1. Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 985 Higashimura-cho, Fukuyama City, Hiroshima 729-02
2. Faculty of Pharmaceutical Sciences Osaka University, 1-6 Yamadaoka, Suita, Osaka 565, Japan
3. Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas 66045
4. INTERx, Merck Sharp & Dohme Research Laboratories, Lawrence, Kansas 66044, USA