Lithium heptadecafluorooctanesulfonate catalyzed Mannich-type and aza-Diels-Alder reactions in supercritical carbon dioxide

The Mannich-type reaction of imines with (1-methoxy-2-methylpropenyloxy)trimethylsilane and aza-Diels-Alder reaction of imines with Danishefsky's diene can be carried out in scCO₂ in the presence of lithium heptadecafluorooctanesulfonate which offer a way to synthesize β-amino carbonyl compounds and nitrogen-containing six-membered ring compounds under environmentally benign conditions.     

Standardization and certification in the area of environmentally degradable plastics

Environmentally degradable polymers and plastics (EDPs) are a group of polymeric materials experiencing a rapid growth in number as well as in their applications and quantities used. The assessment of their key characteristic - degradability, including eventually biodegradability as the ultimate stage, is scientifically and technically a challenging issue and has led to differing interpretations in the past. In order to standardize techniques and criteria a number of standards were established by different standardization bodies which are also used as a basis for certification schemes. An up-to-date inventory of the rapidly growing standardization body is presented with basic interpretation to help guide the non-expert. A basic introduction to EDPs and polymer degradation is added for clarity.     

近临界水中苯丁烯酮合成新方法

试探了一种以水为反应介质合成本丁烯酮的新方法。在近临界水中，以苯甲醛 和丙酮为原料，在不外加任何催化剂、反应温度为260℃、反应时间为6h的条件下 ，苯丁烯酮的产率可达46．2％。该新方法避免了盐类副产物的产生，省去了常规 方法中反庆后繁琐的中和分离步骤。     

Thermoanalytical characterization of carbon/carbon hybrid material, Apple Woodceramics

Woodceramics, a carbon/carbon composite of plant-originated carbon reinforced by glassy carbon from phenolic resin, was prepared from apple pomace at carbonizing temperatures of 1073 K (AWC800) and 1473 K (AWC1200), and characterized by thermoanalytical methods and X-ray diffraction (XRD). Simultaneous differential scanning calorimetry (DSC) and thermogravimetric (TG) showed complicated overlapping reactions similar to those of coal. The initial temperature of pyrolysis was obtained by fitting logistic functions to observed TG data. The results suggested that AWC1200 contained more volatile matter than AWC800. In an inert atmosphere, complicated devolatilization takes place. In an oxidizing atmosphere, thermal change occurs roughly in four steps: desorption of physically adsorbed matter; pyrolysis into aliphatic and aromatic fragments; ignition; combustion of char. The oxidation resistance of AWC1200 was superior to AWC800.     

A novel and efficient approach to highly substituted indolizines via 5-endo-trig iodocyclization

A new approach to indolizines has been developed using a 5-endo-trig iodocyclization of allylic esters followed by isomerization and dehydroiodination facilitated by triethylamine at rt. This mild procedure enabled us to synthesize a number of highly substituted indolizines in good yields.     

CT、MRI对良恶性甲状腺结节的鉴别价值

本文探讨了计算机断层扫描（CT）、磁共振成像（MRI）对良恶性甲状腺结节的鉴别价值。方法：选取2015年3月至2018年3月本院收治的甲状腺结节患者150例，依据病理结果分为恶性48例、良性102例，所有患者均给予CT、MRI检查，分析CT、MRI对良恶性甲状腺结节的鉴别价值。结果发现，MRI总病灶、形态不规则、边界不清/毛糙、信号/密度不均检出率明显高于CT，MRI钙化灶检出率明显低于CT，差异有统计学意义（P<0.05），CT、MRI淋巴结转移检出率比较，差异无统计学意义（P>0.05）；在鉴别良恶性甲状腺结节的敏感度、特异度、准确度中，CT为79.17%、74.51%、76.00%，MRI为83.33%、80.39%、81.33%，CT联合MRI为95.83%、96.08%、96.00%，CT联合MRI明显高于CT、MRI，差异有统计学意义（P<0.05）。说明CT、MRI可作为鉴别良恶性甲状腺结节的重要方法，CT对钙化灶有较高的分辨能力，MRI对软组织及小病灶有较高的分辨能力，CT联合MRI可有效提高其鉴别价值。     

A 4-aminonaphthalimide based environmentally sensitive fluorescence probe

A simply synthesized 4-aminonaphthalimide derivative 1 expresses both polarity and viscosity sensitive fluorescence spectra, indicating its potential usage as an environmentally sensitive fluorescence probe. By comparing the fluorescence behavior of 1 with that of a known 4-aminonaphthalimide derivative 2, it was found that the substitution of the 4-amino group has profound influence on the environmentally sensitive fluorescence properties of 4-aminonaphthalimide.     

H_6P_2W_（18）O_（62）á18H_2O： A green and reusable catalyst for one-pot synthesis of pyrano[4,3-b]pyrans in water

A convenient,effcient and environmentally benign procedure has been developed for the synthesis of pyrano[4,3-b]pyran derivatives via a one-pot,three-component reaction of 4-hydroxy-6-methylpyran-2-one,aldehydes and malononitrile in water using H6P2W18O62á18H2O as catalyst.Reusability of the catalyst and reaction media,short reaction times and easy isolation of products are some added advantages of the present methodology.     

MK-10 Clay–Catalyzed Synthesis of 2-(2′,5′-Disubstituted-1′H-indol-3′-yl)-1H-benzo[d]imidazoles under Conventional and Microwave Irradiation

The synthesis of benzimidazoles has been achieved in a one-pot reaction in excellent yield using a newly developed methodology. 2,5-Disubstituted-3-cyanoacetyl indoles were directly condensed with substituted orthophenylenediamine via microwave irradiation under neat, solid support, and conventional conditions in a short time to afford the corresponding products in good yields. Structures of the products thus obtained were confirmed by their melting points, infrared, ¹H NMR, ¹³C NMR, and mass spectral data.