HOSLUNDIN, HOSLUNDAL, AND HOSLUNDDIOL - 3 NEW FLAVONOIDS FROM THE TWIGS OF HOSLUNDIA-OPPOSITA (LAMIACEAE)

Three new flavonoids (hoslundin 1, hoslundal 4, and hoslunddiol 6) have been isolated from the twigs of Hoslundia opposita. The structure of hoslundin has been determined mainly by the use of 2D n.m.r. long-range delta-C/delta-H correlation in conjunction with the 1D proton-coupled C-13 n.m.r. spectrum, while the structures of the rest were established using H-1 and C-13 n.m.r. spectroscopy. The manner in which 2D n.m.r. long-range delta-C/delta-H correlation experiments are used for determining bond connectivity during the process of structural elucidation is discussed.