Synthesis, characterization and coordination properties of bis(alkyl)selenosalen ligands

New bis (alkyl) selenosalen podand ligands having Se2N2 donor sites have been synthesized by the condensation of unsymmetrical o-formylphenyl alkyl selenide (1-3) with ethylenediamine. The reaction of bis(alkyl)selenosalen podands with Pd(II) and Pt(II) afforded selenoether-selenolate coordination complexes 7-10via cleavage of one of the two Se-C(alkyl) bonds of bis(alkyl)selenosalen podands upon complexation. DFT calculations revealed that the cleavage of Se-C(alkyl) bonds occurred possibly via S(N)2 mechanism instead of a sequence of oxidative addition and reductive elimination reactions. The spectral data and elemental analyses confirmed the formation of selenoether-selenolate complexes. The structures of the podands N,N'-bis[(2-methylseleno)phenylmethylene]-1,2-ethanediamine (4), N,N'-bis[(2-decylseleno)phenylmethylene]-1,2-ethanediamine (5) and the selenoether-selenolate complex 8 have been determined by single crystal X-ray diffraction analysis. The crystal structure of 5 showed SeH interaction with a ladder like 3D supramolecular arrangement via interdigitation of long alkyl chains. Comparison of crystal packing of podands 4 and 5 indicates that the alkyl chain length has significant impact on the crystal packing. The platinum selenolate complex 8 shows a square planar arrangement around the Pt centre, where the Se atoms in the selenolate and the selenoether have nearly equal Pt-Se bond length.     

A new three-component reaction: green synthesis of novel isoindolo[2,1-a]quinazoline derivatives as potent inhibitors of TNF-α

Concurrent construction of five and six membered fused N-heretocyclic ring was achieved via a conceptually new three-component reaction affording 6,6a-dihydroisoindolo[2,1-a]quinazoline-5,11-diones as novel inhibitors of TNF-αin vitro. This represents one of the few examples of direct TNF-α inhibition by small molecules.     

A mild and efficient synthesis of chiral tetrahydroquinolino pyranose derivatives catalyzed by lanthanum(iii) nitrate hexahydrate

A mild and highly efficient synthesis of chiral tetrahydroquinolino pyranose derivatives is described. The reaction of a chiral α,β‐unsaturated aldehyde containing a hydroxyl group with different aryl amines using lanthanum(III) nitrate hexahydrate as a catalyst afforded corresponding chiral tetrahydroquinolinated pyranosides in excellent yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:429–433, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20441     

Tri­phenyl(3,4,5‐tri­iodo­phenyl)­methane

The crystal structure of the title compound, alternatively called 1,2,3‐triiodo‐5‐(triphenylmethyl)benzene, C₂₅H₁₇I₃, is analysed in terms of I⋯I and I⋯π interactions and the herring‐bone T motif between phenyl groups. There are two mol­ecules in the asymmetric unit, denoted A and B. Inversion‐related A mol­ecules are connected via an I⋯π interaction (3.641 Å, to a C—C bond mid‐point) to form an I⋯π dimer, and these dimers are connected through symmetry‐independent B mol­ecules via I⋯I [3.5571 (15) Å] and I⋯π (3.561 Å, to a C—C bond mid‐point) interactions.     

Comparative assessment of two sequential chemical extraction schemes for the fractionation of cadmium, chromium, lead and zinc in surface coastal sediments

Two existing sequential chemical extraction schemes, involving respectively five and six leaching steps with solutions of increasing dissolving power, were compared. The methods have been applied to surface sediment samples collected in a marine estuary zone potentially exposed to contamination arising from nearby industrial activities. A certified reference material (MURST-ISS-A1) consisting of an Antarctic bottom sediment for which no information regarding phase dependent concentration is available, was also analyzed. In order to evaluate the partition of metals among different geochemical forms, the concentrations of cadmium, chromium, lead and zinc were measured in the liquid extracts by Zeeman-corrected flame atomic absorption and by inductively coupled plasma-atomic emission spectrometry. The total metal concentrations were determined after strong acid attack, and the adequacy of this total digestion/dissolution technique was verified by its application to the reference material. Comparison of total metal concentrations with the sum of concentrations associated with the individual phases was employed to assess possible analyte losses or contaminations. Precisions for both sequential procedures were comparable, but some inconsistencies in mass balances were found in one of the samples for the distribution of Zn in the soluble/exchangeable fractions and for Cd in the bound to carbonates form. In addition, the six steps procedure produced lower concentration values in the case of elements associated to the residual fraction. For the five steps method mass balances showed acceptable agreement, with average recoveries in the 87 to 106% range. On the whole, differences in metal distributions were observed, being more marked for the bottom sediment. Significant proportions of the studied elements, with the exception of Cr, were found as easily extractable forms. X-ray diffraction and petrographic observation of the surface sediments allowed qualitative correlation between the leaching results obtained and the presence of defined geochemical phases.     

Synthesis,Crystal Structure,and Spectral Study of a Novel Indenoimidazole Carboxylic Acid Amide

Russian Journal of Organic Chemistry - 3a,8a-Dihydroxy-2,8-dioxo-1,3a,8,8a-tetrahydro-2H-indeno[1,2-d]imidazole-3-carboxamide has been synthesized in 85% yield from ninhydrin and biuret via a green...     

Studies on nepalese crude drugs. XXVIII. Chemical constituents of Bhote Khair, the underground parts of Eskemukerjea megacarpum HARA

From the underground parts of Eskemukerjea megacarpum HARA, two new stilbenes (14, 15) were isolated, together with a known coumarin, 5,7-dihydroxycoumarin (1), a tyramine derivative, trans-feruloyltyramine (2), two pyrogallol derivatives, gallic acid (3) and beta-glucogallin (4), four flavonoids, trifolin (5), hyperin (6), myricetin 3-O-beta-D-galactopyranoside (7), and myricitrin (8), five stilbenes, resveratorol (9), astringenin (10), piceid (11) astringin (12), and resveratorol 3-O-beta-D-(6-O-galloyl)glucopyranoside (13), a flavan-3-ol, (-)-epigallocatechin 3-O-gallate (16), two proanthocyanidins, catechin-(4alpha-->8)-epigallocatechin 3-O-gallate (17) and epicatechin 3-O-gallate-(4beta-->8)-epigallocatechin 3-O-gallate (18), and an anthocyanin, idaein (19). Compounds 14 and 15 were identified as (E)-3,5,3',4'-tetrahydroxystilbene 3-O-beta-D-(6-O-galloyl)glucopyranoside and (E)-3,5,4'-trihydroxystilbene 3-O-beta-D-(6-O-galloyl)glucopyranoside, respectively, based on spectral and chemical data.     

Two new macrocyclic diaryl ether heptanoids from Boswellia ovalifoliolata

The stems of Boswellia ovalifoliolata BAL. & HENRY (Burseraceae) afforded two new macrocyclic diaryl ether heptanoids, ovalifoliolatin A (1) and B (2) together with three known compounds; acerogenin C (3), 3 alpha-hydroxyurs-12-ene (4), and sitost-4-en-3-one (5). The structures were established by means of spectroscopic analysis and compounds 1, 3-5 were evaluated for their antibacterial activity.     

Evaluation of sorption and desorption characteristics of cadmium, lead and zinc on Amberlite IRC-718 iminodiacetate chelating ion exchanger

A chelating type ion exchange resin (Amberlite IRC-718), containing iminodiacetate groups as active sites, has been characterized regarding the sorption and subsequent elution of Cd, Zn and Pb, aiming to metal preconcentration from solution samples of different origins. The methodology developed is based on off-line operation employing mini columns made of the sorbent. The eluted metals were determined by flame atomic absorption spectrometry. The effect of column conditioning, influent pH and flow rate during the sorption step, and the nature of the acid medium employed for desorption of the retained metals were investigated. Working (breakthrough) and total capacities were measured under dynamic operating conditions and the results compared with those obtained with Chelex-100, a resin extensively employed for analytical preconcentration. Structural information on the complexation of metals by the chelating groups was obtained by Fourier Transform infrared spectrometry. The analytical response of the Amberlite sorbent was assessed for the analysis of water samples and digestates of marine sediments.