1. Department of Chemistry and Biochemistry, P.O. Box 97348, Baylor University, Waco, Texas 76798, Cancer Research Institute and Department of Chemistry, Arizona State University, Tempe, Arizona 85287-1604, and Screening Technologies Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Frederick Cancer Research and Development Center, Frederick, Maryland 21702 Kevin_Pinney@Baylor.edu