| Budget Amount *help |
¥24,400,000 (Direct Cost: ¥24,400,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1985: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1984: ¥21,600,000 (Direct Cost: ¥21,600,000)
|
|---|
| Research Abstract |
The absolute stereostructure of various chiral organic compounds were determined by means of X-ray crystallographic and circular dichroic methods. We clarified that the CD exciton chirality method is applicable to the non-degenerate systems containing two or more different chromophores, and determined the following biologically active natural products and synthetic chiral organic compounds: triptycene systems containing an anthracene chromophore; isoamijiol of a dolastane diterpene isolated from a seaweed; unsaturated hydroxy fatty acids, the self defensive substances in rice plant against rice blast disease; optically active Wieland-Miescher ketone analogues bearing an angular protected hydroxymethyl group; carcinogenic benzo[e]pyrene derivatives; trans-2, 3-disubstituted spirocyclopropane-1,9'-fluorene derivatives; 2,2'-spirobibenz[e]indan derivatives; a chiral steroid CD-ring synthon from D-leucine. Furthermore, we established the CD method for determining the absolute stereostructu
… More
re of acyclic glycols.
There are many natural products having a twisted conjugated <pi> -electron system. We have found that for determination of absolute stereostructure of such compounds, the theoretical calculation of CD spectra by the <pi> -electron SCF-CI-dipole velocity MO method is very useful. For instance, we succeeded to determine the absolute stereostructure of (+)-1,8a-dihydro-3,8-dimethylazulene, a labile biosynthetic intermediate for 1,4-dimethylazulene isolated from a liverwort, by calculation of CD spectra using the present MO method. The theoretical conclusion was experimentally proved by the synthesis of suitable chiral model compounds. By applying this method, the absolute stereostructures of the following compounds having a twisted conjugated <pi> -electron system were determined: novel chiral troponoid spiro compounds; a cardiac active constituent of an Okinawan marine sponge, halenaquinol and its derivative; chiral olefins of cis- and trans-4,4'-biphenanthrylidenes. The X-ray and CD methods are complementary each other, and the absolute stereochemistry of the synthetic intermediate of the dihydroazulene model compounds was established by the X-ray crystallographic studies, proving that both of the methods are consistent with each other. Less
|
