Affiliation: | 1. Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro‐cho, Tokushima 770‐8514 (Japan), Fax: (+81)?88‐655‐3051;2. Division of Chemistry, Hokkaido University, Kita‐ku, Sapporo 060‐0810 (Japan), Fax: (+81) 11‐706‐2703 |