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A reversed-phase high performance liquid chromatographic method for the successful separation and determination of 6 synthetic food additives (aspartame, acesulfame potassium, benzoic acid, sodium saccharin, tartrazine and sunset yellow) was developed. A EclipseXDB-C18 column (250×4.6 mm I.D.; 5 µm) was used and the mobile phase contained methanol and 0.02 mol/L ammonium acetate (pH 6.0) (30:70, v/v) was pumped at a flow rate of 0.7 mL/min at room temperature. Successful separation conditions were obtained for all the compounds using an optimized gradient elution within 10 min. The diode array detector was used to monitor the food additives at 230 nm. The method was thoroughly validated, detection limits for all substances varied between 0.03 and 1.35 µg/mg, the intra-day precision (as RSD) ranged from 1.57% to 4.72 %, the inter-day precision (as RSD) was between 2.05 % and 4.18 %. Satisfactory recoveries, ranging from 90.00 % to 109.87 %, were obtained. The proposed system was applied to drink samplesread more
QINGHUA YAN, LI YANG, XIAOQIN MA, HUIGEN FENG
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5-aryl-3-ferrocenyl-1-phenyl-2-pyrazolines have been synthesized by the reaction of α, β-unsaturated ketones with phenylhydrazine in ionic liquid [Bmim]OH. While 4-ferrocenyl-1,4-dihydropyridine-2,6-dimethyl-3,5-dicarboxylic acid alkyl ester have been synthesized by the Hantzsch reaction in ionic liquid [Bmim]OH. Structures of all new compounds have been elucidated by microanalyses, 1H and 13C NMR spectroscopies.read more
JIAN ZHANG, CHENGXIANG SHANG, LONGFEI JIN
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The n-hexane fraction of the leaves of sugar beet was analyzed qualitatively and quantitatively using GC-MS and GC equipped with FID in separate experiments. The crude was extracted using ethanol and fractionated by n-hexane, ethyl acetate and chloroform in the increasing order of polarity. Only the n-hexane fraction was analyzed using GC-MS and GC equipped with FID. The nature of products was confirmed using total ion chromatograms as well as fragmentation pattern. The concentration of the major compounds was determined using the peak area. The n-hexane fraction was found to contain esters in addition to small quantities of other compoundsread more
ZAHID HUSSAIN, PIR MOHAMMAD, KHAIR ZAMAN, KHALID MOHAMMED KHAN, SHAHNAZ PERVEEN, SADAF NIAZ
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4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dyes are important in synthetic and applied chemistry. The reaction of pyrrolomethane 1 with acetyl chloride and boron trifluoride etherate in the presence of triethylamine afforded the 4,4-Difluoro-3,5,8-trimethyl-4-bora-3a,4a-diaza-s-indacene 2a. When benzoylchloride and chloroacetyl chloride were used, phenyl 2b and chloromethyl 2c derivatives formed. The treatment of pyrrolomethane 1 with 3- (phenylthio)propanal 3 in the presence of ytterbium (III) trifluoromethanesulfonate hydrate in catalitic amount yielded the 5-(2-thiophenyl ethane)-1,9-dimethyldipyrromethane 4, which was reacted with DDQ and boron trifluoride etherate in the presence of triethylamine formed 8-(2-thiophenylethan) 4,4-difluoro-3,5dimethyl-4-bora-3a,4a-diaza-3-indacene 5. The oxidation of 8-(thiomethyl) 4,4-difluoro-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene 6 with m-CPBA gave methylsulfonyl product 7. Bromination of 4,4-difluoro-3,5,8-trimethyl-4-bora-3a,4a-diaza-s-indacene 2a yielded 1,2,6,7-tetrabromo-4,4-difluoro-3,5,8-trimethyl-4-bora-3a,4a-diaza-s-indacene 8read more
AHMET TUTAR, RAMAZAN ERENLER, JEAN-FRANÇOIS BIELLMANN
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A new 1,2,3-thiadiazole compound was synthesized and characterized by 1H NMR, MS and HRMS. The crystal structure of the title compound (C12H11ClN2O4S2, Mr = 346.80) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P-1 with a = 8.4425(17) Å, b = 8.9801(18) Å, c = 9.859(2) Å, α = 84.36(3) °, β = 86.71(3)°, γ = 83.25(3)°, V = 737.9(3)Å3, Z = 2, F(000) = 356, Dc = 1.561 g/cm3, μ = 0.557 mm-1, the final R1 = 0.0380 and wR2 = 0.0982 for 2160 observed reflections with I > 2σ(I). A total of 12585 reflections were collected, of which 2601 were independent (Rint = 0.0364). The herbicidal activity of title compound was determined, the results showed the title compound displayed excellent herbicidal activity against Brassica campestris.read more
WEI KE, NA-BO SUN AND HONG-KE WU
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A study into the environmental behavior of pyrimorph in lake water/sediment systems has been carried out. The residue of pyrimorph in water and sediment for aerobic and anaerobic tests was determined, respectively. For aerobic test, the dissipation half-life of pyrimorph was 11.6 days in lake water of water/sediment system and 96.3 days in lake water of control treatment. For anaerobic test, the dissipation half-life of pyrimorph was 5.5 days in lake water of water/sediment system and 42.3 days in lake water of control treatment. Also, the pyrimorph concentration increased gradually in sediment of water-sediment system. The results showed that the dissipation of pyrimorph in water resulted mainly from sediment adsorption of pyrimorph and O2 inhibited the dissipation of pyrimorph. The degradation product of pyrimorph has been detected by HPLC-MS/MS. In the dissipation process, pyrimorph lost morpholine ring and formed an aldehyde compound.read more
ZHUONAN LI, WENBI GUAN, YONGQIANG MA, HENG ZHAO AND ZHAOHAI QIN
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To select nicotine-degrading bacterium for bioaugmented treatment of tobacco wastewater, the activities of antioxidant indicators such as superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH), and the ability to treat pollutants including nicotine degradation and chemical oxygen demand (COD) removal, were compared between Acinetobacter sp. TW and Sphingomonas sp. TY. When complicated toxins were present, the activities of SOD induced in strain TY were significantly higher than those in strain TW. However, the activities of CAT were inhibited in strain TY (CAT/CATLB < 1), but upregulated in strain TW (CAT/CATLB > 1). Additionally, the levels of GSH induced in strain TW were significantly higher than those in strain TY. These findings suggest that the antioxidant ability of strain TW was higher than that of strain TY, especially in tobacco wastewater. Moreover, when applied to the treatment of tobacco wastewater, the rate of nicotine degradation at 24 h was 99.50% for TW and 28.76% for TY, while the rate of COD removal at 48 h was 62.69% for TW and 45.80% for TY. Taken together, these findings indicate that the pollution treatment ability of strain TW was stronger than that of TY, and that the stronger the ability of the antioxidant, the higher the potential for treatment of tobacco wastewaterread more
HONGZHEN HE, MEIZHEN WANG, HUAJUN FENG, XIN ZHENG, DONGSHENG SHEN
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Three new donor - acceptor [4] dendralene compounds have been synthesized. Wittig reaction was used for the preparation of first two compounds and third one by Knoevehagel condensation. Their mass was calculated by APCI mass spectra which are in good agreement with theoretical data. UV-Vis data indicate the cross- conjugation in these systems due to the push-pull intra molecular charge transfer (CIT) sequence from electron donor to acceptor group. The 1H-NMR signals appear in aromatic region confirming the formation of trans (having π- structures) isomers rather than cis may be due to the exposure of the compounds to ambient light. The dominating roll of electron acceptor nitro, methoxy and cyno benzene groups in conjugation is clearly shown. The 13C-NMR spectra which also supported the above analytical data and the number of carbons atoms obtained representing well the structures established.read more
MIR MUNSIF ALI TALPUR, TAJNEES PIRZADA, PETER. SKABARA, THOMAS. WESTGATE, MOHAMMAD RAZA SHAH
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In organic chemistry microwave irradiation has become a common heat source and the use of microwave irradiation is also increasingly studied for polymerization reactions. Polymers have been synthesized at long reaction times by classical thermal methods. In contrast, microwave-assisted polymer synthesis is a well-known and most useful method, which is requiring shorter reaction times. In this study, our aims are to compare THPS and MAPS methods between themselves, and investigate the effect of temperature in MAPS method at different parameters such as reaction times, weight average molecular weight (Mw), polydispersity index (PDI), hydrodynamic radius (Rh), intrinsic viscosity ([]) and Mark Houwink equation constant (a) of copolymers.
Firstly we synthesized N-vinyl-2-pyrrolidone-acrylic acid copolymers [P(VP-co-AA)] both with traditional heating polymer synthesis (THPS) and microwave-assisted polymer synthesis (MAPS) method comparatively in this study. Secondly, to research temperature effect on MAPS method in addition to microwave irradiation power, polymer synthesis at 40 ºC, 50 ºC and 80 ºC were tried.
For analyzing of copolymers Fourier Transform Infrared (FT-IR) spectroscopy and Gel Permeation Chromatography (GPC) system with four detectors were usedread more
KADRIYE KIZILBEY, SERAP DERMAN, ZEYNEP MUSTAFAEVA
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Chromene and spirocyclic 2-oxindole derivatives were readily synthesized in good yields via a one-pot three-component reaction involving Knoevenagel condensation of aromatic aldehyde or isatin with an active methylene reagent then the intermediate was reacted with another different active methylene reagent via a DABCO-catalysed Michael addition to yield the main products. Some advantages of this protocol are good yields, use of available catalysts, simple workup procedure and short reaction times. All synthesized products were characterized by FT-IR, 1H- and 13C-NMR spectroscopy.read more
AKBAR MOBINIKHALEDI, MAHSA JABBARPOUR
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