1. Department of Chemistry, Graduate School of Science Osaka University, Toyonaka, Osaka 560, Japan Department of Chemistry, Graduate School of Science Osaka City University, Sumiyoshi-ku Osaka 558, Japan School of Medicine, Keio University Hiyoshi-4, Kohoku, Yokohama 223, Japan Institute for Molecular Science Myodaiji, Okazaki, Aichi 444, Japan