Scielo RSS <![CDATA[Journal of the Chilean Chemical Society]]> vol. 61 num. 3 lang. es <![CDATA[SciELO Logo]]> <![CDATA[<b>EFFECT OF CONCENTRATION AND MOLECULAR MASS OF PEO ON THE MICELLIZATION AND THERMODYNAMIC BEHAVIOUR OF CETYLTRIMETHYLAMMONIUM BROMIDE (CTAB) IN AQUEOUS PEO-CTAB MIXED SYSTEM</b>]]> Polymer-surfactant mixed systems have attracted much attention due to their importance from the academic as well as applied point of view. Therefore, to evaluate the thermodynamic properties of polymer-surfactant self-assembled system, the critical micelle concentration (CMC) of CTAB and CTAB/PEO mixture was determined at different CTAB/PEO ratios and various molecular masses of PEO by employing surface tensiometric, conductometric, and light scattering techniques. The CMC of CTAB was increased as the concentration and molecular mass of the polymer increased. Using surface tensiometry, the thermodynamics of adsorption, surface excess concentration and the minimum area occupied by surfactant molecules for different surfactant-polymer mixtures were also evaluated. CMC, area per molecule, free energy of micellization and degree of counter ion binding were also determined. It was found that most of these parameters increased as the concentration of polymer increased, whereas the surface excess concentration was found to decrease by increasing the polymer ration in the mixed system. The hydrodynamic radius (Rh) of the micelle particles calculated from dynamic light scattering technique showed a similar trend. Most of the results from different techniques support each others. <![CDATA[<b>INHIBITIVE EFFECT OF DATE EXTRACT ON THE CORROSION OF CARBON STEEL IN ACIDIC MEDIA</b>]]> The inhibitive effect of date extract on the corrosion of Carbon steel in 1M HCl solution has been investigated by weight loss measurement, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The presence of this extract reduces remarkably the corrosion rate of mild steel in acidic solution. The inhibition efficiency was found to increase with increasing inhibitor concentrations due to the adsorption of the inhibitor molecules on the metal surface, this adsorption follows Langmuir's adsorption isotherm. The inhibition efficiency was found to be 85.84% at 1.5V/V% in 1M HCl. Temperature studies revealed a decrease in efficiency with rise in temperature. <![CDATA[<b>THERMODYNAMIC AND ADSORPTION ISOTHERM OF N,N'-BIS(2,4,6-TRIHYDROXYACETOPHENONE)-2,2-DIMETHYLPROPANDIIMINE AS A CORROSION INHIBITOR ON SA-210 STEEL IN ALKALINE NACL SOLUTION</b>]]> Adsorption isotherm of N,N'-bis(2,4,6-trihydroxyacetophenone)-2,2-dimethylpropandiimine (THAPDP) as an environmentally friendly Salen Ligand corrosion inhibitor on mild steel was studied in alkaline solution (pH=10) containing 3% NaCl. Measurements were carried out using electrochemical and surface techniques. Potentiodynamic polarization curves suggested that this compound was an effective corrosion inhibitor for mild steel and the protection efficiency was increased with the increase in inhibitor concentration. The experimental results indicated that this organic compound was a mixed-type inhibitor. Adsorption on the mild steel surface followed the Langmuir isotherm model. Activation parameters and thermodynamic adsorption parameters of the corrosion process such as Ea, ΔH, ΔS, Kads, and AG . were calculated at different temperatures. <![CDATA[<b>LAÇASSE CATALYZED-SYNTHESIS OF 4,4'-BIPHENYLDIAMINE FROM <em>P</em>-CHLOROANILINE. EVALUATION OF ANTIFUNGAL AND ANTIOXIDANT ACTIVITIES</b>]]> Laccase is a copper-containing oxidase that catalyzes reduction of molecular oxygen to water and the oxidation of a phenolic compound. In this paper, laccase was utilized to synthesize 4,4'-Biphenyldiamine using p-chloroaniline as substrate by means of a coupling reaction. The synthesized compound, 4,4'-Biphenyldiamine, presented low antifungal activity against the phytopathogenic fungus Botrytis cinerea, however the antioxidant ability, measurement by ORAC-PGR method, was higher than substrate. This work corresponds to the first report of synthesis 4,4'-Biphenyldiamine, from p-chloroaniline in a lacasse-catalyzed reaction. <![CDATA[<b>ONE POT PREPARATIONS <em>N,N'</em>-ALKYLIDENE BISAMIDE DERIVATIVES CATALYZED BY NANO-TiCL<sub>4</sub>.SiO<sub>2 </sub>WITH ANTIMICROBIAL STUDIES OF SOME PRODUCTS</b>]]> Nano-TiCl4.SiO2 has been introduced to be an extremely efficient catalyst for the preparation of N,N'-alkylidene bisamides from various aldehydes and amides under mild conditions. We synthesized this solid Lewis acid catalyst by the reaction of nano-SiO2 and TiCl4. The processor was simple and environmentally benign with high to excellent yields. Our method has the advantages of high yields, simple methodology, and easy work-up. The antimicrobial and antifungal activities of some of the synthetic compounds were determined by broth microdilution methods as recommended by Clinical Laboratory Standard Institute. Further studies still needed to investigate the other biological activities of the compounds. <![CDATA[<b>IMPROVEMENT OF THE ANTIFUNGAL ACTIVITY AGAINST <i>BOTRYTIS CINEREA</i> OF SYRINGIC ACID, A PHENOLIC ACID FROM GRAPE POMACE</b>]]> The aim of this study was to improve the antifungal activity against Botrytis cinerea of syringic acid by using the enzyme laccase to synthesize a heterodimeric compound by a coupling reaction with aniline. The synthesized heterodimer is a quinone-imine like compound (2,6-dimethoxy-4-(phenylimino)benzenone), which was characterized by using ¹H and 13C NMR, IR, and mass spectrometry. The antifungal activity of the heterodimeric compound against B. cinerea was determined in vitro and showed a higher antifungal effect than the substrates (syringic acid and aniline), inhibiting the mycelial growth with an IC50 value of 0.14mM and delayed 2 hours the conidial germination. Also, using the fluorochrome calcofluor white, cell wall damage was observed when B. cinerea was incubated with the compound. This is the first report on antifungal activity of this type of compound against B. cinerea. <![CDATA[<b>A GREENER APPROACH FOR THE DEGRADATION OF DYE METHYLENE BLUE BY ORGANIC ADDITIVE CATALYSED PHOTO - FENTON PROCESS</b>]]> Fenton and photo-Fenton processes are proven to be most promising techniques for the wastewater treatment methods. It provides an attractive method for degradation of dyes and breaks them into simple mineral form. These are cost effective and ecologically viable techniques with additional advantages of relatively simple approach, use of less hazards chemicals for the degradation and cyclic nature. Thus, it serves as a green chemical and eco-friendly pathway in reducing pollution caused by complex dye molecule and other organic compounds. Present work has been designed to investigate photochemical degradation of dye Methylene blue by photo-Fenton reaction in presence of resorcinol as an additive. Kinetic study of the reaction has been made by using spectrophotometric technique Effect of variation of various operating parameters such as pH, concentration of Fe3+ ion, dye and additive; amount of H2O2 and light intensity has also been observed. A tentative mechanism for the photo-Fenton reaction in presence of organic additive is also given. <![CDATA[<b>FORMATION OF 2D SHEETS THROUGH H</b><b><sup>…</sup></b><b>H INTERACTION IN THE CRYSTAL PACKING OF 1,2-BIS(3-BROMOBENZYLIDENE)HYDRAZNE</b>]]> The title compound was prepared by condensation of 3-bromobenzaldehyde and hydrazine hydrate in absolute ethyl alcohol and in the presence of sulfuric acid. The title Schiff base compound, C14H10Br2N2, crystallizes with one half-molecule in the asymmetric unit in P2(1)/c monoclinic space group. The mid-point of the N-N bond (1.412(13) Å) lies on an inversion center. The molecular skeleton is approximately planar. In the crystal packing of this complex, neighboring molecules are linked to each other by H...H intermolecular interactions to form 2D sheets. <![CDATA[<b>TEMPERATURE DEPENDENCE OF BILAYER PROPERTIES IN LIPOSOMES AND THE USE OF FLUORESCENT PROBES AS A TOOL TO ELUCIDATE THE PERMEATION MECHANISM OF HYDROPHILIC SOLUTES</b>]]> Solute transport across lipidic membranes is a fundamental process for both living organisms and drug delivery. In order to establish the mechanism of solute passive transport through lipidic membranes, we determined the effect of temperature upon the rate of glucose transport (as hydrophilic solute model) through dipalmitoylphosphatidylcholine large unilamellar liposomes and compare the results to those obtained for a variety of fluorescent probes (pyrene, PRODAN, diphenylhexatriene, diphenylhexatriene-TMA). All these probes, independent of their localization in the liposomes, report a monotonous change in the micro-properties sensed with temperature, with a maximum rate of change at the main transition temperature of the bilayer. These results contrast with those obtained for the rate of glucose influx, were it is observed a clear maximum rate of intake at the transition temperature. These contrasting results imply that the microviscosity (common factor for used probes) is not the property of the bilayer that controls the rate off solute transport which, at least in the vicinity of the main transition temperature, is regulated by formation of transient pores, particularly at the transition temperature (Tm). This would indicate that, at least near Tm, glucose and other hydrophilic solutes diffuses through transient pores formed in the bilayer. Interestingly, the presence of these pores does not affect the fluorescence characteristics of the probes. <![CDATA[<b>INTELLIGENT MULTIVARIATE MODEL FOR THE OPTICAL DETECTION OF TOTAL ORGANIC CARBON</b>]]> UV inactivity and fluorescence irradiance of various organic substances are the major drawbacks for a wide applicability of UV based TOC assessment models, especially in drinking water utilities and environmental fields. The adoption of an intelligent model is the key factor to access a reliable and effective detection. The accurate training of the artificial neural network model and backward elimination of less significant parameters, conferred more predictive properties to TOC detection. This led to an efficient optimal TOC detection model based on turbidity, UV254 absorbance and true color. The validation of model performance was investigated through application of untrained scenarios. The outcome of the validation analysis showed a correlation coefficient of 0.87 and root mean square error of 0.48 while the training performance of the model showed 0.95 and 0.33 respectively. The results indicated that the trained ANN model was efficiently capable for TOC detection in water resources based on the main drivers. <![CDATA[<b>RESPONSIVE POLYMER HYBRID GEL CROSS-LINKED BY N,N-(1,2-DIHYDROXYETHYLENE) BISACRYLAMIDE FOR CATALYTIC APPLICATION</b>]]> Copolymer microgel composed of N-isopropyl acrylamide and methacrylic acid, poly(NIPAM-MAA), was synthesized by free radical emulsion polymerization using N,N-(1,2-dihydroxyethylene) bisacrylamide as cross-linking agent. The hybrid microgels poly(NIPAM-MAA)-Au and poly(NIPAM-MAA)-Ag, were synthesized by in-situ reduction of metal ions using sodium borohydride (NaBH4) as reducing agent. The temperature and pH sensitivity of pure and hybrid microgels were studied by dynamic light scattering (DLS) and UV-Visible spectroscopy. The existence of gold and silver nanoparticles inside the microgel network was confirmed by transmission electron microscopy (TEM). Poly(NIPAM-MAA)-Au and poly(NIPAM-MAA)-Ag hybrid microgels were tested for the comparative catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol. The apparent rate constant (k app) for poly(NIPAM-MAA)-Au was found superior than poly(NIPAM-MAA)-Ag. <![CDATA[<b>THE INHIBITION OF STEEL CORROSION IN ACIDIC SOLUTIONS BY A NEW SCHIFF BASE</b>]]> The inhibition effect of 2,2'- (((thiobis (4,1 phenylene)) bis(azanylylidene)) bis(methanylyidene)) bis(4-methoxyphenol) (BIS-IMIN) on the corrosion behavior of 304-stainless steel (SS) in 0.5 M HCl solution was studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. SEM, FT-IR, ¹H-NMR, 13C-NMR methods used for characterization of BIS-IMIN. Potentiodynamic polarization curves indicated that BIS-IMIN act as mixed type inhibitor. The adsorption of the inhibitor was more suited with the Langmuir adsorption isotherm and kinetic parameters Kads, ΔGads Ea , ΔHads, ΔSads were determined at room temperature. The results showed that BIS-IMIN performed well inhibiting effect for the corrosion of the SS. <![CDATA[<b>UV SPECTROPHOTOMETRIC DETERMINATION OF <i>pK'</i>s OF 1,2,4-TRIAZOLINE-3-THIONES IN SODIUM HYDROXIDE SOLUTIONS</b>]]> Using UV spectroscopy the dissociation constants of previously synthesized 4,5-disupstituted-1,2,4-triazoline-3-thiones are determinate. The UV spectra were recorded in aqueous sodium hydroxide solutions at different pH values in the range from 190 to 360 nm, immediately after preparation of the suspension. The pK TH values were obtained experimentally, graphically and by the Characteristic Vector Analysis method. Results show that the investigated compounds have two dissociation processes. The first process belongs to the dissociation of SH proton, while the second dissociation process is dissociation of OH proton. <![CDATA[<b>PHYTOCHEMICAL ANALYSIS OF ALKALOIDS FROM THE CHILEAN ENDEMIC TREE <i>CRYPTOCARYA ALBA</i></b>]]> A phytochemical study of the roots and aerial parts of Cryptocarya alba (Mol.) Looser (Lauraceae), an endemic Chilean tree and the southernmost Cryptocarya species, led for the first time to the isolation and unambiguous characterization of four known alkaloids by NMR techniques: boldine, laurolitsine, laurotetanine and norglaucine, in addition to the previously identified reticuline, and the identification via UHPLC-MS of seven more alkaloids, coclaurine, N-methylcoclaurine, norreticuline, isocorydine, N-methyllaurotetanine, predicentrine and glaucine. In spite of this fairly broad variety of benzyltetrahydroisoquinolines and aporphines, the concentrations of these alkaloids in the different organs of C. alba are quite low, which is in contrast with the sometimes generous yields of alkaloids in this genus. <![CDATA[<b>SYNTHESIS AND ANTIFUNGAL ACTIVITY OF DIARYL HYDRAZONES FROM 2,4-DINITROPHENYLHYDRAZINE</b>]]> A new series of diarylhydrazones derived from 2,4-dinitrophenylhydrazine were synthesized via condensation with aromatic aldehydes whose structures have been determined by mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance spectra. Yields were 50-99%. All compounds were screened in vitro for their antifungal activity. Preliminary results indicated that compounds 3g and 3h exhibited promising antifungal potency. Understanding of the structure of these compounds establishes a preliminary structure-activity relationship to form the basis of further investigation. <![CDATA[<b>RAMAN IDENTIFICATION OF PIGMENTS IN THE WORK OF THE CHILEAN CONTEMPORARY VISUAL ARTIST IGNACIO GUMUCIO</b>]]> The main pigments in the painting by the Chilean artist Ignacio Gumucio were identified by using micro-Raman spectroscopy. Three works by the artist, two paintings with wooden stand and a wall painting were analyzed. Pigments were vibrationally identified from cross-section samples of the contemporary paints on wood Río and Saludo and the wall painting Mental. The blue color Raman bands corresponds to cooper phthalocyanine. In the green areas, the Raman signals were ascribed to the azopigment acetoacetic arylide and copper phthalocyanine; the green color is then the result of a combination of the yellow and blue pigments. Raman bands in the pink areas were assigned to the azopigment β-naphthol. The dark green color in the Saludo paint is due to a chlorinated copper phthalocyanine pigment. Other materials in the artworks were also identified: rutile (TiO2) in Saludo in white areas and calcite (CaCO3) in Mental and Río. On this basis and taking into account the identification of the state of conservation a protocol for the preservation of the artworks Río and Saludo can be assessed. <![CDATA[<b>SIMULTANEOUS DETERMINATION OF SACCHARINE, CAFFEINE, SALICYLIC ACID AND BENZOIC ACID IN DIFFERENT MATRIXES BY SALT AND AIR-ASSISTED HOMOGENEOUS LIQUID-LIQUID EXTRACTION AND HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY</b>]]> Saccharine, caffeine, salicylic acid and benzoic acid were extracted and quantified simultaneously by coupling the salt and air-assisted homogeneous liquid-liquid extraction (SAAHLLE) technique with high-performance liquid chromatography (HPLC). Various parameters such as extraction solvent and its volume, salt and its concentration, volume of injected air, vortex time and sample pH were evaluated and optimized. Analytical parameters of the proposed method were determined under the optimized conditions. The calibration curves showed good linearity in the range of 5-100 μg/mL for saccharine, caffeine, salicylic acid and benzoic acid. The limit of detection (LOD) values for saccharine, caffeine, salicylic acid and benzoic acid were 0.024, 0.013, 0.0048 and 0.0052 ng/mL, respectively. The recoveries were in the range of 88.0-94.0% with RSD values ranging from 3.8 to 6.8%. <![CDATA[<b>SYNTHESIS, ANTI-PHYTOPATHOGENIC AND DPPH RADICAL SCAVENGING ACTIVITIES OF C-PRENYLATED ACETOPHENONES AND BENZALDEHYDES</b>]]> The syntheses of six prenylated acetophenone and benzaldehyde derivatives and their anti-phytopathogenic and antioxidant activities are reported. These compounds were obtained by electrophilic aromatic substitution (S E Ar) of the corresponding arenes and 3-methyl-2-buten-1-ol using ZnCl2 as a Lewis acid catalyst in ethyl acetate. Reasonable to good yields were obtained based on unrecovered aromatic starting material (45-73%). All the synthesized compounds were evaluated against phytopathogenic gram-negative bacteria Agrobacterium tumefaciens, Pseudomonas syringae and Erwinia carotovora and plant fungal pathogens Botrytis cinerea, Phytophthora cinnamomi and Gibberella fujikuroi. The antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity assay and expressed as half maximal inhibitory concentration (IC50) values in μΜ concentrations. The antioxidant activity went from 27.20 μΜ to &gt;100 μΜ. Compound 11 showed statistically significant inhibition of the growth of Botrytis cinerea, and compounds 13 and 15 showed statistically significant inhibition of the growth of Phytophthora cinnamomi, with respect to negative control fungal growth. All six compounds showed bacteriostatic effects against gram-negative plant pathogenic bacteria with IC50 values between 250 and <3.9 μΜ. <![CDATA[<b>DEVELOPMENT OF A KINETIC SPECTROPHOTOMETRY METHOD FOR THE DETERMINATION OF CICLOPIROX OLAMINE IN PHARMACEUTICAL SAMPLE</b>]]> A simple and sensitive kinetic spectrophotometric method was developed for the determination of ciclopirox olamine in pharmaceutical formulations (cream). The method is based on the oxidation of ciclopirox olamine with KMnO4 in alkaline medium to form K2MnO4, a bluish green color compound, at ionic strength controlled and room temperature. The reaction is monitored measuring the rate of change of absorbance at 610 nm. The absorbance-concentration plot corresponding to synthetic pharmaceutical samples (cream) was rectilinear, over the range of 0.32 - 10.0 μg mL-1, with detection and quantification limits of 0.095 μg mL¹ and 0.32 μg mL¹, respectively. Different experimental parameters affecting the development and stability of the reaction product were carefully studied via factorial screening and optimized by univariate method. The determination of ciclopirox olamine by the fixed time method is feasible and more advantageous with the calibration equation obtained at 30 min. The proposed method was validated for the application of the determination of the drug in pharmaceutical sample (cream). <![CDATA[<b>SYNTHESIS OF FUNCTIONALIZED PROPYLAMINEPOLYANILINES AND INVESTIGATION OF THEIR PROPERTIES</b>]]> In present investigation, N-substituted propylaminepolyaniline (N-PAPANI) was prepared by reaction of dimethylsulfoxide solution of polyaniline (emeraldine) base with sodium hydride, then reacted with 3-chloropropylaminehydrochloride. The N-PAPANI was characterized using reflectance Fourier transformation infrared (FTIR), cyclic voltammetry, UV-vis spectroscopy and chemical analysis. Polyaniline (PANI) was also subjected to a reaction with 3-chloropropylaminehydrochloride and ferric chloride in acetonitrile as solvent under refluxing temperature (85-90 °C) (Friedel-Craft synthetic method) to produce ring substituted functionalized PAPANI. Characterization of PAPANI was carried out using various aforementioned techniques. PANI and N-PAPANI polymers exhibited strong UV-vis absorption maxima at 273-294 nm in solution. Cyclic voltammograms of the polymers on an indium-tin oxide (ITO)-coated glass substrate exhibited one pair of reversible redox couples at half-wave oxidation potentials (E1/2) around 0.84-0.86 V and 0.88 V, respectively, versus Ag/AgCl in an acetonitrile solution. The obtained polymers showed good solubility in common organic solvents such as tetrahydrofuran and chloroform compared with emeraldine which is difficult to process due to lack of solubility. Furthermore, these polymers are air stable. <![CDATA[<b>SYNTHESIS OF 1-ARYL-6,6-DIMETHYL-2-PHENYL-6,7-DIHYDRO-1<i>H</i>-INDOL-4(5<i>H</i>)-ONES BY TWO STEPS, IN A THREE-COMPONENT REACTION</b>]]> An efficient method for the synthesis of 1-aryl-6,6-dimethyl-2-phenyl-6,7-dihydro-1H-indol-4(5H)-ones is achieved in two steps, using a three-component reaction of phenacyl bromide, dimedone and aniline derivatives in water-ethanol (1:1) under reflux conditions. <![CDATA[<b>A HIGHLY EFFICIENT SYNTHESIS OF SUBSTITUTED IMIDAZOLES VIA A ONE-POT MULTICOMPONENT REACTION BY USING UREA/HYDROGEN PEROXIDE (UHP)</b>]]> A simple, versatile and highly efficient synthesis of 2,4,5-trisubstituted imidazoles by a condensation reaction of benzil or benzoin, aldehydes and ammonium acetate in the presence of urea/hydrogen peroxide (UHP) as a mild and efficient molecular catalyst in refluxing ethanol is described. The present methodology offers several advantages such as green protocol, inexpensive catalyst, high-to-excellent yields, and simple and easy work-up procedure. <![CDATA[<b>STUDY OF PHYSICAL AND CHEMICAL CHARACTERIZATION OF NANOCOMPOSITE POLYSTYRENE / GRAPHENE OXIDE HIGH ACIDITY CAN BE APPLIED IN THIN FILMS</b>]]> This paper shows a study of Nanocomposite formed by adding reduced Graphene oxide with high acidity and polystyrene. The interest and research in the material is due to the ability of these nanoparticles significantly altering the electrical and mechanical properties of the polymer, even addition of small levels. The existence of functional groups on the graphene oxide containing abundant oxygen such as; epoxy, hydroxyl and carboxylic acid, can be well dispersed in the polymer because of its good interaction with polymer chains. In this study we used the solution by dispersing method to that made the use of solvent tetrahydrofuran (THF), for purposes of obtaining a reaction with functionalization of graphene oxide / polystyrene in time of 48 hours. The analyses of physical-chemical characterizations were made diffraction X-ray (XRD), scanning electron microscopy (SEM), Infrared Spectroscopy (IRD), Thermogravimetric Analysis (TG) and Differential calorimeter by scanning (DSC). The results obtained by XRD diffraction pattern showed a strong expansion in the peak, indicating amorphization on single sheets of graphene oxide due to distorted sp³ sites CO. The morphology of the nanocomposite structure was with surface roughness, folds and rough predominant oxidation process of oxygenated functional groups. Their techniques showed the range of absorption, crystallinity degree and the mass loss. Finally, current and future possible applications of formed polystyrene nanocomposite/ graphene oxide show high acidity efficiency in the use of thin films. <![CDATA[<b>EVALUATION OF THE ANTIOXIDANT ACTIVITY OF THE FLAVONOIDS ISOLATED FROM <i>HELIOTROPIUM SINUATUM</i> RESIN USING ORAC<sub>FL</sub>, DPPH AND ESR METHODOLOGIES</b>]]> The antioxidant capacity has been determined for a number of flavonoid compounds from Heliotropium sinuatum, a plant that grows in arid areas in the north of Chile. The methodologies used were: ORAC FL (oxygen radical absorbance capacity - fluorescein), DPPH (2,2-diphenyl-2-picrylhydrazyl) bleaching and electron spin resonance (ESR). These compounds were studied in homogeneous and heterogeneous media. The results showed that the 7-o-methyleriodictiol and 3-o-methylisorhamnetin are those with the highest antioxidant capacity <![CDATA[<b>SOLID PHASE EXTRACTION AND LC-MS/MS METHOD FOR QUANTIFICATION OF VENLAFAXINE AND ITS ACTIVE METABOLITE O-DESMETHYL VENLAFAXINE IN RAT PLASMA</b>]]> A rapid, simple, sensitive LC-MS/MS method involving a least pretreatment process has been proposed for the quantitative assessment of venlafaxine (VEN) and O-desmethyl venlafaxine (ODV) using cetirizine as an internal standard. The method was validated over the range of 1.03 ng/mL to 453.50 ng/mL (venlafaxine) and 1.32 ng/mL to 585.21 ng/mL (O-desmethyl venlafaxine). The lowest limit of quantification for venlafaxine and O-desmethyl venlafaxine was found to be 1.03 ng/mL and 1.32 ng/mL, respectively. The solid phase extraction procedure provided reliable and reproducible recoveries of the drug as well as its active metabolite with no interference at their retention time. The recovery for all analyzed drugs was found to be in the range of 72.55% to 74.75%. The result indicates that the developed procedure could be considered suitable for carry out simultaneous preclinical pharmacokinetics studies for VEN and ODV. <![CDATA[<b>CRYSTAL STRUCTURE OF 3,4-DIHYDROXY-5-GERANYL-BENZOIC ACID</b>]]> The crystal structure of the aromatic compound 3,4-dihydroxy-5-geranyl-benzoic acid (5) is reported for the first time. This compound was isolated from the resinous exudate of Manto Negro (Heliotropium taltalense I. M. Johnst), an endemic species growing in The Atacama Desert using a combination of High speed counter current chromatography (HSCCC) and permeation through Sephadex LH-20. The structure was elucidated by spectroscopic means and confirmed by X-ray crystal-structure analysis. All OH groups are involved in hydrogen bonding with the average H···O distance of 2.760(3) Å and O-H···O angles in the range 125-159°, so in the crystal packing the molecules are associated by three strong intermolecular hydrogen bonds forming ring with graph-set motif R2²(14) R2²(6). <![CDATA[<b>SYNTHESIS AND X-RAY STRUCTURAL CHARACTERIZATION OF 1-(5-BROMOBENZOFURAN-2-YL)-2-MESITYLETHANONEOXIME AND 1-(5-BROMOBENZOFURAN-2-YL)-2-MESITYLETHANONE-O-(2- PHENYLACETYL)OXIME</b>]]> The selected molecules of benzofuran derivatives were synthesized and their structures were studied using the X-ray crystallography and spectroscopic methods. The 1-(5-bromobenzofurane-2-yl)-2-mesitylethanoneoxime (I), C19H18BrNO2, and 1-(5-bromobenzofuran-2-yl)-2-mesitylethanone-O-(2-phenylacetyl) oxime (II), C27H24BrNO3, crystallize in the monoclinic crystal system in space group P2(1)/c with Z = 4 and in the triclinic system in space group P-1 with Z=2, respectively. The both compounds adopt Ζ conformation. The compound (I) consists of a dimeric arrangement of molecules around an inversion centre formed via a O-H···N intermolecular hydrogen bond linking the molecules - Along the a axis. This centrosymmetric hydrogen-bonded dimers are formed with an R²2 (6) ring motif. The compound (II) forms one dimensional infinite chain via C-H···O hydrogen bond along the a axis. Moreover, in the crystal structures of (I), (II) weak C-H···O, C-H···π and π···π interactions serve to organize formation of a two dimensional network. Moreover a short N1-N1 intermolecular contact [2.89 Å] is observed between inversion-related chains in the crystal structure of (I). The two compounds have essentialy similar bond lengths and angles. The prominent discrepancy is observed for the fragment attaching benzofuran ring with mesityl group. Benzofuran groups and other ring groups are almost planar in the crystal structures of (I) and (II). <![CDATA[<b>SYNTHESIS OF HIGHLY SELECTIVE NANO-STRUCTURED FUNCTIONALIZED SBA-15 METFORMIN PALLADIUM COMPOSITE CATALYST IN PARTIAL HYDROGENATION OF ALKYNES</b>]]> In this research, a heterogeneous Nano-Structured functionalized SBA-15 metformin palladium composite catalyst is reported for the selective hydrogenation of alkynes. In the first place, A series of the heterogeneous mesoporous SBA-15 metformin palladium catalyst were prepared and afterwards the condition and the ratio of used materials were optimized to give rise a suitable high performance catalyst. The final nano-structured catalyst was characterized by X-ray powder diffraction, BET surface area, FT-IR spectrophotometer, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) and served in partial hydrogenation of different alkynes, with high selectivity and high yield. The liquid phase hydrogenation was conducted under mild condition of room temperature and atmospheric pressure. The reactions were monitored every half an hour by gas chromatography and all of them were completed during 4-6 hours. The products were characterized by ¹H-NMR, 13C-NMR, FT-IR, and Mass Spectrometry (MS) that strongly confirmed the (Z)-double bond configuration of produced alkenes. This prepared catalyst is competitive with the best palladium catalysts known for the selective liquid phase hydrogenation of alkynes and can be easily recovered and regenerated with keeping high activity and selectivity over multiple cycles with a simple regeneration procedure. <![CDATA[<b>CRYSTAL STRUCTURE OF (1,4-DIHYDROXYNAPHTHALEN-2-YL) (4'-METHOXYPHENYL) METHANONE</b>]]> Solar photoacylation of 1,4-naphthoquinone with 4-methoxybenzaldehyde to give (1,4-dihydroxynaphthalen-2-yl)(4'-methoxyphenyl) methanone is one representative example of a general procedure to prepare highly functionalized 1,4-dihydroxynaphthalen-2-yl)(phenyl) methanone derivatives. The structure of the title compound was confirmed by x-ray diffraction analysis of a suitable single crystal. <![CDATA[<b>TRANSLOCATION OF TRANSITION METALS DURING THE DEGRADATION OF <i>PINUS RADIATA</i> BY <i>GLOEOPHYLLUM TRABEUM</i> ON THE FOREST SOIL</b>]]> Brown rot fungi (BRF) are highly destructive wood degraders characterized by extensive degradation and mineralization of cellulose and hemicellulose, in most of the cases without causing a substantial removal of lignin. BRF have not a complete cellulase complex neither ligninolytic enzymes, therefore, has been hypothesized that to degrade wood components, a non-enzymatic mechanism based on ·ΟΗ radicals production through Fenton reaction is also involved. The availability of iron limits the Fenton reaction in wood biodegradation by BRF, because this metal (and other transition metals) is found in small amounts in wood. For this reason, it has been postulated that the fungus transport metals from the soil. To study the effect of soil and transition metal translocation (Fe, Cu, and Mn) on wood biodegradation by the BRF Gloeophyllum trabeum, Pinus radiata wood chips (20 years old) were incubated with forest soil in stationary tray bioreactor for a period until 16 weeks. Translocation of transition metals, mass and wood components (extractives, carbohydrates, and lignin) loss, the decrease of holocellulose viscosity and oxalic acid production were determined at different intervals of time. Wood on soil showed a high translocation of transition metals mainly Fe. Translocation of soil metals into the wood was relevant for improving fungal growth and wood decay, which is correlated significantly with higher loss mass and wood components compared with degradation without soil.