1. Contribution from the Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan, Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan, Institute of Applied Biochemistry, University of Tsukuba, Tsukuba 305-8572, Japan, and Hanno Research Center, Taiho Pharmaceutical Co., Ltd., Saitama 357-8527, Japan