1. Bioorganic and Medicinal Chemistry Laboratory, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China, 201203, Medicinal Chemistry Laboratory, Harvard Medical School, McLean Hospital, Belmont, Massachusetts 02478, Department of Psychiatry and Neuroscience Program, Harvard Medical School, Boston, Massachusetts, and Neuropharmacology Laboratory, McLean Hospital, Belmont, Massachusetts 02478