(untitled) - Seo,E.K.; Chai,H.; Constant,H.L.; Santisuk,T.; Reutrakul,V.; Beecher,C.W.W.; Farnsworth,N.R.; Cordell,G.A.; Pezzuto,J.M.; Kinghorn,A.D. (J. Org. Chem., 1999)