1. Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Ji’nan, Shandong 250012, P.R. China
2. Key Lab of Advanced Drug Preparation Technologies (Ministry of Education), State Key Laboratory of Esophageal Cancer Prevention & Treatment, Key Laboratory of Henan Province for Drug Quality and Evaluation, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China