HYDROHALIMIC ACIDS FROM HALIMIUM-VISCOSUM

Several diterpenoid acids, with an ent-halimane skeleton, were isolate d from the aerial parts of Halimium viscosum as methyl esters. Besides the well known hydrohalimic acid, acetoxyhydrohalimic acid, cinnamoyl oxyhydrohalimic acid and 2-hydroxyhydrohalimic acid, three new ones ha ve been identified as methyl 15-Z-cinnamoyloxy-1(10)-ent-halimen-18-oa te, methyl 15-hydroxy-2-oxo-1(10)-ent-halimen-18-oate and methyl 15-me thoxy-1(10)-ent-halimen-18-oate. Their structures have been determined by chemical and spectroscopic methods, using 2D correlation experimen ts (H-1-C-13 and C-13-C-13). Copyright (C) 1997 Elsevier Science Ltd.