1. Laboratory of Medicinal Chemistry School of Pharmacy Kitasato University Tokyo 108-8641 Japan
2. Medicinal Research Laboratories School of Pharmacy Kitasato University Tokyo 108-8641 Japan
3. Division of Liberal Arts, Center for Promotion of Higher Education Kogakuin University Tokyo 192-0015 Japan
4. Department of Chemistry Faculty of Science Josai University Saitama 350-0295 Japan