1. Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Satellite Venture Business Laboratory, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan, and Department of Chemistry, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan