1. Department of Chemistry, Zhejiang University, Hangzhou 310027, China, Key Laboratory for Molecular Design and Nutrition Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China, College of Bioengineering, Chongqing University, Chongqing 400044, China, and Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611