Study of alkaloids from the flora of the Siberian and Altai regions. 6. Crystal and molecular structure of songorine Z-oxime

Oximation of songorine afforded a mixture of its Z- and E-oximes. The crystal and molecular structure of the Z-isomer was established by X-ray diffraction analysis. Its structure was also confirmed by the spectral data (2D ¹H—¹H and ¹³C—¹H NMR spectroscopy and mass spectrometry). The structure of isomeric E-oxime was established by comparing its NMR spectroscopic data (¹H and ¹³C) with the data for the Z-isomer.     

双功能Pd/ZrHP催化剂的制备及其在苯酚选择性加氢反应中的应用

苯酚加氢制备环己酮是合成纤维（尼龙）生产过程中的重要环节。采用微波法快速合成了具有层状结构的固体酸（磷酸氢锆,ZrHP）和ZrHP负载的Pd催化剂,利用X射线衍射（XRD）、扫描电子显微镜（SEM）、高倍透射电子显微镜（HRTEM）、氮气吸附-脱附、X射线光电子能谱（XPS）和程序升温脱附（TPD）技术对催化剂的结构、形貌和表面特性进行了详细的表征,并将其应用于苯酚选择性加氢制环己酮的反应中。研究发现：在温和条件（100℃,1.0 MPa H₂）下,Pd/ZrHP比传统的氧化物（Al₂O₃、SiO₂、MgO）、分子筛（H-Beta）、活性炭（XC-72）负载的Pd催化剂具有更高的活性和稳定性,催化剂表面Pd原子的比活性最高可达612.2 h^-1,并且经过5次循环使用后催化剂无明显失活。结合表征结果推断,金属中心Pd与ZrHP表面的酸性位点之间的协同作用可能是影响苯酚加氢产物停留在环己酮阶段的关键因素。     

Determination of acidity constants of pyridines,imidazoles, and oximes by capillary electrophoresis

The acidity constant in the form of pK_a is one of the most important physicochemical quantities. There are prediction tools available for calculating the pK_a, but they only deliver precise calculated values for a relatively small set of chemicals. For complex structures with multiple functional groups in particular, the error in the predicted pK_a is high due to the application domain of the corresponding models. Thus, we aim to enlarge the dataset of experimentally determined pK_a values using capillary electrophoresis. We, therefore, selected various pyridines, imidazoles, and oximes to determine the pK_a values using the internal standard approach and the classical method. Especially oximes were not investigated in the past, and predictions for them include larger errors. Thus, our experimentally determined values could contribute to an improved understanding of various functional groups impacting the pK_a values and serve as additional datasets to develop improved pK_a prediction tools.     

Enzymatic Prenylation and Oxime Ligation for the Synthesis of Stable and Homogeneous Protein–Drug Conjugates for Targeted Therapy

Targeted therapy based on protein–drug conjugates has attracted significant attention owing to its high efficacy and low side effects. However, efficient and stable drug conjugation to a protein binder remains a challenge. Herein, a chemoenzymatic method to generate highly stable and homogenous drug conjugates with high efficiency is presented. The approach comprises the insertion of the CaaX sequence at the C‐terminal end of the protein binder, prenylation using farnesyltransferase, and drug conjugation through an oxime ligation reaction. MMAF and an EGFR‐specific repebody are used as the antitumor agent and protein binder, respectively. The method enables the precisely controlled synthesis of repebody–drug conjugates with high yield and homogeneity. The utility of this approach is illustrated by the notable stability of the repebody–drug conjugates in human plasma, negligible off‐target effects, and a remarkable antitumor activity in vivo. The present method can be widely used for generating highly homogeneous and stable PDCs for targeted therapy.     

加料方式及底物浓度对Ti-MWW催化剂上环己酮氨肟化反应的影响

 研究了加料方式和底物浓度对钛硅分子筛Ti-MWW催化环己酮液相氨肟化反应的影响. 结果表明,加料方式对 Ti-MWW 催化环己酮氨肟化过程有重要影响,过氧化氢的浓度对反应过程也有一定的影响. 在过氧化氢缓慢加入反应体系的情况下,环己酮转化率和环己酮肟选择性都高于99%, 而且该反应过程以水作溶剂,对环境友好.     

硫酸镓催化法合成环己酮乙二醇缩酮

以环己酮和乙二醇为原料,硫酸镓为催化剂,在微波辐射和无溶剂条件下,合成了环己酮乙二醇缩酮．探讨了酮醇物质的量比、催化剂用量、微波功率和辐射时间对产品收率的影响．结果表明,环己酮乙二醇缩酮的最佳合成条件为：n（环己酮）：n（乙二醇）=1：3,催化剂用量为反应物总质量的2．0％,微波功率为375W,辐射时间为20min．在此条件下,缩酮收率可达96．3％,说明硫酸镓是一种合成环己酮乙二醇缩酮的优良催化剂．     

噁二唑并[5,4-d][1,5]苯并硫氮杂衍生物的合成、表征及晶体结构

以1,5-苯并硫氮杂(1a～1o)为原料, 在三乙胺作用下与α-氯代喹喔啉-2-甲醛肟(2)发生1,3-偶极环加成反应得到一系列噁二唑并[5,4-d][1,5]苯并硫氮杂衍生物3a～3o. 产物的结构经元素分析、IR和1H NMR确认. 并用X射线衍射法测定了化合物3a的晶体结构. 化合物3a属三斜晶系, 空间群P-1, 晶胞参数: a＝0.97376(19) nm, b＝1.0017(2) nm, c＝1.3526(3) nm, α＝78.50(3)°, β＝84.30(3)°, γ＝68.26(3)°, Mr＝486.58, V＝1.2005(4) nm3, Dc＝1.346 Mg/m3, Z＝2, F(000)＝508.     

过氧化环己酮对二苯并噻吩的氧化脱硫研究

二苯并噻吩（dibenzothiophene DBT）及其衍生物是重油、减压馏分油及渣油中的主要硫化物。在通常的加氢脱硫中,二苯并噻吩系列是较难脱除的一类有机硫。近年来,以二苯并噻吩系列为模型的深度脱硫研究发展迅速。李建源等对二苯并噻吩及其衍生物为模型的氧化脱硫（Oxidative desulfurization ODS）、加氢脱硫、吸附脱硫及生物脱硫等作了较为详尽的报道。     

壳聚糖钴配合物的合成及光催化产氢性能

通过一锅法合成了壳聚糖钴配合物(Cs-Co)催化剂.电感耦合等离子体质谱与X光电子能谱测试结果表明,Cs-Co中Co元素的含量为1. 1 mmol/g,Co为正二价.在优化条件下,18 mg Cs-Co催化剂的总催化产氢量达到12. 7 m L(80 min),催化产氢速率为30258μmol·g^-1·h^-1.通过研究Cs-Co的光催化并结合电化学方法,提出了可能的光催化机理.     

含取代噁唑结构的新型吡唑肟衍生物的合成与生物活性

为了发现具有良好生物活性的吡唑肟化合物,以唑螨酯为先导化合物,在吡唑肟中引入取代噁唑结构,设计并制备了20个未见文献报道的新型吡唑肟衍生物,利用1H NMR,13C NMR和元素分析确证了目标产物的结构.生物活性测试结果显示,部分目标化合物在500和100μg/mL浓度下对粘虫或蚜虫表现出优良的杀虫活性,其中5-(3-氟苯氧基)-1,3-二甲基-1H-吡唑-4-甲酰基-O-{[5-(4-氯苯基)噁唑-2-基]甲基}肟(9j)、5-(4-氟苯氧基)-1,3-二甲基-1H-吡唑-4-甲酰基-O-{[5-(4-氯苯基)噁唑-2-基]甲基}肟(9k)、5-(4-叔丁基苯氧基)-1,3-二甲基-1H-吡唑-4-甲酰基-O-{[5-(4-氯苯基)噁唑-2-基]甲基}肟(9r)和5-(4-甲氧基苯氧基)-1,3-二甲基-1H-吡唑-4-甲酰基-O-{[5-(4-氯苯基)噁唑-2-基]甲基}肟(9s)在浓度为100μg/mL时对粘虫的防治效果均达100%,5-(4-溴苯氧基)-1,3-二甲基-1H-吡唑-4-甲酰基-O-{[5-(4-氟苯基)噁唑-2-基]甲基}肟(9g)和9s在浓度为100μg/mL时对蚜虫的杀灭活性均为100%.此外,化合物9s在500μg/mL时对朱砂叶螨的防治效果为70%.