Molecular Recognition and Catalytic Functions of Novel Macrocyclic Compounds

我们制备了一种以L-天冬氨酸残基为连接单元的章鱼环状化合物，连接在一个大环环和四个双链碳氢化合物之间。这种阳离子主体与阴离子和非离子疏水客体强烈结合，并表现出源于疏水和静电相互作用的诱导-匹配客体结合行为。我们还制备了一个具有三个邻苯二酚部分和六个碳氢链的六环六元环，前者作为金属结合部位。研究了环磷酰胺铁络合物在水中的包合行为。当环烷的邻苯二酚链段配位到Fe^-lt；3-gt；时，疏水客体的结合常数比没有金属配位的六角环的结合常数大。由于疏水、静电和配位作用，目前的金属结合型六角鱼对有机客体具有显著的包合能力。维生素B依赖的酶催化v…伴随着碳骨架重排的异构化反应增多。为了模拟依赖维生素B的酶的催化功能，我们一直在处理疏水性维生素B；12&gt；的衍生物。我们成功地构建了以章鱼环番为辅酶模型和疏水性维生素B_12&gt；为辅酶模型的人工维生素B_12&gt；依赖全酶。通过将吡哆醛-5‘-磷酸和疏水的烷基铵底物同时结合到宿主空腔中，形成席夫碱物种，显示底物的选择性，章鱼环番作为人工维生素B6依赖的全酶的有效酶模型。我们制备了另一种结构特征的环状环状分子：笼型立方体分子，每个面由一个2，11，20，29-四氮杂[3.3.3.3]对环芳环组成。该宿主具有8个叔胺基团，在酸性介质中以聚阳离子宿主的形式存在。寄主表现出对大小敏感和区域选择性的分子鉴别。第二个笼型环番由两个大环骨架1，6，20，25-四氮杂[6.1.6.1]组成。对环番2，11，20，29-四氮杂[3.3.3.3]对环状链段。这种阳离子主体将阴离子和非离子疏水荧光客体结合到其内腔中，并对水介质中选定的氨基酸进行显著的手性识别。较少

We prepared an octopus cyclophanes having L-aspartate residues as connector units interposed between a macrocyclic ring and four double-chain hydrocarbon segments. This cationic host strongly binds anionic and nonionic hydrophobic guests and exercises the induced-fit guest-binding behavior originating from both hydrophobic and electrostatic interactions. We also prepared a hexapus cyclophane having three catechol moieties and six hydrocarbon chains, the former acting as the metal binding sites. The inclusion behavior of a Fe-complex of the hexapus cyclophane was examined in water. When the catechol segments of the cyclophane are coordinated to Fe^<3+>, the binding constant for hydrophobic guests becomes larger than that of the hexapus cyclophane without metal coordination. The present metal-bound hexapus cyclopahne exhibits marked inclusion capability toward organic guests, as arising from hydrophobic, electrostatic, and coordination effects. Vitamin B_<12>-dependent enzymes catalyze v … More arious isomerization reactions accompanied with carbon-skeleton rearrangements. In order to simulate catalytic functions of vitamin B_<12>-dependent enzymes, we have been dealing with hydrophobic vitamin B_<12> derivatives. We succeeded in constructing an artificial vitamin B_<12>-dependent holoenzyme composed of an octopus cyclophane as an apoenzyme model and hydrophobic vitamin B_<12> as a coenzyme model. The octopus cyclophane acts as an effective apoenzyme model for constitution of an artificial vitamin B_6-dependent holoenzyme by simultaneous incorporation of pyridoxal-5'-phosphate and a hydrophobic alkylammonium substrate into the host cavity to give the Schiff-base species, showing the substrate selectivity.We prepared cyclophanes of another structural feature ; a cage-type cubical molecule with six faces each consisting of a 2, 11, 20, 29-tetraaza[3.3.3.3] paracyclophane ring. This host possesses eight tertiary aminomoieties and acts as a polycationic host in acidic media. The host shows size-sensitive and regioselective molecular discrimination. The second cage-type cyclophane is composed of two macrocyclicskeletons, 1, 6, 20, 25-tetraaza[6.1.6.1.] paracyclophane 2, 11, 20, 29-tetraaza[3.3.3.3] paracyclophane segments. This cationic host incorporates anionic and nonionic hydrophobic fluorescent guests into its in ternal cavityand exercises marked chiral discrimination toward selected amino acids in aqueous media. Less