The Purification of Glucose Type Glycosyl Nitrate and the Synthesis of Spacer—armed N—Acetyllactosamines and Their Dimers

Our previous paper1,2reported the results of selective synthesis of mannose type glycosides and their dimers in our attempt to synthesize derivatives of N-acetyllacto- samine, which could have potential activity of anti-metastasis3. Further studies on the glycosylation of the accepters exploiting glycosyl nitrate instead of the acetate as donor showed interesting chemoselectivity between the two kinds of donor, namely, the glucose type and the mannose type. The reactivity difference of the t…     

C_(60)离子束撞击固体表面的坍塌沉积(Ⅰ)共焦显微拉曼光谱研究

为了研究C60的结构特性，我们最近在实验中将加这后的C60离子束沉积在固体表面，对其沉积后的形态进行了共焦显微拉曼光谱的表征．在记录的光谱中已检测不出C60原有的特征谱问，说明C60离子在高速憧击固体表面后，已经完全失去了原有的球状构型．C60的t）［R实验在自制的串级飞     

钴(Ⅱ)与5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯络合物吸附波及其应用

钴 (Ⅱ )在NH3·H2O -NH2OH·HCl-5_(5_硝基_2_吡啶偶氮)_2,4_二氨基甲苯体系中有一灵敏的极谱波 ,其峰电位Vp 为 -1.20V(vsSCE) ,钴质量浓度在0.25～25μg/L范围内与峰电流Ip′有良好的线性关系 ,检出限为0.12μg/L;经多种电化学方法证明该波为络合物吸附波 ,其电极过程为不可逆过程 ,电子转移数为2 ,此外还试验了多种离子对峰电流Ip′的影响;所拟方法已用于维生素B12 和模拟样中痕量钴的测定     

A novel diacetylenic bilirubin

An etiobilirubin‐IIβ analog with the central C(10) CH₂ group replaced by a diacetylene unit ( 1 ) was synthesized by base‐catalyzed condensation of bis‐[3‐methyl‐4‐ethyl‐5‐formylpyrrol‐2‐yl]‐diacetylene ( 3 ) with 3‐methyl‐4‐ethyl‐5‐p‐toluenesulfonyl‐2‐pyrrolinone ( 10 ). Diacetylenic rubin 1 is a dark red solid, giving orange solutions with uv‐visible absorption maxima near 460 nm.     

A Study of Multi-order Semidifferential Oscillographic Chronopotentiometry

ASemiintegralelectroanalysishasbeenimprovedanddevelopedsinceOldhamlwhofirstintroduceditinl972,andiswidelyaPpliedtoseveralkindsofpolarographicanalysis"'suchaslinearsweepvoltammetry,cyclicvoltammetryandanodicstrippingvoltanunetry.Anewfieldinelectroanalysis,neopolarographicmethod,isformed.Thismethodhasmanyadvantages,forexample,highsensitivity,goodresolvingpower,simPlicityofinstrUmentstructureandlowcost.Itissuitableforthestudyoffastanalysisandfastelectrodereaction.Determinationcanbecarriedouteve…     

色谱灰色数模的建立及其应用研究(Ⅰ)──连续GM(1,N)模型的建立及色谱保留行为的预测

应用灰色系统理论和最小二乘原理，推导出连续GM（1，N）模型，并将该模型用于高效液相色谱中溶质保留行为的预测．研究了烷烃、烷基苯及对羟基苯甲酸酯等化合物的容量因子与流动相组成、容量因子与碳数、保留时间与温度、保留时间与碳数的关系，并建立了相应的数学模型，经验证，预测结果良好．     

2-氰基-3-甲硫基-3-取代甲氨基丙烯酸酯类化合物的合成及其除草活性

A series of 2-cyano-3-methylthio-3-substituted methylaminoacrylates were synthesized as herbicidal inhibitors of photosystem Ⅱ （PSⅡ） electron transport, in order to estimate the effect of fluorine atom, pyridyl group, chirality and ester chain on activity. The important intermediate 2-fluoro-5-aminomethylpyridine was synthesized with high yield. The bioassay results showed that most of rifle compounds had high herbicidal activity in postemergence treatment. The introduction of an a-methyl into the 3-substituted methylamino could improve the activity notably. The replacement of hydrogen by chlorine or fluorine group and phenyl by pyridyl group showed different effects, and at the same time, the ester chain affected the activity too.     

Low-temperature electrothermal vaporization of thenoyltrifluoroacetone complex of Sc(III) and Y(III) for sample introduction in an inductively coupled plasma atomic emission spectrometry,and their determination in biological samples

A new method for inductively coupled plasma atomic emission spectrometry (ICP-AES) determination of trace Sc and Y, based on gaseous compound introduction into the plasma as their thenoyltrifluoroacetone (TTA) complexes by electrothermal vaporization was developed. Using the reagent TTA as chemical modifier can not only enhance the analytical signals, but also reduce the vaporization temperature. At a temperature of 1,000 °C the trace Sc and Y can be vaporized completely into ICP. The factors affecting the formation of the chelate and its vaporization behavior, such as drying time, vaporization temperature/time, reaction medium and the amount of TTA, were investigated in detail. Under the optimized conditions (drying temperature/time 100 °C/10 s, vaporization temperature/time 1,000 °C/4 s), the limits of detection for Sc and Y were 19 pg and 34 pg (3), respectively, and the relative standard deviations for Sc and Y were 4.2% (c _Sc=0.2 g mL^–1; n=7) and 2.6% (c _Y=0.5 g mL^–1; n=7). The linear ranges of the calibration graphs cover three orders of magnitude. The method was applied to the analysis of the biological reference materials (GBW 07602, bush branches and leaves; GBW 07604, poplar leaves), and the results obtained were in good agreement with the certified values.     

KNa(3)In(9): a Zintl network phase built of layered indium icosahedra and zigzag chains. Synthesis,structure, bonding,and properties

This phase was discovered following direct fusion of the elements in welded Nb tubes at 550 degrees C and equilibration at 300 degrees C for 1 week. Single-crystal X-ray diffraction analysis reveals that KNa(3)In(9) crystallizes in an orthorhombic system (Cmca, Z = 8, a = 9.960(1) A, b =16.564(2) A, c = 17.530(2) A, 23 degrees C). The structure contains a three-dimensional indium network built of layers of empty In(12) icosahedra that are each 12-bonded and interconnected by 4-bonded indium atoms that also form zigzag chains. All cations bridge between cluster faces or edges, and their mixed sizes appear critical to the stability of this particular structure, which does not occur in either binary system. Both empirical electron counting and EHTB band structure calculations on the macroanion indicate that the bonding in this structure is closed-shell, whereas resistivity and magnetic susceptibility measures show that the compound is a moderately poor metal.     

新冠病毒刺突蛋白及其受体的结构与相互作用

Biochemistry is a branch subject of chemistry, which is the study of chemical structures and processes associated with living organisms. COVID-19 pandemic is a problem for human beings. From the perspective of biochemistry, this paper demonstrates the chemical structure and interactions of SARS-CoV-2's spike protein and its receptor (human angiotensin converting enzyme 2), and summarizes the related research progresses. The authors hope to provide insights for the development of COVID-19 vaccine.