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

点击翻译按钮获取中文摘要

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.