1. Department of Chemistry, Faculty of Engineering, Kanagawa University, Rokkakubashi, Yokohama 221, Japan, Oral Care Research Laboratories, Lion Corporation, Sumida-ku, Tokyo 130, Japan, Laboratory of Chemistry, Faculty of Informatics, Teikyo Heisei University, 2289-23 Uruido, Ichihara, Chiba 290-01, Japan, and Laboratory of Chemistry, School of Design and Architecture, Nagoya City University, 2-1-10 Kitachikusa, Chikusa-ku, Nagoya 464, Japan