1. Department of Process Research, Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, Department of Process Research, Merck Frosst Centre for Therapeutic Research, 16711 Route Trans-Canadienne, Kirkland, Québec, Canada H9H 3L1, and Department of Chemistry, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854-8066