排序方式: 共有130条查询结果,搜索用时 15 毫秒
41.
Ismet Basaran Umit Cakir 《Journal of inclusion phenomena and macrocyclic chemistry》2014,78(1-4):179-184
o-Dihydroxy-3-(methylphenyl)-chromenones (coumarins; 3a–3c) were synthesized from trimethoxybenzaldehydes through a reaction with the corresponding methylphenyl-acrylonitrile in pyridine·HCl and then H3O+. Dihydroxycoumarins reacted with the ditosylate or dichloride derivatives of tri- or tetraethyleneglycols in the presence of CH3CN/Na2CO3 and macrocyclic ethers with a coumarin moiety were obtained. The chromatographically purified new coumarin-crown ethers (5a–5f) were identified by IR, 1H NMR, and Mass spectrometry. The binding constants of Na+ with the coumarin-crown ethers were determined in an 80 % dioxane/water binary solvent system at 25 °C from conductance measurements. 相似文献
42.
1,2-bis(p-aminophenoxy)ethane was obtained with reduction of 1,2-bis(p-nitrophenoxy)ethane and Pd/C as catalyst in hydrazine hydrate. Co(II), Cu(II), and Ni(II) complexes of aromatic bidentate
diamine were prepared. The structure of the ligand and its complexes were characterized by IR, elemental analysis, magnetic
susceptibility, conductivimetry, UV-Vis and 1H NMR spectroscopy. The metal/ligand mole ratios were found to be 1:1. The general compositions of these complexes are found
to be [CoLCl2], [CuLCl2], and [CoLCl2].
The text was submitted by the authors in English. 相似文献
43.
44.
Ahmet Demirbas Sule Ceylan Neslihan Demirbas 《Journal of heterocyclic chemistry》2007,44(6):1271-1280
The synthesis and structural properties of two kinds of thiosemicarbazide derivatives ( 2a‐c and 3a‐c ) and one kind of semicarbazide derivatives ( 4a, 4b ) have been described. These compounds were synthesized by treating 2‐(4‐amino‐3‐alkyl‐5‐oxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)acetohydrazides ( 1a‐c ) with benzyl isothiocyanate, 3‐florophenyl isothiocyanate and benzylisocyanate, respectively. The synthesis of 4‐amino‐3‐alkyl‐1‐[(4‐alkyl‐5‐mercapto(or 5‐oxo)‐4H‐1,2,4‐triazol‐3‐yl)methyl]‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones ( 5a‐c, 6a‐c and 7 ) have been performed from the reaction with sodium hydroxide. On the other hand, the acidic treatment of compounds 2b, 3b and 4b has afforded 4‐amino‐3‐(4‐chlorobenzyl)‐1‐[(5‐alkylamino‐1,3,4‐thidazol(or 1,3,4‐oxazol)‐2‐yl)methyl]‐4,5‐dihydro‐1H‐1,2,4‐triazol‐5‐ones ( 8, 9 and 10 ). The condensation of thiosemi(or semi)carbazide derivatives ( 2a‐c, 3c and 4b ) with 4‐chlorophenacylbromide have resulted in the formation of 2‐[4‐amino‐3‐alkyl‐5‐oxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl]‐N′‐(3,4‐dialkyl‐1,3‐thiazol(or oxazol)‐2(3H)‐yliden]acetohydrazides ( 11a‐c, 12, 13 ), while their condensation with chloroacetic acid has produced 2‐[4‐amino‐3‐alkyl‐5‐oxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl]‐N′‐[3‐(3‐alkyl)]‐4‐oxo‐1,3‐thiazolidin(or oxazolidin)‐2‐yliden}acetohydrazides ( 14, 15 and 16 ). The spectral data and elemental analyses have support the proposed structures. 相似文献
45.
Moury R Moussa G Demirci UB Hannauer J Bernard S Petit E van der Lee A Miele P 《Physical chemistry chemical physics : PCCP》2012,14(5):1768-1777
Hydrazine borane (N(2)H(4)BH(3)) is the novel boron- and nitrogen-based material appearing to be a promising candidate in chemical hydrogen storage. It stores 15.4 wt% of hydrogen in hydridic and protic forms, and the challenge is to release H(2) with maximum efficiency, if possible all hydrogen stored in the material. An important step to realize this ambitious goal is to synthesize HB with high yields and high purity, and to characterize it fully. In this work, we report a 2-step synthesis (salt metathesis and solvent extraction-drying) through which N(2)H(4)BH(3) is successfully obtained in 3 days, with a yield of about 80% and a purity of 99.6%. N(2)H(4)BH(3) was characterized by NMR, IR, XRD, TGA and DSC, its stability in dioxane and water was determined, and its thermolysis by-products were characterized. We thus present a complete data sheet that should be very useful for future studies. Furthermore, we propose a discussion on the potential of HB (with H(2) released by either thermolysis or hydrolysis) in chemical hydrogen storage. 相似文献
46.
47.
Umit Hakan Yildiz Chia Wei Sheng Diyar Mailepessov Diana Chia Xueqi Susana Geifman Shochat Bo Liedberg 《Analytical and bioanalytical chemistry》2012,404(8):2369-2375
This contribution introduces a fluorescence assay for real-time determination of the activity of p97/VCP, a 540-kDa homo-hexameric enzyme, belonging to the AAA-ATPase family. A fluorescent reporter “poly 1-(3-((4-methylthiophen-3-yl)oxy)propyl)quinuclidin-1-ium” (poly PTQ) is used to monitor the hydrolysis of ATP to ADP by p97/VCP. The proposed assay relies on the different strength of coordination of ATP and ADP to the polymer backbone. We used recovery of fluorescence intensity on addition of p97/VCP to a poly PTQ/ATP solution to determine the enzymatic activity. The kinetic data K m and V max were 0.30?mmol?L?1 ATP and 0.134?nmol ATP min?1?μg?1 enzyme, respectively. The specificity of the assay was investigated by using an unhydrolyzable ATP analogue and sensitivity against p97 mutagenesis was further examined by detection of the activity of wild type and truncated p97/VCP. Our study demonstrates that determination of the real-time activity of p97/VCP is possible, because of the superior sensitivity and very fast optical response of poly PTQ. Figure
Illustration of fluorescence based detection mechanism for real-time determination of the activity of ATPase by water-soluble polythiophene 相似文献
48.
The present paper proposes a preconcentration procedure for phosphorus determination by using ultraviolet-visible spectrophotometer. It is based on the formation of phosphomolybdate and its reduction to molybdenum blue. Phosphorus extraction as phosphomolybdenum blue complex was performed onto Amberlite XAD-4. The optimization step was carried out using two-level full factorial design. Three variables (resin amount, sample volume, flow rate) were regarded as factors in the optimization. The relative standard deviation was 2% at 0.08 μg mL−1. The limit of detection was found to be 2.23 μg L−1 (N = 15). The proposed solid-phase extraction procedure was applied to phosphorus in some fruit leaves, natural waters, and a standard reference material (SRM 1515 apple leaves). 相似文献
49.
Arif Mermer Neslihan Demirbas Ummuhan Cakmak Ahmet Colak Ahmet Demirbas Manikandan Alagumuthu Sivakumar Arumugam 《Journal of heterocyclic chemistry》2019,56(9):2460-2468
The synthesis of N‐substituted‐5‐arylidenerhodanines was carried out by the optimized one‐pot sequential four‐component procedure with the condensation between 4‐aminobenzenesulfonamide, suitable aldehyde, ethyl bromoacetate, and carbon disulfide. In addition to traditional method, microwave‐irradiated and ultrasound‐irradiated techniques were implemented in water at ambitious conditions, and the target compounds were obtained in high yields and purity without purification methods. The enzyme inhibition activity of newly synthesized compounds on carbonic anhydrase (II) was also evaluated. The reference inhibitor molecule was sulfanilamide, the IC50 value of which was 3.5 μM. It was also found that the IC50 values of all examined molecules were in nanomolar level and much smaller than those of sulfanilamide. The inhibition between 93.5 and 99.6% was observed in the presence of new compounds synthesized in the present study at the accessible maximum concentration in the reaction mixtures. 5j , among the tested compounds possessing the lowest IC50 value, was found to be the most potent carbonic anhydrase (II) inhibitor. 相似文献
50.
Inclusion complex of naphthalene with methyl-beta-cyclodextrin in water has been formed. The aqueous solutions of the various amounts of Co2+ve Mn2+salts have been added to naphthalene-methyl-beta-cyclodextrin (NAP-Me-β-CD) inclusion complexes. Fluorescence properties of the naphthalene (NAP) compound have been utilized to observe the changes in fluorescence intensities. Stern-Volmer quenching constants and fluorescence quantum yields have been calculated. Characterization of the resulting complex by FT-IR and 1H NMR technique has been determined. Fluorescence lifetime measurements have been made in the presence and absence of the quenching reagent and Gibbs free energy change has been calculated. 相似文献