8-(Acetyloxy)-6-methyl-3,9-dimethylene-2-oxo-2,3,3a,4,6a,7,8,9,9a,9b-decahydroazuleno[4,5-b]furan-4-yl 3-(acetyloxy)-2-hydroxy-2-methylbutanoate AIDS-144427 AIDS144427 NSC666858