A New ent-Clerodane Diterpene from Hymenaea courbaril var. altissima

a new ent-clerodane and two known ent-labdanes were isolated from the barks of hymenaea courbaril var. altissima (ducke). the new diterpene was identified, after esterification with diazomethane, as methyl (-)-(5r,8s,9s,10r)-clerod-3-en-15-oate and known diterpenes were identified as methyl (-)-copalate and methyl (-)-eperuate. from the etoac extract of seed pods a known methyl (-)-zanzibarate was isolated. the structures of isolated compounds were elucidated based on spectroscopic studies.