1. Biomedical Chemistry Research Center, Department of Chemistry and Biological Sciences, University of Cincinnati, Cincinnati 45221-0172, OH, USA
2. Mallinckrodt Medical Inc., 675 McDonnell Blvd, P.O. Box. 5840, St. Louis 63134, MO, USA
3. Merck and Co. Inc., WP 78-110, West Point 19486, PA, USA
4. Chemistry Department, Florida State University, Tallahassee 32306, FL, USA