Molecular Recognition by Steroidal Cyclophanes "Cholaphanes" and a Control of Photochemical Reaction Using Them.

胆酸被用作合成胆红素、胆碱和笼状主体的构筑块。对这些主体的分子识别进行了研究。(1)双环胆碱能化合物的合成及其分子识别：合成了具有三个胆酸桥的双环胆碱能团。对氨基酸衍生物、β-吡喃葡萄糖苷和核苷进行了识别。在8种核苷中，胸腺嘧啶核苷是选择性的，其结合常数为10~(-4)M^~(-1)~(-1)。(2)合成了一个以胆酸为基团的分子裂隙，以两个胆酸基团为基团，合成了一个由两个胆酸基团连接而成的双足型主体分子。它与2，6-萘二甲醇的结合常数约为10^2M^&lt；-1&gt；构象分析和VT^1H核磁共振实验表明，客体分子的加入可以使胆酸甲酯分子的构象转变为裂隙结构。(3)创造了一种新的通道结构；单晶X-射线分析表明，胆酸甲酯与琥珀酸二甲酯形成的3α位具有9-蒽甲氧基的分子络合物具有新的通道结构，这在胆酸的笼合物化学中尚未见报道。这两个主体分子通过羟基之间的分子间氢键形成了一种握手型的构筑块。(4)双环胆烷作为一种潜在的光敏剂，在萘衍生物的光环加成反应中起到了光敏剂的作用。然而，没有观察到使用这种方法的不对称诱导。还需要进一步研究。

Cholic acid was used as a building block for the synthesis of cholaphanes, dipodants, and clathrate hosts. Molecular recognition with these hosts was investigated.(1) Synthesis of bicyclic cholaphanes and molecular recognition with them ; Bicyclic cholaphanes possessing three cholic acid bridges were synthesized. Recognition of amino acid derivatives, beta-glucopyranosides, and nucleosides were cbserved. Thymidine was included selecively among 8 nucleosides with the binding constant in the order of 10^4 M^<-1>.(2) Synthesis of a molecular cleft possessing a cholic acid moiety as a podant ; A dipodant-type host molecule consisted from a naphthalenetetracarboximide moiety as a spacer connected with two cholic acid moieties as podants was synthesized. The dipodant showed an association with 2,6-naphthalenedimethanol with the binding constant of ca.10^2 M^<-1>. Conformational analysis with VT^1 H NMR experiments showed that the dipodant can change its conformation to the cleft-type by an inclusion of the guest molecule.(3) Creation of a novel channel structure ; Single crystal X-ray analysis of the molecular complex of methyl cholate possessing 9-anthracenecarbonyloxy moiety at 3alpha-position with dimethyl succinate showed the novel channel structure which has not been reported yet in the clathrate chemistry of cholic acid. The two molecule of host formed a shake-hands type building block via intermolecular hydrogen bonding between the OH groups. The building blocks were networked through hydrogen bonding between the carbonyl oxygen of anthracene carbonyl moiety and the OH group at the 7 position.(4) Bicyclocholaphane as a potential photosensitizer ; It was demonstrated that the bicyclocholaphane acted as a photosensitizer in the photocycloaddition of naphthalene derivatives. However, an asymmetric induction using this was not observed. Further study required.