1. Department of Chemistry and Materials Science, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8551, Japan, Research Laboratories, Taisho Pharmaceutical Co., Ltd., 1-403, Yoshino-cho, Saitama-shi, Saitama 330-8530, Japan, and Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8551, Japan