Alcohols and phenols were efficiently acylated with acetic anhydride in the presence of vanadyl sulfate (VOSO4.3H2O) at room temperature in high yields.

Results of lattice Monte Carlo simulation are presented for the behavior of a mixture of oil-water-amphiphile in different conditions. For the first time, the phase transitions between different types of microemulsion are modeled, in a qualitative manner, using the concept of solvent accessible surface area. All of the simulations are run in canonical (N, V, T) ensemble. Simple cubic lattices with the dimension of 50 have been used to avoid any size or surface effects of the boxes. Periodic boundary conditions and excluded volumes are used to mimic the box of simulation as a bulk of solution. All of the results are in good qualitative agreement with previous theoretical and experimental results.

Bamboo charcoal coated with silver (BC/Ag) was prepared by activation and chemical reduction processes at different AgNO3 contents (10-30 wt.%). The spectroscopic characterizations of the formation processes of BC/Ag composites were studied using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. These composites were introduced in epoxy resin to be a microwave absorber and mixed polyethylene to be an infrared stealth plate. Microwave absorbing properties were investigated by measuring complex permittivity, complex permeability and reflection loss in the 2-18 and 18-40 GHz microwave frequency range using the free space method. The thermal extinction measurements in the 3-5 and 8-12 mm were done to evaluate the shielding affectivity of infrared. The results showed that a significant thermal extinction and a wider absorption frequency range could be obtained by adding silver to bamboo charcoal.

A quantitative structure-property relationship (QSPR) study based on the wavelet neural network (WNN) technique was performed for the prediction of gas chromatography retention indexes of methyl-substituted alkanes produced by insects. In addition to the simple structural descriptors, semi-empirical quantum chemical calculations at the AM1 (Austin Model 1) level were used to find the optimum 3D geometry of the studied molecules and a numbers of descriptors were calculated with HyperChem and Dragon software. A stepwise MLR (Multiple Linear Regression) method was used to select the best descriptors, and the selected descriptors were used as input neurons in a wavelet neural network model. The average relative error was 2.2%.

To pursue optimum condition in liquid-liquid-liquid microextraction (LLLME), extraction parameters dominating extraction efficiency were investigated by theoretical considerations. The theoretical considerations discussed equilibrium model for equilibrium LLLME and non-equilibrium model for dynamic LLLME. A method described here is a dynamic LLLME technique combined with high-performance liquid-chromatography ultraviolet absorbance detection (HPLC/UV) to determine traces of nitrophenols in water. Analytical parameters such as organic phase, acceptor phase volume, sample agitation, extraction time, acceptor phase NaOH concentration, donor phase HCl concentration, salt addition, and absorption wavelength were identified as variable settings. Relative standard deviation (RSD, 1.8-4.4%), coefficient of estimation (R2, 0.9994-0.9999), and detection limit (0.032-0.065 ng mL-1) were achieved under the variable settings. The proposed method was successfully applied to the analysis of a lake water sample, and the relative recoveries of nitrophenols from spiked water sample were up to 92.5%. The variable settings of LLLME close to optimization was responsible for an acceptable extraction efficiency.

A highly selective and sensitive catalytic method for the determination of trace amounts of titanium(IV) was developed. The method is based on the catalytic effect of titanium(IV) on the methylene blue-ascorbic acid redox reaction. The reaction was followed spectrophotometrically by measuring the change in absorbance of methylene blue at 665 nm, 5 minutes after the initiation of the reaction. In this study experimental parameters were optimized and the effect of the presence of various cations and some anions on the determination of titanium(IV) was examined. The calibration graph was linear in the range of 3-25 ng mL-1 of titanium(IV). The relative standard deviation for the determination of 10 and 20 ng mL-1 of titanium(IV) were 2.64% and 1.51%, respectively (n = 8). The detection limit calculated from three times of standard deviation of blank 3Sb was 0.6 ng mL-1. The method was successfully applied to the determination of titanium(IV) in tap water and ore samples.

The preparation of a series of bis-pyrazolo[3,4-b:4¢,3¢-e]pyridines by the reaction of 5-aminopyrazole with aldehydes in ionic liquid [bmim]Br is described. This new method has the advantages of easier work-up, milder reaction conditions, high yields and environmental friendliness compared with other methods.

Some new (3,5-aryl/methyl-1H-pyrazol-1-yl)-(5-arylamino-2H-1,2,3-triazol-4-yl)methanones were synthesized and characterized by 1H NMR, 13C NMR, MS, IR spectra data and elemental analyses or high resolution mass spectra (HRMS). During the procedure, Dimroth rearrangement was used in this synthesis.

Cyclocondensation of polystyrene-supported a-selenopropionic acid with amidoximes in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) followed by oxidative deselenation efficiently afforded 5-vinyl 1,2,4-oxadiazoles in good yield and purity with a facile work-up procedure.

The role of the small exterior hydrophobic cluster (SEHC) in the strand region of the N-terminal b-hairpin of ubiquitin on the structural stability and the folding/unfolding kinetics of the protein have been examined. We introduce a Phe®Ala substitution at residue 4 in the strand region of the N-terminal b-hairpin of the ubiquitin. A peptide with the same amino acid sequence as the first 21 residues of the mutated ubiquitin has also been synthesized. The F4A mutation unfolds the hairpin structure of the peptide segment without disruption of the turn. The same mutation does not seem to affect the overall structure, but the stability of the mutated full-length protein decreases by approx. 2 kcal/mol. Kinetically, the entire hairpin structure is implicated in the transition state during folding of the wild type protein. The rate of refolding is retarded by the F4A mutation in ∼80% of the protein molecules. The F4A substitution also increases the unfolding rate of the protein by 10 fold. Thus the hydrophobic side-chain of Phe-4 not only contributes to the stability of the hairpin, but also to the stability of the entire protein by forming a cluster together with the hydrophobic residues on the C-terminal strand.

The reactions of Cd(NO3)2×4H2O with NH4SCN and 2,4-dpa (2,4-dpa = 2,4-dipyridineamine) in CH3OH afforded the one-dimensional coordination polymer [Cd(NCS)2(2,4-dpa)2]n, 1, while reaction of Cd(NO3)2×4H2O with NH4SCN and PmPa (PmPa = 2-(1-piperazinyl)pyrimidine) in CH3OH gave complex of the type [Cd(NCS)2(PmPa)2]n, 2. Each of the 2,4-dpa ligand in complex 1 is coordinated to the Cd2+ metal center through pyridyl nitrogen atoms to form the one-dimensional chain structures. The distorted {CdN4S2} octahedral coordination geometry around Cd2+ center is completed by pairs of bidentate thiocyanato ligands. Complex 2 has the 1-D arrangement constructed through one-dimensional double m(N,S) end-to-end bridging thiocyanato groups bridged Cd(II) chains interconnected through PmPa ligands.

The mean centering of ratio kinetic profiles method was used for the simultaneous determination of binary mixtures of Ni(II) and Zn(II) in water samples, without prior separation steps. The method is based on the difference in the rate of the reaction of Ni(II) and Zn(II) with xylenol orange at pH 5.3. The method allows rapid and accurate determination of Ni(II) and Zn(II). The analytical characteristics of the methods for the simultaneous determination of binary mixtures of Ni(II) and Zn(II) were calculated. The linear range was 0.025-2.400 mg mL-1 and 0.025-2.20 mg mL-1 for Zn(II) and Ni(II), respectively. Interference effects of common anions and cations were studied, and the method was successfully applied to the simultaneous determination of Zn(II) and Ni(II) in water samples.

A voltammetric method using a poly(1-methylpyrrole) modified glassy carbon electrode was developed for the quantification of adrenaline. The modified electrode exhibited stable and sensitive current responses towards adrenaline. Compared with a bare GCE, the modified electrode exhibits a remarkable shift of the oxidation potentials of adrenaline in the cathodic direction and a drastic enhancement of the anodic current response. The separation between anodic and cathodic peak potentials (DEp) for adrenaline is 30 mV in 0.1 M phosphate buffer solution (PBS) at pH 4.0 at modified glassy carbon electrodes. The linear current response was obtained in the range of 7.5 ′ 10-7 to 2.0 ′ 10-4 M with a detection limit of 1.68 ′ 10-7 M for adrenaline by square wave voltammetry. The poly(1-methypyrrole)/GCE was also effective to simultaneously determine adrenaline, ascorbic acid and uric acid in a mixture and resolved the overlapping anodic peaks of these three species into three well-defined voltammetric peaks in cyclic voltammetry. The modified electrode has been successfully applied for the determination of adrenaline in pharmaceuticals. The proposed method showed excellent stability and reproducibility.

The effects of experimental conditions on the fractal structure of electrosynthetic polyparaphenylene films were studied by electrochemical impedance spectroscopy. The results indicate that, at the potential range (0-0.6 V), the film surface fractal dimension rises while the corresponding charge transfer resistances Rct decrease as charge increases. This is consistent with the oxidized behavior of the conducting polymer. As for the degradation of electrolytes, scanning electron microscopy observations of poly(para-pheneylene) (PPP) film provide evidence of the close relationship between the degradation of electrolytes and the film morphology, also in good agreement with the electrochemical impedance results interpretation. The X-ray photoelectron spectroscopic analysis results present that the relative oxygen content ratio (O/C) of the films increases with the times the electrolyte is used, which reveals that the degradation of the electrolyte may result in a compact and passivation PPP film.

A procedure is described for the liquid-liquid extraction and recovery of bismuth(III) from succinate solution using 2-octylaminopyridine (2-OAP) as an extractant. The quantitative extraction of bismuth(III) occurs from 0.004 to 0.007 M sodium succinate solution of pH 2.5-10 using 0.036 M 2-OAP in chloroform. The extracted metal ion has been recovered by stripping with (3′ 10 mL) 0.5 M nitric acid. The log-log plot of distribution ratio versus succinate concentration and distribution ratio versus 2-OAP concentration gave slopes of 2.0 and 0.9, respectively, indicating a metal-succinate ratio of 1:2 and a metal : 2-OAP ratio of 1:1. The ion pair complex has a high distribution ratio in chloroform, while other solvents are poor. The extractants are stable towards prolonged acid contacts and there is no loss in its extraction efficiency even after recycling ten times. The extraction behaviour of some commonly associated metal ions, namely Ga(III), Cd(II), Zn(II), Cr(VI), Cu(II), Ba(II), Sb(III), Sn(IV), Tl(I) and Pb(II), has also been investigated. Based on partition data, conditions have been identified for attaining some separations of bismuth(III) from other metal ions; these conditions are extended for the recovery of pure bismuth from ore and alloys. Thermodynamic quantities for the extraction process were calculated.

Simple, reliable, sensitive and accurate kinetic spectrophotometric and spectrofluorimetric methods were proposed for the determination of ciprofloxacin hydrochloride (CPX) and norfloxacin (NRX) in pure form and in pharmaceuticals. The methods are based on coupling the studied drugs with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in the presence of alkaline borate buffer. Spectrophotometric measurement was achieved by recording the absorbance at 477 nm after a fixed time of 20 and 15 min on a water bath adjusted at 70 ± 1 °C for CPX and NRX, respectively. The same product exhibited emission peaks at 540 nm. The different experimental parameters affecting the development and stability of the color were carefully studied and optimized. The absorbance concentration plots were linear over the ranges 3-18 and 2.5-15.0 mg/mL for CPX and NRX, respectively, while the fluorescence concentration plots were linear over the ranges 0.06-0.36 and 0.05-0.30 mg/mL for CPX and NRX, respectively. The limit of detection of the kinetic method was about 0.2 mg/mL for both drugs while the fluorescence measurement enabled their detection at a concentration of about 0.012 mg/mL. The proposed methods were successfully applied for the assay of the two drugs in their commercial products. The results obtained were statistically compared with those obtained by reference HPLC and spectrophotometric methods. The stoichiometry of the reaction was determined and the reaction pathway was postulated.

The sesquiterpene capnellene-8b,10a-diol (1) was isolated from non-polar extract of the soft coral Capnella sp. Ten acylation products of capnellene-8b,10a-diol were prepared: 10a-hydroxy-8b-O-benzoylcapnellene (2), 10a-hydroxy-8b-O-p-toluoylcapnellene (3), 10a-hydroxy-8b-O-4-chlorobenzoylcapnellene (4), 10a-hydroxy-8b-O-2-furoylcapnellene (5), 10a-hydroxy-8b-O-2-thiophenoylcapnellene (6), 10a-hydroxy-8b-O-4-fluorobenzoylcapnellene (7), 10a-hydroxy-8b-O-4-propylbenzoylcapnellene (8), 10a-hydroxy-8b-O-cinnamoylcapnellene (9), 10a-hydroxy-8b-O-4-nitrobenzoylcapnellene (10), and 10a-hydroxy-8b-O-4-anisoylcapnellene (11). The structures of capnellene-8b,10a-diol as well as its derivatives were established through standard spectroscopic analysis. The in vitro cytotoxic activities of the eleven compounds were evaluated against Hela, KB, Daoy, and WiDr human tumor cell lines.

The synthesis of some new S-nucleosides of 5-(4-pyridyl)-4-aryl-4H-1,2,4-triazole-3-thiols (4a-n) is described. Direct glycosylation of (4a-n) with tetra-O-acetyl-a-D-glucopyranosyl bromide in the presence of potassium hydroxide followed by deacetylation using dry ammonia in methanol gave the corresponding 3-S-(b-D-glucopyranosyl)-5-(4-pyridyl)-4-aryl-4H-1,2,4-triazoles (6a-n) in good yields. All the compounds were fully characterized by means of 1H NMR, 13C NMR spectra and elemental analyses. To assist in the interpretation of the spectroscopic data, the crystal structure of 3-S-(2¢,3¢,4¢,6¢-tetra-O-acetyl-b-D-glucopyranosyl)-5-(4-pyridyl)-4-phenyl-4H-1,2,4-triazole (5a) was determined by X-ray diffraction.

3H-1,5-benzodiazepines were synthesized by the condensation of o-phenylendiamine and various 1,3-diketones in the presence of various heteropolyacid (HPA) catalysts under mild conditions in very good yields and with high selectivity.

Prostacyclin is involved in many pathological conditions, such as sensitization of inflammation induced pain and isovolumetic distention. Therefore, antagonism of prostacyclin action may be useful in the alleviation of these conditions. In this study, novel potent prostacyclin antagonists, 2-[4-(imidazolin-2-ylideneamino)benzyl]-indan-1-ones were synthesized from their respective substituted indanones in three steps. The construction of the amino-imidazole moiety of these derivatives is achieved by using in situ generation of chloro-imidazole and reaction with their respective anilines. Thus, these N-substituted 2-imidazolines can be prepared safely and efficiently. Moreover, these compounds show potent prostacyclin antagonistic activity by inhibition of prostacyclin agonist induced ERK1/2 phosphorylation in human erythroleukemia cells. Moreover, we observed an increase in activity with the increase in electro-donating property of the substitution on the indanone aromatic ring. Prostacyclin antagonists with increased potency may be designed based on these findings. These compounds may also be invaluable tools for the study of the physiological functions of prostacyclin.

Three new compounds, 2,4-dimethoxy-6-methylbenzene-1,3-diol (1), salmoquinone (2), and 3-(4-hydroxyphenyl)-4-isobutyl-1H-pyrrole-2,5-dione (3), together with six known compounds, 2-methoxy-6-methyl-p-benzoquinone (4), 2,3-dimethoxy-5-methyl-p-benzoquinone (5), 2-hydroxy-5-methoxy-3-methyl-p-benzoquinone (6), eburcoic acid (7), fomefficinic acid C (8), and a pyrroledione (9), were isolated from the mycelium of Antrodia salmonea. The structures of these compounds were elucidated by spectrometric analyses including IR, NMR, and MS. Among these compounds, 4 and 5 exhibited cytotoxicity against KB, HepG2, and H2058 cell lines.

A few kinds of novel Schiff base complexes have been prepared by three-component reaction of the substituted hydroxyacetophenone with several aliphatic diamines and transition metals such as; Cu(II), Co(II), Mn(II), Zn(II) and UO2(II) under mild reaction conditions. The products have been afforded with excellent yields and appropriate reaction times. The structures of these ligands have been characterized by their IR, 1H NMR, 13C NMR and MS spectral and physical data.

A thorough phytochemical investigation of the whole plant of Saxifraga montana H. afforded a new glucoside, methyl 6²-O-(E)-p-hydroxycinnamoxyl-glucosyringate (1), and seventeen known natural products, 3-methyl-6-methoxy-3,4-dihydroisocoumarin-8-O-b-D-glucospyranoside (2), gallic acid (3), glucosyringic acid (4), daphnoretin (5), chamaejasmoside (6), myricetin (7), quercetin (8), quercetin-3-O-b-D-galactopyranoside (9), quercetin-3-O-a-L-arabinoside (10), quercetin-3-O-b-D-glucospyranoside (11), rutin (12), quercetin-3-O-b-D-glucopyranosyl (6-1) glucopyranoside (13), ursolic acid (14), 5,28-stigmastadien-3b-ol (15), b-sitosterol (16), b-daucosterin (17), 6¢-palmitoxyl-b-daucosterin (18). On the basis of various spectroscopic methods, especially intensive 2D-NMR (COSY, HMQC and HMBC), FAB-MS and HR-ESI-MS techniques, their structures were elucidated.

Direct iodination of several reactive aromatic compounds like hydroxy substituted acetophenones and aldehydes with pyridinium iodochloride (PyICl) proceeded smoothly to afford the corresponding aromatic iodides in good to excellent yield. Pyridinium iodochloride has been found to be an efficient solid iodinating reagent with no hazardous effect and it can be handled safely.

By condensing 2-aminobenzothiazole with 2-hydroxy-1-naphthaldehyde, 2-hydroxybenzaldehyde, 4-methoxybenzaldehyde, 4-hydroxybenzal-dehyde, benzaldehyde and 4-dimethylaminobenzaldehyde, and five Schiff bases Ia-Ie are prepared. Also, two Schiff bases IIa and IIb are prepared by condensation of 2-amino-3-hydroxypyridine with 2-hydroxy-1-naphthaldehyde and 2-hydroxybenzaldehyde. The 1H NMR, IR and UV/Vis spectra of these seven Schiff bases are investigated. The signals of the 1H NMR spectra as well as the important bands in the IR spectra are considered and discussed in relation to molecular structure. The UV/Vis absorption bands in ethanol are assigned to the corresponding electronic transitions and the electronic absorption spectra of Schiff bases Ib and IIb are studied in organic solvents of different polarities. The UV/Vis absorption spectra of 2-amino-3-hydroxypyridine Schiff bases IIa and IIb are investigated in buffer solutions of different pH values containing 5% (v/v) methanol, and the results are utilized for the determination of pKa and DG* of the ionization of the phenolic OH-groups. The fluorescence spectra of IIa and IIb are studied in organic solvents of different polarities. The obtained spectral results are confirmed by some molecular calculations using the atom super position and electron delocalization molecular orbital theory for the Schiff base IIb.

A mixture of ethyl formate and a catalytic amount of silica sulfuric acid or Al(HSO4)3 as suitable formylating systems can formylate various alcohols to their corresponding formate ester derivatives under mild, nearly neutral and heterogeneous conditions at room temperature with good to excellent yields.

Benzoxazole derivatives were obtained in high yields with excellent purity from the condensation of 2-aminophenol with benzaldehydes and benzoic acids in the presence of a catalytic amount of heteropolyacids (HPAs).

The ozonolysis of 1-substituted allyl silyl ethers or 1-substituted allyl carboxylates followed by treatment with bases gave the corresponding a-silyloxymethyl- or a-acyloxymethyl-ketones in good yields. It is proposed to proceed via the corresponding a-silyloxy- or a-acyloxyaldehydes intermediates followed by 1,4-group migration. The results of theoretical calculations are applicable to explain the experimental results.

In recent years, ionic liquids have attracted much attention as useful synthetic solvents. Compared with classical molecular solvents, the ionic liquids are environmentally benign reaction media. A variety of quinoline derivatives have been synthesized under ionic liquid conditions using Amberlyst-15 as catalyst.

A new and efficient method for the synthesis of 4-aryl-2-phenyloxazoles is described which is based upon the reaction of a-[(2,4-dinitrobenzene)sulfonyl]oxy ketone intermediates with benzamide in ionic liquid.

The synthesis of neoflavene and neoflavenes with methoxy substituents at different positions are described. As starting materials, various salicylaldehydes were run through sequential reactions such as O-allylation, Grignard reaction, oxidation, Wittig reaction, and ring-closing metathesis to yield the target neoflavenes in good yield. Among the prepared neoflavenes, 7-methoxy-4¢-methoxyneoflavene (6e) and 8-methoxy-4¢-methoxyneoflavene (6f) exhibiting potential cell toxicities against various cells were disclosed. In particular, 6f which exhibited an IC50 value of 6.5 ± 2.0 and 5.1 ± 1.1 mM against gastric carcinoma and lung carcinoma cells in vitro was found, respectively. Meanwhile, the structure and activity relationship of our synthesized neoflavenes is further discussed briefly.

Two new ent-kaurane diterpenoids, 15b-hydroxy-6,7-seco-6,11b:6,20-diepoxy-1a,7-olide-ent-kaur- 16-ene (1), 11a,15a-dihydroxy-6b-methoxy-6,7-seco-6,20-epoxy-1a,7-olide-ent-kaur-16-ene (2), together with four known diterpenoids, nodosin (3), isodocarpin (4), odonicin (5) and maoyecrystal F (6) were isolated from the aerial parts of Isodon nervosus. The structures of the new compounds were elucidated on the basis of their spectral evidence, especially on 2D NMR.

The effect of ethyl xanthate(I) and propyl xanthate(II) on the kinetics of hydroxylation by mushroom tyrosinase (MT) has been investigated at 20 °C in 10 mM phosphate buffer solution, pH 6.8. 4-[(4-Methylphenyl)azo]-phenol (MePAPh) was used as a synthetic substrate for the enzyme for cresolase reaction. The results show that ethyl xanthate and propyl xanthate can activate or inhibit the cresolase activity of mushroom tyrosinase depending on the concentration of these effectors. Both I and II act uncompetitive at relatively high concentrations (20-50 mM). The inhibition constant (Ki) values for I and II are 13.8 and 11 mM, respectively. However, both I and II act as activators at relatively low concentrations (0-11.5 mM). Activation of the enzyme in low concentrations of xanthates arises from increasing the affinity of binding for the substrate as well as increasing the enzyme catalytic constant. The activation constant (Ka) values for I and II are 1.88 and 2.68 mM, respectively. The enzyme has two distinct sites for both effectors. The first one is a high-affinity activation site and the other is a low-affinity inhibition site.