tert-Butyl isocyanide revisited as a convertible reagent in the Groebke-Blackburn reaction

tert-Butyl isocyanide can serve as the convertible reagent in Groebke-Blackburn multi-component reactions. The effective removal of the tert-butyl group from the resulting imidazo[1,2-a]azines and -azoles is achieved on a gram scale in two steps without chromatographic purification.     

Palladium‐Catalyzed Multi‐Component Reactions of N‐Tosylhydrazones, 2‐Iodoanilines and CO2 towards 4‐Aryl‐2‐Quinolinones

A palladium‐catalyzed three‐component reaction between N‐tosylhydrazones, 2‐iodoanilines and atmospheric pressure CO₂ was developed whereby a tandem carbene migration insertion/lactamization strategy afforded 4‐aryl‐2‐quinolinones in moderate to good yields. Notably, a wide range of functional groups were tolerated in this procedure. This protocol features the simultaneous formation of four novel bonds; two C?C, one C=C and one C?N (amide), representing an efficient methodology for incorporation of CO₂ into heterocycles.     

An efficient synthesis of imidazo[2,1-b][1,3]thiazins via a one-pot,three-component and solvent-free reaction

A simple and eco-friendly method for the synthesis of novel imidazo[2,1-b][1,3]thiazin derivatives has been developed via the one-pot, three-component and solvent-free reaction of thiohydantoins, aromatic aldehyde and 5,5-dimethylcyclohexane-1,3-dione in the presence of catalytic amount of p-toluene sulfonic acid, in good and excellent yields.     

Chemical synthesis of magnetic nanocrystals:Recent progress

Colloidal chemical synthesis of various types of magnetic nanocrystals is discussed with regard to recent discoveries. We first outline the chemical preparation of single-component magnetic nanocrystals with controlled size, shape, and uniformity based on several solution-phase methods, especially thermal decomposition and/or reduction method. Then we discuss the synthetic strategies of multi-component nanocrystals incorporating at least one magnetic component by manipulating heterogeneous nucleation and growth process. Toward the end, approaches for preparing hollow/porous magnetic nanocrystals are highlighted. We believe that the summarized chemical synthesis will pave the way for the future development of extraordinary magnetic nanocrystals.     

大数值孔径多组分玻璃柔性光纤的制备及影响因素分析

大数值孔径多组分玻璃柔性光纤在医用光纤内窥镜中具有广阔的应用前景.采用La2O3 -Nb2O5 -SiO2-B2O3-RO玻璃系统作纤芯,用自制相匹配的低折射率玻璃材料作包层拉制的柔性光纤的数值孔径为0.8725,光的接受角为122°,扩大了医用光纤内窥镜的观察范围,满足了医疗仪器观察诊断的特殊需要.给出了La2O3 ...     

Modification of polyamide-6 structure by combined methods of solid-phase extrusion

Potentialities of new combined deformation schemes, including the solid-state extrusion through conical die (ED) and equal-channel multiple angle extrusion (ECMAE) implemented in different sequences to modify the structure and properties of semicrystalline polymers, have been studied for polyamide-6 (PA-6) as an example. It is shown that deformation by the ED–ECMAE scheme gives the best complex of physical and mechanical properties. A significal improvement of elastic and strength properties of PA-6 with a conserved high level of plastic characteristics has been observed.     

多组份计算中封闭性模型研究

在使用单速度多组份方法计算多介质混合网格中的物理量时,需要给出一种封闭模型来使控制方程封闭。本文分析了压力增量相等封闭性模型存在基础遭到破坏的原因,之后在保证流场守恒性的前提下构造可以保证假设基础的可解方程组对压力增量相等封闭性模型进行修正,给出了一种改进方法。使用改进的模型进行了爆轰驱动飞片问题的计算,计算结果表明,改进的模型能很好的追踪物质界面和冲击波位置,同时较好的抑制界面处压力、内能震荡。     

ICP-AES法测定石灰石、白云石中的Al_2O_3,CaO,TFe_2O_3,MgO,MnO,SiO_2,TiO_2

采用无水碳酸钾＋硼酸处理样品,电感耦合等离子体发射光谱法同时测定石灰石及白云石中7种组分,筛选了不同仪器参数条件,对各组分分别选用2条相对谱线强度适中的谱线进行分析,并以元素平均值的模式输出数据结果,测定的相对标准偏差小于0.60%.经对国家一级石灰石及白云石标准物质分析验证,结果与标准值吻合.     

Streamlined access to 2,3-dihydropyrazino[1,2-a]indole-1,4-diones via Ugi reaction followed by microwave-assisted cyclization

An efficient method is developed to construct drug-like 2,3-dihydropyrazino[1,2-a]indole-1,4-diones from 1H-indole-2-carboxylic acids, ethyl pyruvate, isocyanides, and primary amines via a one-pot, two-step procedure involving Ugi reaction and microwave-assisted cyclization.