1. Natural Products Laboratory, Division of Medicinal Chemistry and Natural Products, School of Pharmacy, University of North Carolina at Chapel Hill, North Carolina 27599, Graduate Institute of Pharmaceutical Chemistry, China Medical College, Taichung 400, Taiwan, Republic of China, Drug Synthesis and Chemistry Branch, Developmental Therapeutics Program, Division of Cancer Treatment, Diagnosis and Centers, and Laboratory of Molecular Pharmacology, Division of Basic Sciences, National Cancer Institute,...