The synthesis of four 3,9-dideazapurines is described. In order to achieve
the desired substitution pattern, a new approach to the pyrrolo[2,3-c]pyrid
ine ring system was devised utilizing the Gassman reaction as the key step
for its construction. The four target heterocycles were all evaluated for t
heir ability to inhibit human erythrocytic purine nucleoside phosphorylase.