Synthesis and Molecular Recognition of Spherand-type Calixarenes

1.我们成功地开发了一系列具有三个和四个联芳烃单元的羟基[1-n]间联苯芳的简便和选择性合成方法，包括碱催化的5，5 ′-二叔丁基-2，3 ′-二氧杂环己烷，2'-以碱金属氢氧化物为碱，在二甲苯回流条件下，用甲醛与二羟基联苯反应，合成了一系列亲电芳香族化合物为了提高杯芳烃与客体分子的结合能力，研究了杯芳烃的取代反应和酚氧的O-烷基化反应。O-取代基的构象异构的影响已经建立。在酚氧上引入较大的烷基应导致其中联芳烃单元内的OR基团不能彼此通过的情况。这意味着围绕Ar-Ar σ-键的旋转被阻碍，并且每个联芳烃单元被固定在一定的构型中。例如，在C ...更多信息 四聚体的四种不同的非对映异构体，其中两种是手性的：a）一种化合物，其中所有的双芳烃单元具有相同的构型（RRRR或SSSS，D_4-对称性）; B）其中一个联苯单元的构型不同于其它三个联苯单元的构型的化合物（RRRS或SSSR）; c）（RSRS=SRSR）;或d）（RRSS=SSRR）. 3.分子构型的研究我们首次证明了球-型杯芳烃与溴乙酸乙酯烷基化形成的离子载体具有良好的金属和铵离子络合性能和有趣的立体化学。发现这些化合物具有球状物和杯芳烃的组合性质。因此，与杯[6]芳烃和杯[8]芳烃中相同的官能化酚单元相比，由于双芳烃单元而导致的受限环构象可以增加金属离子结合的选择性。虽然迄今为止只得到了两种立体异构体，但通过改变烷基化条件和试剂，可以得到具有D_3-和D_4-对称性的衍生物，这将成为更大的潜在主体分子如手性拆分的有趣的构件。少

1.The development of synthesis of sperand-type calixarenes We have succeeded to develop a convenient and selective synthesis of a series of hydroxy[1_n]metabiphenylophanes with three and four biarene units involving base-catalyzed condensation of 5,5'-di-tert-buty1-2,2'-dihydroxybiphenyl with formaldehyde under xylene reflux depending on the alkaline metal hydroxide as a base.2.Studies on reactivities and propcties Electrophilic aromatic substitution reactions and O-alkylation of phenolic oxygenes of the spherand-type calixarenes were studied in order to increase the binding abilities for the guest molecules. The influence of O-substituents on the conformational isomerism has been established. Introduction of larger alkyl groups on the phenolic oxygens should lead to a situation where the OR groups within a biarene unit cannot pass each other. That means the rotation around the Ar-Ar sigma-bond is hindered and each biarene unit is fixed in a certain configuration. For example, in the c … More ase of the tetramer four different diastereomers of which two are chiral should be expected : a)A compound in which all biarene units have the same configuration (RRRR or SSSS,D_4-symmetry) ; b)A compound in which the configuration of one biphenyl unit differs from that of the other three(RRRS or SSSR) ; c)(RSRS=SRSR) ; or d)(RRSS=SSRR).3.Studies on molecular recognitions We have demonstrated for the first time that the derivatives of the spherand-type calixarenes formed by alkylation with ethyl bromoacetate give ionophores with promising complexation properties for metals and ammonium ions and interesting stereochemistry. These compounds are found to have combined properties of both the spherands and the calixarenes. Thus the restricted ring conformation due to the biarene units may increase the selectivity in the binding of metal ions as compared to the same functionalized phenolic units in calix[6]arene and calix[8]arene. While to date only two stereoisomers have been obtained, variation of the alkylation conditions and reagents could lead to the derivatives with D_3-and D_4-symmetry, which will serve as interesting building blocks for larger potential host molecule such as chiral recognitions. Less