Concise and Efficient Synthesis of Dehydropeptide Analogues from Unsaturated 5（4H）—Oxazolone

Some dehydropeptide analogues were directly synthesized by the reaction of unsaturated oxazolones with free amino acids.     

聚合物复合材料填充剂的表面性质及其分散性的研究

本文通过反气相色谱技术研究了未处理的、硅烷偶联剂处理的和钛酸酯偶联剂处理的三种Al(OH)_3粉末的表面性质,并通过塑化仪和扫描电子显微镜研究了Al(OH)_3填充聚丙烯体系的流变行为及其在聚丙烯中的分散效果.结果表明Al(OH)_3的表面性质对其在聚丙烯介质中的分散效果有着重要的影响.     

红霉素A9-（1-异丙氧基环已基）肟的合成及其晶体结构

合成表征了红霉素A9-（1-异丙氧基环已基）肟的E和Z异构体，并在丙酮-水混 合溶液中培养出了前者的单晶，X射线衍射表明，其结构为正交晶系，P2_12_12_1 空间群，晶胞参数：a=2.3101(5) nm, b=2.3761(5) nm, c=0.97066(19)nm, V=5. 3279(8) nm~3，Z=4，μ=0.088 mm~(-1)，F(000)=2064, D_c=1.176 g/cm~3。E-红 霉素A 9-（1-异丙氧基环已基）肟的晶体结构图明显表明1-异丙氧基环已基保护基 确实使十四元大环的构象发生了扭曲，使6-OH的周围空间不再拥挤，从而导致6- OH甲基化的选择性提高。     

Studies on Aggregation Interaction between Reduced Denatured Egg White Lysozymes during Refolding Procedure in Urea Solution

The aggregation interaction between reduced-denatured egg white lysozymes during refolding procedure in urea solution was studied by means of reducing and non-reducing protein electrophoreses. Results of non-reducing sodium dodecyl sulphate polyacrylamide gel electrophoresis （SDS-PAGE） of the supernatant and aggregate precipitate formed in refolding process show that except being refolded to native egg white lysozymes, the reduced-denatured lysozymes can also form the aggregates with molecular weights （MW） being separately about 30.0 and 35.0 kD, while the reducing SDS-PAGE and the refolding results in the presence of sodium dodecyl sulphate show that these aggregates are formed chiefly through the misconnection of disulfide bonds between the reduced-denatured lysozymes, and the aggregate precipitates are formed through the non-covalent interactions between the aggregates with molecular weight being about 30.0 kD. From the results of electrophoresis and size-exclusion chromatographic analyses, it can be inferred that the aggregates with molecular weights being about 30.0 and 35.0 kD are bi-molecular and tri-molecular egg white lysozyme aggregates, respectively. And finally, a suggested refolding mechanism of reduced-denatured egg white lysozymes in urea solution was presented.     

A new anode material LiMoS2 for use in rechargeable Lithium Ion Batteries

The novel applications of molybdenum disulfide in recent research were reviewed, such as in lubricant, catalyst and photoelectrochemical solar cells. Recently, we found that LiMoS2 is a good candidate for new anode materials for lithium ion batteries with high lithium storage capacity.Here, the anode material LiMoS2 was synthesized by a hydrothermal method at 150℃ and the electrochemical characterization as an anode material for lithium ion batteries was examined.put in Teflon-lined stainless steel autoclaves of capacity 40 mL. Distilled water was used to fill the autoclaves to 70 % of the total volume. The autoclaves were maintained at 150℃ for 24 h and then cooled naturally. The resulting dark-gray powders were filled and washed with distilled water,diluted hydrochloric acid and ethanol, successively. The final products were dried at 80℃ for 24 h.The powder X-ray diffraction pattern showed the prepared LiMoS2 was amorphous structure. A test cell using LiMoS2 as the active material was discharged and charged between 3 and 0.01 V with respect to Li metal at a constant current density of C/5 (that is, one lithium per formula unit in 5 hours). During the first discharge, the potential rapidly drops to reach a large plateau at 2.2 V, then slowly drops to the other plateau at 0.8 V, and then continuously decreases down to 0.01V. There is only a plateau at 1.35 V in the subsequent discharge curves. The plateaus of charge potential appear at about 1.9 V.The irreversible loss was 41% in the first cycle. The ratio of discharge and charge is more than 99%in the subsequent cycles. Moreover, the ratio of discharge and charge almost reaches 100% after thedemonstrated that LiMoS2 has a very high capacity and a good cycle-ability as an anode material forlithium ion batteries.     

人参中总皂甙的超声波快速提取方法研究

建立了人参中总皂甙超声波半微量快速提取方法，与索氏提取法相比，此法提取时间由索氏法的1－2个工作日缩短到30min，节省大量试剂，综合提取效率提高数十倍，与索氏提取法对照分析表明，此法可完全满足人参中总皂甙的快速测定要求。     

C_(59)F_(2n)HN(n=1,2)异构体的结构与稳定性的理论研究

分别用MNDO和AM1两种半经验方法,对C59F2nHN (n = 1, 2) 的异构体进行几何构型全优化,结合频率分析及HF/6-31G单点能计算,确定了各异构体的基态结构及其相对稳定性。计算结果表明,C59HN的F加成物的立体选择性规律与C60的不同,最稳定异构体不是1-2加成物。C59F2HN的最稳定异构体是1-4加成的6, 18-或12, 15-异构体; C59F4HN的最稳定异构体是1-4,1-4加成的6, 18; 12, 15-异构体,其能量远小于其它各异构体的能量。N原子取代碳笼骨架C原子后,改变了碳笼F加成物的立体选择性规律。     

氯代膦烯化合物与零价钯的氧化加成反应机理探讨

与氯代烯烃或芳烃相反, 氯代膦烯与零价钯的氧化加成反应可以在温和条件下进行. 提出了可能的反应机理. 起始卤代膦烯的结构决定了反应历程和最终产物的结构.     

Evaluating and clustering retrosynthesis pathways with learned strategy

With recent advances in the computer-aided synthesis planning (CASP) powered by data science and machine learning, modern CASP programs can rapidly identify thousands of potential pathways for a given target molecule. However, the lack of a holistic pathway evaluation mechanism makes it challenging to systematically prioritize strategic pathways except for using some simple heuristics. Herein, we introduce a data-driven approach to evaluate the relative strategic levels of retrosynthesis pathways using a dynamic tree-structured long short-term memory (tree-LSTM) model. We first curated a retrosynthesis pathway database, containing 238k patent-extracted pathways along with ∼55 M artificial pathways generated from an open-source CASP program, ASKCOS. The tree-LSTM model was trained to differentiate patent-extracted and artificial pathways with the same target molecule in order to learn the strategic relationship among single-step reactions within the patent-extracted pathways. The model achieved a top-1 ranking accuracy of 79.1% to recognize patent-extracted pathways. In addition, the trained tree-LSTM model learned to encode pathway-level information into a representative latent vector, which can facilitate clustering similar pathways to help illustrate strategically diverse pathways generated from CASP programs.

Tree-structured long short-term memory neural model learns to understand the retrosynthesis design strategies from patent-extracted retrosynthetic pathway data.     

含松香骨架的新型手性季铵盐相转移催化剂的合成及其在不对称环氧化反应中的应用

以天然松香为原料合成了4个新型手性季铵盐类相转移催化剂, 并用于催化不对称查尔酮环氧化反应, 发现这类手性相转移催化剂可以有效地催化查尔酮的不对称环氧化, 环氧化产物ee最高达20%.