1. Department of Chemistry, University of Southern California, Los Angeles, CA 90089—0744
2. Current address: Department of Pathology, School of Medicine, University of Southern California, Los Angeles, CA 90033
3. Department of Pharmacology and Medicine, School of Medicine, University of North Carolina—Chapel Hill, Chapel Hill, NC 27514
4. Current address: Wenzhou Institute of Pesticide Research, Huiqiaopu, Wenzhou, Zhejiang, China
5. Current address: Wyeth Laboratories, P.O. Box 8299, Philadelphia, PA 19101—82
6. Current address: Department of Pharmacology, School of Medicine, Yale University, New Haven, CT 06510