2D NMR-STUDIES OF THE STRUCTURES OF THE STEREOSELECTIVE ADDUCTS OF THE DEHYDROCOSTUS LACTONE WITH PYRIMIDINE-DERIVATIVES

Analysis of H-1-H-1 n.O.e. effects observed for the adducts on C-13 (1 0-18) of dehydrocostus lactone and different pyrimidine derivatives sh own that H-7 and H-ll protons are in trans position. The NOESY cross p eaks analysis and x-ray molecular structure of adduct 10 are in excell ent agreement with the experimental data. Complete assignments of the C-13 signals of some adducts based on D-1 and 2D H-1 and C-13 NMR tech niques are reported.