1. Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, Baoshan, Shanghai, 200444, P. R. China
2. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Zhang Jiang Hi-Tech Park, Pudong, Shanghai, 201203, P. R. China
3. University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, P. R. China
4. UCB, 87 Cambridge Park Drive, Cambridge, Massachusetts 02140, United States