1. Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
2. Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
3. Medicinal Chemistry Department, Neuroscience Discovery Research, AbbVie Deutschland GmbH & Co. KG, Ludwigshafen 67061, Germany