Binuclear platinum(II) complexes of the type [Pt2Cl2(μ-L)(μ-pz) (PR3)2] [L=SC5H4N or S2P(OR′)2]

Binuclear platinum complexes of general formula [Pt₂Cl₂(-L)(-pz)(PR₃)₂] [L = 2-Spy, py = pyridyl, S₂P(OR)₂ (R = Et or i-Pr); pz = pyrazolate; PR₃ = PEt₃, PMe₂Ph or PMePh₂] have been synthesized. They adopt a cis configuration in which the phosphine ligands are trans to the single atom bridging ligand, L.     

A Stability-Indicating LC Assay Method for Pemetrexed Disodium

This present work describes the development of a stability-indicating high performance liquid chromatographic method for the quantitative determination of pemetrexed disodium. Pemetrexed disodium is an antifolate antineoplastic agent that exerts its action by disrupting folate-dependent metabolic processes essential for cell replication. The chromatographic separation was achieved on an ACE 3 C18 HPLC column using a mobile phase consisting of a mixture of buffer (solvent A) and organic modifier acetonitrile (solvent B). Forced degradation studies were performed on bulk sample of pemetrexed disodium using acid (0.5 N hydrochloric acid), base (0.5 N sodium hydroxide), oxidation (10% v/v hydrogen peroxide), heat (60 °C) and UV light (254 nm). Degradation of the drug substance was observed in base hydrolysis. Degradation product formed under acid and base hydrolysis was found to be starting material. The stressed samples were assayed using the developed LC method and the mass balance found was close to 99.5%, thus proving its stability-indicating power. The developed method was validated with respect to linearity, accuracy, precision and robustness.     

Effect of poly (lactic acid)‐graft‐glycidyl methacrylate as a compatibilizer on properties of poly (lactic acid)/banana fiber biocomposites

The main aim of this study was to synthesis of poly (lactic acid) (PLA)‐graft‐glycidyl methacrylate (GMA) as well as its influence on the properties of PLA/banana fiber biocomposites. PLA‐graft‐GMA graft copolymer (GC) was synthesized by melt blending PLA with GMA using benzoyl peroxide and dicumyl peroxide as initiators. Graft copolymerization was confirmed by FTIR and ¹H‐NMR spectroscopic studies. PLA/silane treated banana fiber (SiB) biocomposites with various GC concentrations were prepared by melt blending followed by injection molding techniques. The influence of GC content on the mechanical, thermal and moisture resistance properties of the composite was investigated. The addition of 15 wt% GC content in the biocomposite provided optimum tensile and flexural strength, which is attributed to the greater compatibility between fiber and PLA matrix. The thermal properties of biocomposites have been evaluated using thermogravimetric analysis which provided evidence of improved interfacial adhesion between SiB and PLA by the addition of GC. Additionally, GC enhanced the moisture absorption resistance of biocomposites. These results indicated that GC is indeed a good candidate as a compatibilizing agent to improve the compatibility in PLA/fiber biocomposites. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and surface treatment of magnetite nanoparticles for tuning hydrophobicity and colloidal stability

Post-synthetic surface modification of magnetite nanoparticles synthesized by a modified co-precipitation process was carried out with triethoxy-terminated perfluoropolyether (PFPE) oligomers. The chemisorption of PFPE oligomers on the surface of magnetites was confirmed by ATR-FTIR and TGA analyses. The efficiency of surface modification of the oligomer to prevent the aggregation of magnetite nanoparticles was studied with the dynamic light scattering technique by measuring the hydrodynamic diameter and polydispersity index of the surface treated nanoparticles, together with their zeta potential. Aggregation kinetics profiles were constructed for surface treated nanoparticles. The obtained data was compared with magnetite nanoparticles treated with critic acid, to assess the efficiency of the surface modification with the PFPE oligomers. The comparison showed that the bifunctional PFPE oligomer treated nanoparticles are characterized by improved colloidal stability and hydrophobicity.     

C−H Bond Activation/Arylation Catalyzed by Arene–Ruthenium–Aniline Complexes in Water

Water‐soluble arene–ruthenium complexes coordinated with readily available aniline‐based ligands were successfully employed as highly active catalysts in the C?H bond activation and arylation of 2‐phenylpyridine with aryl halides in water. A variety of (hetero)aryl halides were also used for the ortho‐C?H bond arylation of 2‐phenylpyridine to afford the corresponding ortho‐ monoarylated products as major products in moderate to good yields. Our investigations, including time‐scaled NMR spectroscopy and mass spectrometry studies, evidenced that the coordinating aniline‐based ligands, having varying electronic and steric properties, had a significant influence on the catalytic activity of the resulting arene–ruthenium–aniline‐based complexes. Moreover, mass spectrometry identification of the cycloruthenated species, {(η⁶‐arene)Ru(κ²‐C,N‐phenylpyridine)}⁺, and several ligand‐coordinated cycloruthenated species, such as [(η⁶‐arene)Ru(4‐methylaniline)(κ²‐C,N‐phenylpyridine)]⁺, found during the reaction of 2‐phenylpyridine with the arene–ruthenium–aniline complexes further authenticated the crucial roles of these species in the observed highly active and tuned catalyst. At last, the structures of a few of the active catalysts were also confirmed by single‐crystal X‐ray diffraction studies.     

Ruthenium(II) polypyridyl complexes: potential precursors, metalloligands, and topo II inhibitors

Neutral and cationic mononuclear complexes containing both group 15 and polypyridyl ligands [Ru(kappa3-tptz)(PPh3)Cl2] [1; tptz=2,4,6-tris(2-pyridyl)-1,3,5-triazine], [Ru(kappa3-tptz)(kappa2-dppm)Cl]BF4 [2; dppm=bis(diphenylphosphino)methane], [Ru(kappa3-tptz)(PPh3)(pa)]Cl (3; pa=phenylalanine), [Ru(kappa3-tptz)(PPh3)(dtc)]Cl (4; dtc=diethyldithiocarbamate), [Ru(kappa3-tptz)(PPh3)(SCN)2] (5) and [Ru(kappa3-tptz)(PPh3)(N3)2] (6) have been synthesized. Complex 1 has been used as a metalloligand in the synthesis of homo- and heterodinuclear complexes [Cl2(PPh3)Ru(micro-tptz)Ru(eta6-C6H6)Cl]BF4 (7), [Cl2(PPh3)Ru(mu-tptz)Ru(eta6-C10H14)Cl]PF6 (8), and [Cl2(PPh3)Ru(micro-tptz)Rh(eta5-C5Me5)Cl]BF4 (9). Complexes 7-9 present examples of homo- and heterodinuclear complexes in which a typical organometallic moiety [(eta6-C6H6)RuCl]+, [(eta6-C10H14)RuCl]+, or [(eta5-C5Me5)RhCl]+ is bonded to a ruthenium(II) polypyridine moiety. The complexes have been fully characterized by elemental analyses, fast-atom-bombardment mass spectroscopy, NMR (1H and 31P), and electronic spectral studies. Molecular structures of 1-3, 8, and 9 have been determined by single-crystal X-ray diffraction analyses. Complex 1 functions as a good precursor in the synthesis of other ruthenium(II) complexes and as a metalloligand. All of the complexes under study exhibit inhibitory effects on the Topoisomerase II-DNA activity of filarial parasite Setaria cervi and beta-hematin/hemozoin formation in the presence of Plasmodium yoelii lysate.     

Synthesis and characterization of some novel 2‐{2‐[1‐(3‐substituted‐phenyl)‐1H‐1,2,3‐triazol‐4‐yl‐] ethyl}‐1‐substituted‐1H‐benzo [d] imidazole derivatives

Synthesis of some novel 2‐{2‐[1‐(3‐substitutedphenyl)‐1H‐1,2, 3‐triazol‐4‐yl‐]ethyl)‐1H‐benzo[d]‐imidazole derivatives, by the condensation of o‐phenylenediamine with 3‐(1‐(3‐substituted‐phenyl)‐1H‐1,2,3‐triazol‐4‐yl) propanoic acid and then subsequent reactions with different substituted alkyl halides as electrophiles are mentioned. The synthesized compounds were characterized by ¹H NMR, EI‐MS and IR spectroscopic techniques.     

Detection of amitraz,a formamidine-based pesticide using chromogenic spray reagent by thin-layer chromatography

JPC – Journal of Planar Chromatography – Modern TLC - In the present study, we developed a simple, sensitive and selective thin-layer chromatographic method for the detection and...     

Organic Brønsted acid-catalyzed cycloadditions of o-quinone methides with 1, 3-dicarbonlys: Facile access to xanthenones and chromanones

The in-situ generation of o-quinone methides and their inverse-electron-demand Diels–Alder reaction in the presence of pentacarboxycyclopentadiene—an organic Brønsted acid—has been reported. The synthesis of xanthenones and chromanones in good to excellent yields from the [4 + 2] cycloaddition of quinone methides with 1, 3-dicarbonyls and Meldrum's acid has been accomplished. The development of this method helps in generating a number of biologically potent heterocycles with medicinal applications.     

New synthetic strategy for Friedlander condensation of 4-amino-2-oxo-2H-chromene-3-carbaldehyde by heterogeneous catalysis

Chromenopyridines are an important class of compound because of their diverse biological activities. In the present work, we have developed convenient route for the synthesis of chromeno[4,3-b] pyridine derivatives ( 3a – e , 5a – e , and 7a – d ) by Friedlander condensation of 4-amino-2-oxo-2H-chromene-3-carbaldehyde with various active methylene compounds. We have used mixed metal oxide catalyst such as nanomaterial Zinc titanate. The reaction was carried out for various solvent systems, also we have altered the concentration of the catalyst. The 2-propanol/water solvent system and 5 mol% catalyst concentration are best as far as yield and rate of reaction are concerned. The structures of the synthesized compounds were confirmed by ¹H NMR, ¹³C NMR, mass spectra, and elemental analysis.