1. The Second Laboratories, Research and Development Center, Nagase & Co., Ltd., 2-2-3 Murotani, Nishi-ku, Kobe 651-2241, Japan, Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan, and Product Development Section 4, Bio/Fine Chemicals Division, Nagase ChemteX Corporation, 2-2-3 Murotani, Nishi-ku, Kobe 651-2241, Japan