1. Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan, and Research Division, Sumitomo Pharmaceuticals Co., Ltd. 1-98, Kasugade Naka 3-Chome, Konohana-ku, Osaka 554-0022, Japan tanabe@kwansei.ac.jp