1. State Key Laboratory of Applied Organic Chemistry and Department of Chemistry Lanzhou University Lanzhou 730000 P. R. China
2. School of Pharmacy Lanzhou University Lanzhou 730000 P. R. China
3. School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules Shanghai Jiao Tong University Shanghai 200240 P. R. China
4. School of Pharmaceutical Sciences Zhejiang University of Technology Hangzhou 310014 P. R. China