STEREOCHEMISTRY OF SAMARCANDIN-TYPE SESQUITERPENOID COUMARINS. CRYSTAL STRUCTURES OF FESHURIN AND NEVSKIN

摘要

The crystal and molecular structures of the sesquiterpenoid coumarins feshurin and nevskin were determined by x-ray crystal structure analyses. The absolute configuration of feshurin was established as (1'R,2'R,6'S,9'R and C10'S); of nevskin, (1'R,2'R,6'R,C9'R and C10'S). The absolute configurations of eight diastereomers of the samarcandin-type sesquiterpenoid coumarins were refined. Channel-type cavities (35.4% of the total volume) along the crystallographic a axis formed as a result of intermolecular H-bonds and contained disordered solvates in the crystal packing of nevskin.