1. Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, Japan, Institute of Bioorganic Chemistry, 3-34-17 Ida, Nakahara-ku, Kawasaki 211, Japan, and Institute of Microbial Chemistry, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141, Japan