氮杂环丙烷与CO_2反应的最新研究进展

二氧化碳既是温室气体的主要成分,也是储量丰富的碳资源,研究二氧化碳的转化与利用有着重要的意义。总结了近几年各种催化体系催化氮杂环丙烷与CO_2的环加成反应,包括不可回收催化剂、可回收催化剂和无催化剂体系,以及各体系对氮杂环丙烷与CO_2环加成反应产物收率和区域选择性的影响。     

HKUST-1单位点铜催化CO2/CS2成环耦合三氟甲基化反应

以烯丙基胺类为底物，Togni''s Reagent Ⅱ〔1-（三氟甲基)-1,2-苯碘酰-3(1H)-酮〕为三氟甲基源，CO2或CS2为C1合成子，高稳定性金属有机框架HKUST-1的Cu2(O2C)4双轮桨节点的单位点铜为催化剂，在温和条件下耦合CO2/CS2成环与三氟甲基化反应。对碱性添加剂、溶剂、反应温度、催化剂负载量等反应条件进行了优化。结果表明，在5%的HKUST-1〔基于Cu2(O2C)4双轮桨节点，催化剂最简分子结构为Cu2(BTC)4/3·2H2O，相对分子量为439.28 g/mol〕、CO2压力为101.325 kPa、45 ℃的最佳反应条件下，含不同取代基的底物能以69%～87%的产率得到三氟甲基-噁唑烷酮医药中间体。自由基捕获实验验证了该反应可能的反应机理。催化剂HKUST-1可循环使用5次仍保持良好催化活性和晶态结构。使用CS2替代CO2时，可得到具有中枢神经调节作用的三氟甲基-噻唑烷硫酮衍生物，体现出该体系对硫毒化的耐受性。     

5-Benzylidene-4-Oxazolidinones Are Synergistic with Antibiotics for the Treatment of Staphylococcus aureus Biofilms

The failure of frontline antibiotics in the clinic is one of the most serious threats to human health and requires a multitude of novel therapeutics and innovative approaches to treatment so as to curtail the growing crisis. In addition to traditional resistance mechanisms resulting in the lack of efficacy of many antibiotics, most chronic and recurring infections are further made tolerant to antibiotic action by the presence of biofilms. Herein, we report an expanded set of 5-benzylidene-4-oxazolidinones that are able to inhibit the formation of Staphylococcus aureus biofilms, disperse preformed biofilms, and, in combination with common antibiotics, are able to significantly reduce the bacterial load in a robust collagen-matrix model of biofilm infection.     

Catalytic Asymmetric Conjugate Addition of Mercaptans to β‐Substituted‐β‐Trifluoromethyl Oxazolidinone Enoates: Access to Chiral Trifluoromethylated Tertiary Thioethers and Thiols

The first asymmetric conjugate addition of mercaptans to β‐substituted‐β‐trifluoromethyl oxazolidinone enoates has been developed. The opposite enantiomers of adducts, containing a trifluoromethylated hetero‐quaternary stereogenic centers, could be obtained by utilizing two pseudo‐enantiomeric Cinchona alkaloid‐derived tertiary amine/squaramides as catalysts. Potassium dihydrogen phosphate was found to accelerate the reaction rate without compromising the enantioselective excess. A variety of chiral trifluoromethylated tertiary thioethers and thiols were readily prepared with excellent enantioselectivity.

     

唑烷酮类化合物的光合成研究

通过光化学方法取代传统的金属催化等法合成重要的药物中间体唑烷酮,反应条件温和、操作简便、产率较高且污染少.同时研究了丙酮、甲醇、乙腈3种溶剂与水的不同配比对反应产物的影响.随着溶剂极性增加,立体选择性有一定提高.     

哌嗪基[口恶]唑烷酮类衍生物的合成及其体外抗菌活性研究

以S-环氧氯丙烷和3,4-二氟硝基苯为原料,设计并合成了12个哌嗪取代[口恶]唑烷酮类化合物,其结构均经高分辨1HNMR和MS确认。以利奈唑胺为参照物,对合成的化合物进行了金黄色葡萄球菌、链球菌和大肠杆菌的体外抗菌实验,结果表明,合成的化合物有一定抗菌活性,但活性均明显低于利奈唑胺。     

二氧化碳资源化利用的研究进展

介绍了作为温室气体的主要组成且储量丰富的可再生资源CO_2资源化利用的重要意义和主要方法。综述了将CO_2催化转化成高附加值的燃料、高分子材料、精细化工中间体和药物中间体的各类反应以及CO_2作为环境友好介质的研究进展。重点介绍了CO_2转化成有机碳酸酯及噁唑啉酮类化合物以及超临界CO_2作为环境友好溶剂在药物提取、新型材料制备与加工和有机化学反应等领域的应用。对CO_2资源化利用的发展前景和面临的挑战进行了展望。     

Copper‐Catalyzed Four‐Component Coupling between Aldehydes,Amines, Alkynes,and Carbon Dioxide

A simple and efficient synthesis of oxazolidinones was developed through a copper‐catalyzed coupling of aldehydes, amines, and terminal alkynes under atmospheric pressure of carbon dioxide.     

Atmospheric Pressure of CO2 as Protecting Reagent and Reactant: Efficient Synthesis of Oxazolidin‐2‐ones with Carbamate Salts,Aldehydes and Alkynes

Carbon dioxide (CO₂) has been wildly employed as an environmentally benign C₁ resource for organic synthesis in the recent years. The capture of CO₂ with primary amines easily provides the corresponding carbamate salts. We described herein that carbamate salts are a useful reactant for the synthesis of oxazolidin‐2‐ones via the reaction with aromatic aldehydes and aromatic terminal alkynes. A variety of oxazolidin‐2‐ones with different functional groups were synthesized in 68–91% yields with only a 5 mol% amount of CuI as catalyst. It was found that the synergetic effect of iodide is important for the transformation. Notable, the captured CO₂ serves not only as a protecting reagent for electron‐rich primary amine to avoid catalyst poisoning, but also as a reactant for the construction of oxazolidin‐2‐ones.