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11.
P. R. Latthe P. S. Shinge Bharati V. Badami P. B. Patil S. N. Holihosur 《Journal of Chemical Sciences》2006,118(3):249-256
3-[4-(Azidocarbonyl)]phenylsydnone (2) obtained from 3-(4-hydrazinocarbonyl) phenylsydnone (1) on Curtius rearrangement with alcohols, water and amines afforded the corresponding carbamates (3a-h), 4,4′-(sydnone-3-yl) diphenyl urea (4) and 4-(heterocyclyl)phenyl ureas (5a-l). Compounds (5a-l) on one-pot ring conversion yielded the 1,3,4-oxadiazolin-2-one derivatives (6a-l), which on reaction with N2H4 gave the 4-amino-1,2,4-triazolin-3-ones (7a-l). All these compounds exhibited moderate antimicrobial activity against the few microbes tested. The carbamates have been
found to be more toxic against fourth instar larvae ofAedes aegypti, in particular, then-butyl derivative (3e). 相似文献
12.
一类积分不等式的推广 总被引:1,自引:0,他引:1
对一些基本的积分不等式进行了推广,给出了含有n个无关变元的更广泛的非线性积分不等式.利用所得的不等式讨论了某些非线性积分方程解的有界性. 相似文献
13.
在程序升温条件下 ,用DSC研究了标题化合物的放热分解反应动力学 .用线性最小二乘法、迭代法以及二分法与最小二乘法相结合的方法 ,以积分方程、微分方程和放热速率方程拟合DSC数据 .在逻辑选择建立了微分和积分机理函数的最可几一般表达式后 ,用放热速率方程得到相应的表观活化能 (Ea)、指前因子 (A)和反应级数 (n)的值 .结果表明 :该反应的微分形式的经验动力学模式函数、Ea 和A值分别为 (1-α) 0 .44、2 30 .4kJ/mol和 10 18.16s-1.借助加热速率和所得动力学参数值 ,提出了标题化合物放热分解反应的动力学方程 .该化合物的热爆炸临界温度为 30 2 .6℃ .上述动力学参数对分析、评价标题化合物的稳定性和热变化规律十分有用 . 相似文献
14.
The total synthesis of an alkylcitrate secondary metabolite from the fungi Trichoderma viride is described. An ester dienolate [2,3]-Wittig rearrangement and a S. Julia-Kocienski olefination served as key C/C-connecting transformations. The highly convergent synthesis consists of a longest linear sequence of 17 steps. 相似文献
15.
Anuj Mittal Swaminathan Sivaram 《Journal of polymer science. Part A, Polymer chemistry》2005,43(21):4996-5008
A tridentate ligand, BPIEP: 2,6‐bis[1‐(2,6‐diisopropyl phenylimino) ethyl] pyridine, having central pyridine unit and two peripheral imine coordination sites was effectively employed in controlled/“living” radical polymerization of MMA at 90°C in toluene as solvent, CuIBr as catalyst, and ethyl‐2‐bromoisobutyrate (EBiB) as initiator resulting in well‐defined polymers with polydispersities Mw/Mn ≤ 1.23. The rate of polymerization follows first‐order kinetics, kapp = 3.4 × 10?5 s?1, indicating the presence of low radical concentration ([P*] ≤ 10?8) throughout the reaction. The polymerization rate attains a maximum at a ligand‐to‐metal ratio of 2:1 in toluene at 90°C. The solvent concentration (v/v, with respect to monomer) has a significant effect on the polymerization kinetics. The polymerization is faster in polar solvents like, diphenylether, and anisole, as compared to toluene. Increasing the monomer concentration in toluene resulted in a better control of polymerization. The molecular weights (Mn,SEC) increased linearly with conversion and were found to be higher than predicted molecular (Mn,Cal). However, the polydispersity remained narrow, i.e., ≤1.23. The initiator efficiency at lower monomer concentration approaches a value of 0.7 in 110 min as compared to 0.5 in 330 min at higher monomer concentration. The aging of the copper salt complexed with BPIEP had a beneficial effect and resulted in polymers with narrow polydispersitities and higher conversion. PMMA obtained at room temperature in toluene (33%, v/v) gave PDI of 1.22 (Mn = 8500) in 48 h whereas, at 50°C the PDI is 1.18 (Mn = 10,300), which is achieved in 23 h. The plot of lnkapp versus 1/T gave an apparent activation energy of polymerization as (ΔE≠app) 58.29 KJ/mol and enthalpy of equilibrium (ΔH0eq) to 28.8 KJ/mol. Reverse ATRP of MMA was successfully performed using AIBN in bulk as well as solution. The controlled nature of the polymerization reaction was established through kinetic studies and chain extension experiments. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4996–5008, 2005 相似文献
16.
Monika Goikoetxea María J. Barandiaran José M. Asua 《Journal of polymer science. Part A, Polymer chemistry》2007,45(24):5838-5846
The mechanisms involved in the formation of n‐butanol during the synthesis of butyl acrylate containing latices were investigated. The experimental results showed that neither the hydrolysis of butyl acrylate nor of the ester bond in the butyl acrylate segments of the polymer played a major role in the formation of n‐butanol, which was mainly generated from the polymer backbone, by transfer reactions to polymer chain followed by cyclization. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5838–5846, 2007 相似文献
17.
A. V. Ivanov M. Yu. Tsentalovich E. G. Kogan L. G. Tomilova N. S. Zefirov 《Russian Chemical Bulletin》2008,57(8):1676-1679
The chlorination of benzene, toluene, and o-xylene with molecular chlorine in the presence of the phthalocyanine complexes of different structures was studied. The transformations
of the catalysts during the reaction were investigated.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1644–1647, August, 2008. 相似文献
18.
Chin‐Ping Yang Ruei‐Shin Chen Kuei‐Hung Chen 《Journal of polymer science. Part A, Polymer chemistry》2003,41(7):922-938
To investigate the position and amount of the CF3 group affecting the coloration of polyimides (PIs), we prepared 2,2‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]hexafluoropropane ( 2 ) with four CF3 groups with 2‐chloro‐5‐nitrobenzotrifluoride and 2,2‐bis(4‐hydroxyphenol)hexafluoropropane. A series of soluble and light‐colored fluorinated PIs ( 5 ) were synthesized from 2 and various aromatic dianhydrides ( 3a – 3f ). 5a – 5f had inherent viscosities ranging from 0.80 to 1.19 dL/g and were soluble in amide polar solvents and even in less polar solvents. The glass‐transition temperatures of 5 were 221–265 °C, and the 10% weight‐loss temperatures were above 493 °C. Their films had cutoff wavelengths between 343 and 390 nm, b* values (a yellowness index) ranging from 5 to 41, dielectric constants of 2.68–3.01 (1 MHz), and moisture absorptions of 0.03–0.29 wt %. In a comparison of the PI series 6 – 8 based on 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane, 2,2‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]propane, and 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane, we found that the CF3 group close to the imide group was more effective in lowering the color; this means that CF3 of 5 , 7 , and 8f was more effective than that of 6c . The color intensity of the four PI series was lowered in the following order: 5 > 7 > 6 > 8 . The PI 5f , synthesized from diamine 2 and 4,4′‐hexafluoroisopropylidenediphthalic anhydride, had six CF3 groups in a repeated segment, so it exhibited the lightest color among the four series. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 922–938, 2003 相似文献
19.
The aim of this work is to study the dynamic formation and dissociation of trions and excitons in double barrier resonant tunneling diodes. We propose a system of rate equations that takes into account the formation, dissociation and annihilation of these complexes inside the quantum well. From the solutions of the coupled equations, we are able to study the modulation of excitons and trions formation in the device as a function of the applied bias. The results of our model agree qualitatively with the experiments showing the viability of these rate equations system to study the dynamics of complex systems. 相似文献
20.
The reactions of 2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-trione with dimethyl sulfate, benzyl chloride, and allyl bromide afforded the corresponding 2-alkyl-2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-triones and 3-(alkoxy)-6,11-dihydroanthra[2,1-d]isothiazole-6,11-diones. The reactions of 2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-trione and its S-oxide with a formaldehyde—secondary amine system yielded 2-[(alkylamino)methyl]-2,3,6,11-tetrahydroanthra[2,1-d]isothiazole-3,6,11-triones and 2-[(alkylamino)methyl]-3,6,11-trioxo-2,3,6,11-tetrahydroanthra[2,1-d]isothiazole 1-oxides, respectively. 相似文献