaluate Chemisorption of Divalent Metals on Aminated Silicas

Adsorption processes of Cu(II), Co(II), and Hg(II) on two aminated silica gel surfaces with immobilized ethylenediamine and diethylenediamine groups were studied by a new 2(3) full factorial design. Two metal quantity levels, temperatures of 25 and 50 degrees C, and silica amounts of 100 and 200 mg were employed. Our study indicates that higher factorial design levels increase adsorption for all metals evaluated, with the exception of the mass parameter. Adsorption is also significantly affected by important antagonistic and synergistic effects involving all factors. Both functionalized silica gel surfaces present higher interactions and good perspectives in preconcentration studies for mercury. The factorial design results are also discussed in terms of some solvation properties for each of the metals studied. Copyright 2001 Academic Press.     

Kristallstruktur und Konformation eines linearen Pentapyrrols

The crystal structure of the pentapyrrin1 was determined by X-ray diffraction methodes at two temperatures (298K and 97K). It is the first structure determination of a linear polypyrrole with more than four pyrrole rings. In the crystal, the molecule is located on a crystallographic two-fold axis, which passes through the central pyrrole ring. It assumes a helical overall-conformation, which is stabilized by intramolecular hydrogen bonding. The acidic proton at the nitrogen atom of the central pyrrolic ring is disordered, being observed with half occupancy at two symmetry-equivalent positions off the crystallographic diad. Attempts to remove the disorder by cooling to 97K were unsuccessful, since no indication for a phase transition was detected.

     

Antioxidant activity of (+)-bergenin: a phytoconstituent isolated from the bark of Sacoglottis uchi Huber (Humireaceae)

(+)-Bergenin (1) was isolated from Sacoglottis uchi, a species of vegetable found in the Amazon region and popularly used for the treatment of several hepatic problems. The structure of 1 was fully characterized using IR, GC-MS and NMR (1D and 2D) analyses. This phytoconstituent has been used as an oriental folk medicine for the treatment of many diseases and shows antihepatotoxic properties. Tests with beta-carotene, DPPH and a heterogeneous Fenton system were carried out, confirming the antioxidant activity of 1. Theoretical calculations were performed to investigate the formation of the radical derivatives of 1 using *H, *OH, *CH(3), and *CCl(3) as initiator radicals. DFT thermodynamic calculations showed that the methoxyl group (O-6-CH(3)) is the most favorable site for radical attack. Frontier molecular orbital analysis showed that nucleophilic radical attack is favored on the aromatic ring of 1 where the LUMO is localized, with antibonding character with respect to the O-6-CH(3) bond. The possibilities of attack at other sites on 1 were investigated in detail in order to understand the regiospecificity of this reaction.