Highly Efficient Synthesis of Tricyclic Perimidines under Microwave Heating

A new and efficient access to (Z)‐N‐(2‐argio‐1‐(1H‐perimidin‐2‐yl)vinyl)benzamide derivatives from readily available substrates in HOAc is described with aid of microwave irradiation. The results of our study provide a simple, straightforward synthetic route to these interesting classes of 2‐substituted perimidines analogs in excellent yields.     

Graphene‐based solid‐phase extraction disk for fast separation and preconcentration of trace polycyclic aromatic hydrocarbons from environmental water samples

Graphene has great potentials for the use in sample preparation due to its ultra high specific surface area, superior chemical stability, and excellent thermal stability. In our work, a novel graphene‐based SPE disk was developed for separation and preconcentration of trace polycyclic aromatic hydrocarbons from environmental water samples. Based on the strong π–π stacking interaction between the analytes and graphene, the analytes extracted by graphene were eluted by cyclohexane and then determined by GC‐MS. Under the optimized conditions, high flow rate (30 mL/min) and sensitivity (0.84–13 ng/L) were achieved. The proposed method was successfully applied to the analysis of real environmental water samples with recoveries ranging from 72.8 to 106.2%. Furthermore, the property of anticlogging and reusability was also improved. This work reveals great potentials of graphene‐based SPE disk in environmental analytical.     

Copper-Catalyzed Cyanopropylation of Activated Alkenes

A practical copper-catalyzed alkylarylation of activated alkenes with azobisisobutyronitrile (AIBN) and beyond has been developed, in which incorporation of 3^o nitrile moiety into an oxindole scaffold proceeded smoothly through cascade radical addition/C(sp²)-H cyclization. The use of readily available AIBN as radical source and inexpensive CuI as catalyst, as well as broad substrate scope and the simplicity of operation and handling, make this protocol a highly attractive approach to oxindoles bearing 3^o nitrile moiety.     

Chemoselectivity Control: Gold(I)‐Catalyzed Synthesis of 6,7‐Dihydrobenzofuran‐4(5H)‐ones and Benzofurans from 1‐(Alkynyl)‐7‐oxabicyclo[4.1.0]heptan‐2‐ones

New and chemoselective gold(I)‐catalyzed transformations of 1‐(arylethynyl)‐7‐oxabicyclo[4.1.0]‐ heptan‐2‐ones were developed. Two completely different products—6,7‐dihydrobenzofuran‐4(5H)‐ones and benzofurans—could be obtained from the same starting material. The selectivity is determined by the ligand of the gold catalyst: triphenylphosphine delivers 6,7‐dihydrobenzofuran‐4(5H)‐ones, and 1,3‐bis(diisopropylphenyl)imidazol‐2‐ylidene leads to benzofurans. Eleven examples of each case are provided. The mechanistic suggestions for the pathways to both product types are supported by isotope labeling experiments.     

Application of Polyglycerol Diisostearate Ethoxylates in Microemulsion

Effect of surfactants [polyglycerol diisostearate ethoxylates (PGDIS-E31, PGDIS-E36 and PGDIS-E40) and Tween-80], alcohols (1,2-propandiol, ethanol, 1-propanol, 1-butanol, 2-butanol and 1-pentanol), oils [isopropyl palmitate (IPP), isooctyl palmitate (IOP), dioctyl carbonate (DOC), and dioctyl hexanediate (DOH)], temperature and sodium chloride on the microemulsion formation of the surfactant/alcohol/oil/water system has been investigated by the pseudo-ternary phase diagrams. The capacities of the four surfactants in the microemulsion formation of the surfactant/alcohol/IPP/water system at surfactant/alcohol of 2:1 are in the order of PGDIS-E31 > PGDIS-E36 > Tween-80 > PGDIS-E40, whatever alcohol (ethanol, 1-propanol, and 1-butanol) is used. PGDIS-E31 and 1-butanol exhibit best synergism in the microemulsion formation. In addition, the volume, structure and polarity of oil all influence the microemulsion formation. At the optimum weight ratio 2:1 of PGDIS-E31/1-butanol, the microemulsion region of the PGDIS-E31/1-butanol/IPP/water system is the largest among the studied systems. The microemulsion system of PGDIS-E31/1-butanol/IPP/water is not sensitive to lower temperature such as 40°C. It is also not sensitive to sodium chloride when the concentration of sodium chloride is in the range of 0 to 1.0%.     

Fractal Aperture Distribution of Activated Carbon Fiber and Adsorption Behavior to Low‐Density Benzene Steam

Based on the J(x) fractal distribution function of aperture given by Jaroniec, this article suggests another function K(x), a variant of J(x) but offering new insight. We then use these two functions to characterize three kinds of activated carbon fiber (ACF) of different specific areas. This article also provides the fractal distribution of the aperture and the isotherm of nonpolarity benzene steam on the ACF specimens and the relationship between them.     

Surface Properties and Solubility of Simvastatin in the Micelles of Polyglycerol Diisostearate Ethoxylates

A series of polyglycerol diisostearate ethoxylates with two hydrophobic chains were prepared by the reaction of polyglycerol diisostearate with ethylene oxide. Surface properties including water solubility, cloud temperature, critical micelle concentration, emulsification, and the solubilizing capacity of polyglycerol diisostearate ethoxylates for simvastatin were investigated in comparison with those of Tween‐80. The critical micelle concentrations of all polyglycerol diisostearate ethoxylates are less than 0.01 mmol l^?1, which is one order of magnitude lower than that of Tween‐80. Polyglycerol diisostearate ethoxylates show better emulsification than Tween‐80. For enhancing the solubility of simvastatin in micelles, polyglycerol diisostearate ethoxylates also are superior to Tween‐80.     

Synthesis and crystal structure of a new one-dimensional system with end-to-end single dicyanamide bridges between nickel(II) centres

The complex [Ni(tn)₂{N(CN)₂}]ClO₄ (tn=trimethylenediamine) has been synthesized and the structure has been determined. The complex forms a one-dimensional chain structure via the bidentate bridging ligand dicyanamide. A two-dimensional networks is formed via interchain hydrogen bond interactions.     

溴酚蓝和亚甲蓝双显色体系萃取光度法测定铜

向三元络合物[Cu(phen)_3)BPB的二氯乙烷萃取液中,加入KCN水溶液,形成的[Cu(CN)_2)~-和溴酚蓝离子(BPB)进入水相,向其中加入与BPB颜色相近的亚甲蓝(MB)再进行萃取光度测定。因萃取液中[MB_2BPB)和[Cu(CN)_2)MB两者的吸光作用,使本方法具有很高的灵敏度,ε=1.77×10~5L·mol~(-1)·cm~(-1)。铜含量在0～5μg/25ml遵从比耳定律,对含铜量为10~(-8)g/ml的水样测定5次,相对标准偏差为2％。     

甲烷在二元碱土金属复合体系催化剂上的氧化偶联

碱土金属氧化物或碳酸盐为多种类型甲烷氧化偶联制取C_2烃催化剂的重要组分之一.有关纯碱土金属氧化物及含氧酸盐的研究表明,这类化合物具有较强的表面碱性及高温P型半导性而对活化甲烷生成C_2烃有较高活性,关于不同碱土金属化合物之间混合形成的二元碱土金属复合体系催化剂的报导仍不多见,Aika等人曾报导用BaO与CaO或MgO混合的催化剂上在1073K时可以获得61.1%C_2烃选择性和14.2%的C_2烃收率,但BaO易在反应条件下与水反应生成Ba(OH)_2而腐蚀器壁,不利于长期操作.本文报导了一系列不同碱土金属化合物之间形成的二元碱土复合体系催化剂上甲烷氧化偶联的反应结果.结果表明,这类催化剂由于其结构稳定、活性好而值得进一步研究.