紫外辐照法合成环蕃醛

利用254 nm紫外光对[2.2]对环蕃氯仿溶液进行辐照,得到两种主要产物4-醛基-[2.2]-对环蕃和4,4'-(乙基-1,2-二取代)二苯甲醛,利用核磁共振波谱仪(NMR)和气相色谱-质谱联用(GC-MS)技术手段对产物的结构进行分析研究。 同时对反应条件进行探究,发现当氯仿和水同时存在时才能生成醛基,并由此提出了提出了可能的反应机理:通过瑞默-提曼反应使CHCl₂·自由基加成到苯环上并进一步生成醛基。     

p,p′-芳炔桥连的四联萘拓扑环芳分子的设计与合成

基于联萘衍生物手性构型高度稳定的特点, 以光学活性的(R)-2,2'-二乙炔基-1,1'-联萘为模板, 设计了3个有趣的拓扑环芳分子——含有4个手性联萘单元的(R,R,R,R)-2a～2c, 并探讨了它们的合成. 合成路线涉及三甲基硅(Me₃Si-)保护基的控制导入, 对位取代的芳基连接桥的链接, 保护基的脱去以及分子间偶合成环4个步骤. 用比旋光度([α]_D), MS, IR, UV-Vis, ¹H和¹³C NMR以及元素分析表征了这些化合物.     

Photochemical Bromination of 2,5-Dimethylbenzoic Acid as Key Step of an Improved Alkyne-Functionalized Blue Box Synthesis**

Cyclobis(paraquat-p-phenylene), also known as “blue box”, is a highly electron-deficient macrocycle, widely used as a molecular receptor for small electron-rich molecules. Inserting a reactive functional group onto the molecular structure of this cyclophane is paramount for its inclusion into complex architectures. To this aim, including an alkyne moiety would be ideal, because it can participate in click reactions. However, the synthesis of such alkyne-functionalized cyclophane suffers from several drawbacks: the use of toxic and expensive CCl₄, the need for high-pressure reactors, and overall low yield. We have revised the existing synthesis of this cyclophane derivative bearing an alkyne moiety, to overcome all these limitations. In particular, photochemical radical bromination is adopted to obtain a sensitive intermediate. We demonstrated that the synthesized host molecule can be functionalized via click reactions and take part in radical-radical interactions. Our work makes a key functionalized paraquat macrocycle more accessible, facilitating the development of novel redox-responsive systems.     

咪唑环番仿生新体系研究进展

仿生化学是当今化学的挑战性领域之一。咪唑环番是构筑仿生体系的优良基体,但迄今研究工作极少。本文简要评述了咪唑的选择性反应和咪唑衍生物的选择性合成、新型咪唑环番和咪唑鎓环番的设计合成及仿生功能研究的一些新进展。     

一种含有手性联萘“铰链”单元的环芳分子的设计、合成及表征

基于联萘衍生物手性构型高度稳定以及联萘结构中2个萘平面的两面角可以在一定范围内张合的特点, 分别以光学活性的(R)和(S)-2,2'-二乙炔基-1,1'-联萘为模板, 设计了一种含有8个“铰链”结构单元的新的环芳分子¾—(R,R,R,R,R,R,R,R)-3和(S,S,S,S,S,S,S,S)-3. 其合成路线涉及间苯基连接桥的链接, 保护基的脱去和控制导入以及分子间偶合等步骤. 用MS, IR, UV-Vis, ¹H和¹³C NMR以及元素分析等技术对中间体和目标化合物进行了结构表征. 测定并比较了2个目标化合物的比旋光度[α]_D和圆二色(CD)性质. 在CH₂Cl₂溶液中, 两个异构体(R,R,R,R,R,R,R,R)-3和(S,S,S,S,S,S,S,S)-3的[α]_D²⁵值分别为－911.8和＋908.6, 并且它们的CD谱表现出对称的镜像特征．这些实验结果清楚地反映了它们之间的对映异构关系.     

Cyclophane‐Type Chlorin Dimers from Dynamic Covalent Chemistry of 2,18‐Porphyrinyl Dicyanomethyl Diradicals

2,18‐Bis(dicyanomethyl)‐substituted Ni^II porphyrin 8 and Zn^II porphyrin 11 were prepared and subjected to oxidation with PbO₂ in CH₂Cl₂ at 298 K to give cyclophane‐type chlorin dimers ( 9 )₂ and ( 12 )₂ as a consequence of double recombination of biradicals 9 and 12 , respectively. Dimer ( 9 )₂ takes a syn‐conformation of two distorted Ni^II chlorins but ( 12 )₂ takes an anti‐conformation of relatively planar Zn^II chlorins. At 298 K, dimer ( 9 )₂ is stable and its ¹H NMR spectrum is sharp but becomes broad at high temperature, while the ¹H NMR spectrum of ( 12 )₂ is considerably broad even at 298 K but becomes sharper at low temperature. These results indicate that the chlorin dimers dissociate to radical species, but the activation barrier of the dissociation of ( 12 )₂ is much less than that of ( 9 )₂. The involvement of diradicals in dynamic covalent chemistry has been suggested by thermal scrambling of hetero dimer ( 16 )₂ to give homo dimers ( 9 )₂ and ( 15 )₂.     

[10]Paracyclophanediamides and their octadehydro derivatives: novel exotopic receptors with hydrogen-bonding sites on the bridge

2,9-Diaza-1,10-dioxo[10]paracyclophanes were prepared in short steps from the terephthaloyl chlorides via the corresponding 4,6-diyne derivatives, and the amide groups on the bridge endow the skeleton with the guest-binding properties as demonstrated by complexation with adrenaline by hydrogen bonds. The chiral auxiliaries on the bridge induce diastereomeric preference in terms of the planar chirality for the octadehydro derivative with a rigid diyne unit in crystal.     

新型三(四硫富瓦烯)环蕃的合成和性质

利用四(3'-碘丙硫基)四硫富瓦烯和四硫富瓦烯二钠盐反应合成新的三(四硫富瓦烯)环蕃, 并通过循环伏安法和化学氧化法分别对其氧化还原性质和紫外光谱进行了研究.     

“黑洞型”缺电子联吡啶环蕃的合成

利用2,3,5,6-四氟-1,4-苯二甲酸为原料, 经过酯化、还原及溴代, 合成1,4-二溴甲基-2,3,5,6-四氟苯. 以其为原料在低温下利用模板效应合成高度缺电子的“黑洞型”缺电子联吡啶环蕃化合物, 经过连续液液萃取及离子交换得到“黑洞型”缺电子联吡啶环蕃单体. 产品经¹H NMR, ¹³C NMR, MS表征. 利用变温核磁共振技术研究“黑洞型”缺电子联吡啶环蕃与经典的双环(百草枯-对苯撑)型缺电子联吡啶环蕃在溶液中的变化.