1. Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Zhongshan Guangdong 528400 China
2. Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education; Yunnan Provincial Center for Research & Development of Natural Products, School of Chemical Science and Technology Yunnan University Kunming Yunnan 650091 China
3. State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences, Chinese Academy of Sciences Shanghai 200032 China