... Pyrek Division of Medicinal Chemistry and Pharmaceutics, Life Sciences Mass Spectrometry Facility, College of Pharmacy, University of Kentucky, Lexington, KY 40536 Received June 16, 1993 ... Heterocyclic Chem., 30, 1645 (1993 ... 1650 I. Stoilov, DS Watt, JP Goodman and J. St. ...