17333-85-6Relevant articles and documents
Spectroscopic and thermal properties of newly mixed azocalix[4]arene ester derivatives
?zkinali, Sevil
, p. 81 - 89 (2014/05/06)
The mono-, di-, tri-, and tetra-acryloyl esters of p-chloroazocalix[4]arene which include the first examples of mixed azo ester dyes were synthesized by reacting acryloyl chloride with sodium salts of p-chloroazocalix[4]arene in tetrahydrofuran with inert atmosphere. Diazonium salt of p-chloroaniline was synthesized by using n-amlynitrite and coupled with calix[4]arene in anhydrous condition. This is the diazo coupling reactions used for the first time for synthesized azocalix[4]arene. The characterization of synthesized compounds by spectroscopic methods revealed that azocalix[4]arenes adopt a cone conformation if they contain at least one free phenolic group. The structures of these compounds have been characterized by infrared (IR), ultraviolet-visible (UV-VIS), proton nuclear magnetic resonance (1H NMR) and carbon nuclear magnetic resonance (13C NMR). Differential thermal analysis (DTA), thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to determine the thermal behaviors of the compounds.
Synthesis and biological evaluation of nitromethylene neonicotinoids based on the enhanced conjugation
Lu, Siyuan,Zhuang, Yingying,Wu, Ningbo,Feng, Yue,Cheng, Jiagao,Li, Zhong,Chen, Jie,Yuan, Jing,Xu, Xiaoyong
, p. 10858 - 10863 (2014/01/06)
The neonicotinoids with a nitroconjugated system had excellent bioactivity, which could rival imidacloprid, and has been previously reported. However, the photodegradation and hydrolysis of this series of neonicotinoids was very quick according to our further investigation, which cannot be developed as a pesticide further. The approach to further enhance the conjugation was tried not only to increase the bioactivities but also to improve the stability in water and in the sun. A substituted phenyl group was introduced into the furan ring of compound 3. A total of 13 novel neonicotinoid analogues with a higher conjugation system were designed and synthesized. The target molecular structures have been confirmed on the basis of satisfactory analytical and spectral data. All compounds presented significant insecticidal activities on cowpea aphid (Aphis craccivora), cotton aphid (Aphis gossypii), and brown planthopper (Nilaparvata lugens). The stability test exhibited that the stability of novel analogues in water and under the mercury lamp has been improved significantly in comparison to compound 3.
Substituent effects on the thermal cis-to-trans isomerization of 1,3-diphenyltriazenes in aqueous solution
Chen, Nan,Barra, Monica,Lee, Ivan,Chahal, Navjot
, p. 2271 - 2277 (2007/10/03)
The thermal cis-to-trans isomerization of some symmetrically p,p′-disubstituted 1,3-diphenyltriazenes has been studied by means of laser-flash photolysis techniques. The geometric isomerization is catalyzed by general acids and general bases as a result of acid/base-promoted 1,3-prototropic rearrangements. Acid catalysis becomes more prominent as the electron-donating character of the para substituent increases, while base catalysis becomes more important as the electron-withdrawing character of the para substituent increases. In addition, the rate ascribed to the interconversion of neutral cis rotamers through hindered rotation around the nitrogen-nitrogen single bond is found to decrease as the electron-withdrawing character of the para substituent increases. Rates of interconversion of neutral cis rotamers are also found to decrease with decreasing solvent polarity, which is indicative of the involvement of a polar transition state. On the other hand, kinetic investigations of the acid-catalyzed decomposition of target triazenes are consistent with an A1 mechanism.
Mechanism of the Oxidation of NADH by Quinones. Energetics of One-Electron and Hydride Routes
Carlson, Brian W.,Miller, Larry L.
, p. 479 - 485 (2007/10/02)
The kinetics of NADH oxidation by 7 o-benzoquinones and 14 p-benzoquinones were studied by using buffered aqueous solutions and UV/vis spectroscopy.For each quinone the rate law was first order in NADH and first order in quinone.The rate constants varied from 0.0745 to 9220 M-1s-1.Variation of the pH from 6 to 8 gave no change in rate.The use of 4-D and 4,4-D2NADH revealed kinetic isotope effects.The dideutero data gave kH/kD in the range 1.6-3.1 for p-quinones and 4.2 for 3,5-di-tert-butyl-o-quinone.When p-quinones were used, the log k was a linear function of Eo for the quinone/hydroquinone monoanion (Q/QH(1-)) couple with a slope of 16.9 V-1. o-Quinones reacted about 100 times more rapidly, but the same linear relationship with a slope of 16.4 V-1 was observed.Comparisons to data for one-electron-transfer reactions indicate that such mechanisms are not involved.A hydride-transfer mechanism accommodates all the data, and rate-limiting hydrogen atom transfer followed by electron transfer cannot be ruled out.
Dediazoniations of Arenediazonium Ions in Homogeneous Solutions. Part XVI. Kinetics and Mechanisms of Dediazoniation of p-Chlorobenzenediazonium Tetrafluorobarate in Weakly Alkaline Aqueous Solutions under Nitrogen Gas
Schwarz, Wolfgang,Zollinger, Heinrich
, p. 513 - 528 (2007/10/02)
The kinetics of reactions of p-chlorobenzenediazonium ions in aqueous buffer solutions (pH 9.0-10.6) under N2 (5 ppb of O2) have been measured between 20 and 50 deg C.The formation of trans-diazotate is first-order with respect to the concentration of hy
