1. Laboratory of Medicinal Chemistry, College of Pharmacy, Ewha Womans University, Seoul 120-750, Korea, Department of Industrial Safety and Hygiene, Kyungin Women's College, Incheon 407-050, Korea, and College of Pharmacy, Seoul National University, Seoul 151-742, Korea
2. Laboratory of Medicinal Chemistry, Division of Basic Sciences, National Cancer Institute, NIH, Bethesda, Maryland 20892