1. a Chemical Medicine Institute, Tianjin Tasly Group Co. Inc. , Tianjin, P. R. China
2. b Department of Chemistry , Shandong University , Jinan, P. R. China
3. c Institute of Organic Chemistry, Ebarhard-Karls-University Tübingen , Tübingen, Germany
4. d Pharmaceutical and Medicinal Chemistry Department , National Research Centre , Cairo, Egypt