1. Laboratory of Medicinal Chemistry, Center for Cancer Research, NCI−Frederick, NIH, Frederick, Maryland 21702; Laboratory for the Structure of Matter, Naval Research Laboratory, Washington, D.C. 20375; Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, NIH, Bethesda, Maryland 20892, Katholieke Universiteit Leuven, Rega Institute, Minderbroedersstraat 10, B-3000 Leuven, Belgium; Experimental Retrovirology Section, Center for...