1. Department of Organic Chemistry, Graduate
School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
2. Department of Chemistry, Graduate School of
Science, Osaka Prefecture University, Sakai,
Osaka 599-8531, Japan
3. Research Center of Medicinal Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa, Tokyo 142-8501, Japan