10.alpha.H-Ambrosa-2,11(13)-dien-12-oic acid, 6.beta.-hydroxy-4-oxo-, .gamma.-lactone 509-93-3 AMBROSIN Azuleno[4,5-b]furan-2,9-dione, 3,3a,4,5,6,6a,9a,9b-octahydro-6,9a-dimethyl-3-methylene-, [3aS-(3a.alpha.,6.beta.,6a.alpha.,9a.beta.,9b.alpha.)]- NSC85235