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

胆酸被用作用于合成胆甾烷、双足和包合物宿主的结构单元。分子识别与这些主机进行了研究。(1)双环胆甾烷的合成及其分子识别研究合成了具有三个胆酸桥的双环胆甾烷。观察了氨基酸衍生物、β-吡喃葡萄糖苷和核苷的识别。在8种核苷中选择性地包括胸苷，其结合常数为10^4 M^<-1>。(2)以胆酸为基的分子裂缝的合成以萘四甲酰亚胺为间隔基，以胆酸为基，合成了一种双基型主体分子。该偶极物与2，6-萘二甲醇结合，结合常数约为10^2 M^<-1>。用VT^1H NMR实验进行构象分析表明，通过包含客体分子，偶极子可以将其构象改变为裂缝型。(3)一种新型通道结构的产生：3 α位上含有9-蒽羰氧基的胆酸甲酯与丁二酸二甲酯形成的分子复合物的单晶X射线分析表明，这种新型通道结构在胆酸的包合物化学中未见报道。两个主体分子通过OH基团之间的分子间氢键形成了握手型结构单元。结构单元通过蒽羰基的羰基氧与7位的OH基团之间的氢键形成网络。(4)双环胆甾烷作为一种潜在的光敏剂研究了双环胆甾烷在萘衍生物的光环加成反应中的光敏作用。然而，没有观察到使用这种方法的不对称诱导。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.