http://www.sciforum.net/conf/ecsoc-14 The 14th International Electronic Conference on Synthetic Organic Chemistry The 14th International Electronic Conference on Synthetic Organic Chemistry http://www.sciforum.net/presentation/436 Dye sensitized solar cells (DSSCs) are currently attracting widespread academic and commercial interest for the conversion of sunlight into electricity because of their low cost and high DSSCs are similar to natural photosynthesis in the initial processes involving in light-harvesting and charge separation. To gain a better understanding of the role of the sensitizer, particularly of its electronic structure and excited-state properties in the efficiency of dye-sensitized solar cell devices, we have carried out Density Functional Theory (DFT) and Time Dependent DFT (TDDFT) calculations in solution of the geometry, electronic structure and optical absorption spectra of a Chl a derivative (methyl 3-devinyl-3-carboxypyropheophorbide a; Phe a) and its Mg-Phe a and Zn-Phe a -derived sensitizers. Calculations have been performed using the B3LYP exchange correlations functional, as implemented in the Gaussian03 program package. The geometries of were first optimized in vacuum using density functional 6-311G(d) method. Solvation effects were included by means of the Conductor-like polarizable continuum model (C-PCM) in the dichloromethane solvent. There are good agreement between the experimental and the TDDFT calculated absorption spectra of three Different Chlorophyllous sensitizers. From the orbital analysis and the orbital spatial orientation of HOMO and LUMO for Phe a, Mg-Phe a and Zn-Phe a -derived sensitizers, the result shows that Phe a seems to provide higher photo-to-electric conversion efficiencies. 2010-11-11 2010-11-11T00:00:00Z http://www.sciforum.net/presentation/496 Catalytic oxidation of cyclohexane by two metalloporphyrins {manganese and iron 5, 10, 15, 20-meso-tetrakis-(p-chlorophenyl) porhyrin}immobilized in mesoporous MCM-48 with TBHP in acetonitril was investigated. It was found that immobilization significantly enhances catalytic activity as compared to the homogenous system. 2010-11-05 2010-11-05T00:00:00Z http://www.sciforum.net/presentation/394 We studied the description of charge-transfer excitations in [CuL2]+ (L=6,6′-dimethyl-2,2′-bipyridine-4,4′-bis(propenoic acid)) dye sensitizer. This dye was studied using density functional theory (DFT), and the electronic absorption spectrum was investigated via time-dependent DFT (TD-DFT) with several hybrid functional, both in the gas phase and in acetonitrile solution. We also have investigated HOMO and LUMO levels in gas and solvent phases for these dyes. The HOMOLUMO transition describes all lowest singlet excited states. We performed TDDFT calculations at the B3LYP/6-31G(d) level of theory. Solvation effects were included by the conductor-like polarizable continuum model (CPCM ). The excitation in the range 500-800 nm of absorption spectra confirms metal-to-ligand charge-transfer (MLCT) transitions. The results of this work suggest that the copper complexes are effective as sensitizers for DSSCs and they can replace ruthenium (II) complexes. 2010-11-05 2010-11-05T00:00:00Z http://www.sciforum.net/presentation/495 5-(3,5-Dibromo-2-hydroxyphenyl)-2,3,4-trihydro-1,2,4-triazole-3-thione(4) and 3-[(5-bromo-or 3,5-dibromo-2-hydroxy-phenylmethylene)-amino]-4-oxo-imidazolinidin-2-thiones(7a,b)were prepared via the reaction of 2,3,5trisubstituted benzaldehyde thiosemicarbazones(2a,b)with bromine in acetic acid and ethylchloroacetate in presence of fused sodium acetate. While 5-(4-methylphenyl-2-[3,5-dibromo-2-hydroxy-phenylmethylene)-hydrazion]-thiazole(5) prepared via reaction of (2b) with 4-methyl phenacylbromide. Acylation of (2b) and (5) with acetic anhydride gave the corresponding diacetyl derivatives (3) and (6). 2010-11-03 2010-11-03T00:00:00Z http://www.sciforum.net/presentation/493 2-(5-Mercapto-4-phenyl-4H-[1,2,4]triazol-3-ylmethyl)-6-p-tolyl-4,5-dihydro-2H-pyridazin-3-one (3) was prepared according to the established sequenced procedures 1-3 . Subsequently by using selected alkylating agents; compounds 4a-c were prepared via regioselective S alkylation procedure4. Alternatively, compounds 5a-c were prepared via regioselective addition procedure 4 . Under Mannich condition, some interesting compounds 7a,b and 8a,b were successfully prepared. On the other hand, the azides 10 and 15 coupled with amino acid esters 11a-d and 15a- d to give amino acids derivatives 12a-d and 16a-d in good to moderate yield respectively. The structural elucidation of products is reported and also some of the products were screened for their antimicrobial activity. 2010-11-03 2010-11-03T00:00:00Z http://www.sciforum.net/presentation/494 1-acetyl-3-[(5-bromo-2-acetoxy-phenylmethylene)-amino]-4-oxo-imidazolidin-2-thione (2) and 5-acetyl-3-[(5-bromo-2-hydroxy-phenylmethylene)-amino]-4-oxo-imidazolidin-2-thione(3)prepared by Acylation of 3-[(5-bromo-2-hydroxy-phenylmethylene)-amino]-4-oxo-imidazolidin-2-thione(1) by different method. The reaction of 3-[(5-bromo-2-hydroxy-phenylmethylene)-amino]-4-oxo-imidazolidin-2-thione (1) with bromine in presence of glacial acetic acid resultthe 5-bromo- 3-[(5-bromo-2-hydroxy-phenylmethylene)-amino]-4-oxo -imidazolidin-2-thione (4). The Acylation of compound (4) with acetic anhydride led to formation 5-bromo-1,5-diacetyl-3-[(5-bromo-2-acetoxy-phenylmethylene)-amino]-4-oxo-imidazolidin-2-thione (5). The hydrazinolysis of compound (1) with hydrazine hydrated led to formation of 2, 4-dihydrazino-3-[(5-bromo-2-hydroxy-phenylmethyl)-amino]-imidazolidine (6). The condensation of compound (1) with different aldehyde led to formation of (7a-c). The action of acetic anhydride on compounds (7a-c) under reflux led to formation of (8a-c). 2010-11-03 2010-11-03T00:00:00Z http://www.sciforum.net/presentation/415 The electronic, structural and spectroscopic properties of the Coumarin NKX-2697 dye in gas and water solvent by the conductor-like polarizable continuum model (CPCM) to account for soulate-solvent interactions have been investigated by means of combined DFT/TD-DFT calculations. Using time dependent density functional theory (TD-DFT), we calculate excitation energies and oscillator strengths. The spectra in the range of 470-1100 nm were found to originate from transitions.We also have investigated HOMO and LUMO levels in gas and solvent phases for this dye. Inclusion of the solvent leads to important changes of the energies and composition of the molecular orbitals of the dye. 2010-11-03 2010-11-03T00:00:00Z http://www.sciforum.net/presentation/393 Molecular geometries, electronic structures, and optical absorption spectra were investigated using density functional theory (DFT) at the HF/3-21G and B3LYP/3-21G levels for heteroleptic ruthenium dye, both in the gas phase and in water solution. The vertical excitation energies were calculated within the framework of the time-dependent DFT (TD-DFT) approach, whereas the solvent effects were taken into account using the conductor like polarizable continuum model (CPCM). Our results show that the three highest occupied molecular orbitals (HOMOs) are composed of Ru 4d orbitals. The spectra in the range of 350-600 nm were found to originate from metal-to-ligand charge-transfer (MLCT) transitions. The solvent effects lead to changes in both the geometries and the absorption spectra. The results of this work suggest that Ruthenium-based complexes might be effective sensitizers for next-generation dye-Sensitized Photoelectrochemical Cell. 2010-11-03 2010-11-03T00:00:00Z http://www.sciforum.net/presentation/488 ZSM-11 samples were synthesized and treated with small amounts of Pt and Au substrates (1 & 4wt% metal). The effects of this treatment on the structural, textural, and catalytic properties of the employed zeolite were studied. The acidity of Pt and Au-containing ZSM-11 solids was determined. The techniques employed were XRD, pyridine adsorption using FTIR-technique, N2 adsorption at -196 ºC, and catalytic conversion of isopropyl alcohol at 110-275 ºC using a flow technique. The treatment of ZSM-11with Au and Pt-species resulted in a structure collapse of 23, 19 %, respectively without much affecting its crystallite size. The specific surface areas of zeolites decrease slightly by treatment with Pt and Au species while their microporosity increased from 79 to 91%. All catalysts investigated behaved as selective dehydration solids having activities which increased by treating with Pt or Au species. The samples treated with 4 wt% Pt showed the biggest activity. The selectivity towards propene formation was also found to increase by treatment with Pt or Au species. 2010-11-02 2010-11-02T00:00:00Z http://www.sciforum.net/presentation/491 We have studied the complexation between an adamantane derivative labelled with the fluorescent probe Alexa 488 and the three natural cyclodextrins (-, - and -CD) by Fluorescence Correlation Spectroscopy (FCS), demonstrating the ability of this technique to detect association and to determine the corresponding equilibrium constants with no need for changes in the fluorescence properties of the guest. At low CD concentrations the observed increase of the diffusion time of the probe is mainly due to the complexation of the adamantyl moiety, but further changes are observed when increasing CD concentration that are attributed to the formation of CD aggregates. These aggregates appear at quite low CD concentrations and seem to be formed by a small number of CD molecules. These results show the potential of FCS for the study of CD self-assembly, a recently-recognized phenomenon that could be used to improve certain applications of CDs. 2010-11-02 2010-11-02T00:00:00Z http://www.sciforum.net/presentation/490 Starting from 7-hydroxy-4-methylcoumarin which was prepared via pechmann condensation, some comarin derivatives were synthesized depending on several reactions which are condensation with aldehydes, Mannich reaction, alkylation and reaction with hydrazine hydrate. The prepared compounds were evaluated for their microbiological activity against Grame +ve bacteria Bacillus Subtilis, Gram –ve bacteria Serratia marcenses and fungi Trichoderma Sp. 2010-11-02 2010-11-02T00:00:00Z http://www.sciforum.net/presentation/489 A new kind of surfactants with chelating properties named N-Acyl ethylenediamine triacetate (N-acyl ED3A) of different hydrocarbon chain lengths were synthesized from anhydrous ethylene diamine, fatty acid chlorides (Capryloyl, Lauroyl, myristoyl, palmitoyl, stearoyl or oleoyl chloride) and chloroacetic acid. The chemical structures of the prepared compounds were confirmed using different spectroscopic techniques, primarily Fourier transform infrared spectroscopy and nuclear magnetic resonance. The surface properties including surface and interfacial tension, foaming height, emulsification power, calcium ion stability, stability to hydrolysis and critical micelle concentration (CMC) were determined. The trisodium N-acyl ethylenediamine triacetates have been found to combine the properties of strong surfactancy, extreme mildness with a high tolerance to water hardness, and ability to chelate metal ions, which indicates a promising application prospect in many fields. 2010-11-02 2010-11-02T00:00:00Z http://www.sciforum.net/presentation/492 Two new disazo compounds containing 4,4'-diaminostilbene- 2,2'-disulfonic acid and 4,4'-diaminobenzanilide as middle components were synthesized and characterized by thin layer chromatography (TLC), electronic spectra (VIS), FT/IR and 13 C-NMR spectroscopy. According to the results of the colouristic evaluation, the studied azo compounds can be ranged in the direct dye's class. The individual human skin tolerance for these azo compounds was evaluated by in vivo imagistic skin studies and the obtained results indicate that, from dermatologic point of view, the azo compounds may be used as textile dyes. Further, the compounds were evaluated for antibacterial activity against Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Pseudomonas aeruginosa and Proteus vulgaris by the disk diffusion method. The screening data releaved that the studied azo compounds exhibited antimicrobial activity against most of the tested species, presenting a particular interest against Staphylococcus aureus and Escheria coli. 2010-11-02 2010-11-02T00:00:00Z http://www.sciforum.net/presentation/486 Synthesis of 1,3,5-tris(2-aryloxyethyl)isocyanurates by esterification of 1,3,5-tris(2-hydroxyethyl)isocyanurate under microwave irradiation in a direct and efficient way in solvent free conditions. 2010-11-02 2010-11-02T00:00:00Z http://www.sciforum.net/presentation/487 3-Nitro-4-chloroquinoline 3 was converted to the azides 5/6. The azides were cyclized on thermolysis to furoxanes 7/8. Deoxygenation to furazane 9 was achieved by reaction with triphenylphosphane. The reaction conditions were studied by differential scanning calorimetry (DSC). The azides 5/6 gave with triphenylphosphane the phosphazenes 10/11, which were cleaved to the aminoquinolone 12 2010-11-02 2010-11-02T00:00:00Z http://www.sciforum.net/presentation/485 Microwave assisted synthesis of 1,3,5-tris(2-hydroxyethyl)isocyanurate carbamates under solventless conditions in short times and good yields is described. 2010-11-01 2010-11-01T00:00:00Z http://www.sciforum.net/presentation/433 The formation of complexes between alkaline cations and molecular bowls (MBs), curved conjugated systems related with fullerene (C 60 ), is studied using DFT calculations. The series of MBs is constructed starting with benzene and additional hexagonal or pentagonal rings are added symmetrically to complete the C 60 structure. All the MBs studied form stable cation–π complexes by both of its sides: concave and convex. In all cases complexes with the cation in the convex side are more stable than their corresponding partner inside the bowl. The stability of the complexes is determined by the polarizing power of the cation and by the molecular electrostatic potential and the polarizability of the bowl. Additionally, size effects are observed when bulky cations are placed in the concave side of the largest bowls. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/477 At the explanation of the spectra peculiarities of phenylsulfones by general formula C6H5SO2R the arguments in favour of intramolecular effect of functional groups position in the fragment R through the spatial on the value of phenyl protons chemical shifts ðiHhave been adduced. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/423 Glycosyl (iso) thioureas being an important intermediate in the synthesis of thioureido carbohydrates herein we reported the synthesis of per–O–acetyl lactosyl aryl isodithiobiuret derivatives. These compounds were synthesized by nucleophilic addition of per-O-acetyl lactosyl aryl isothiourea to tolyl isothiocyanate. Structures of these compounds were confirmed on the basis of IR, HNMR, Mass spectra and elemental analysis. These compounds were also screened for their in vitro antimicrobial activities against bacteria S. aureus, E. coli, P. vulgaris, P. aeruginosa and fungi A. niger, Penicillium. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/430 0-N-Methylpurpuramine E has been successfully synthesized in 2 steps in good yield from readily available starting materials. Structural elucidation has been confirmed through direct comparison with spectroscopic data of isolated natural product.20-N-Methylpurpuramine E has been shown to have MIC = 5 μg mL-1 against Mycobacterium bovis. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/414 Efficient synthesis, besides other, of dibromide, diazide, diamine and diesters derived from (11R,12R)-9,10-dihydro-9,10-ethanoanthracene-11,12-dimethanol (3), a chiral bicyclic diol with C 2 symmetry, was developed. Esterification of 3 with saturated and unsaturated carboxylic acids and acids chlorides leads to the corresponding normal-, olefinic- and acetylenic diesters in average yields of 81%. Also more efficient techniques for the preparation of starting diol 3 in higher yields as well as for a very simple separation of DCU from reactions carried out following DCC/DMAP method are described. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/473 2- and 3-nitrobenzofurans are studied in polar thermal Diels-Alder reactions whit normal electron demand using several and structural different dienes. A very strong electron-acceptor group, such as nitro group, push the dienophilic character of these heterocyclic compounds and owing to this substituent is easily extruded under thermal conditions make this reaction sequence a simple method of organic compound's families with heteroatom rings preparation. This work is specifically concerned with theoretical studies using DFT methods. 2-nitrobenzofuran and 3-nitrobenzofuran react as dienophile against isoprene, 1-trimethylsilyloxy-1,3-butadiene, the Danishesfky diene and the Rawal's diene, taking part in a normal demand DA cycloaddition reactions. These reactions could be considered a domino process that is initialized by a polar D-A reaction, and the latter concerted elimination of nitrous acid from the [4 + 2] cycloadduct yields the corresponding dibenzofurans. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/396 A series of benzothiazolylthioacetyl amino acid and peptide derivatives including glycoside, hydrazide and hydrazone moieties were synthesized with the aim of evaluating their antifungal activity. Their chemical structures were confirmed by 1 H NMR, IR, mass spectrometry and elemental analyses. Out of the thirty two tested compounds three derivatives have enhanced activity as fluconazole at 100 ppm and six at 1000 ppm toward Candida albicans whereas, they were actually inactive toward Aspergillus flavus. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/432 Three new asymmetric Schiff base compounds, (E)-methyl 2-(2-(2-hydroxy-3-methoxybenzylideneamino)ethylamino)cyclopent-1-enecarbodithioate[H 2 cd3-OMesalen](1), (E)-methyl 2-(2-(3,5-di-tert-butyl-2-hydroxybenzylideneamino)ethylamino)cyclopent-1-enecarbodithioate[H 2 cd di tertbutsalen] (2) and (E)-methyl2-(2-(3-hydroxy-4-methoxybenzylideneamino)ethylamino)cyclopent-1-enecarbodithioate[H 2 cd4-OMesalen] (3) have been prepared. The compounds have been studied with IR, 1 H NMR, 13 C NMR and microanalysis. The crystal structure of (1) has been also determined. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/417 Skin penetration enhancers are used in the formulation of transdermal delivery systems for drugs that are otherwise not sufficiently skin-permeable. The series of seven esters of 6-(2,5-dioxopyrrolidin-1-yl)-2-(2-oxoazepan-1-yl hexanoic acid as potential transdermal penetration enhancers was formed by multistep synthesis. The general synthetic approach of all newly synthesized compounds is presented. Structure confirmation of all generated compounds was accomplished by IR, 1H, 13C NMR and HR-MS spectroscopy. All the prepared compounds were analyzed using RP-HPLC method for the lipophilicity measurement and their lipophilicity (log k) was determined. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/481 The title compound, 3-chlorohimacha-3-one has been synthesized by catalytic oxidation with ruthenium trichloride and sodium periodate of 3-chlorhimachl-6,13-ene(1). .The structure of this new compound was confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR and EI-Ms spectral analysis. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/419 The enzyme thymidine phosphorylase (TPase) is involved in the metabolism of thymidine. It catalyses the phosphorolysis of several nucleoside analogues serving as antiviral or antitumour agents. Besides, it also plays an important role in the angiogenesis. Thus, inhibition of TPase activity may serve as a plausible therapeutic strategy for the treatment of cancer. In this report, the structure-based design, synthesis, and anti-TPase activity of a class of novel inhibitors of TPase are described using fused bicyclic 1,3,5-triazine-2,4-dione or 1,3,5-triazine-2-thioxo-4-one as the core scaffold, and the latter scaffold shows some activity in TPase enzyme assay. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/441 Novel quinoline derivatives was designed as anticancer iron chelators. Structurally they combine active moieties of known quinoline and thiosemicarbazone bioeffectors. For the synthetic part of study we applied microvawe assisted techniques MAOS. Resulted compounds exhibited interesting anticancer activities against HCT116 cancer cells. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/472 The process of anion transport trough a synthetic ion channel based in anion···π interactions is studied by means of computational methods. Employing two models for the units forming the channel, the calculations indicate that stable complexes are formed with any of bromide, chloride, fluoride or hydroxide anions. All these complexes exhibit strong interactions in the gas phase. When studied in water no favourable complexation was obtained for any of the anions studied, so anion···π interactions, though strong, are not capable of overcoming the cost of anion dehydration. However, it has been found that a process of hydroxide displacement by another anion is indeed favourable in water. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/398 The structural data and vibrational frequencies of 1- and 2-silaallenes have been studied computationally using the Gaussian 03 suite of programs. All of 15 normal modes were assigned to one of six types of motion (symmetrical stretching, antisymmetrical stretching, scissoring, rocking, wagging, twisting) determined by a group of quantum chemical analysis. Predicted geometric features, vibrational frequencies, and infrared intensities are also reported herein. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/480 1,2-O-(R)-Trichloroethylidene-α-D-xylo-1,4-furanodialdose hydrate was obtained fromα-chloralose via conventional sodium metaperiodate cleavage-oxidation reaction. 1,2-O-(R)-trichloroethylidene-α-D-xylo-1,4-furanodialdose thiosemicarbazonewas obtained from the reaction of 1,2-O-(R)-trichloroethylidene-α-D-xylo-1,4-furanodialdose hydrate with thiosemicarbazide in the presence of an acid catalyst. The structure of thiosemicarbazone product was characterized with NMR and FTIR spectroscopic methods. This new compound (5) was evaluated for its antimicrobial activity against Gram-positive, Gram-negative bacteria and C. albicans using the well diffusion and microdilution method. The thiosemicarbazone product shows significant growth inhibitory activity against bacteria Staphylococcus aureus, Escherichia coli, Kocuria rhizophila, Bacillus cereus, Enterobacter aerogenes and showed moderate activity against Candida albicans. The minimal inhibitory concentrations (MIC) experiments revealed that tested compound exhibited variable MICs and selective antimicrobial activity, depending on the microbial strains. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/476 5- and 8-nitroquinolines are studied as dienophiles in polar thermal Diels-Alder reactions whit normal electron demand using several and structural different dienes, and chloroform as solvent media. A very strong electron-acceptor group, such as nitro group, push the dienophilic character of these heterocyclic compounds and owing to this substituent is easily extruded under thermal conditions. When the cited dienophiles were reacted with isoprene, 1-trimethylsilyloxy-1,3-butadiene and de Danishesfky diene, under different reaction conditions they showedtheir dienophilic character taking part in a normal demand DA cycloaddition reactions. These cycloaddition reactions were analyzed in presence of ionic liquids (IL´s). In this sense was used ethyl ammonium nitrate (NEA) as protic IL´s and another composed by 1-butyl-3-methyl-imidazolium [bmim] as the cation and tetrafluoroborate as the anion [BMIM] [BF4]. The presence of IL´s improved the yields and the reaction conditions are softer. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/475 The 1H, 13C and 15N NMR spectra, both in solution and in the solid state, of five 1,2-phenylenediamines have been recorded. Assignment of all the signals has been achieved and chemical shifts and coupling constants determined. When necessary homo- and heteronuclear 2D NMR experiments have been performed. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/484 We report two unexpected findings ocurring after treatment of the antitumor drug mitomycin C with dithiols. The first finding relates to the reaction of mitomycin C with exactly one molar equivalent of dithiol to form a mitosene-like material with unusual physico-chemical properties. The second finding was the formation of unexpected dimeric mitosenes when the reaction of MC with dithiols was quenched at short reaction times. We hypothesize that both events are originated by an unprecedetended deaziridination reaction. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/483 We report that the clinically used antitumor drug mitomycin C reacts with excess dithiols to give dithiol cross-links as major products. Mechanistic studies reveal that three dithiol molecules participate at different stages of the reaction: in the reductive activation of mitomyicin C, in an alkylation at C1, and in an additional reduction that activates C10 for the second-arm alkylation by the dithiol. We hypothesize that the reactions reported here indicate that mitomycin C could act as a mechanism-based inhibitor of enzymes containing a dithiol active site. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/392 A comparative study of 6-methoxy-, 7-methoxy- and 6,7-dimethoxycarbostyrils revealed, that both, the 6 and the 7-methoxy group have different effects to the fluorescence properties of carbostyrils such as fluorescence wavelength, quantum yield and Stoke's shift. A further important influence is visible from the electron acceptor properties of the substituent in position 4 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/479 the synthesized compounds are aryl/ 4-substituted Thiourea as evident by elemental and UV, IR and NMR spectral data. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/474 We have generated different resveratrol-coumarin hybrids with the aim of evaluate their biological applications and their pharmacological properties, particularly the inhibitory activity of monoamine oxidase enzyme. According to that, a first series of 3-aryl-4-hydroxycoumarins has been synthesized starting from aryl boronic acids and phenyliodonium zwitterions precursors by a palladium-catalyzed coupling reaction. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/397 part of the present armory of the clinicians. The synthesis and antibacterial activity of several new ethyl 2-amino-4-methylthiazole-5-carboxylate(1)5derivatives substituted at 2nd position by aryl aldehydes of the thiazole moiety have shown some to increase the antibacterial activity of thiazole. In this study we thought to synthesize thiazole system incorporating substituted aryl aldehydes. The most active compound was 4-methyl-5-hydrazine hydrate-2-(4-methoxy-3-hydroxy benzene) methyleneamino thiazole-5-carboxylate (3c) equipotent to Ciprofloxacin.C2 position of thiazole ring requires large hydrophilic, electronegative functional moieties like substituted phenyl ring etc for enhanced antibacterial activity of thiazole. In our compounds alkyl (methyl) group is present, still most of the compounds show good antibacterial activity.C5 position of thiazole ring requires small hydrophobic, electronegative functional moieties like amino, hydrazine hydrate attach with ester for antibacterial activity of thiazole in general. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/420 We present here the preparation of the precursor for stereoselective synthesis of (+)-lactacystin starting from D-glucose. The first step is conversion of D-glucose to 1,2:5,6-di-O-isopropylidene-α-D-gulofuranose. The second step is introduction of a methyl group at C5 and preparation of compound 9. This compound can be used as a precursor of target molecule of (+)-lactacystin 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/373 The design and synthesis of new calamitic benzothiazole-based liquid crystals, 2-[4-(4-alkyloxybenzoyloxy)phenyl]benzothiazoles, are presented. The target compound was characterized using spectroscopic techniques, such as FT-IR, NMR (1H & 13C), microanalysis and EI-MS. The liquid crystalline behaviours of these compounds were thoroughly examined by differential scanning calorimetry and polarizing optical microscope techniques. These materials exhibited enantiotropic nematic phase with high thermal stability. Smectic A phase starts to emerge as monotropic phase from C10 member and changes into enantiotropic phase from C12 and persists up to C16 members. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/421 Polymorphism of active pharmaceutical ingredients (APIs) gets increasing attention as an important physico-chemical parameter influencing bioavailability and stability of API and pharmaceuticals. Co-crystals of API with common pharmaceutical excipients become very important as a tool to tune up solubility and absorption. Bisphosphonates (e.g. alendronate, risedronate, ibandronate) are widely used in clinical practice. They are indicated for the treatment and prevention of osteoporosis. They are powerful inhibitors of bone resorption, but their gastrointestinal adsorption is only about 1% due to their high hydrophilicity. Some experiments were designed to prepare co-crystals of risedronate. In the present study various mixtures of risedronate and excipients were prepared. All the prepared mixtures (solid compounds) and/or new entities were analyzed by means of FT-NIR, FT-Raman spectroscopy and solid state NMR. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/418 Iminosugars are one of the most interesting discoveries in the field of natural products recent years due to their promissing biological activity. We report synthesis of 1-deoxynojirimycin building block using D-glucose as the starting material and the [3,3]-sigmatropic aza-Claisen rearrangement as the key step of our synthesis. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/478 novel oleanen type triterpenoid, has been isolated from butanolic extract of the seeds of Ricinus communis. Its structure was elucidated as 3-O-[β -D-glucoronopyranosyl-(1→ 3)-α –L-rhamnopyranosyl-(1→ 2)β-D-glucopyranosyl]-4α,20α-hydroxy methyl olean-12-ene-28-oic acid on the basis of spectral evidences i.e. FTIR, 1H NMR, 13C NMR and FAB-MS data. The isolated saponin was tested for its antibacterial and antifungal activity, where the growth of microbes was found to be inverse function of concentration of saponin. The MIC value for E.coli was found to be 260µg/mL and that of Staphylococcus aureus was 350µg/mL 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/482 We report that the clinically used antitumor drug mitomycin C is reductively activated in vitro by simple thiols; a mechanism for this activation is proposed based on kinetic data and the identification of mitosene metabolites. The biological implications of these findings are discussed. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/416 The synthesis of symmetrical and non-symmetrical 4,6-disubstituted pyrimidines was performed by one-pot or stepwise palladium-catalyzed cross-coupling reactions respectively using indium reagents. 2010-10-31 2010-10-31T00:00:00Z http://www.sciforum.net/presentation/444 In this study, immobilized Iron (III) complex of meso-tetrakis(p-chlorophenyl) porphyrin [FeIII(TClPP)] on modified silica gel by 3-aminopropyl group has been used as a heterogeneous catalysts for oxidation of benzhydrol by t-butyl hydroproxide (TBH). The reaction was performed at room temperature to afford benzophenone in high yields and short reaction time. Furthermore, the catalyst can be reused for at least 3 reaction cycles without significant lose of its activity. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/446 Nano-OrderedZn-MCM-41 materials were synthesized using different zinc sources and applied for liquid phase Beckman rearrangement of 4-hydroxyacetophenone oxime to acetaminophen. The reaction conditions such as amount of the catalyst and solvent were optimized to afford acetaminophen in high yields. it Aprotic solvents with high dielectric constant are preferred for this transformation. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/471 Benzaldehydes undergo Wittig olefination with alkoxycarbonylmethylidenephos­phorane in 10w% aqueous NaOH. The cinnamates are hydrolysed under the conditions and cinnamic acids are obtained after simple extractive work-up. Under the same conditions, benzaldehydes react with alkoxycarbonylbromomethy­lidenephosphorane to give arylpropiolic acids. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/454 Phenyl selenol and the zinc-selenolate PhSeZnCl can be conveniently employed for the stereospecific and stereoselective synthesis of vinyl selenides. These reactions occur with moderate to high yields and can be accomplished in eco-compatible conditions using a biphasic acidic system or directly an aqueous suspension. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/456 Ethyl 4-methyl-2-oxo-7-phenylthio-2,3,6,7-tetrahydro-1H-1,3-diazepine-5-carboxylate and/or ethyl 6-methyl-2-oxo-4-(phenylthiomethyl)-1,2,3,4-tetrahydropyrimidine-5-carboxylate were obtained in the reaction of ethyl 4-chloromethyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimi-dine-5-carboxylate with PhSNa or PhSK with or without PhSH, depending on the reagent ratio, reaction time or temperature, as a result of ring expansion and/or nucleophilic substitution. The reaction pathway was affected strongly by the basicity-nucleophilicity of the reaction media. The results obtained were confirmed by reactions of 4-mesyloxymethyl-6-methyl-5-tosyl-1,2,3,4-tetrahydropyrimidin-2-one with PhSNa/PhSH and ethyl 4-chloro-methyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate with NaCN/HCN or NaCH(COOEt)2/CH2(COOEt)2. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/391 Elimination of 4 haloidbenzenes, benzoic acid and diphenyl spectral parameters from all investigated dependencies DdiH–s and DCAP–s seems to be logically grounded. Such elimination is explained by specific behavior of this compounds in NMR 1H spectra. In this connection R correlation coefficient essentially increases in all diagrams with above constants elimination. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/455 Esterification reaction of phthalic anhydride with 2-ethyl hexanol was investigated using sulfated titanium dioxide nano catalyst. The influence of reaction time, catalyst amount and alcohol/anhydride molar ratio was studied using a rotatable central composite design (CCD). The optimum values of factors were: 83 min for the time, 9 %wt catalyst, 9:1 alcohol:anhydride molar ratio. The maximum yield of 93% at optimum conditions was obtained. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/468 The parallel kinetic resolution of racemic secondary arylalkyl alcohols using an equimolar amount of quasi-enantiomeric active esters and zinc chloride is discussed. The levels of enantiomeric recognition were high leading to enantiomerically enriched alcohols in good yield. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/470 A new convenient procedure for the bromination of aromatic side chains was efficiently achieved by using a combination of tetrachlorosilane (TCS) and N-bromosuccinimide (NBS) at ambient conditions. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/434 A facile, one pot three-component procedure for the efficient synthesis of novel 2'-aminobenzimidazolomethylnaphtols derivatives was developed by the reaction of 2-aminobenzimidazole, 2- naphtol and aromatic aldehydes in the presence of L-proline under grinding and solvent free condition at room temperature. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/443 The additives influence on the photochemical reactivity of 1,3-dinitrobenzoyleneurea was studied. Amines having different chemical nature, iso-propylic alcohol and sodium salt of mandelic acid proved to be efficient additive to activate the title compounds activity. The additive role is electron and/or H-atom transfer ability improving. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/457 In the presence of strong bases (NaH, DBU, KOH), ethyl 4-chloromethyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate and 4-mesyloxymethyl-6-methyl-5-tosyl-1,2,3,4-tetrahydropyrimidin-2-one are transformed into novel tricyclic compounds, diethyl 9-methyl-5-methylene-3,11-dioxo-2,3,4,5,6a,7,10,11-octahydro-1,6-methano[1,3]diazepino[1,7-e][1,3,5]-triazocine-6,8(1H)-dicarboxylate and 9-methyl-5-methylene-6,8-ditosyl-1,2,4,5,6,6a,7,10-octahydro-1,6-methano[1,3]diazepino[1,7-e][1,3,5]triazocine-3,11-dione, respectively. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/439 Tetrabutylammonium phthalimide-N-oxyl (TBAPINO) was used as an efficient organocatalyst to catalyze the Strecker reaction of diverse aldimines with trimethylsilylcyanide (TMSCN) in EtOH. The reaction proceeded smoothly at room temperature to afford the corresponding α-aminonitriles in quantitative yields under mild reaction conditions. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/467 A route for the preparation of five- and six-membered ring α/β - and α/γ-glycoamino acids is described starting from D-Glucose. The α/β glycoamino acids were synthesized using a DAST-promoted ring contraction as a key step followed by hydrolysis, acetylation, oxidation and attachment of the α-amino acid. The α/γ-glycoamino acids were synthesized by cleavage of the benzylidene protecting group as the first step, accompanied with subsequent oxidation, acetylation and attachment of the α-amino acid. At the present, we are focusing our attention in synthesizing these α/β-glycoamino acids at a higher scale by using other non-corrosive fluorinating agents. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/380 A series of sixteen pyrazinamide analogues with the -CONH- linker connecting the pyrazine and benzene rings was synthesized by the condensation of chlorides of substituted pyrazinecarboxylic acids with ring-substituted (chlorine) anilines and characterized. The results of in vitro antimycobacterial screening indicated some interesting antimycobacterial activity. 6-Chloro-N-(4-chlorophenyl)pyrazine-2-carboxamide (6) has shown the highest activity against Mycobacterium tuberculosis strain H37Rv (65% inhibition at 6.25 μg mL-1). The highest antifungal effect against Trichophyton mentagrophytes, the most susceptible fungal strain tested, was found for 6-chloro-5-tert-butyl-N-(3,4-dichlorophenyl)pyrazine-2-carboxamide (16) (MIC = 62.5 μmol mL-1). 6-Chloro-5-tert-butyl-N-(4-chlorophenyl)pyrazine-2-carboxamide (8) was the most active in the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts (IC50 = 43.0 μmol mL-1). The compounds were analyzed using RP-HPLC to determine lipophilicity. Optimal log P value for studied series was not confirmed.For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed, as well as their structure-activity relationships (SAR). 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/450 A series of substituted benzaldehyde hepta-O-acetyl-b-lactosyl thiosemicarbazones were synthesized by condensation reactions of hepta-O-acetyl-b-lactosyl thiosemicarbazide with corresponding substituted benzaldehydes. Structures of thiosemicarbazones were confirmed by spectroscopic (IR, NMR) methods. The 1H and 13C NMR spectra of substituted acetophenone peracetylated b-lactosyl thiosemicarbazones have been recorded and discussed. The magnetic resonance signals in their NMR spectra show the relationships between the structure and positions of the substituted groups by Hammett's regression. The b anomeric configuration of these thiosemicarbazones was confirmed on the basis of the coupling constant J = 9.5–8.5 Hz between proton NH-4 of thiosemicarbazone bond and proton H-1' in lactosyl component 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/386 A homologous series of cholesteryl 4'-alkyloxybiphenyl-4-carboxylates (CnH2n+1OC6H4 C6H4COOCh, where Ch = cholesteryl) possessing different length of alkyl chain (n = 6, 8, 10, 12, 14, 16, 18) were synthesized. Phase transition temperatures and thermal parameters were obtained from differential scanning calorimetry. Observation under optical polarizing microscope revealed all the members of the series possessing SmA property. Additional mesophase was observed for lower members whereby the C6-14 derivatives displayed fan-shaped and oily streaks textures of cholesteric phase. The influence of structural changes on the mesomorphic properties is discussed. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/428 Synthesis and characterization of new amphiphilic azobenzenes with non ionic character is presented. The synthetic methodology is simple and versatile which allows the generation of molecular diversity from the same precursors in an easy way. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/469 In this work, vegetable polyols as a potential replacement of petroleum polyols were investigated. The two-stage method of preparation natural oil-derived polyols was presented. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/466 There are many of pathogen parasite species with different susceptibility profile to antiparasitic drugs. Unfortunately, almost QSAR models predict the biological activity of drugs against only one parasite species. Consequently, predicting the probability with which a drug is active against different species with a single unify model is a goal of the major importance. In so doing, we use Markov Chains theory to calculate new multi-target spectral moments to fit a QSAR model that predict by the first time a mt-QSAR model for 500 drugs tested in the literature against 16 parasite species and other 207 drugs no tested in the literature using spectral moments. The data was processed by Linear Discriminant Analysis (LDA) classifying drugs as active or non-active against the different tested parasite species. The model correctly classifies 311 out of 358 active compounds (86.9%) and 2328 out of 2577 non-active compounds (90.3%) in training series. Overall training performance was 89.9%. Validation of the model was carried out by means of external predicting series. In these series the model classified correctly 157 out 190, 82.6% of antiparasitic compounds and 1151 out of 1277 non-active compounds (90.1%). Overall predictability performance was 89.2%. In addition we developed four types of non Linear Artificial Neural Networks (ANN) and we compared with the mt-QSAR model. The improved ANN model had an overall training performance was 87%. The present work report the first attempts to calculate within a unify framework probabilities of antiparasitic action of drugs against different parasite species based on spectral moment analysis. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/453 Herein we present results of a Quantitative Structure-Activity Relationship (QSAR) studies to classify and design, in a rational way, new antitrypanosomal compounds by using non-stochastic and stochastic bond-based quadratic indices. A data set of 440 organic chemicals, 143 with antitrypanosomal activity and 297 having other clinical uses, is used to develop QSAR models based on Linear Discriminant Analysis (LDA). Non-stochastic model correctly classifies more than 93% and 95% of chemicals in both training and external prediction groups, respectively. On the other hand, the stochastic model shows an accuracy of about the 87% for both series. As an experiment of virtual lead generation, the present approach is finally satisfactorily applied to the virtual evaluation of 9 already synthesized in house compounds. The in vitro antitrypanosomal activity of this series against epimastigote forms of Trypanosoma cruzi is assayed. The model is able to predict correctly the behaviour for the majority of these compounds. Four compounds (FER16, FER32, FER33 and FER 132) showed more than 70% of epimastigote inhibition at a concentration of 100µg/mL (86.74%, 78.12%, 88.85% and 72.10%, respectively) and two of these chemicals, FER16 (78.22% of AE) and FER33 (81.31% of AE), also showed good activity at a concentration of 10µg/mL. At the same concentration, compound FER16 showed lower value of cytotoxicity (15.44%), and compound FER33 showed very low value of 1.37%. Taking into account all these results, we can say that these three compounds can be optimized in forthcoming works, but we consider that compound FER33 is the best candidate. Even though none of them resulted more active than Nifurtimox, the current results constitute a step forward in the search for efficient ways to discover new lead antitrypanosomals. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/462 β-cyclodextrin―citric acid derivatives were synthesized trough heating of mixture of citric acid, cyclodextrin and Na2HPO4 as a catalyst. The degree of substitution of the derivatives was estimated by determination of citric acid by HPLC in the samples hydrolysates. Sorption properties of β-cyclodextrin―citric acid derivatives were determined using spectrophotometric method with methyl orange as a model sorbate. Sorption properties of β-cyclodextrin―citric acid derivatives were compared to native β-cyclodextrin. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/465 A QSAR study has been performed on a series of substituted pyrido[3,2-b]pyrazinones as potent and selective PDE-5 Inhibitors. The compounds in the selected series were characterized by spatial, molecular and electrotopological descriptors using QSAR module of molecular design suite (V-Life MDSTM 3.5). Correlations between inhibitory activities and calculated predictor variables were established through partial least square regression (stepwise forward) method. The generated QSAR models reveal that the topology of the molecules crucially influences the desired inhibitory activity of pyrido[3,2-b]pyrazinones. PDE-5 inhibition can be well defined by the models generated and the molecules are more selective towards PDE –5 while PDE –6 and PDE –11 inhibitory activities cannot be well delineated by the help of generated QSAR models. So PDE-5 selective compounds can be synthesized based on the assumption of the present QSAR analysis. The best model shows 90% correlation for PDE-5 inhibitory activity which explains good reliability of the model. However cross correlated regression coefficients (Q2) 0.5959 further validate the model significance. The present study imply that the PDE-5 inhibition can be augmented primarily by increasing molecular refractivity and number of carbons connected to the aromatic rings, single bonds and by decreasing number of carbons connected to the double bonds. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/388 DFT computations were carried out to characterize the 17Oand 2H electric field gradient, EFG, in various bisphosphonic acids derivatives. The computations were performed at the B3LYP level with 6-311++G (d, P) standard basis set. Calculated EFG tensors were used to determine the 17O and 2H nuclear quadrupole coupling constant, c and asymmetry parameter, η. The results showed that various substituents have a strong effect on the Nuclear Quadrupole Resonance (NQR) parameters (c, η) of 17O in contrast with 2H NQR parameters. The NQR parameters were studied in order to find the correlation between electronic structure and activity of structure. Investigations showed that substitutions on the carbon atom in P-C-P are important in bisphosphonates drug properties. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/458 Several ionic liquids used as catalyst for three-component Mannich reactions of aldehydes, amines, and naphthols at room temperature. The used ionic liquids include 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4), 1-octyl-3- methylimidazolium tetrafluoro-borate ([Omim]BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF4), butyl dimethylimidazolium tetrafluoroborate ([Bdmim]BF4), 1-octyl-3-methylimidazolium nitrate ([Omim]NO3), 1-methylimidazolium sulfuric acid ([Hmim]HSO4) and 1-methylimidazolium trifluoroacetic acid ([Hmim] Tfa). Higher yields were obtained in the presence of [Hmim]Tfa in comparison with other ionic liquids. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/459 1,2,4,5-Benzenetetracarboxylic acid (H4btec) with transition metal ions Co(II) and Ni (II), give two coordination complexes, C10H16CoO14 (I) and C10H18Na2NiO16 (II). These complexes have been synthesized by a fast and efficient method under microwave irradiation. These compounds have been characterized by FT-IR spectroscopy and elemental analysis. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/445 A QSAR study has been performed on a series of substituted pyrido[3,2-b]pyrazinones as potent and selective PDE-5 Inhibitors. The compounds in the selected series were characterized by spatial, molecular and electrotopological descriptors using QSAR module of molecular design suite (V-Life MDSTM 3.5). Correlations between inhibitory activities and calculated predictor variables were established through partial least square regression (stepwise forward) method. The generated QSAR models reveal that the topology of the molecules crucially influences the desired inhibitory activity of pyrido[3,2-b]pyrazinones. PDE-5 inhibition can be well defined by the models generated and the molecules are more selective towards PDE –5 while PDE –6 and PDE –11 inhibitory activities cannot be well delineated by the help of generated QSAR models. So PDE-5 selective compounds can be synthesized based on the assumption of the present QSAR analysis. The best model shows 90% correlation for PDE-5 inhibitory activity which explains good reliability of the model. However cross correlated regression coefficients (Q2) 0.5959 further validate the model significance. The present study imply that the PDE-5 inhibition can be augmented primarily by increasing molecular refractivity and number of carbons connected to the aromatic rings, single bonds and by decreasing number of carbons connected to the double bonds. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/422 A molecularly imprinted solid-phase extraction (MISPE) procedure based on precipitation polymerization was developed for the simultaneous extraction of dexamethasone (DM) and its structural isomer, betamethasone (BM), from biological matrices. A DM-imprinted polymer was synthetized using methacrylic acid as monomer and divinylbenzene as cross-linker, and the porogen was a mixture of acetonitrile and toluene (3:1). After removal of the template, loading, washing and elution steps were optimized. The maximun recovery of DM and BM was achieved when loading with toluene and washing with 5% acetonitrile in toluene, and eluting with 1% acetic acid in methanol. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/452 Reaction of substituted acetophenone (hepta-O-acetyl-b-maltosyl)thiosemicarbazones with ethyl bromoacetate was investigated. It's indicated that the nature of solvents and the catalysts affected the reaction yields, and that the microwave-assisted heating method gave higher yields of products than the conventional heating one. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/463 The title compound, [6-Diethylamino-9-(2-octylcarbamoyl-phenyl)-xanthen-3-ylidene]-diethyl-amine was synthesized in high yield by an amidation with N-octylamine in a CEM Discover microwave at 60°C for 2 hrs. Its structure was characterized by Ultraviolet-Visible and fluorescence spectral analysis. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/464 The four-membered spiro-heterocycles; ethyl cyano(1-methyl-2,4-dioxospiro{1,3-quinoline-3,4'-[1,3]dithietane}-4'-ylidene)- acetate 2a, -malononitrile 2b, -acetylacetone 2c and thiazetidine isomer 3 were prepared under phase transfer catalysis conditions (PTC). The thermal treatment of dithietanes 2a–c led to the bis-quinolinyl sulfide 4. Some interesting nucleophilic addition followed by cyclization reactions were carried out with the dithietane 2a to give the corresponding novel dispiro derivatives 5–8, 10–13, and 15. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/461 Mn(III) tetra (4-methoxyphenyl) porphyrin (MnTMePP) was synthesized inside the nanocages of zeolite-X according to "ship-in-bottle " model. MnTMePP was impregnated (MnP-NaX imp) and encapsulated (MnP-NaX) in the zeolite matrix and had been used as an active heterogeneous catalyst for thymol hydroxylation. The oxidation results were improved by immobilization of metalloporphyrin inside zeolitic faujasite in compression with homogeneous catalyst (MnTMePP). The hydroxylation reaction was performed at 25 ° C and atmosphere pressure by using H 2 O 2 / Ammonium acetate. All catalysts were characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM) Ultraviolet-Visible (UV-Vis) spectroscopy analyses. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/451 Reaction of substituted acetophenone (hepta-O-acetyl-b-lactosyl)thiosemicarbazones with ethyl bromoacetate was performed in the presence of anhydrous sodium acetate using microwave-assisted heating method. The reaction yields were 64-80%. Structure of 2-iminothiazolidin-4-one products was confirmed by spectroscopic methods. Isomer ratios 2 and 2' were determined by 1H NMR. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/435 Novel transition metal(II) complexes, [M(L1)2Cl2] and [M(L2)2Cl2], were synthesized from the reaction of MCl2.nH2O (M = Co, Ni, Cu) with (Z)-1-(1-(1H-indol-3-yl)ethylideneamino)quinolin-2(1H)-one (L1) or (E)-1-(2-hydroxybenzylideneamino)quinolin-2(1H)-one (L2). The ligands were obtained from coumarin. N-amino quinoline-2-one (2) has been synthesized by the reflux of coumarin (1) with hydrazine hydrate in ethanol for 12 hr. The azomethines (L1, L2) were prepared from the corresponding aryl aldehydes. The synthesized compounds were and characterized by element chemical analysis, molar conductance, magnetic susceptibility measurements, and spectral (electronic, and FT-IR) studies. The IR spectral data suggest the involvement of sulphur and azomethane nitrogen in coordination to the central metal ion. On the basis of spectral studies, an octahedral geometry has been assigned for all complexes. The free ligands and its metal complexes have been tested in vitro against a number of microorganisms in order to assess their antimicrobial properties. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/384 In this work, the Tetracarboxyphenylporphyrin Covalently Bound to Silica was used as adsorbent to remove Crystal Violet (CV) from aqueous solution. Silica gel immobilizing Tetracarboxyphenylporphyrin (TCPP) chromophore was prepared by the reactions of 3-aminopropyl silica gel (SiO2-NH2) with the TCPP. The 3-aminopropyl silica gel (SiO2-NH2) was selected as the carrier because of its ability to immobilize the functional groups through a covalent bond. Micrometer-sized SiO2-NH2 beads were prepared by reacting silica gel with 3-aminopropyl(triethoxy)silane (H2N(CH2)3Si(OEt)3). The immobilization of TCPP chromophores on SiO2-NH2 was performed by the sol-gel method. The bond formation was confirmed by the appearance of an amide bond at 1650 and 1539 cm−1 in the FT-IR spectra. The SiO2-NH2-TCPP was used as adsorbent for removing Crystal Violet from aqueous solutions. The dye adsorption experiments were carried out by using bath procedure. UV-visible absorption spectroscopy was used to record the adsorption behavior. The pH effects, the contact time and the initial dye concentration were changed to obtain the best experimental conditions. The dye adsorption equilibrium was rapidly attained after 25 min of contact time. The experimental data were best fitted to isotherm models. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/460 Copper sulfide nanoparticles were synthesized by microwave irradiation, by the decomposition of [Cu(NH2CSNH2)2]Cl2 complex, formed by the reaction of copper(II) acetate, thiourea (Tu) in the presence of surfactant Sodium dodecyl sulfate (SDS). X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) used to characterize the product. The result nanoparticles have a diameter of about 60-70 nm. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/431 A novel rapid one-pot four-component reaction between resorcinol, aromatic aldehydes, malononitrile and ammonium acetate in aqueous media was performed under microwave irradiation for the synthesis of 1,4-dihydroquinoline derivatives. The main advantages of this method are the short reaction time, high yields, despite absence of any catalyst, and simple work-up. 2010-10-30 2010-10-30T00:00:00Z http://www.sciforum.net/presentation/448 A series of per-O-acetyl-b-D-glycosyl thiosemicarbazones 4 and 5 of benzaldehydes and acetophenones were obtained from reaction of per-O-acetyl-b-maltosyl thiosemicarbazide 1 with corresponding carbonyl compounds (2 and 3) in ethanol or acetic acid as solvent using microwave-assisted method. The positions of the magnetic resonance signals in their NMR spectra and the substituent's nature have been indicated by Hammett's regression. The b anomeric configuration of these thiosemicarbazones was confirmed on the basis of the coupling constant J = 9.0–9.5 Hz between proton NH-4 of thiosemicarbazone bond and proton H-1' in maltose component. Structures of thiosemicarbazones were confirmed by spectroscopic methods 2010-10-28 2010-10-28T00:00:00Z http://www.sciforum.net/presentation/449 A new series of polyoxygenated amido isoborneols has been synthesized and tested on the enantioselective addition of diethylzinc to benzaldehyde and the results compared to a series of related amino isoborneols. The observed different behavior has been explained on the basis of catalytic quelates previously proposed by us 2010-10-27 2010-10-27T00:00:00Z http://www.sciforum.net/presentation/437 The condensation of 3-methoxy or 3-ethoxy-2-hydroxybenzaldehyde and 1,2 diamine -2-methylpropane, to yield at the dianionic hexadentate Schiff base ligands H2 Ln (H2 L1 , H2 L2 respectively). The ligands have been characterised by elemental analysis, IR, 1H and 13C NMR spectroscopies and mass spectrometry (ES). The crystal structure of the two ligands was solved by X-ray crystallography, revealing its ability to bind metal centres. 2010-10-25 2010-10-25T00:00:00Z http://www.sciforum.net/presentation/372 A new proton transfer compound of 2, 9-dimethyl-1, 10-phenantroline and d-tartaric acid was synthesized and studied by using DFT and ab initio HF methods. The chemical formulas for the proton transfer ion pair is (dmpH) 2+ (d-tartH) 2–.9H2O, where dmp = 2, 9-dimethyl-1, 10-phenantroline and d-tartH2 = d-tartaric acid. In this crystal structure, d-hydrogen tartrate anions are joined together in a head-to-tail fashion via short hydrogen. A number of intermolecular O–H···O, N-H···O and C–H···O hydrogen bonding interactions, as well as π–π stacking, play important roles in this crystal structure. The geometrical parameters of (dmpH)2+(d-tartH)2– , 9H2Oion pair have been optimazed with the B3LYP method of density functional theory (DFT) and ab initio Hartree-Fock (HF) methods for comparison. Theoretical calculations confirm a number of intermolecular O–H···O, N-H···O and C–H···O hydrogen bonding interactions, as well as π–π stacking, play important roles in this crystal structure. 2010-10-25 2010-10-25T00:00:00Z http://www.sciforum.net/presentation/442 5H-Pyrido[4,3-b]indole was obtained from 3-formylindole in 16% overall yield by Jackson and Shannon modification of the Pomeranz-Fristch isoquinoline synthesis. The final cyclisation occurred but the removal of the tosyl group and oxidation of the dihydrocompound was not efficient. Changes in the concentration of the acid catalyst gave 29% as the best yield for the last step. An NMR study of the cyclisation is described. 2010-10-25 2010-10-25T00:00:00Z http://www.sciforum.net/presentation/440 In order to evaluate the application of new oxobenzopyrano[6,7-d]oxazoles as photocleavable protecting groups, a series of model alanine and β-alanine ester conjugates were synthesised by reaction with the corresponding halomethylated heterocycles. Photocleavage studies of conjugates in methanol/HEPES buffer (80:20) solution at different wavelengths of irradiation (250, 300 and 350 nm) revealed the quantitative release of the amino acids, the best results being obtained for 8-(chloromethyl)-2-methyl-6-oxo-6H-benzopyrano[6,7-d]oxazole. 2010-10-25 2010-10-25T00:00:00Z http://www.sciforum.net/presentation/438 Valine and phenylalanine were used as model amino acids for the synthesis of ester conjugates with a fused oxobenzopyran, in order to evaluate its applicability as a photocleavable protecting group for solution phase organic and peptide synthesis. The behaviour of the corresponding conjugates towards photocleavage was evaluated by irradiation in methanol/HEPES buffer (80:20) and acetonitrile/HEPES buffer (80:20) solutions, in a photochemical reactor at different wavelengths (300 and 350 nm), followed by HPLC/UV monitoring. 2010-10-25 2010-10-25T00:00:00Z http://www.sciforum.net/presentation/387 We synthesized a new hybrid organo-inorganic polyoxometalate from Na2WO4 and di-sodium salt of para-nitrophenyl ester of phosphoric acid, Na2C6H4NO2@[PW12O40]. Photochemical activity of the compound towards mandelic acid and isopropyl alcohol was studied. It was shown that the polyoxometalate synthesized behaves itself as a powerful photooxidazing agent and/or a catalyst of the photochemical oxidation of the said H-atom donors by nitrocompound in the presence of oxygen. 2010-10-22 2010-10-22T00:00:00Z http://www.sciforum.net/presentation/375 In this study, a series of nine 4-chloro-2-(3,4-dichlorophenylcarbamoyl)phenyl N-alkylcarbamates was prepared. The procedures for synthesis of the compounds are presented. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. For the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed, as well as their structure-activity relationships (SAR). 2010-10-22 2010-10-22T00:00:00Z http://www.sciforum.net/presentation/383 A series of Schiff base ester, 4-{[(4-iodophenyl)imino]methyl}phenyl alkanoates possessing different number of carbon atoms at the terminal alkanoyloxy chain (Cn-1H2n-1COO-, n = 4, 6, 8, 10, 12, 14) was synthesized. C4 member was found non-mesogenic, whilst C6 to C14 derivatives exhibited enantiotropic smectic A phase with fan-shaped texture. It was found that the length of terminal alkanoyloxy chain influenced the mesomorphic properties. 2010-10-22 2010-10-22T00:00:00Z http://www.sciforum.net/presentation/424 The synthesis of two new symmetrical disazo direct dyes containing 4,4'-diaminostilbene-2,2'disulphonic acid as middle component and 3-chlorosalicylanilide and 4-chlorosalicylanilide as coupling components are presented. The synthesized dyes were analyzed by thin layer chromatography (TLC), electronic spectra (VIS) and HPLC technique. Their structures were elucidated by FT/IR and 13C-NMR spectroscopy. The CIELAB (1976) colour space was used in all the colour measurements for the two disazo stilbene dyes under the CIE recommended illuminants: D65 (natural day light), A (tungsten light), F2 (fluorescent light) and the standard 10° observer respectively. The colour difference (ΔEab*) was calculated against one standard 2010-10-22 2010-10-22T00:00:00Z http://www.sciforum.net/presentation/389 The aromaticities of all possible dinitro, diamino substituted diaza derivatives of benzene; pyrazine, pyrimidine and pyridazine, have been investigated by computational calculations at the level of B3LYP/6-31G(d,p). The NICS (0), NICS (0.5), NICS (1.0) data have been reported herein. 2_5,6A_2,4N and 3_2,3A_5,6N are found to be the most aromatic structures among all. The results indicated that, the more closer the nitro groups to the aza points, the more aromatic the structure. 2010-10-22 2010-10-22T00:00:00Z http://www.sciforum.net/presentation/400 A systematic investigation of the Ge(CH3)2, CH3GeSiH3, CH3GeGeH3, XGeCY3 (X; Y = H, F, Cl, Br) species was carried out using the DFT functionals BLYP, B3LYP and BHHLYP. Predicted are the singlet-triplet energy gaps and four types of neutral-anion separations: adiabatic electron affinity (EAad), zero-point vibrational energy corrected EAad(ZPVE), vertical electron affinity (EAvert), and vertical detachment energy (VDE). The basis sets used for all atoms are of double-ζ plus polarization quality with additional s- and p-type diffuse functions denoted DZP++. The geometries are fully optimized with each functional independently. Vibrational frequency analyses are performed to compute zero-point energy corrections and to determine the nature of the stationary points. The EAad(ZPVE) values (eV) obtained with the BHLYP functional is Ge(CH3)2 = 0.46 eV, CH3GeSiH3 = 1.22 eV and CH3GeGeH3 = 1.26 eV, and FGeCCl3 = 1.66 eV. The singlet-triplet splittings range from 1.28 eV (HGeCF3) to 2.22 eV (FGeCCl3). The XGeCY3 (Y = Br) species are most often characterized by three-membered cyclic systems involving the divalent germanium atom, the carbon atom and a halogen atom. The predicted results are helpful for the synthesis, characterizations, and applications of these germylene derivatives. 2010-10-22 2010-10-22T00:00:00Z http://www.sciforum.net/presentation/382 Efficient synthesis, besides other, of dibromide, diazide, diamine and diesters derived from (11R,12R)-9,10-dihydro-9,10-ethanoanthracene-11,12-dimethanol (3), a chiral bicyclic diol with C2 symmetry, was developed. Esterification of 3 with saturated and unsaturated carboxylic acids and acids chlorides leads to the corresponding normal-, olefinic- and acetylenic diesters in average yields of 81%. Also more efficient techniques for the preparation of starting diol 3 in higher yields as well as for a very simple separation of DCU from reactions carried out following DCC/DMAP mehod are described. 2010-10-22 2010-10-22T00:00:00Z http://www.sciforum.net/presentation/385 Isomerization reactions between nitroso oxide and nitrocompounds in both triplet and singlet states were studied with quantum chemistry methods. Calculated activation parameters for different paths of the isomerization reactions. It was shown that both in the singlet and triplet states the said reaction proceeds to the nitrocompound formation direction. 2010-10-22 2010-10-22T00:00:00Z http://www.sciforum.net/presentation/425 Condensation of pentaethylenehexamine and 3-bromo-5-chlorosalicylaldehyde yielded the bisimidazolidine Schiff base ligand 5,6'-(1E,1'E)-(2,2'-(3,3'-(ethane-1,2- diyl)bis(2-(3-bromo-5-chloro-2-hydroxyphenyl)imidazolidine-3,1-diyl))bis(ethane- 2,1-diyl))bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(2-bromo-4- chlorophenol), H4L. This diimine could be suitably characterised both in the solid state and in solution. 2010-10-21 2010-10-21T00:00:00Z http://www.sciforum.net/presentation/426 Condensation of the selectively tosilated N-(2-aminobenzyl)-4-methylbenzenesulfonamide with 2-hydroxybenzaldehyde gives rise to (E)-N-(2-(2- hydroxybenzylideneamino)benzyl)-4-methylbenzenesulfonamide in the solid state, as the crystal structure determined shows, and which in solution shows equilibrium between the acyclic imine and 2-(3-tosyl-1,2,3,4-tetrahydroquinazolin-2-yl)phenol 2010-10-21 2010-10-21T00:00:00Z