AIDS-138081 AIDS138081 NSC644193 Pungiolide A Spiro[2H-cyclohepta[b]furan-3(4H),6'(2'H)-furo[2',3':5,6]cyclohepta[1,2-b]pyran]-2,2'-dione, 7'-acetyl-3',3a,3'a,4',4'a,7,8,8a,8'a,9',10',10'a-dodecahydro-8'a-hydroxy-7,9'-dimethyl-3'-methylene-6-[(1E)-3-oxo-1-butenyl]-