1. Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Biotecnología de Asturias, Universidad de Oviedo, 33006-Oviedo (Asturias), Spain, Rasayan Inc., 2802 Crystal Ridge Road, Encinitas, California 92024-6615, United States, and Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine/Veterans Affair Medical Center, Decatur, Georgia 30033, United States