Unusual ent-isopimarane-type diterpenoids from the wood of Excoecaria agallocha

Three new ent-isopimarane-type diterpenoids with unusual 3,4-seco (1) and seven membered lactone moieties (1-2), along with four known compounds (4-7) were isolated from the acetone extract of Excoecaria agallocha. Their structures were established as agallochaexcoerins D-F (1-3) by spectroscopic data interpretation and chemical evidence.