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191.
Ahmad Shaabani Ali Hossein Rezayan Afshin Sarvary Sajjad Keshipour Hamid Reza Khavasi 《Tetrahedron letters》2010,51(31):4091-3424
An unexpected coupling reaction between isocyanides and carboxylic acids which led to the synthesis of highly stable symmetrical and unsymmetrical alkylamidine and arylamidine carbocations under mild reaction conditions is described. The structures of these compounds were confirmed by IR, mass, 1H NMR, 13C NMR, and single-crystal X-ray diffraction studies and a plausible mechanism is proposed. 相似文献
192.
Mohammad Bayat Hossein Imanieh Nader Zabarjad Shiraz Mohammad Shah Qavidel 《Monatshefte für Chemie / Chemical Monthly》2010,15(2):333-338
Abstract
Isocyanides, dialkyl acetylenedicarboxylates, and non-cyclic anhydrides, for example acetic anhydride or benzoic anhydride, react in one-pot to afford 2,5-diaminofuran derivatives and dialkyl (E)-2-[(N-acyl-N-alkylamino)carbonyl]-2-butenedioates in fairly good yields at room temperature. 相似文献193.
Younes Ghasemi Abdolali Mohagheghzadeh Zahra Ostovan Maryam Moshavash Sara Rasoul-Amini Mohammad Hossein Morowvat 《Chemistry of Natural Compounds》2010,46(5):734-737
Biotransformation of several monoterpene ketones, including carvone, pulegone, piperitone, menthone, and fenchone, was carried
out by the locally isolated unicellular microalgae Chlorella vulgaris. The microalgal strain was isolated during a screening program from soil samples collected from paddy-fields of Fars Province,
in the south of Iran. Chlorella vulgaris was cultured in 250 mL conical flasks, each containing 50 mL of BG-11 liquid medium and 20 μL levels of terpene substrates,
incubated at a temperature of 28±2°C and illuminated continuously with fluorescent lamps with shaking at 80 rpm. The metabolites
were identified by thin-layer chromatography and GC-MS. Chlorella vulgaris has the ability to reduce the C=C double bond of carvone to yield trans-dihydrocarvone and cis-dihydrocarvone. The cell line reduced menthone and pulegone to the same product and gave menthol. Study of Chlorella vulgaris with substrates of piperitone and fenchone showed no reaction in these substrates. Chlorella vulgaris MCCS 012 was assigned according to the 18S rRNA gene sequence. The DNA sequence of the 18S rRNA gene of Chlorella vulgaris MCCS 012 was recorded in the NCBI under the accession number EU374170. 相似文献
194.
Javad Safaei-Ghomi Tayebeh Ahmadi Hossein Batooli 《Chemistry of Natural Compounds》2010,46(5):816-818
195.
Naser Seyed-Matin Amir Hossein Jalili Masih Hosseini Jenab Seyed Majid Zekordi Ali Afzali Chapar Rasouli Akbar Zamaniyan 《Plasma Chemistry and Plasma Processing》2010,30(3):333-347
The carbon dioxide reforming of methane to synthesis gas under DC-pulsed plasma was investigated. The effects of specific
input energy and feed ratio on the product distribution and also feed conversion was studied. At the input energy of about
11 eV/molecule per methane and/or carbon dioxide the feed conversion of 38% for CH4 and 28% for CO2 and product selectivity of 74% has been attained for H2 and CO at feed flow rate of 90 ml/min. The energy consumption in this work displays potential to further study and optimization
of the process. The importance of the electron impact reactions in the process was discussed. The results show that by prudent
tuning of system variables, the process be able to run in the way of synthesis gas, instead of hydrocarbon production. 相似文献
196.
Saeed Aminzadeh Hossein Naderi-Manesh Khosro Khajeh Bijan Ranjbar Naser Farrokhi 《Applied biochemistry and biotechnology》2010,160(7):1921-1932
Acid-induced unfolding of a Tetracoccosporium sp. polygalacturonase enzyme (PG) was studied by a comprehensive series of biophysical and biochemical techniques. At pH 1.0,
PG acquires partially folded state, which reveals characteristics of molten globule (MG) state, i.e., reduction of defined
tertiary structure with minimal changes in the secondary structure. In this study PG unfolds exposing its hydrophobic surface
to a greater extent than the native form at acidic pH with more tryptophan residues exposed to the solvent. Collectively,
our data imply the presence of MG state of PG at low pH, suggesting the phenomenon of hydrophobic collapse model for folding
and integration into cell membrane. 相似文献
197.
Aliakbar Dehno Khalaji Gholamhossein Grivani Samaneh Jalali Akerdi Kazuma Gotoh Hiroyuki Ishida Hossein Mighani 《Structural chemistry》2010,21(5):995-1003
Two thiosemicarbazones, (E)-2-(2,4-dimethoxybenzylidene)thiosemicarbazone (24-MBTSC (1)) and (E)-2-(2,5-dimethoxybenzylidene)thiosemicarbazone (25-MBTSC (2)), derived from 2,4-dimethoxybenzaldehyde and 2,5-dimethoxybenzaldehyde, respectively, with thiosemicarbazide have been synthesized and their structures were characterized by elemental analyses, FT-IR, 1H NMR spectroscopy, and X-ray single-crystal diffraction analysis. Molecular orbital calculations have been carried out for 1 and 2 by using an ab initio method (HF) and also density functional method (B3LYP) at 6-31G basis set. Compound 1 crystallizes in the monoclinic system, space group P21/c, with a = 8.1342(5) Å, b = 18.1406(10) Å, c = 8.2847(6) Å, β = 109.7258(17)°, V = 1150.75(12) Å3, and Z = 4, whereas compound 2 crystallizes in the orthorhombic system, space group Pbca, with a = 11.0868(6) Å, b = 13.1332(6) Å, c = 15.9006(8) Å, V = 2315.2(2) Å3, and Z = 8. The compounds 1 and 2 displays a trans-configuration about the C=N double bond. 相似文献
198.
199.
Hassan Karami Amir Aminifar Hossein Tavallali Zeinol-Abedin Namdar 《Journal of Cluster Science》2010,21(1):1-9
CdO–ZnO nanocomposite was fabricated by a sol–gel pyrrolysis method based on the poly vinyl alcohol (PVA) polymeric network.
The prepared nanocomposite was carefully characterized using scanning electron microscopy, X-Ray dispersive energy analysis,
ICP-atomic emission spectroscopy, X-Ray diffraction, transmission electron microscopy and UV–visible spectroscopy. The structure,
composition, and morphology of this composite depend on a number of aspects: the amounts of cadmium salt, zinc salt, and PVA
in the initial solution, the solvent composition, and the pyrrolysis temperature. The obtained results showed that the nanocomposite
had excellent linear nanoclusters created from nanograins. Each nanograin was made of a CdO core, completely covered by ZnO
layers. Total diameter of each nanograin was 70–90 nm. 相似文献
200.
Mohammad Najafi Hossein Roghani-Mamaqani Mehdi Salami-Kalajahi Vahid Haddadi-Asl 《高分子科学》2010,28(4):483-497
<正>An optimized and high-performance Monte Carlo simulation is developed to take thorough account of four different cases of termination in styrene ATRP.According to the simulation results,the bimolecular termination rate constant sharply drops throughout the polymerization when either chain-length dependency of termination rate constant,gel effect,or both together is applied to the simulation.In addition,as expected,the initiator is quickly decomposed at the early stages of the polymerization.The concentration of the catalyst in lower oxidation state decreases at first and then plateaus at higher conversion;furthermore,the steady concentration of M_t~nY/L in the polymerization is the highest when the chain-length-dependent diffusion-controlled termination rate constant is employed in the simulation.The rates of deactivation and chain end degradation reactions are also smaller in this case.Therefore,the fraction of dormant chains is higher throughout the reaction and consequently the portion of dead polymers decreases.Besides,molecular weight increases linearly with conversion;however,when neither gel effect nor chain-length dependency of termination rate constant is considered,the molecular weight deviates from linearity at the end of the reaction.The peak of chain length distribution shifts toward higher molecular weight too during the reaction.Finally,the molecular weight distribution broadens at higher conversion;however, the chain length distribution of polymers produced under conditions of applying chain-length-dependent diffusion-controlled termination rate constant is narrower. 相似文献