Natural Products Laboratory, Division of Medicinal Chemistry and Natural Products, School of Pharmacy, The University of North Carolina, Chapel Hill, North Carolina 27514. Received June 23, 1986 a-Methylene-y-lactones covalently linked to adenine (3), hypoxanthine (4), and guanine (5) were synthesized by using the convenient Reformatsky-type reaction between ethyl a-(bromomethy1) acrylate and the proper purine ketones. In vitro ...